CN1152913A - Process for the preparation of 3-(methylthio) propanal - Google Patents

Abstract

A method for continuously preparing 3-(methylthio)propanal. The liquid reaction medium is contacted with the gaseous acrolein feed stream in a gas/liquid contact section. The reaction medium contains 3-methylthiopropanal, methyl mercaptan and a catalyst for the reaction of methyl mercaptan with acrolein. The gaseous acrolein feed stream contains acrolein vapor and noncondensable gases. Acrolein is transferred from the acrolein feed stream to the reaction medium and reacts with methylmercaptan in the reaction medium to form a liquid reaction product comprising 3-methylthiopropanol. Noncondensable gases are separated from the liquid reaction products. The reaction product is divided into a product fraction and a recycle fraction, and the recycle fraction is recycled back to the gas/liquid contact section.

Description

The method for preparing 3-(methylthio group) propionic aldehyde

Background of invention

The present invention relates to the preparation of 3-methylthiopropionaldehyde, more particularly, relate to a kind of in the gas/liquid reactions system continuation method of direct production 3-(methylthio group) propionic aldehyde.

3-(methylthio group) propionic aldehyde (hereinafter claiming " MMP ") is an intermediate of producing d, 1-methionine(Met) and 2-hydroxy-4-methylthiobutyric acid (" HMBA ").Methionine(Met) is a kind of main amino acid, and animal feedstuff compositions lacks this component usually.HMBA provides the methionine(Met) source, and it is widely used as the methionine(Met) supplement in animal feed formulation.For producing HMBA or methionine(Met), need be substantially free of the MMP of impurity usually.

MMP reacts by propenal and methyl mercaptan and produces.In the MMP of routine preparation method, liquid propene aldehyde and methyl mercaptan are sent in the reactor that liquid phase MMP product is housed.Being reflected at liquid phase carries out.In order to produce the MMP of required quality, in this method, use the purified propenal, and/or be used to produce before HMBA or the methionine(Met), earlier distillation MMP product.

Propenal is that high toxicity and combustible material are arranged.It is prepared by propylene gaseous oxidation on solid-phase catalyst usually, generates the vapor reaction crude product that contains water vapor, vinylformic acid, acetaldehyde and other organic by-products.Usually, the treated vinylformic acid of removing of gas contacts so that absorb propenal with refrigerated water then.The aqueous solution that generates is steamed.

US4225516 discloses the continuation method that a kind of propenal product gas that is made by the propylene catalyzed oxidation is produced MMP.In this method, the at first treated vinylformic acid of removing of gas, cooling makes water vapor condensation then.React acceptable level in order to make vapour content drop to MMP, final condensing temperature is 0～-5 ℃.Treated and refrigerative propenal gas stream contact with liquid MMP stream in countercurrent absorber, and propenal is absorbed among the MMP.Contain the MMP liquid flow of dissolving propenal and loop back the MMP reactor that adds methyl mercaptan at this.This method is reacted by methyl mercaptan and MMP and is carried out, and generates half mercaptal of MMP, and half mercaptal generates other MMP with acrolein reaction in liquid phase again.Therefore, this method requires to have in reaction mixture until half mercaptal of 1% (weight) exists.The MMP product is discharged from system with the speed that equates with the throughput rate of MMP in the reactor, simultaneously most of MMP logistics is recycled to the propenal absorption tower.

For propenal quantitatively is absorbed among the MMP, US4225516 requires to enter the absorption tower at circulation MMP and was cooled to 0～-15 ℃ in the past earlier.Water vapor is cooled to the main investment and the process cost of the required freezing US4225516 of the accounting for patented method of-15 ℃ low temperature 0～-5 ℃ of following condensation with MMP.And, because reaction is carried out through generating half mercaptal,, lower productivity is arranged so the kinetics of conversion reaction is quite slow, therefore the process cost of this method is further increased.

Though low temperature absorption has improved the balance rate of recovery of propenal, it has also increased impurity such as acetaldehyde and has been absorbed in quantity in the MMP product.And because washing tower is what to separate with reactor, the propenal that absorbs in washing tower can not consume in absorber portion immediately.Therefore, propenal usually in liquid phase trifoliate orange tired, thereby mass transfer force is descended.The high density of propenal also makes the possibility increase that is generated by product by reaction between propenal and the MMP in MMP liquid.

Summary of the invention

Several purpose of the present invention provides improving one's methods of a kind of MMP of preparation; Provide a kind of can be by the continuous mode method of operating; A kind of high productivity method of operating that has is provided; A kind of available crude propylene aldehyde raw material method of operating is provided; Provide a kind of propenal absorption or condensation not to need the refrigerated method; A kind of method that does not need the storing liquid propenal is provided, the method for the gaseous acrolein feed operation that a kind of continuous oxidation of hydro carbons that is fit to propylene or other directly obtains particularly is provided; A kind of method of operating under the independent situation that contains water that do not generate in the MMP reaction mixture is provided; And the method that provides a kind of production need not be further purified just can be directly used in the high quality MMP of preparation methionine(Met) or HMBA.

In brief, the present invention relates to the method for a kind of continuous MMP of preparation, wherein liquid reaction medium contacts with the gaseous acrolein feed stream in the gas/liquid contact segment.Reaction medium contains MMP, methyl mercaptan and the catalyzer that is used for methyl mercaptan and acrolein reaction.The gaseous acrolein feed stream contains acrolein vapor and noncondensable gas.Sending into the propenal of contact segment and the relative proportion of methyl mercaptan is stoichiometry equivalent basically.Propenal is transferred to the reaction medium from feed stream, and directly reacts in reaction medium with methyl mercaptan, and generation contains the liquid reacting product of MMP, and does not generate the half methylthio group acetal of intermediate MMP in a large number.From liquid reacting product, isolate noncondensable gas, reaction product is divided into product cut and recycle fraction, then recycle fraction is recycled to the gas/liquid contact segment.In the conversion zone of being made up of gas/liquid contact segment and circulation section, propenal and methyl mercaptan react in liquid medium, and liquid reacting product enters circulation section from the gas/liquid contact segment, and recycle fraction loops back the gas/liquid contact segment through circulation section.Methyl mercaptan is sent into more such positions of conversion zone, so that do not have excessive methyl mercaptan that a large amount of generation of sufficiently long time intermediate half methylthio group acetals are arranged in the zone of conversion zone.

The invention still further relates to the method for a kind of continuous production MMP, wherein liquid reaction medium contacts with the gaseous acrolein feed stream in the gas/liquid contact segment.Reaction medium contain MMP, methyl mercaptan and be used for methyl mercaptan and propenal between catalyst for reaction.The gaseous acrolein feed stream contains acrolein vapor, non-condensable gas and water vapor.Propenal is transferred to the reaction medium from feed stream, and reacts in reaction medium with methyl mercaptan, generates the liquid reacting product that contains MMP.Water vapor is such with the ratio of propenal in the propenal feed stream, so that because the condensation of water in the feed stream does not have significant second liquid phase to exist in liquid reacting product yet.From liquid reacting product, isolate non-condensable gas, reaction product is divided into product cut and recycle fraction, then recycle fraction is recycled to the gas/liquid contact segment.

The invention still further relates to the method for a kind of continuous MMP of preparation, wherein liquid reacting product contacts with the gaseous acrolein feed stream in the gas/liquid contact segment, reaction medium contain MMP, methyl mercaptan and be used for methyl mercaptan and propenal between catalyst for reaction.The gaseous acrolein feed stream contains acrolein vapor, non-condensable gas and water vapor.Propenal is transferred in the reaction medium from feed stream, and reacts with methyl mercaptan in reaction medium, generates the liquid reacting product that contains MMP.In the propenal feed stream, the mol ratio of water vapor and propenal is not more than about 0.3.From liquid reacting product, separate noncondensable gas, reaction product is divided into product cut and recycle fraction, recycle fraction is recycled to the gas/liquid contact segment.

The invention still further relates to the method for a kind of continuous MMP of preparation, wherein liquid reaction medium contacts with the gaseous acrolein feed stream in the gas/liquid contact segment, and feed stream and reaction medium adverse current are by the gas/liquid contact segment.Reaction medium contain MMP, methyl mercaptan and be used for methyl mercaptan and propenal between catalyst for reaction.The gaseous acrolein feed stream contains acrolein vapor and non-condensable gas, thus propenal transfer to the reaction medium from feed stream, then in reaction medium with methyl mercaptan reaction, generate the liquid reacting product that contains MMP.The liquid that is retained in gas/liquid counter current contact section is enough to make in the gas/liquid contact segment, and the propenal that is contained in the feeding gas transforms at least 90%.From liquid reacting product, isolate non-condensable gas, reaction product is divided into product cut and recycle fraction, then recycle fraction is recycled to the gas/liquid contact segment.

The invention still further relates to the method for a kind of continuous MMP of preparation, wherein liquid reaction medium contacts with the gaseous acrolein feed stream in the gas/liquid contact segment, and reaction medium contains MMP, methyl mercaptan and is used for methyl mercaptan and the catalyzer of acrolein reaction.The gaseous acrolein feed stream contains vinylformic acid aldehyde vapour and non-condensable gas.Propenal is transferred to reaction medium from feed stream, and propenal and methyl mercaptan react in the reaction medium of first conversion zone that contains the gas/liquid contact segment then, generates the intermediate liquid reaction product.From intermediate liquid precursor reactant product, isolate non-condensable gas, then the intermediate liquid reaction product is divided into intermediate product cut and recycle fraction, recycle fraction is recycled to the gas/liquid contact segment.First conversion zone is made up of gas/liquid contact segment and circulation section, and liquid reacting product enters circulation section from the gas/liquid contact segment, and recycle fraction loops back the gas/liquid contact segment by circulation section.The intermediate product cut makes residual propenal and methyl mercaptan change into MMP by plug flow reactor.

The invention still further relates to the method for a kind of continuous MMP of preparation, wherein liquid reacting product contacts with the gaseous acrolein feed stream in the gas/liquid contact segment.Reaction medium contain MMP, methyl mercaptan and be used for methyl mercaptan and propenal between catalyst for reaction.The gaseous acrolein feed stream contains acrolein vapor, non-condensable gas and vinylformic acid steam.Propenal is transferred to the liquid reaction medium from feed stream, and reacts with methyl mercaptan in reaction medium, generates the liquid reacting product that contains MMP.The mol ratio of vinylformic acid steam and propenal is not more than about 0.1 in the propenal feed stream.From liquid reacting product, separate non-condensable gas, then reaction product is divided into product cut and recycle fraction, recycle fraction is recycled to the gas/liquid contact segment.

The invention still further relates to the method for a kind of continuous MMP of preparation, wherein generate crude propylene aldehyde reaction product stream and come the production acrolein vapor by the hydro carbons catalytic gas phase oxidation.With crude propylene aldehyde reaction product logistics cooling, water vapor and propenal are therefrom condensed, make refrigerative propenal gas stream, be used to change into MMP, feed stream contains propenal and non-condensable gas.Liquid reaction medium contacts with the gaseous acrolein feed stream that contains described refrigerative propenal gas stream in the gas/liquid contact segment, and this section stagnation pressure is not more than about 3 normal atmosphere.Reaction medium contains MMP, methyl mercaptan and is used for methyl mercaptan and the catalyzer of acrolein reaction.Propenal is transferred in the reaction medium from feed stream, and reacts in reaction medium with methyl mercaptan, generates the liquid reacting product that contains MMP.From liquid reacting product, isolate non-condensable gas, then reaction product is divided into product cut and recycle fraction, recycle fraction is recycled to the gas/liquid contact segment.

The invention still further relates to the method for a kind of continuous MMP of preparation, therefore the crude reaction product gas stream cooling that wherein will be made by hydrocarbon catalyticing oxidation obtains containing the cooling gas logistics of propenal and the condensation product of moisture, vinylformic acid and residual quantity propenal.Make cooling gas logistics and condensate separation, the tower bottom distillate that the condensation product fractionation is obtained containing the overhead fraction of propenal then and be substantially free of propenal.Overhead fraction mixes with the cooling gas logistics, the propenal logistics that obtains merging.Liquid reaction medium contacts with the gaseous acrolein feed stream in the gas/liquid contact segment.Reaction medium contains MMP, methyl mercaptan and the catalyzer that is used for methyl mercaptan and acrolein reaction.The propenal gas stream of gaseous acrolein feed stream for merging contains propenal, non-condensable gas and water vapor.Propenal is transferred to reaction medium from feed stream, and reacts with methyl mercaptan in reaction medium, generates the liquid reacting product that contains MMP.From liquid reacting product, isolate non-condensable gas, then reaction product is divided into product cut and recycle fraction, recycle fraction is recycled to the gas/liquid contact segment.

The invention still further relates to a kind of method of the continuous 3-of preparation methylthiopropionaldehyde.This method comprises that liquid reaction medium contacts in the gas/liquid contact segment of conversion zone with the gaseous acrolein feed stream.Reaction medium contains 3-methylthiopropionaldehyde, methyl mercaptan and is used for methyl mercaptan and the catalyzer of acrolein reaction.The gaseous acrolein feed stream contains acrolein vapor and non-condensable gas.Gaseous acrolein feed stream and reaction medium are also flowed by the gas/liquid contact segment.Propenal is transferred to reaction medium from feed stream, and reacts in reaction medium with methyl mercaptan, generates the liquid reacting product that contains MMP.From liquid reacting product, isolate non-condensable gas, then reaction product is divided into product cut and recycle fraction.Recycle fraction is recycled to the gas/liquid contact segment.By heat from described liquid reaction medium indirect transfer to another fluidic method, remove reaction heat from conversion zone.The cycle rate of liquid medium and be such from the position of conversion zone heat-obtaining, thus the variation of the temperature of liquid reaction medium in whole described conversion zone be not more than approximately ± 5 °F.

It is very clear that the other objects and features of the invention will become from following description.

The simple declaration of accompanying drawing

Fig. 1 is the schema of the inventive method, and the thick gaseous acrolein product continuous production MMP that is made by the oxidation of propylene continuous catalysis is described;

Fig. 2 is the schema of the preferred process of the present invention, wherein produces MMP by methyl mercaptan and propenal in turbulent gas lift recirculation reactor;

Fig. 3 is the explanatory view that is applicable to the gas lift recirculation reactor of low pressure drop operation;

Fig. 4 is the explanatory view that is used for the conduction type gas lift recirculation reactor of low pressure drop operation;

Fig. 5 is used for the explanatory view that methyl mercaptan and propenal change into the tray column reactor of MMP;

Fig. 6 adopts the take over a job explanatory view of the inventive method of plug flow reactor of tray column reactor;

Fig. 7 is the explanatory view of a kind of method of the present invention, wherein crude propylene aldehyde reaction product gas send into and gas rises recirculation reactor make propenal and methyl mercaptan react before the treated vinylformic acid of removing basically;

Fig. 8 is the explanatory view of a kind of method of the present invention, and wherein crude propylene aldehyde reaction product gas is sent into the counter-current tower plate-type reactor and made propenal and the methyl mercaptan reaction treated vinylformic acid of removing basically in the past.

The explanation of preferred embodiment

According to the present invention, in containing the gas/liquid reactions system of liquid MMP, produce MMP by methyl mercaptan and gaseous acrolein feed stream.In the gas/liquid contact segment, the liquid phase that contains MMP and catalyzer contacts with the gas that contains propenal and non-condensable gas with methyl mercaptan.Propenal is transferred to liquid phase from gas phase, and direct and methyl mercaptan reaction in liquid phase, generates newly-increased MMP.With the contacting of gas/liquid contact segment in or in the liquid exit of contact segment and the MMP circulation loop between the import, with exothermic heat of reaction by taking away by heat transfer equipment such as chuck or coil pipe mobile heat-transfer fluid.

In the gas/liquid contact segment, can closely contact by gas/liquid and obtain high mass transfer coefficient, and can make the impellent of mass transfer preferably reach maximum by in gas phase, keeping piston flow basically.Can reach gas/liquid and closely contact by operation in turbulent scope, for example have quite high superficial gas velocity and liquid speed to characterize in its available burble district, wherein since the bubble as a result of turbulent flow constantly merge and break.Such turbulent-flow conditions also promotes the chuck of heat from the heat transfer equipment that the gas/liquid contact segment is delivered to contact segment links to each other or the two-forty of coil pipe.In addition, can carry out gas/liquid by gas in contact segment and liquid countercurrent contacts.In the embodiment, reaction heat is preferably passed to the cold fluid of external heat exchanger behind the present invention, and the MMP reaction medium circulates by external heat exchanger.

Keep equimolar amount to add in the reaction medium by methyl mercaptan and propenal are gone up substantially, can not generate half mercaptal of MMP basically.Therefore, methyl mercaptan and propenal direct reaction generate MMP.Because this reaction path is than faster by the approach that generates half mercaptal, so speed of reaction is higher 3～10 times than the speed of reaction that US4225516 disclosed method obtains.Under the speed of reaction that novel method obtains, the rate limiting of propenal from the mass transferring in gas phase to the liquid phase conversion rate.But, found when keeping turbulent-flow conditions, can obtain high mass transfer coefficient by the preferred embodiment of the invention.And because propenal and methyl mercaptan direct prompt reaction in liquid phase, the propenal that enters liquid phase is consumed immediately, thereby has improved the impellent of mass transfer.Therefore, total rate of mass transfer is high.The common influence of direct reaction and high rate of mass transfer makes reaction system of the present invention that high productivity be arranged.

With reference to figure 1,, in acrolein reaction device 1, generate propenal continuously by propylene, propane or other hydrocarbon raw material catalyzed oxidations in the presence of water vapor and non-condensable gas that is fit to.The crude propylene aldehyde product gas that when raw material is propylene, flows out from reactor contain have an appointment 4 to about 10% (volume) propenal, about 0.3 to about 1.0% (volume) vinylformic acid, at the most about 1.0% (volume) propylene, at the most about 1.0% (volume) propane, at the most about 0.5% (volume) propionic aldehyde, about 0.1 to about 0.4% (volume) acetaldehyde, about 30 to about 50% (volume) water vapor and about 40 to about 55% (volume) non-condensable gas, non-condensable gas comprises oxygen, nitrogen, carbon monoxide and carbonic acid gas.Treated its water vapor of remarkable minimizing of crude product gas and acrylic acid content then.Preferably, crude product cools off in indirect heat exchanger 3, and vinylformic acid and water vapor are condensed from thick gaseous product.Though refrigerated water can be used as cooling fluid in interchanger 3, the also water of environment for use temperature economically is as tap water, well water or cooling tower water.Vinylformic acid and water obtain containing the cooling propenal feed gas stream of following component as the condensation of heat-eliminating medium with envrionment temperature water in interchanger: about 5 to about 25% (volume) (more generally about 7 to about 15% (volume)) propenal, about at the most 0.1 (preferably about at the most 0.01) % (volume) vinylformic acid, about at the most 2.0% (volume) propylene, about at the most 1.0% (volume) propane, about at the most 1.0% (volume) propionic aldehyde, about at the most 0.5% (volume) acetaldehyde, about 1 to about 8 (preferred about 1 to about 3) % (volume) water vapor and about 60 to about 80% (volume) non-condensable gas.Preferably, the mol ratio of water vapor and propenal is about 0.05 to about 0.3 in the cooling gas logistics, and preferred about 0.05 to about 0.15, and the mol ratio of vinylformic acid and propenal is 0 to about 0.01, preferred 0 to about 0.001.Can in device for counter-currently contacting gas such as packing tower, contact by the absorption agent of gas in case of necessity, at first vinylformic acid be removed from crude propylene aldehyde product gas with routine.The gas that flows out resorber can further cool off by the indirect heat exchanger in resorber downstream, makes water vapor condensation.

Then refrigerative propenal feed gas stream is sent in the reaction medium that contains circulation MMP stream of continuous flow reactor 5.Reactor 5 is equipped with cooling jacket 7.Circulation MMP contains the catalyzer that is useful on methyl mercaptan and acrolein reaction.Catalyzer can inject continuously or off and in any position easily in loop.How easily methyl mercaptan position in office is sent in the MMP recycle stream, but preferably sends into propenal or introduce the position at propenal and introduce the position of upstream slightly.Therefore, make two-phase reaction mixture, wherein propenal is in the liquid phase that contains MMP and catalyzer with contain between the gas phase of non-condensable gas and distribute.Methyl mercaptan also can distribute between this two-phase, is dissolved in liquid phase basically but observe it.Catalyzer is the organic acid salt of amine normally.In the gas/liquid contact segment, to introduce point from propenal and extend downstream, propenal is transferred to liquid phase from gas phase gradually, and directly continuous and methyl mercaptan reaction in liquid phase, generates MMP.Methyl mercaptan at first is distributed between the two-phase, for acrolein reaction, it is also transferred in the liquid gradually.

Contained water vapor also is condensate in the MMP logistics of gas/liquid contact segment in the propenal feed gas.Make the water vapor partial condensation by cooling reactor 5 upstream crude propylene aldehyde reaction product gas, it is enough low that the mol ratio of water vapor and propenal is remained on, so that do not form tangible second (aqueous) liquid phase in the gas/liquid contact segment; In can not separating with the MMP reaction medium Anywhere of reaction system, and in gas/liquid contact segment or liquid reacting product, there is any second liquid phase to exist owing to containing water.Preferably, the water-content of circulation MMP medium is not more than about 6% (weight), is generally about 1 to about 6% (weight).Under preferred temperature of reaction, as what hereinafter discuss, the water of these concentration still is dissolved in the MMP phase fully.As noted above, water vapor is not more than about 0.3 to the mol ratio of propenal in feed gas stream.Determined water-content that this ratio is enough to control the MMP circulatory mediator with enough low concentration to prevent under the temperature of the liquid outlet of gas/liquid contact segment, forming the water that contains that separates.

The existence of excessive propene acid in the MMP product also can be by preventing with room temperature water cooling crude propylene aldehyde reaction gas.Vinylformic acid condensation from thick gas stream obtains going to the gaseous acrolein feed stream of MMP reactor in water cooler, wherein the mol ratio of vinylformic acid and propenal is not more than about 0.01 in feed stream, preferably be not more than about 0.001, and that the concentration of vinylformic acid steam is not more than is about 0.1%, preferably is not more than about 0.01%.

Keep turbulent-flow conditions by preferred in the section of touching by making the two-phase flow velocity be in the turbulent region of as above stipulating in gas/liquid.Be swift in response and carry out, generate the two phase reaction product mixtures, it contains the liquid phase of MMP product and catalyzer and contains the gas phase of non-condensable gas.The reaction product that reactor is discharged is sent into separator 9, make gas phase and liquid phase separation there.The gas phase that will contain propane, propylene, propionic aldehyde, acetaldehyde and water vapor is discharged into from separator disperses operating device, as incinerator.Contain under the occasion of unabsorbed propenal of any significant amounts or unreacted propylene at discharging gas, a part of emission gases can be recycled to the propylene oxidation reactor.But, high rate of mass transfer and first-class substantially mol propylene aldehyde and methyl mercaptan are added in the reaction system and combine in the gas/liquid contact segment, are contained about 90 usually to about 97% (volume) non-condensable gas and the only about 0.01 discharging gas logistics to about 0.03% (volume) propenal.Usually, discharging gas also contains to have an appointment and 1 is suitable for the torch that burns to about 2% propylene, this quantity, and non-condensable gas and residual organic steam can be from associating propenal/MMP manufacturing installation removings by torch.On the other hand, a part of emission gases logistics is capable of circulation, and the source of a kind of water vapor and non-condensable gas is provided for the propylene oxidation reactor.

From separator, extract pure MMP product out by products export 10, and a large amount of MMP is recycled to reactor from separator.The MMP product is substantially free of methyl mercaptan, propenal and is contained in impurity in the propenal feeding gas.Need not be further purified, the MMP product just can be used as the intermediate of making HMBA.

Reaction can be carried out to about 3 normal atmosphere (preferred about 1.5 to about 2 normal atmosphere) at about 30 to about 70 ℃ (preferred about 40 to about 50 ℃) and stagnation pressure about 1.Methyl mercaptan and propenal are sent in the reaction medium to about 1.2 (preferred about 1.00 to about 1.02) for about 0.95 in molar ratio.As indicated, the propenal charging contains about 5 to about 25% (volume) propenal, and preferred about 7 to about 15% (volume).Most preferably, the acrolein vapor feed stream contains about 10 to about 15% (volume) propenal.

Be lower than under about 50 ℃ temperature of reaction, favourable propenal balance provides the effective especially mass transfer force to liquid phase between the liquid and gas, but significantly be lower than under 40 ℃ the temperature, the logistics of refrigerated refrigerant may need, and the kinetics of reaction may begin to limit productive rate.And, also become unfavorable in the balance distribution of acetaldehyde under the lower temperature of reaction between gas phase and liquid phase, the concentration of acetaldehyde in the product that separator is discharged is increased.Particularly preferred temperature of reaction is about 40 to about 45 ℃.Can by heat from reaction mixture be delivered to mobile the chuck around the gas/liquid contact segment at the most 35 ℃ the method for cooling tower water temperature of reaction is controlled at rapidly in this temperature range.Along with reaction consumes dissolved propenal, along with the imbalance that the consumption of propenal causes, other propenal is transferred in the liquid phase from gas gradually.Therefore, in the most preferred embodiment of the present invention, for control reaction temperature or promote not need during propenal is from the gas transfer to the liquid phase or not wish freezing.

Though high pressure also helps mass transfer, in the gas/liquid contact segment of turbulent flow,, consequently do not need to use high-pressure reactor at normal pressure or near reaching mass transfer rapidly under the normal pressure.And by reactor being remained on the middle pressure level, for the propenal product gas is sent into the MMP reactor, the pressure that adopts in the propylene oxidation reactor may be enough, does not need mechanically compress gas.

Though with level of acrolein is that the about 5 gas feed logistics to about 25% (volume) are feasible, if feed gas contains at least about 10% (volume) propenal, rate of mass transfer increases.On the other hand, the too high absorptive capacity excess load that may make the gas/liquid contact segment of level of acrolein may be to reclaiming propenal and by the productive rate of propenal MMP disadvantageous effect being arranged from gas phase.Further balanced for the various factors of the representative acrolein reaction device operation of the direct requirement that makes present method and influence, can think the concentration of feed gas be about 10 to about 15% (volume) be best.

By excessive slightly mercaptan is arranged in reaction mixture, can make the transformation efficiency maximum of propenal, can avoid handling unreacted propenal basically.Be controlled at every mol propylene aldehyde in the mol ratio of reactant and have an appointment under 1.00 the occasions to the scope of about 1.02 moles of methyl mercaptans, the direct reaction between mercaptan and the propenal has precedence over the half methylthio group acetal that generates intermediate MMP.Therefore, realize the two-forty reaction, quite low capital cost of high productivity and reactor and operational cost are arranged.Available known the whole bag of tricks of specialty of the ratio of reactant controlled.Preferably, with the circulation MMP logistics in vapor-phase chromatography periodic analysis vapour/liquid contact segment downstream, the adjusting that relative propenal and methyl mercaptan feeding rate are made any necessity makes methyl mercaptan keep suitably excessive and does not generate half mercaptal.On line analyzer can be used for this purpose.In the beginning process, this method is all with continuous round-robin steady state way operation.Therefore, in case reach steady state conditions, just can be with the adding of methyl mercaptan and propenal than being adjusted to 1.0 basically.

Conventional catalyst and catalyst concn can be used for this reaction.Such catalyzer comprises various organic amines such as pyridine, vulkacit H or triethylamine.Organic acid is commonly used to suppress the propenal polymerization.For example under the occasion of using acetate pyridinium salt catalyzer,, make catalyst concentration be maintained at about 0.2 to about 1.0%, preferred about 0.35 to about 0.5% by regularly or continuously catalyzer being added to liquid phase.

Than big 1 order of magnitude of throughput rate of MMP, preferably approximately 20 is to about 50 times, so that co-current reactor shown in Figure 1 is back-mixing basically in liquid phase at least for the cycle rate of MMP.Various two-phase reactors all can be used for this reaction, for example and flow tubular reactor, stirred-tank reactor or counter-current reactor such as wet-wall tower, bubble tower, packing tower or tray column.In order to promote rapid mass transfer, gas phase preferably to be piston flow.In piston flow, in gas phase, produce the propenal concentration gradient, and in the gas/liquid contact segment, keep this concentration gradient along the reactant stream, so the impellent of the comprehensive average impellent that provides of mass transfer during significantly greater than axial mixing in gas phase.The gas lift recirculation reactor is particularly preferred, because it can be by the gas phase plug flow operation, and because a large amount of non-condensable gases can be used for the circulation of MMP liquid phase and produce fabulous liquid mixing in reactor in the logistics of propenal gas feed.Therefore, can save mechanical moving element, as pump or agitator.On the other hand, use counter-current tower have good especially outside, particularly make under the occasion of the pressure drop minimum by the gas/liquid contact segment at needs.

What Fig. 2 illustrated is loop type gas lift recirculation reactor equipment of the present invention, and it is used for such integrated process, wherein with thick gas-phase propene aldehyde cooling, and directly sends into the MMP reactor.In this described integrated process, propylene (or other be fit to hydro carbons) and air mixed, and send in the reactor 101 that the catalyzer that is suitable for the hydrocarbon oxidation acrolein is housed with dilution water steam and/or non-condensable gas.By with the air and the propylene of band as above-mentioned thinner mixed the reactor feed logistics, then mixture is come preheating by heat is delivered to mixture from crude propylene aldehyde product gas in indirect heat exchanger 111.In countercurrent packed tower resorber 113, part refrigerative product gas contacts with liquid absorption medium, so that remove vinylformic acid from gas stream.The resorber effluent air is by another indirect heat exchanger 103, so that further cooled product gas and make vinylformic acid and therefrom condensation of water vapor.Preferably, only remove vinylformic acid and excessive water vapor, so just do not need vinylformic acid resorber and gas stream by the needed pressure drop of resorber by condensation.Then refrigerative propenal product gas is sent into gas lift recirculation reactor 105.

Reactor 105 has last conduit (" upper reaches arm ") 117, and chuck 107 is housed, and cooling fluid can circulate by chuck.Reactor also has conductance official (" dirty arm ") 119 down, and it communicates with upper reaches arm fluid flow by loop, bottom 121 with the upper reaches arm.Upper reaches arm 117 has the gas/liquid contact segment.What fluid flow communicated between the upper end of two arms is separator 109.Dirty arm 119, loop, bottom 121 and separator 109 constitute circulation section together, and the reaction between propenal and the methyl mercaptan therein can continue after reaction medium is discharged the gas/liquid contact segment.Therefore, conversion zone comprises gas/liquid contact segment and circulation section.The position of cycle rate and chuck 107 is such, thus the variation of temperature by the MMP liquid reaction medium of conversion zone in the arm of reactor upper reaches be not more than approximately ± 5 ℃, preferably be not more than approximately ± 2 ℃.

In full scale plant, available a plurality of reactor loop and a single separator combination obtain required throughput.Upper reaches arm 117 has the gas feed 123 of introducing refrigerative propenal feed gas in its lower end, and dirty arm 119 has the fluid inlet 125 of introducing steam or liquid methyl mercaptan.On the other hand, methyl mercaptan can the propenal feed gas introduce point or near introducing.Where catalyzer can continuous or in office off and on just the injection.Preferably, the feed points of propenal and methyl mercaptan is enough approaching, so that between feed points no matter in that part of conversion zone, the MMP medium can contain excessive methyl mercaptan, this methyl mercaptan and propenal than and wherein be that the residence time of circulation MMP medium is not enough to obviously generate half mercaptal under the main absolute methyl mercaptan concentration.In airlift reactor since in the loop diluting effect of a large amount of round-robin MMP streams, the concentration of methyl mercaptan and any excessive all very little to propenal concentration.The upper reaches arm has the gas/liquid contact segment, and its size is definite like this, so that two phase flow is in the burble zone, and wherein gas is dispersed in the successive liquid phase with the form of discontinuous bubble, perhaps is in the scope between burble and the slug flow.The liquid head difference that is produced by two-phase fluid in the arm of upper reaches and liquid phase in the dirty arm density lower than having causes liquid circulation.In order to produce preferred flow condition, the gas superficial rate adaptation in the arm of upper reaches is arrived about 0.1 between about 0.5 meter per second.Under the combination of such gas speed and height for reactor, gas hold up is about 5 to about 20% in the arm of upper reaches, and superficial liquid velocity is about 0.3 to about 3.0 meter per seconds in last arm.In order to obtain required cycle rate, the height in gas lift loop is preferably about 20 to about 30 feet, is about 10 to about 15 pounds/inch at the gaseous acrolein opening for feed to the gaseous tension that reactor needs ²(gauge pressure), promptly about 67 to about 100KPa (gauge pressure).Must the time pump can be contained in the loop 121, bottom, to help circulation and to reduce the height of the upper reaches arm 117 that needs.

By being controlled at the apparent speed of gas phase and liquid phase in the arm of upper reaches, so that two phase flow is in the method in burble zone, can reach mass transfer satisfied especially from the gas phase to the liquid phase.In burble, the dispersion in continuous liquid phase provides maximum mass transfer area to gas as small bubbles.The suitable equilibrium of liquids and gases speed can keep stable burble condition, prevents the gathering and the sluggishness of bubble.Available as principle following document description is published New York, 1972 years with rational accuracy prediction to this effective speed range: Govier and Aziz work " complex mixture flowing in pipe " VanNostrand Reinhold company.Particularly referring to the 324th to 325 page, its explanation air/water system flow model is with the variation of fluid rate.Because flow model depends on fluid properties and caliber,, may need the experiment of some routines in order to determine the optimum flow rate of specific system.Should be appreciated that method of the present invention also can still obtain maximum mass transfer by operation under turbulent burble condition at the slug flow region operation.

In order to start the reactor of Fig. 2, circulation loop is filled MMP basically, after this can begin to introduce propenal feed gas and methyl mercaptan immediately.Even at normal temperatures, the reaction carry out with sufficiently rapid speed so that exothermic heat of reaction make rapidly reaction-ure mixture reach preferred 40 ℃+temperature, under this temperature, carry out steady state operation.

Use the gas lift recirculation reactor, implement the available propenal rate of recovery of method of the present invention be at least about 98%, transformation efficiency be at least about 97% and the propenal productive rate be at least about 95%.The rate of recovery is defined as the ratio that propenal participates in transferring to the feed gas in the liquid phase, and transformation efficiency is defined as the ratio of the participation propenal that consumes in reaction; Productive rate is defined as the ratio of propenal in the feed gas that changes into straight product MMP.

When method of the present invention is produced the device serial operation of propenal with the method for propylene catalyzed oxidation, can not cause that by product growing amount or MMP product degradation amount increase in the propenal feed gas owing to impurity such as propylene, propane, acetaldehyde, propionic aldehyde, oxygen, carbon monoxide, carbonic acid gas exist.Therefore, this method can be economically and the combination of propenal production equipment, and do not need condensation, the purifying of propenal and store under liquid state.This method is specially adapted to and the combination of such propenal production method, and promptly in this propenal production method, crude propylene aldehyde product gas is acrolein vapor and the mixture that contains the indifferent gas of low concentration of water steam and organic impurity.

Under the occasion of using the loop type airlift reactor, the back pressure that is produced by the pressure drop in the arm of upper reaches is tending towards making the pressure in the acrolein reaction device to be elevated to the level that is higher than optimum pressure.The resorber that this back pressure can be used in preparation purified liquid propene aldehyde by cancellation at least and partial offset.Pressure drop at the resorber two ends in conventional propenal method then is applied to back pressure on propylene or other hydrocarbon oxidization devices.And the disadvantageous effect of any pressure drop all can be by any the avoiding in many countermeasures in the gas lift recirculation reactor.For example, by in the gas discharge line of separator, compressor being installed, moderate negative pressure can be added on the separator 109.As noted above, can reduce the necessary height of gas/liquid contact segment by the mechanical cycles of MMP reaction medium.

What Fig. 3 illustrated is another gas lift circulating reaction system, and it is useful in operation under the low especially gas pressure drop.The gaseous acrolein feed stream is introduced by the inlet pipe in dirty arm 219 221, rather than resembles among Fig. 2 at the bottom introducing propenal gas near the upper reaches arm.Introducing startup gas by the inlet pipe in upper reaches arm 217 224 makes the circulation in the gas lift recirculation reactor loop begin to start.The height that starts inlet pipe is lower than the height of inlet pipe 221 at least slightly, but both can be in the equally high position that needs in the gas return path, so that the liquid head in the loop does not produce too high back pressure at gas introducing point.Propenal feed gas or rare gas element all can be used for starting.In case the circulation of MMP reaction medium is set up, can begin to introduce the propenal feed gas by inlet pipe 221, as long as two phase flow extends to inlet pipe 224 or when above from inlet pipe 221, just stop to introduce and start gas.Methyl mercaptan can be in office what send into the position easily, for example near propenal charging place or charging place, or send into by starting gas tube.Catalyzer can inject in the loop Anywhere.The gas/liquid contact segment comprises that the part that dirty arm 219 is lower than import 221 adds whole upper reaches arm 217.The balance of circulation loop comprises that circulation section and gas/liquid contact segment and circulation section constitute conversion zone together.Because the part of two-phase section is than the length in the arm 219 in upper reaches arm 217, two phase reaction thing mixture keeps down mobile in arm 219.Reactor continues to operate with the liquid head difference that the liquid head of import 221 tops is determined then.Under the moderate occasion of liquid head, it is minimum that pressure drop is reduced to.If when the apparent liquid velocity that the restriction of the pressure drop on the liquid head difference of permission produces is lower than the optimum value of effective mass transfer, so just vertical dimension remedies under the gas inlet point by increasing, to increase the residence time of mass transfer.

In another yes-no decision, can use through-flow cast gas lift recirculation reactor, wherein the propenal feed gas is introduced draft tube.This system illustrates in Fig. 4.Reactor 305 is included in the draft tube 319 of garden column type reactor 309 radial center, constitutes the dirty arm of gas lift recirculation reactor system.Circle ring area between draft tube 319 and the reactor wall constitutes upper reaches arm 317, and draft tube and circle ring area constitute MMP round-robin loop together.The gaseous acrolein feed stream is sent into by the dipping tube import 321 in draft tube 319.To those skilled in the art is that conspicuous and Fig. 3 points out, methyl mercaptan and catalyzer can be introduced any position easily in the loop.The inlet pipe in the arm 317 324 that cycles through on annulus in gas lift recirculation reactor loop is introduced and is started gases and start.Though dipping tube is shown single outlet pipe, import 324 is preferably the ring-like bubbler around drainage tube, at whole periphery outlet is arranged.As the reactor among Fig. 3, the height that starts import is lower than the height of import 321 at least slightly, and the height at both places is that to reduce back pressure needed.Circulation begins by same procedure as above shown in Figure 3, after this can begin to send into the propenal feed gas by import 321, as long as two phase flow just stops to introduce startup gas when import 321 extends to import 324.The long more two phase reaction thing mixture that keeps of two-phase region in annulus arm 317 flows downward in draft tube.Reactor is used in the definite liquid head difference continuation operation of liquid head of import 321 tops then.Under the situation of not remarkably influenced gas pressure drop, the vertical dimension of dipping tube outlet below draft tube can resemble for mass transfer provide suitable residence time required big.Can take reaction heat away from the reactor of Fig. 3 by the chuck around the reactor 305 or the coil pipe in reactor or other heating surfaces.Except reducing liquid head difference with the apparent liquid velocity under the situation that prevents from the acrolein reaction device is produced excessive back pressure with the residence time, substantially the same for the preferred operational condition of Fig. 3 reactor and Fig. 2.

Another embodiment preferred of the present invention illustrates in Fig. 5.In this embodiment, be reflected in the tray column 405 and carry out, liquid MMP reaction medium is by tray column 405 circulations.Liquid MMP sends into by the liquid-inlet 406 of cat head, and the gas feed 421 of propenal feed gas at the bottom of by tower sent into.Methyl mercaptan is also being sent at the bottom of the tower or near at the bottom of the tower, preferably sends into by identical import 421.There is the gas/liquid contact segment inside of tower, and the mutual adverse current of gas phase and liquid phase stream is by the gas/liquid contact segment, and the mass transfer from the gas phase to the liquid phase mainly occurs on the column plate.Take place in the circulation section that is reflected at liquid bath at the bottom of upflow tube in the liquid phase on the column plate, between the column plate and the tower and constitutes to the circulation line of liquid-inlet 406.When gas flowed on tower, propenal was transferred in the liquid phase gradually, so that is substantially free of propenal from the cat head expellant gas, and by incinerator, torch or similarly emission control equipment emptying.

Different with the gas lift of the homothermic basically recirculation reactor of Fig. 2-4, column plate type reactor adiabatic operation basically itself.The liquid reacting product mixture is discharged at the bottom of the tower, and is divided into the product cut that takes out from this process and through cooling with return recycle fraction in the tower.Pump 430 provides power for recirculation.By removing reaction heat for the cooling tower water in the indirect heat exchanger 407 with heat passage.Be absorbed in fully in the liquid phase in order to ensure propenal, the circulation MMP that discharges from interchanger 407 is preferably by second indirect heat exchanger 408, there by to chilled brine recycle stream to be cooled off about below 10 ℃ or 10 ℃ with heat passage, and preferred 0 to about 10 ℃.The MMP cut that a part of water cooler 407 is discharged is recycled to tower bottom column plate inlet 422, i.e. the 6th of the tower of 20 blocks of plates the or the 8th actual plate in case of necessity.Though be partly recirculated to the temperature distribution that the bottom of tower has changed tower, in this embodiment and in all circulation MMP reaction mediums are recycled to the embodiment of cat head, react and all in whole tower, take place.

Because adiabatic operation basically has thermograde in tower.Liquid stream in the tower is about 50 to about 60 ℃ at the bottom of be heated to tower at about 0 of cat head to about 10 ℃ preferably.Because the tower expellant gas contacts with MMP at low temperatures, obtain favourable balance, the rate of recovery of propenal can reach＞99%, in order to promote the reaction in the gas/liquid contact segment, preferably is raised to about 40 ℃ at least at the liquid medium temperature of the liquid outlet of tower.Temperature rising by gas/liquid contact segment liquid medium is preferably about 20 to about 80 ℃.Because only gas pressure drop takes place at gas in by the passage that remains on the liquid on the column plate basically, available plate tower reactor produces very moderate back pressure to the acrolein reaction device.

In the system of Fig. 5, replace column plate that the means that promote mass transfer between gas phase and the liquid phase can be provided with filler.But, preferably use tray column, because the gas/liquid contact segment of adverse current is near plug flow conditions.Packing tower may easier generation channel and eddy current, just absorbs and the impellent of reaction, and it has sacrificed the benefit of piston flow, can't provide enough liquid holdup in addition, makes to carry out basically in the liquid phase that is reflected at the gas/liquid contact segment fully.Reaction not exclusively also makes mass transfer force descend in liquid phase, thereby make the total speed decline of reaction in the gas/liquid contact segment and the residence time in the conversion zone that is made of gas/liquid contact segment and circulation section is increased, be the required residence time of acrolein conversion rate that reaches required.

Preferably, liquid holdup should be enough to provide the transformation efficiency at least about 95% in the gas/liquid contact segment, and more preferably at least 99%, most preferably at least about 99.5%.For this reason, hold-up should be enough to provide about 2 to about 5 hours effective residence time preferably by the net production of MMP in the gas/liquid contact segment, more preferably from about 3 to about 4 hours.In the tray column of conventional design, be not more than about 4 hours in effective residence time that liquid holdup provides and reach at least 99.5% transformation efficiency down.This concentration corresponding to propenal and methyl mercaptan in the MMP product cut is not more than about 0.5% (weight).Because this reaction is a mass transfer limit, in circulation section, for example in tower still or circulation MMP pump jar, do not provide required other reaction volume.Therefore, in the gas/liquid contact segment ratio of liquid hold-up volume and the effective volume of circulation section should be at least about 2, preferably be at least about 5, more preferably at least about 15, even higher.As practical situation, compare with the gas/liquid contact segment in tower, the residence time in circulation section be can ignore ground little.For effective mass transfer with remove reaction heat, the cycle rate by tower and interchanger is at least the several times of the net rate that MMP produces usually.Therefore, should be appreciated that the one-pass residence time only needs about 0.5 to about 1 hour by the ratio of liquid hold-up volume with cycle rate, though by the effective residence time in the ratio tower of liquid hold-up volume and clean throughput rate preferably in above-mentioned scope.

Another benefit of operating in the adverse current tray column is to obtain high rate of mass transfer under low gas pressure drop.Found to be not more than about 2 to about 5 pounds/inch in pressure drop ²Can obtain satisfied rate of mass transfer down.

In another yes-no decision, the system of Fig. 5 can be used as bubble column operation.But the pressure drop in bubble tower is than much bigger in tray column or packing tower.Under such certain situation is under the acceptable occasion in quite high pressure drop promptly, owing in the arm of the upper reaches of reactor, produce disorder, so the gas lift recirculation reactor is preferred.

Particularly preferred embodiment in Fig. 7 and the 8 explanations combined method of the present invention.In each preferable methods, the treated vinylformic acid of removing from gas basically of crude propylene aldehyde reaction gas guarantees that simultaneously all propenal reclaim fully basically.The treatment process that Fig. 7 explanation and gas lift circulation MMP reaction system are used in combination, and the treatment process that Fig. 8 explanation and low pressure adverse current tray column MMP combination of reactors are used.

In the method for Fig. 7, the mixture of hydro carbons, water vapor, oxygen and the non-condensable gases that propylene or other are fit to generates the crude propylene aldehyde reaction gas of above-mentioned composition by being enclosed in the suitable catalyzer in the aldehyde reaction device 601.Incoming mixture comes preheating by the heat transmission of crude reaction gas in the feed preheater of the interchanger 611 that comprises indirect heat exchange.Crude product is further cooling in indirect heat exchanger 603, and vinylformic acid and water are condensed from thick gaseous product.Can directly send into continuous N MP reactor 605 from the gas phase that water cooler is discharged.But the condensation product that generates in condenser 603 contains the propenal that is enough to be worth recovery usually.Therefore, in the method for Fig. 7, the condensation product that leaves condenser therefrom reclaims residual propenal through distillation, the vapor phase that generation can merge with the gas phase that condenser obtains, constitute the charging of reactor, and generate the acrylic acid liquid phase that contains that from this method, to remove.More particularly, as shown in the figure, the logistics of two-phase gas/liquid flows out condenser 603, and flows to flasher 627, and its further cooling is there for example passed through the cooling fluid in the coil pipe in the heat transferred flasher.Flasher also as the separator of steam and liquid, discharge from the bottom by phlegma, and gas phase is discharged from the top.Phlegma is delivered to separation column 629, and it is equipped with reboiler of being made up of indirect heat exchanger 631 and the condenser of being made up of indirect heat exchanger 633.This tower has at least 2 usually, preferred 4～6 theoretical sections.From the effusive steam of cat head partial condensation interchanger 633.Phlegma is back in the tower, and vapor phase is mixed with the cooling propenal gas phase of leaving flasher 627.Preferably, the vapor portion of condensation is such in interchanger 633, thus tower in the mole reflux ratio at least about 0.5 time operation, between preferred about 1 to about 2.The tower base stream of discharging from tower 629 contains water has an appointment 3 to about 5% vinylformic acid, and level of acrolein preferably is not more than about 0.1% (weight) less than 1% (weight).The cat head of discharging from tower flows out the owner will contain propenal, usually greater than 75% (mole), more generally greater than about 90% (mole).

As shown in the figure, mix with the gas phase of discharging, obtain being used for the propenal feed gas of reactor 605 from flasher 627 from the overhead materials that tower 629 is discharged.The propenal feed gas is by above-mentioned forming usually, but acrylic acid content is usually less than 200ppm, more generally is lower than about 100ppm.Reactor 605 is operated in the mode identical with Fig. 2 reactor 105, and sleeve pipe 607, upper reaches arm 617, dirty arm 619, loop, bottom 621, propenal feed points 623 and methyl mercaptan supply line 625 all have corresponding to the identical effect of the reactor assemblies of Fig. 2 and substantially the same structure.

The method of Fig. 8 is used acrolein reaction device 701, reactant gases/feed gas interchanger 711, water cooler and fractional distillating tube 703 (be used for remove anhydrate and vinylformic acid from crude reaction gas), flasher 727, vinylformic acid separation column 729, and they provide the reactor 601 that resembles Fig. 7, interchanger 611, fractional distillating tube 603, flasher 627 and propylene acid tower 629 identical effect respectively.The running of the acrolein reaction of Fig. 8 and crude propylene aldehyde reaction gas processing system also with Fig. 7 be comparable, flasher 627 and the preferred operations pressure in the tower 629 of different the is flasher 727 of Fig. 8 and the preferred operations pressure ratio Fig. 7 in the separation column 729 are much lower.For example, the preferred operations pressure that removes in the circulation at the vinylformic acid of Fig. 7 is about 20 to about 30 pounds/inch ²(gauge pressure), and the preferred operations pressure in the respective cycle of Fig. 8 only is about 15 to about 20 pounds/inch ²(gauge pressure).Than there is lower pressure drop to make the vinylformic acid of Fig. 8 remove circulation by gas lift recirculation reactor 607 lower working pressure is arranged by tray column 705.Lower working pressure even can more effectively remove vinylformic acid, thus the treated propenal feed gas that enters reactor 705 contains vinylformic acid＜100ppm usually, more generally＜60ppm.The overhead materials that obtains from tower 729 contains at least about 75% (mole) propenal in addition, more generally at least about 90% (mole).Tray column reactor 705 is operated in the identical mode of Fig. 5 reactor, and methyl mercaptan and propenal import 723, recycle pump 730, interchanger 707 with 708 and MMP liquid medium return tube 706 with the corresponding assembly of Fig. 5 reaction system identical effect and substantially the same structure are arranged with 722.

Fig. 6 illustrates another selective embodiment of the present invention, wherein designed or operated the partially or completely successive reaction system 501 of back-mixing, to obtain the residence time less than required final transformation efficiency requirement, the reaction medium that leaves reactor 501 reacts completely so that make by plug flow reactor 511.Reactor 501 is the tray column reactor as shown in Figure 6.But the application of piston flow refining reaction device is equally applicable to the round-robin adverse current gas/liquid stream reaction system of Fig. 5 or 8 or is applicable to Fig. 2 or 7 gas lift recirculation reactor.In the method for Fig. 6, bottom gas feed 521 chargings of propenal and the methyl mercaptan tray column reactor 505 by reaction system 501, and liquid MMP reaction medium circulates by system enter at cat head by liquid-inlet 506.By transferring heat in the cooling tower water in indirect heat exchanger 507 and 508, from round-robin MMP logistics, remove reaction heat.Through port 509 takes out the liquid reacting product cut that contains residual propenal and methyl mercaptan by plug flow reactor 511 subsequently from the recycle materials flow of system 501.Temperature about 30 to about 70 ℃, the residence time about 0.1 to about 0.5 hour down the application of the plug flow reactor of operation make the residence time in the round-robin adverse current gas/liquid stream reaction system more much lower than the residence time in Fig. 5 reaction system.For example, the residence time based on the back-mixing formula reaction system of clean outflow product only is under the occasion of 0.2～1 hour (is 0.2～0.75 hour as the liquid hold-up in the tray column reactor), and the through port 509 reaction product liquid cut that flows out these systems therefore contain have an appointment 0.5 to about 1% propenal and about 0.5 to the occasion of about 1% methyl mercaptan, total residence time in plug flow reactor 511 is not more than about 0.5 hour, can obtain containing the final reacting product that is not more than about 0.3% propenal and is not more than about 0.3% methyl mercaptan in plug flow reactor 511 exits.Plug flow reactor 511 is operated under thermal insulation basically.But as temperature being remained in the required scope, chuck 513 can provide heat or cooling.

The MMP reaction product of producing can be directly used in preparation 4-methylthio group butyronitrile in the method for explanation in Fig. 1～8, does not remove high-boiling-point impurity or lower-boiling impurity and do not need to distill in advance.This has not only saved and has been used for distillatory investment and process cost, and avoids owing to generate the inevitable loss of yield that other high boiling point causes in the MMP distillation tower.Can react by MMP product and prussic acid and produce 4-methylthio group butyronitrile (HMBN).And HMBN can be by changing into 4-hydroxy-4-methylthiobutyric acid (HMBA) with sulfuric acid or other mineral acid hydrolysis.MMP or HMBN are refining without distillation or other, and HMBN can change into HMBA, and the latter can be used as the animal-feed supplement as the methionine(Met) source.As mentioned above, the MMP that produces with method of the present invention can change into HMBN, and the most handy US4524077 of HMBN (Ruest etc.) disclosed method or US4912257 (Hernandez) disclosed method change into HMBA.In the patented method of Ruest, HMBN is hydrolysis in sulfuric acid, and with not extracting the HMBA product with the miscible solvent of water from hydrolysate basically, extract stream obtains 85～90% (weight) HMBA aqueous solution through distillation.In the patented method of Her-nandez, hydrolysate neutralizes with ammonia, makes it be divided into two-phase, and the organic phase evaporation is obtained 85～90%HMBA aqueous solution.

Following examples explanation the present invention.

Embodiment 1

React in gas lift recirculation reactor shown in Figure 2 by methyl mercaptan and propenal and to prepare MMP.The height of reactor is 3 feet (0.914m), and the internal diameter of upper reaches arm is 0.5 inch (1.27cm).Gas/liquid separation 109 has the cylinder of MMP product overflow port, is used for the drain that pipe connecting under the liquid level of dirty arm that MMP loops back reactor loop and top are used to discharge non-condensable gas.Before the introducing reactant, fill reactor loop with the MMP that contains 0.4% (weight) acetate pyridinium salt catalyzer of having an appointment.Blasting air by 1/16 inch orifice plate at propenal feed gas import 123 places makes the MMP in the reactor begin circulation.Blast at air and to make the MMP round-robin simultaneously, make hot water pass through chuck 107, the temperature of circulation MMP is controlled to 41 °F.

Make by the listed synthetic crude propylene aldehyde logistics of forming of table 1.With this logistics by sending into reactor at the bubbler at import 123 places.Methyl mercaptan is sent into by identical orifice plate.Propenal and methyl mercaptan about in molar ratio 1.0 are sent into by bubbler to 1.02.The absolute speed that reactant stream is introduced is listed table 1 in.Superficial gas velocity in the arm of upper reaches, liquid reactor volume, the liquid reactions residence time, the rate of recovery, reactor productive rate, continuous operation time, the average make-up catalyst feeding rate of reaction-ure feeding and the mean rate that water is introduced in the propenal feed gas in reactor also listed table 1 in.

In the bubbler at import 123 places is dispersed in two kinds of reaction-ure feedings liquid in the arm of upper reaches, and in this arm, produces and add gas column.Therefore, the liquid in the dirty arm of not aerating is forced downwardly the bottom that flows into the upper reaches arm by bottom U type bend pipe, and continues to move upward by the dispersion gas in the arm of upper reaches.

In the arm of two-phase upper reaches, the separator from the gas bubbler of bottom to the top forms reaction-ure mixture, and it is made up of liquid phase that contains MMP, methyl mercaptan and catalyzer and the gas phase that contains propenal.Propenal and methyl mercaptan absorb rapidly in the liquid phase, and two kinds of absorbed reactants react to each other, and generate the MMP product.Though speed of reaction is very fast, but still the rate limiting step of formation present method.Some limited gas-phase reaction between propenal and the methyl mercaptan also appears.The temperature of the gas/liquid contact segment in the arm of reactor upper reaches is rejected to exothermic heat of reaction in the recirculated cooling water by chuck 107, makes it to be maintained at about 41 °F.

Because under situation without mechanical stirring or recycle pump, obtain highly turbulent flow and fine dispersive two phase flow by simple gas lift circulating system, therefore simple loop reactor reaches total reactant charging (being propenal and the methyl mercaptan) rate of recovery greater than 95%, and in fact the reactant of all recovery all changes into required MMP product in the same reactor loop.Product and the composition that does not discharge the gas logistics are with fixed attention also listed table 1 in.

Although in the propenal feed gas stream, contain the impurity higher (propylene, propane, acetaldehyde, propionic aldehyde and water), because the existence of these impurity, seldom or do not have by product to generate or product degradation than general charging.Particularly, this experiment and some other this reaction system that experiment showed, can be held and have in the fair propenal feed gas stream greater than the water foreign matter content of 3% (volume) and the water-content that generates in the circulating liquid in the steady state operation process greater than 6% (weight).

Because the rapid round-robin result of violent mixing that turbulent flow produces in the gas/liquid contact segment and the reaction medium of MMP has prevented partial focus or concentration imbalance.This has also suppressed the generation of undesirable by product conversely.

Table 1

Experimental result and material balance average reactor temperature=41.00 ℃ raw materials components mole ratio, the rate of recovery=95.85% of the propenal/methyl mercaptan=0.99 liquid reactor volume=650.00ml product liquid residence time=4.97 hour reaction-ure feeding

The reactor productive rate:

Aldehyde weight/(propenal+methyl mercaptan) charging is heavy=and 94.88%

Aldehyde mole/propenal charging mole=94.35%

Aldehyde mole/methyl mercaptan charging mole=average the feeding rate of 94.35% catalyzer=0.0102 Grams Per Minute

Logistics 1 logistics 2 logistics 3 logistics 4

The outlet of inlet gas mixture methyl mercaptan inlet product exit gas

Grams Per Minute % (weight) Grams Per Minute % (weight) Grams Per Minute % (weight) Grams Per Minute % (weight) O ₂0.675 14.934 0.0 0.0 0.0 0.0 0.675 20.571N ₂2.222 49.158 0.0 0.0 0.0 0.0 2.222 67.713CO ₂0.074 1.630 0.0 0.0 0.0 0.0 0.074 2.245CO, 0.016 0.360 0.0 0.0 0.0 0.0 0.016 0.495 propylene, 0.062 1.372 0.0 0.0 0.0 0.0 0.062 1.889 propane, 0.063 1.394 0.0 0.0 0.0 0.0 0.063 1.920 methyl mercaptan, 0.0 0.0 1.018 100.0 0.010 0.438 0.025 0.608 acetaldehyde, 0.024 0.539 0.0 0.0 0.004 0.195 0.020 0.608 propionic aldehyde, 0.081 1.792 0.0 0.0 0.022 0.992 0.059 1.783 methacrylaldehyde, 1.174 25.979 0.0 0.0 0.012 0.507 0.017 0.531M-ALDEH, 0.0 0.0 0.0 0.0 2.080 91.733 0.049 1.480 catalyst, 0.0 0.0 0.0 0.0 0.011 0.465 0.0 0.0 water 0.129 2.844 0.0 0.0 0.129 5.669 0.0 0.0 add up to 4.520 100.00 1.018 100.00 2.267 100.00 3.281 100.00 temperature ℃ 51.0 26.0 40.0 40.0 pressure (pound/inch²(gauge pressure)) 8.4 4.8 0.0 0.0

Embodiment 2～23

Use the device of Fig. 2, propenal and methyl mercaptan reaction generate MMP.This method is carried out with the same way as of general description among the embodiment 1, but has done change aspect the propenal concentration in mol ratio, gas feed cumulative volume speed and the gas incoming mixture of propenal and methyl mercaptan in service temperature, reactor feed.Processing condition and productive rate for embodiment 2-23 are listed table 2 in.

Charging to superficial gas velocity, import propenal concentration, temperature of reaction, catalyst concn, the residence time and propenal and methyl mercaptan has likened measurement or mensuration to.Carried out statistical study to determine the influence of operational variable to methyl mercaptan concentration in propenal concentration and the liquid phase in productivity, the propenal rate of recovery, propenal productive rate, the liquid phase.The result lists table 3 in.

Table 2

Embodiment 2 embodiment 3 embodiment 4

40.00 ℃ 40.50 ℃ 39.00 ℃ of average operation temperature

Molar feed ratio, propylene 0.95 0.98 1.23

Aldehyde/methyl mercaptan

Go the gas of bubbler to mix 3.020 liters/minute 2.826 liters/minute 2.763 liters/minute

Logistics., standard state

Propylene 15.170% (body) 9.890% (body) 7.234% (body) in the inlet gas mixture

Aldehyde concentration

Propylene 1.360% (body) 1.183% (body) 1.944% (body) in the exit gas

Aldehyde concentration

At the bottom of the arm of upper reaches apparent 1.347 feet/1.261 feet/1.233 feet/

Gas velocity., standard state second second second

Liquid reactor volume 886.00ml 756.00ml 684.00ml

The 7.40 hours 11.54 hours 17.87 hours product liquid residence time

The reaction-ure feeding rate of recovery 89.68% 84.29% 75.85%

The reactor productive rate:

Aldehyde is heavy/(propenal+first 87.90% 83.22% 74.75%

Base mercaptan) charging is heavy

Aldehyde mole/propenal advances 89.97% 84.13% 68.40%

The material mole

Aldehyde mole/methyl sulphur 85.59% 82.17% 83.81%

Alcohol charging mole

Continuous operation time 5.10 hours 2.75 hours 2.75 hours

Average catalyst feeding rate 0.0105 Grams Per Minute 0.0061 Grams Per Minute 0.0061 Grams Per Minute

Average water feeding rate 0.0 Grams Per Minute 0.0 Grams Per Minute 0.0 Grams Per Minute

Embodiment 5 embodiment 6 embodiment 7

41.00 ℃ 40.00 ℃ 40.00 ℃ of average operation temperature

Molar feed ratio, propylene 1.07 1.26 1.17

Aldehyde/methyl mercaptan

Go the gas of bubbler to mix 3.128 liters/minute 3.232 liters/minute 3.249 liters/minute

Compound stream., standard state

Propylene 16.563% (body) 20.648% (body) 9.240% (body) in the inlet gas mixture

Aldehyde concentration

Propylene 2.560% (body) 4.467% (body) 2.417% (body) in the exit gas

Aldehyde concentration

At the bottom of the arm of upper reaches apparent 1.395 feet/1.441 feet/1.449 feet/

Gas velocity., standard state second second second

Liquid reactor volume 741.00ml 738.00ml 760.00ml

The 6.08 hours 5.04 hours 12.85 hours product liquid residence time

The reaction-ure feeding rate of recovery 87.44% 88.12% 76.32%

The reactor productive rate:

Aldehyde is heavy/(propenal+first 85.47% 85.53% 75.32%

Base mercaptan) charging is heavy

Aldehyde mole/propenal advances 84.01% 77.31% 70.16%

The material mole

Aldehyde mole/methyl sulphur 89.51% 97.60% 82.36%

Alcohol charging mole

Continuous operation time 2.00 hours 1.58 hours 3.66 hours

Average catalyst feeding rate 0.0083 Grams Per Minute 0.0105 Grams Per Minute 0.0068 Grams Per Minute

Average water feeding rate 0.0 Grams Per Minute 0.0 Grams Per Minute 0.0 Grams Per Minute

Embodiment 8 embodiment 9 embodiment 10

45.00 ℃ 44.00 ℃ 44.00 ℃ of average operation temperature

Molar feed ratio, propylene 1.06 1.05 0.99

Aldehyde/methyl mercaptan

Go the gas of bubbler to mix 3.708 liters/minute 2.538 liters/minute 3.755 liters/minute

Logistics., standard state

Propylene 21.000% (body) 29.591% (body) 21.253% (body) in the inlet gas mixture

Aldehyde concentration

Propylene 3.005% (body) 3.770% (body) 1.588% (body) in the exit gas

Aldehyde concentration

At the bottom of the arm of upper reaches apparent 1.654 feet/1.177 feet/1.675 feet/

Gas velocity., standard state second second second

Liquid reactor volume 734.00ml 682.00ml 520.00ml

The 3.95 hours 3.50 hours 2.55 hours product liquid residence time

The reaction-ure feeding rate of recovery 88.95% 92.46% 91.84%

The reactor productive rate:

Aldehyde is heavy/(propenal+first 57.55% 90.94% 90.10%

Base mercaptan) charging is heavy

Aldehyde mole/propenal advances 85.33% 88.82% 90.40%

The material mole

Aldehyde mole/methyl mercaptan 90.26% 93.52% 89.73%

The charging mole

Continuous operation time 3.20 hours 1.98 hours 2.40 hours

Average catalyst feeding rate 0.0182 Grams Per Minute 0.0252 Grams Per Minute 0.0139 Grams Per Minute

Average water feeding rate 0.0 Grams Per Minute 0.0 Grams Per Minute 0.0 Grams Per Minute

Embodiment 11 embodiment 12 embodiment 13

50.00 ℃ 42.00 ℃ 43.00 ℃ of average operation temperature

Molar feed ratio, propylene 1.00 1.04 0.96

Aldehyde/methyl mercaptan

Go the gas of bubbler to mix 3.760 liters/minute 3.476 liters/minute 3.619 liters/minute

Logistics., standard state

Propylene 19.405% (body) 14.409% (body) 18.471% (body) in the inlet gas mixture

Aldehyde concentration

Propylene 2.100% (body) 2.138% (body) 1.285% (body) in the exit gas

Aldehyde concentration

At the bottom of the arm of upper reaches apparent 1.677 feet/1.550 feet/1.703 feet/

Gas velocity., standard state second second second

Liquid reactor volume 527.00ml 529.00ml 649.00ml

The 2.89 hours 4.31 hours 3.51 hours product liquid residence time

The reaction-ure feeding rate of recovery 89.52% 87.37% 92.64%

The reactor productive rate:

Aldehyde is heavy/(propenal+methyl 88.01% 85.57% 90.52%

Mercaptan) charging is heavy

Aldehyde mole/propenal advances 88.18% 83.97% 92.07%

The material mole

Aldehyde mole/methyl mercaptan 87.80% 87.48% 88.76%

The charging mole

Continuous operation time 2.65 hours 2.48 hours 2.13 hours

Average catalyst feeding rate 0.0346 Grams Per Minute 0.0097 Grams Per Minute 0.0195 Grams Per Minute

Average water feeding rate 0.0 Grams Per Minute 0.0571 Grams Per Minute 0.0 Grams Per Minute

Embodiment 14 embodiment 15 embodiment 16

55.00 ℃ 41.00 ℃ 45.00 ℃ of average operation temperature

Molar feed ratio, propylene 1.01 0.97 1.01

Aldehyde/methyl mercaptan

Go the gas of bubbler to mix 3.946 liters/minute 2.924 liters/minute 3.124 liters/minute

Logistics., standard state

Propylene 18.137% (body) 16.049% (body) 18.547% (body) in the inlet gas mixture

Aldehyde concentration

Propylene 2.322% (body) 0.503% (body) 2.429% body in the exit gas)

Aldehyde concentration

At the bottom of the arm of upper reaches apparent 1.760 feet/1.304 feet/1.393 feet/

Gas velocity., standard state second second second

Liquid reactor volume 525.00ml 650.00ml 600.00ml

The 3.07 hours 4.97 hours 4.13 hours product liquid residence time

The reaction-ure feeding rate of recovery 85.35% 94.22% 86.24%

The reactor productive rate:

Aldehyde is heavy/(propenal+methyl 83.94% 92.34% 84.06%

Mercaptan) charging is heavy

Aldehyde mole/propenal advances 83.58% 93.79% 83.84%

The material mole

Aldehyde mole/methyl mercaptan 84.36% 90.68% 84.31%

The charging mole

Continuous operation time 2.27 hours 4.88 hours 4.42 hours

Average catalyst feeding rate 0.0162 Grams Per Minute 0.0102 Grams Per Minute 0.0113 Grams Per Minute

Average water feeding rate 0.0 Grams Per Minute 0.0922 Grams Per Minute 0.1018 Grams Per Minute

Embodiment 17 embodiment 18 embodiment 19

42.00 ℃ 40.00 ℃ 39.00 ℃ of average operation temperature

Molar feed ratio, propylene 0.95 1.06 1.13

Aldehyde/methyl mercaptan

Go the gas of bubbler to mix 3.238 liters/minute 2.481 liters/minute 2.073 liters/minute

Logistics., standard state

Propylene 15.622% (body) 25.019% (body) 29.440% (body) in the inlet gas mixture

Aldehyde concentration

Propylene 0.961% (body) 3.160% (body) 2.772% (body) in the exit gas

Aldehyde concentration

At the bottom of the arm of upper reaches apparent 1.444 feet/1.106 feet/0.925 foot/

Gas velocity., standard state second second second

Liquid reactor volume 880.00ml 800.00ml 800.00ml

The 6.60 hours 5.48 hours 5.14 hours product liquid residence time

The reaction-ure feeding rate of recovery 92.06% 86.71% 96.40%

The reactor productive rate:

Aldehyde is heavy/(propenal+methyl 89.09% 82.06% 93.72%

Mercaptan) charging is heavy

Aldehyde mole/propenal advances 91.38% 79.94% 88.76%

The material mole

Aldehyde mole/methyl mercaptan 86.53% 84.65% 100.23%

The charging mole

Continuous operation time 5.33 hours 5.40 hours 4.00 hours

Average catalyst feeding rate 0.0134 Grams Per Minute 0.0157 Grams Per Minute 0.0167 Grams Per Minute

Average water feeding rate 0.0 Grams Per Minute 0.0 Grams Per Minute 0.0 Grams Per Minute

Embodiment 20 embodiment 21 embodiment 22

37.00 ℃ 43.00 ℃ 46.00 ℃ of average operation temperature

Molar feed ratio, propylene 0.94 0.70 1.25

Aldehyde/methyl mercaptan

Go the gas of bubbler to mix 2.259 liters/minute 2.440 liters/minute 2.531 liters/minute

Logistics., standard state

Propylene 26.870% (body) 27.026% (body) 33.558% (body) in the inlet gas mixture

Aldehyde concentration

Propylene in the exit gas-2.753%

1.850% (body) 12.143% (body)

Aldehyde concentration (body)

At the bottom of the arm of upper reaches apparent 1.008 feet/1.088 feet/1.129 feet/

Gas velocity., standard state second second second

Liquid reactor volume 850.00ml 765.00ml 792.00ml

The 5.25 hours 3.83 hours 4.95 hours product liquid residence time

The reaction-ure feeding rate of recovery 92.91% 92.23% 74.65%

The reactor productive rate:

Aldehyde is heavy/(propenal+methyl 90.42% 88.57% 71.13%

Mercaptan) charging is heavy

Aldehyde mole/propenal advances 93.31% 105.97% 64.65%

The material mole

Aldehyde mole/methyl mercaptan 87.25% 74.33% 80.53%

The charging mole

Continuous operation time 3.00 hours 2.40 hours 1.40 hours

Average catalyst feeding rate 0.0139 Grams Per Minute 0.0069 Grams Per Minute 0.0 Grams Per Minute

Average water feeding rate 0.0 Grams Per Minute 0.0 Grams Per Minute 0.0 Grams Per Minute

Embodiment 23

39.00 ℃ of average operation temperature

Molar feed ratio, propylene 0.63

Aldehyde/methyl mercaptan

Go the gas of bubbler to mix 2.276 liters/minute

Logistics., standard state

Propylene 19.476 (body) % in the inlet gas mixture

Aldehyde concentration

Propylene in the exit gas-1.573%

Aldehyde concentration (body)

At the bottom of the arm of upper reaches apparent 1.015 feet/

Gas velocity., standard state second

Liquid reactor volume 792.00ml

5.65 hours product liquid residence time

The reaction-ure feeding rate of recovery 91.16%

The reactor productive rate:

Aldehyde weight/(propenal+methyl 82.88%

Mercaptan) charging is heavy

Aldehyde mole/propenal advances 105.03%

The material mole

Aldehyde mole/methyl mercaptan 66.51%

The charging mole

Continuous operation time 5.00 hours

Average catalyst feeding rate 0.0 Grams Per Minute

Average water feeding rate 0.0 Grams Per Minute

Table 3

Operational variable is to the influence of experimental result

The variable result

Test VG YA T CC TR A/M PR REC YIELD CA CM

Feet per second % (mole) ℃ % (weight) (hour) (%) % (weight) % (weight) of (ratio) Grams Per Minute (%)

041684 1.30 16.1 41 .47 5.0 0.97 2.27 94.2 92.3 0.51

(TYPICAL) 1.34

010984A 1.02 19.5 39 0.4 5.7 0.63 2.34 91.2 82.9 .051 8.85

011984B 1.13 33.6 46 0.4 5.0 1.25 2.77 74.7 71.1 4.35 0.20

042584 1.76 18.1 55 0.4 3.1 1.01 2.94 85.4 83.9 1.30 0.28

050284 1.68 19.4 50 0.7 2.9 1.00 3.13 89.5 88.0 0.05 1.60

061384B 1.44 20.7 40 .39 5.0 1.26 2.54 88.1 85.5 2.43 0.43

061384A 1.40 16.6 41 .32 6.1 1.07 2.11 87.4 86.5 .158 .913

052384 1.45 9.24 40 .43 12.8 1.17 1.03 76.3 75.3 .775 .487

061484B 1.23 7.23 39 .39 17.9 1.23 0.66 75.9 74.8 1.12 .291

VG=superficial gas velocity, feet per second

YA=import propenal concentration, % (mole)

T=temperature of reactor, ℃

CC=catalyzer (acetate pyridine) concentration, % (weight)

TR=based on residence time of product speed, hour

A/M=propenal is to the charge ratio of methyl mercaptan, mol ratio

The speed of the product of PR=obtain, Grams Per Minute

REC=propenal is to the percentage recovery of charging, %

YIELD=propenal charging changes the percentage of aldehyde product, % into

Propenal concentration in CA=liquid, % (weight)

The concentration of methyl mercaptan in CM=liquid, % (weight)

Embodiment 24

Use method shown in Figure 2, carry out 50 hours continuous operation with the propenal feed gas of propylene catalyzed oxidation production in the laboratory reaction device.In operation process, the temperature in gas lift loop is controlled at about 40 ℃, constantly monitor the charge ratio of propenal and methyl mercaptan per half an hour with isolating gas chromatograph analysis reactor liquid sample.Final aldehyde product is made up of following:

Acetaldehyde 0.11% (weight)

Methyl mercaptan 0.88

Propenal 0.07

Vinyl carbinol 0.29

Acetate 0.35

Vinylformic acid 0.52

Beta-hydroxy propionic aldehyde 0.27

Pyridine 0.19

MMP 89.02

Molecular weight is 190 by product 0.18

Water 7.00

In industrial operation, wherein water management is to more generally content is as 2%, and the content of MMP is greater than 94%.Quite high beta-hydroxy propionic aldehyde content is owing to surpass the result that the water of the water-content that cooling propenal feed gas can be easy to reach in commercial run exists.

Embodiment 25

Use method shown in Figure 2 in wet wall reactor and horizontal circuit reactor, to compare test.The synthesis of acrolein feeding gas is used for these tests.In the steady state operation process, with gc analysis product liquid sample, to determine aldehyde, residual propenal, methyl mercaptan and by-product impurities.On the basis of these analyses, calculate to determine propenal percentage recovery, product yield and the reactor content balance of each test.Experimental data is used for the two-phase reactor model, obtains average mass transfer coefficient and reaction kinetics rate constant.Also measurements and calculations gas hold up and liquid circulation rate data.

The physical size of reactor system is listed table 4 in temperature, gas velocity and the liquid rate of each test.Reaction conditions, feeding rate, productive rate and average mass transfer coefficient relatively list table 5 in.

Table 4

Reactor size and operational variable

Reactor tube apart actuator temperature gas velocity liquid rate

The circulating .5 of gas lift " internal diameter * 3.5 '

(the 35-55 ℃ of 2.2-4.0 liter in 2.5 " external diameter * the 8 "/minute 4.0-12 liter of or5 ' w/spool)/minute

Wet wall type .5 " internal diameter * 4.5 ' 4 " external diameter * 6 " 30-48 ℃ of 3.0-6.5 liter/minute .6-.8 liter/minute

Horizontal circuit .5 " internal diameter * 7.5 ' 3 " external diameter * 11 "

37-40 ℃ of 2.5-3.4 liter in 4 " external diameter * 13 "/minute 9.5-13.3 liter/minute

Table 5

The typical consequence of test reactor

The gas lift wall horizontal circuit that wets

Test number 041,684 110,184 011685

Inlet gas concentration, % (body) propenal 16.0 16.8 17.3

The concentration of working off one's feeling vent one's spleen, % (body) propenal 0.503 1.92 3.82

Temperature of reactor, ℃ 41.0 36.0 40.0

Superficial gas velocity, feet per second 1.304 1.46 1.39

Superficial liquid velocity, feet per second 3.5 0.3 5.7

Strength of fluid

% (weight) propenal 0.51 0.71 0.05

% (weight) methyl mercaptan 1.30 0.20 1.35

The gaseous mixture feeding rate, Grams Per Minute 4.43 4.84 4.56

The propenal feeding rate, Grams Per Minute 1.174 1.372 1.352

Methyl mercaptan steam feed speed, Grams Per Minute 1.042 1.160 1.095

Aldehyde product speed, Grams Per Minute 2.267 2.306 2.118

Feed recovery rate (propenal+methyl sulphur 94.2 88.2 82.1

Alcohol), % (weight)

Reactor productive rate (aldehyde/propenal+methyl sulphur 92.34 87.33 80.97

Alcohol), % (weight)

Average mass transfer coefficient, mol normal atmosphere 150 120 50

Hour

Embodiment 26

According to method shown in Figure 5, the reaction medium that will contain MMP, methyl mercaptan and catalyzer contacts in the tray column that 20 blocks of column plates are arranged with the acrolein vapor logistics.Be not recycled to the bottom of tower from water cooler 407 effusive MMP reaction mediums.And all circulation MMP are by water cooler 408 and be recycled to cat head.The 5th section liquid phase indirect heat transfer carries out each section cooling from the liquid phase of end section with from the bottom.The acrolein vapor logistics with 662.4 pound-mols/hour speed send into tower at the bottom of, it contains 15% (volume) propenal, 0.28% (volume) acetaldehyde, 17% (volume) water vapor and 83% (volume) non-condensable gas.Methyl mercaptan with 100 pound-mols/hour speed send into tower at the bottom of.

The MMP reaction medium with about 600 pound-mols/hour speed send into cat head.The MMP product logistics that contains 97.3% (weight) MMP with about 110.4 pound-mols/hour speed from tower, take out.

Embodiment 27

The 428.1 gram MMP that embodiment 24 is produced are incorporated with in the 1000ml reactor of cooling jacket and agitator.HCN (105.4g) measured in 50 minutes send into identical reactor, in this process, temperature is remained between 35～40 ℃.When the HCN charging finished, temperature was raised to 45 ℃, made reaction continue to carry out 30 minutes again, made MMP change into 2-hydroxy-4-methylthiobutyric acid (HMBN) fully (527.7g).Analyze and find to contain 90.8%HMBN, all the other major parts are water, catalyzer and some low concentration impurities.

Embodiment 28

To by the 515gHMBN of embodiment 27 preparation in 50 minutes, under 60 ℃, be added in 65.9% (weight) aqueous sulfuric acid (584.2g) of the 1000ml jacketed reactor that is contained in agitator.The mixture that generates reacted under 65 ℃ 10 minutes again, and it is complete to make HMBN change into first hydrolysis reaction of corresponding amides.Under 80 ℃, hot water (378.5g) is added to then in the mixture in the reactor, then the temperature of mixture is raised to 82 ℃ and carries out second hydrolysis reaction that acid amides changes into HMBA and by-product monoammonium sulfate.Reaction continued 2.5 hours, and second hydrolysis reaction is finished.On the other hand, can make the required reaction times shorten nearly 50% by hydrolysis temperature being raised to 90～100 ℃.Analyze final hydrolysate and find that it contains the 32.1%HMBA monomer, 0.11%HMBA dipolymer and less than 0.02% acid amides with less than 0.02% nitrile, remaining is monoammonium sulfate by product and water.The said hydrolyzed product is contacted with methyl iso-butyl ketone (MIBK) (MIBK) solvent, with extraction HMBA product.Extraction liquid is evaporated under 70 ℃, vacuum, from HMBA, separate solvent.Analyze the not solvent-laden product in bottom and find that it contains 74.8%HMBA monomer and 7.0%HMBA dipolymer, all the other mainly are water and sulfate ion.This product contains the water-content of a little higher than normal value.By further evaporation water-content is dropped in the normal 11-12% scope.

Embodiment 29

According to method shown in Figure 7, in catalyticreactor 601, the propylene catalyzed oxidation generated crude propylene aldehyde reaction product gas.Propylene, water vapor and AIR MIXTURES are sent into reactor by interchanger 611, make the mixture preheating at interchanger 611 by conducting heat from reaction product gas.In interchanger 603, make reaction product gas cooling and partial condensation, be created on 37.8 ℃ mixing liquid/gas logistics.Then flasher 627 is sent in this logistics, it further cools off and is separated into and contains propenal (18.9% (weight)) there, nitrogen (71.1% (weight)), oxygen (2.8% (weight)), propane (2.1% (weight)), propylene (1.8% (weight)), water vapor (0.9% (weight)), vinylformic acid (80ppm), acetaldehyde (0.2% (weight)), carbon monoxide (0.6% (weight)), carbonic acid gas (1.7% (weight)) and formalin (140ppm) refrigerative gas stream, and moisture (75.4% (weight)), the condensate stream of propenal (20.0% (weight)) and vinylformic acid (3.1% (weight)).Cooling gas logistics and condensation product all are in 26 pounds/inch of 23.2 ℃ and absolute pressures ²Condensation product is sent into separation column 629, and it is 23 pounds/inch of tower top pressures there ²Following distillation.By partial condensation, and is 1 time condensation product to be back in the tower with the mole reflux ratio from the effusive steam of cat head.Generate aqueous waste at the bottom of tower, it contains vinylformic acid (3.9% (weight)) and propenal (711ppm).Overhead product contains propenal (94.2% (weight)), acetaldehyde (1.1% (weight)), water vapor (4.6% (weight)) and less than the vinylformic acid of 1ppm.To mix with the effusive cooling gas logistics of flasher from the overhead materials that separation column obtains, obtain 23 pounds/inch of 26.5 ℃, stagnation pressure ²Under the merging propenal gas stream that contains propenal (24.6% (weight)), acetaldehyde (0.3% (weight)), water vapor (1.2% (weight)), propane (1.9% (weight)), propylene (1.6% (weight)) and vinylformic acid (76ppm).This gas is fed in by import 623 in the circulation MMP reaction medium in the low loop 621 of gas lift recirculation reactor 605 with methyl mercaptan.Be absorbed by propenal in the flowing of upper reaches arm and reacting, obtaining at 40 ℃, 16 pounds/inch ²From the product of upper reaches arm discharge, it contains MMP (75.9% (weight)), methyl mercaptan (0.2% (weight)), propenal (0.3% (weight)), water (1.5% (weight)), propane (0.5% (weight)), propylene (0.5% (weight)), nitrogen (19.1% (weight)), oxygen (0.8% (weight)), acetaldehyde (0.1% (weight)), formalin (157ppm), vinylformic acid (126ppm), pyridine (0.2% (weight)) and acetate (0.2% (weight)) down.In gas/liquid separation 609, from liquid MMP reaction medium, tell non-condensable gas, the MMP reaction medium is delivered to the upper reaches arm of reactor by dirty arm and loop, bottom, and mix with other propenal gas and methyl mercaptan.At 40 ℃, 15 pounds/inch ²Under remove the MMP product, it contains MMP (97.4% (weight)), acetate (0.2% (weight)), pyridine (0.2% (weight)), methyl mercaptan (80ppm), formalin (180ppm), acetaldehyde (520ppm), vinylformic acid (160ppm), water (1.8% (weight)) and propenal (0.2% (weight)).

Embodiment 30

According to method shown in Figure 8, in catalyticreactor 701, propylene is produced crude propylene aldehyde reaction product gas through catalyzed oxidation.Propylene, water vapor and AIR MIXTURES are sent into reactor by interchanger 711, in interchanger, make the mixture preheating by from reaction product gas, conducting heat.Reaction product gas cools off in interchanger 703 and partial condensation, generates 37.8 ℃ mixing liquid steam stream.Then flasher 727 is sent in this logistics, it is further cooled and is divided into and contains propenal (19.1% (weight)) there, nitrogen (71.0% (weight)), oxygen (2.8% (weight)), propylene (1.8% (weight)), propane (2.1% (weight)), water vapor (0.9% (weight)), vinylformic acid (40ppm), acetaldehyde (0.2% (weight)), carbon monoxide (0.6% (weight)), the cooling gas logistics of carbonic acid gas (1.7% (weight)) and formalin (140ppm) and moisture (75.8% (weight)), propenal (19.5% (weight)), the condensate stream of acetaldehyde (0.5% (weight)) and vinylformic acid (3.1% (weight)).Cooling gas logistics and condensation product all are in 17 pounds/inch of 15.2 ℃, absolute pressure ²Down.Condensation product is sent into separation column 729, and it is 15 pounds/inch of tower top pressures there ²Following distillation.The steam that leaves cat head is by partial condensation, and is 1 condensation product to be back in the tower with the mole reflux ratio.Produce aqueous waste product at the bottom of tower, it contains vinylformic acid (3.9% (weight)) and propenal (0.6% (weight)).Overhead product contains propenal (94.0% (weight)), acetaldehyde (0.2% (weight)), water vapor (3.6% (weight)) and less than the vinylformic acid of 1ppm.The overhead product that separation column is obtained mixes with the effusive cooling gas logistics of flasher, generates to be in 16 pounds/inch of 18.2 ℃, stagnation pressure ²The merging propenal gas stream that contains propenal (24.5% (weight)), acetaldehyde (0.3% (weight)), water vapor (1.0% (weight)), propane (1.9% (weight)), propylene (1.6% (weight)) and vinylformic acid (76ppm).This gas is sent among the circulation MMP by the import 723 of tray column reactor 705 bottoms with methyl mercaptan.Gas upwards flows by tower and the MMP reaction medium adverse current that flows downward.The reaction medium that contains MMP (96.7% (weight)), propenal (962ppm) and methyl mercaptan (0.14% (weight)) enters cat head under 0 ℃.Reaction product at 62 ℃ of following outflow towers contains methyl mercaptan (0.14% (weight)), propenal (960ppm) and MMP (96.8% (weight)).Reaction product is given water coolant by indirect heat transfer there through interchanger 707 circulations, and it is cooled to 32.2 ℃.The recycle stream that is less than 2/3 slightly is recycled to the column plate of middle part approximately of reactor 705 from the outlet of interchanger 707.Rest part circulating reaction medium and catalyst mix are also passed through interchanger 708, to chilled brine reaction medium is cooled to 0 ℃ by indirect heat transfer there.To be recycled to the top of tray column reactor 705 from interchanger 708 effusive part circulatory mediators by pipeline 706.Between tray column reactor 705 bottoms and interchanger 707 imports, from circulation MMP reaction medium, take out product stream.On the other hand, product can reclaim from water cooler 707 or water cooler 708 outlets.Product stream contains MMP (96.8% (weight)), methyl mercaptan (0.14% (weight)) and propenal (960ppm).The ratio that MMP reaction medium cycle rate and net products are extracted out between the speed is about 15: 1.

Claims (13)

1. method for preparing continuously 3-(methylthio group) propionic aldehyde, it comprises:

Liquid reaction medium contacts in the gas/liquid contact segment with the gaseous acrolein feed stream, described reaction medium contains 3-(methylthio group) propionic aldehyde, methyl mercaptan and be used for methyl mercaptan and propenal between catalyst for reaction, described gaseous acrolein feed stream contains acrolein vapor and non-condensable gas, entering the propenal of described contact segment and the relative proportion of methyl mercaptan is stoichiometry equivalent basically, thereby propenal is transferred in the described reaction medium from described feed stream, and direct and methyl mercaptan reaction in reaction medium under the condition of the half methylthio group acetal that does not generate intermediate 3-methylthiopropionaldehyde basically, generate the liquid reacting product that contains 3-(methylthio group) propionic aldehyde;

From described liquid reacting product, separate described non-condensable gas;

Described reaction product is divided into product cut and recycle fraction; And

Described recycle fraction is recycled to described gas/liquid contact segment; In the conversion zone that comprises described gas/liquid contact segment and circulation section, in described liquid medium, propenal and methyl mercaptan reaction, described liquid reacting product enters circulation section from described gas/liquid contact segment, and described recycle fraction loops back described gas/liquid contact segment by circulation section, methyl mercaptan is sent into described conversion zone in such position, so that does not have excessive methyl mercaptan that a large amount of described intermediate half (methylthio group) acetals that generate of sufficiently long time are arranged in any zone of described conversion zone.

2. method for preparing continuously 3-(methylthio group) propionic aldehyde, it comprises:

Liquid reaction medium contacts in the gas/liquid contact segment with the gaseous acrolein feed stream, described reaction medium contain 3-(methylthio group) propionic aldehyde, methyl mercaptan and be used for methyl mercaptan and propenal between catalyst for reaction, described gaseous acrolein feed stream contains acrolein vapor and non-condensable gas, so propenal is transferred in the described reaction medium from described feed stream;

Propenal and methyl mercaptan react in described liquid reaction medium in comprising first conversion zone of described gas/liquid contact segment, generate the intermediate liquid reacting product;

From described intermediate liquid reacting product, separate described noncondensable gas;

Described intermediate liquid reacting product is divided into intermediate product cut and recycle fraction; And

Described recycle fraction is recycled to described gas/liquid contact segment, first conversion zone and the circulation section that comprise described gas/liquid contact segment, described liquid reacting product enters circulation section from described gas/liquid contact segment, and described recycle fraction loops back described gas/liquid contact segment by circulation section; And

Make described intermediate product cut by plug flow reactor, make residual propenal and methyl mercaptan change into 3-(methylthio group) propionic aldehyde.

3. according to the method for claim 17, wherein by the ratio of reaction volume speed with clean throughput rate, the residence time in described first conversion zone is about 0.2 to about 1 hour.

4. according to the method for claim 18, wherein said feed stream and described liquid reaction medium adverse current are by described gas/liquid contact segment, and liquid holdup is enough to make the residence time of liquid in described gas/liquid contact segment to count about 0.5 to about 0.75 hour by the liquid hold-up volume and the ratio of clean throughput rate in described gas/liquid contact segment.

5. method for preparing continuously 3-(methylthio group) propionic aldehyde, this method comprises:

The crude reaction product gas stream that cooling is made by hydrocarbon catalyticing oxidation, thereby the condensation product that obtains containing the cooling gas logistics of propenal and contain water, vinylformic acid and residual quantity propenal;

From described cooling gas logistics, separate described condensation product;

The described condensation product of fractionation, the tower bottom distillate that obtains containing the overhead fraction of propenal and be substantially free of propenal;

Described overhead fraction is mixed the propenal gas stream that obtains merging with described cooling gas logistics;

Liquid reaction medium contacts in the gas/liquid contact segment with the gaseous acrolein feed stream, described reaction medium contain 3-(methylthio group) propionic aldehyde, methyl mercaptan and be used for methyl mercaptan and propenal between catalyst for reaction, described gaseous acrolein feed stream contains described merging propenal gas stream and contains acrolein vapor, non-condensable gas and water vapor, therefore propenal is transferred to the described reaction medium from described feed stream, and react in reaction medium with methyl mercaptan, generate the liquid reacting product that contains 3-(methylthio group) propionic aldehyde;

From described liquid reacting product, isolate non-condensable gas;

Described reaction product is divided into product cut and recycle fraction; And

Described recycle fraction is recycled to described gas/liquid contact segment.

6. according to the method for claim 27, wherein said tower bottom distillate contains less than about 1% (weight) propenal.

7. according to the method for claim 28, wherein said tower bottom distillate contains less than about 0.1% (weight) propenal.

8. according to the method for claim 27, wherein said feed gas contains less than about 0.1% (volume) vinylformic acid.

9. according to the method for claim 27, wherein said cut carries out in having at least about the distillation tower of 2 theoretical stages, is not more than about 30 pounds/inch at pressure head ²Operate at least about 0.5 time with reflux ratio.

10. according to the method for claim 32, wherein pressure head is not more than about 20 pounds/inch ², the level of acrolein of described tower bottom distillate is less than about 0.1% (weight).

11. according to the method for claim 27, wherein said crude propylene aldehyde reaction product gas cools off to cooling fluid by conducting heat in indirect heat exchanger, thereby makes water and vinylformic acid condensation, and generates the logistics of two-phase gas/liquid crude propylene aldehyde product;

By flasher and vapour liquid separator, further condensation is carried out in two-phase logistics therein further cooling, and isolates described condensation product from described cooling propenal gas stream with the logistics of described two-phase gas/liquid propenal product; And

Described condensation product is delivered to separation column from described flasher and vapour liquid separator and is carried out described fractionation.

12. a method for preparing 3-(methylthio group) propionic aldehyde continuously, this method comprises:

Liquid reaction medium contacts in the gas/liquid contact segment of conversion zone with the gaseous acrolein feed stream, described reaction medium contains 3-methylthiopropionaldehyde, methyl mercaptan and is used for methyl mercaptan and the catalyzer of acrolein reaction, described gaseous acrolein feed stream contains acrolein vapor and non-condensable gas, therefore propenal is transferred to the described reaction medium from described feed stream, and react in described reaction medium with methyl mercaptan, generate the liquid reacting product that contains 3-(methylthio group) propionic aldehyde;

Make described feed stream and described reaction medium and stream by described contact segment, therefore propenal is transferred to described reaction medium from described feed stream, and react in described reaction medium with methyl mercaptan, generate the liquid reacting product that contains the 3-methylthiopropionaldehyde;

From described liquid reacting product, separate described noncondensable gas;

Described reaction product is divided into product cut and recycle fraction;

Described recycle fraction is recycled to described gas/liquid contact segment; And

By heat passage another fluidic method of giving being taken out reaction heat from described conversion zone from described liquid reaction medium, the cycle rate of described liquid medium and be such from the position of conversion zone heat-obtaining, thus the temperature variation of described liquid reaction medium by described conversion zone be not more than approximately ± 5 °F.

13. method according to claim 35, wherein said conversion zone comprises described gas/liquid contact segment and circulation section, described liquid reacting product is discharged into circulation section from described gas/liquid contact segment, described recycle fraction is circulated back to described gas/liquid contact segment by circulation section, and the temperature variation of described liquid reaction medium in described circulation section be not more than ± and 2 °F.

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