WO2024103456A1 - Catalyst for hydroformylation of olefins, preparation method therefor, and use thereof - Google Patents

Abstract

Provided are a catalyst for hydroformylation of olefins, a preparation method therefor, and use thereof. The catalyst comprises a metal center, a phosphoramidite ligand containing a carbazole group, and a monosubstituted phosphite ester. The preparation method comprises: mixing a metal precursor, the phosphoramidite ligand containing the carbazole group, and the monosubstituted phosphite ester to obtain the catalyst. The use comprises: carrying out a hydroformylation reaction on an olefin, synthesis gas (carbon monoxide and hydrogen), and the catalyst to prepare an aldehyde product. The catalytic system has high reactivity, good selectivity, small amount of a metal catalyst, and a high olefin conversion rate, and a normal-to-iso ratio of the aldehyde product can be as low as (0.5-1.8):1, thereby being able to achieve the purpose of increasing the yield of isomeric aldehyde.

Description

Catalyst for olefin hydroformylation and preparation method and use thereof Technical Field

The embodiments of the present application relate to the field of organic and chemical synthesis, for example, a catalyst for olefin hydroformylation and a preparation method and use thereof.

Background technique

At present, hydroformylation reaction (Hydroformlation), also known as OXO reaction, refers to the reaction of olefins and synthesis gas ( _H2 and CO) under transition metal catalysis to generate aldehyde or alcohol compounds. Hydroformylation reaction was first discovered by O. Roelen in 1938 in the Fischer-Tropsch synthesis at Ruhr Chemical Company in Germany, and was soon applied to the process of propylene hydroformylation to butyraldehyde. It has now become one of the most important homogeneous catalytic reactions in petrochemicals. Aldehyde compounds can be further converted into compounds such as alcohols, acids, esters, Aldol condensation products and acetals. These compounds are widely used in medicine, pesticides, fragrances, detergents, plasticizers, surfactants, etc., and have a wide range of uses.

Isobutyraldehyde is an important organic chemical raw material, widely used as a solvent or plasticizer. Many fine chemical products can be derived from isobutyraldehyde, such as synthetic isobutanol, neopentyl glycol, methacrylic acid, methyl methacrylate, 2,2,4-trimethyl-1,3-pentanediol, methyl ethyl ketone, calcium pantothenate, isobutyrate or isobutyronitrile, etc., and more chemical products can be synthesized with these products as raw materials, and they are all widely used. With the development of the petrochemical industry, the demand for isobutyraldehyde is increasing.

Industrially, isobutyraldehyde is mainly derived from the byproduct of carbonylation of propylene to butanol and octanol. In recent years, the production of butanol and octanol has been trying to produce more butyraldehyde by optimizing or adjusting the isomer ratio of the device. For example, the currently popular "low-pressure carbonyl rhodium method" uses excessive trialkylphosphine as a ligand with a ligand concentration of 5%-15%. The isomer ratio of butyraldehyde in this process is 6-10. In order to improve the reaction selectivity and avoid the use of a large amount of monophosphine ligands (such as PPh ₃ ), those skilled in the art have developed a series of ligands such as the Bisbi series, the Xantphos series and the Biphephos series with large sterically hindered substituents. This type of ligand shows good activity and selectivity for butyraldehyde in the hydroformylation reaction. The high isomer ratio production process has resulted in less and less isobutyraldehyde as a byproduct, and isobutyraldehyde is difficult to store and transport, which has greatly restricted the development of isobutyraldehyde and its downstream products.

For olefin hydroformylation devices with mature related applications, the product normal-to-iso ratio can be changed by adjusting the operating conditions, among which it is crucial to use a mixture of diphosphite and monophosphite as a ligand. For example, CN201753511A reported a method for reducing or increasing the normal-to-iso ratio by increasing or decreasing the synthesis gas partial pressure in the first reaction zone; CN101657407A reported that during the reaction process, an organic polyphosphite was reacted with water in the reaction, and the organic polyphosphite ligand was decomposed to reduce its molar ratio with the transition metal to achieve the purpose of reducing the normal-to-iso ratio; CN102741210A disclosed a method for increasing or decreasing the normal-to-iso ratio by increasing or decreasing the rhodium catalyst circulating liquid returned to the first reactor; CN103951550A disclosed a method for increasing or decreasing the normal-to-iso ratio by increasing or decreasing the olefin concentration in the first reaction zone, but such methods belong to special operating conditions and it is difficult to maintain the long-term stable operation of the device.

In order to solve the problem of shortage of isobutyraldehyde raw materials, related research has been continuously followed up, and a series of methods for synthesizing isobutyraldehyde have emerged one after another. For example, CN112169829A discloses a bifunctional catalyst for highly selective preparation of isobutyraldehyde by propylene hydroformylation. The catalyst is to impregnate cobalt salt and nitrogen-containing compound precursor into the acidic molecular sieve pores, and then carbonize at a higher temperature to generate in situ active center cobalt carbide highly dispersed in the molecular sieve pores, and at the same time generate N-modified carbon layer on the surface of cobalt carbide. This method uses a fixed bed reactor, with a propylene conversion rate of up to 89%, and an isobutyraldehyde yield of up to 79%, but the reaction temperature is as high as 200°C, and the overall utilization rate of propylene is low.

CN113416126A discloses a method for preparing isobutyraldehyde with high selectivity by hydroformylation of propylene. In the method, a copper carbide bimetallic catalyst capable of stabilizing the presence of secondary carbonyl ions is designed. In the catalyst, CO is adsorbed on the catalyst, and the copper carbide activates the carbonyl carbon to combine with the secondary carbonyl ion, and finally generates isobutyraldehyde with hydrogen dissociated on the copper carbide and nickel.

CN109675579A discloses a method for preparing a catalyst for synthesizing isobutyraldehyde from methanol and ethanol or propanol, wherein a certain amount of vanadate, citric acid and two or three of nitrates such as Fe, Cu, Ni, Zr, Ca, Ce, etc. are dissolved in an aqueous solution, and then the mixed solution is evaporated to dryness at high temperature in a constant temperature water bath, polar drying is performed at 100-120°C, and calcined at a temperature of 400-600°C in a muffle furnace to prepare a unique solid catalyst with a structure of V-Fe-M-N (M is Cu or Ni, and N is one of Zr, Ca and Ce). The catalyst has good catalytic performance in the reaction of preparing isobutyraldehyde and co-producing isobutyraldehyde from methanol and ethanol or propanol in one step.

CN104321297A discloses a catalyst and method with improved selectivity for isobutyraldehyde through catalyst induction, in which supramolecular ligand assembly comprises tri(3-pyridyl)phosphine, a magnesium-centered tetraphenylporphyrin coordination complex and a ligand formed in situ by inserting the first olefin into a carbonyl rhodium bond, so that the catalytic system formed is more selective for branched aldehydes.

However, the methods for increasing the production of isomeric aldehydes in the related art are different, and there are problems of poor selectivity and low activity.

Summary of the invention

The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

The embodiment of the present application provides a catalyst for olefin hydroformylation, a preparation method and use thereof. The catalytic system has high reaction activity, good selectivity, a small amount of metal catalyst, a high olefin conversion rate, and a significant reduction in the normal-to-iso ratio in aldehyde products, thereby achieving the purpose of increasing the production of isomeric aldehydes.

In a first aspect, an embodiment of the present application provides a catalyst for olefin hydroformylation, the catalyst comprising a metal center, a phosphoramidite ligand containing a carbazole group, and a monosubstituted phosphite;

The structural formula of the phosphoramidite ligand containing a carbazole group is as follows:

In the formula: R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ in the phosphoramidite compound are independently selected from one of hydrogen, halogen, C1-C4 alkyl, C1-C4 alkoxy, phenyl, trifluoromethyl or trimethylsilyl.

The catalyst provided in the present application forms a specific metal/phosphoramidite catalytic system by using a metal precursor, a phosphoramidite ligand containing a carbazole group and an auxiliary agent monosubstituted phosphorous acid ester (ROPO ₂ H ₂ ), so that the catalyst system has high reaction activity and stability. The catalyst system reacts with a certain proportion of propylene or butene and synthesis gas at a certain temperature and pressure to produce aldehyde products, which can increase the proportion of isomeric aldehyde products in the aldehyde products and realize efficient preparation of isomeric aldehyde products.

In the present application, the normal-to-iso ratio in the aldehyde product refers to the molar ratio of normal aldehyde to isomeric aldehyde in the obtained product.

In the present application, the halogen is a halogen element, such as fluorine, chlorine, bromine or iodine.

In the present application, the C1-C4 alkyl group refers to a branched or straight-chain alkyl group having 1-4 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl.

In the present application, the C1-C4 alkoxy group refers to a group formed by connecting a "C1-C4 alkyl" to an O atom.

As a preferred technical solution of the present application, the metal center includes one or a combination of at least two of iron compounds, cobalt compounds, nickel compounds, ruthenium compounds, rhodium compounds, iridium compounds or palladium compounds, preferably a metal cobalt compound and/or a metal rhodium compound, and more preferably a metal rhodium compound.

Preferably, the monosubstituted phosphite includes one or a combination of at least two of monoethyl phosphite, monopropyl phosphite, monobutyl phosphite, monophenyl phosphite or mono(trimethylsilyl)phosphite.

As a preferred technical solution of the present application, the molar ratio of the metal center to the phosphoramidite ligand containing a carbazole group is (1-8):1, for example, it can be 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3:1, 3.2:1, 3.4:1, 3.6:1, 3.8:1, 4:1, 4.2:1, 4.4:1, 4.6:1, 4.8:1, 5:1, 5.2:1, 5.4:1, 5.6:1, 5.8:1, 6:1, 6.2:1, 6.4:1, 6.6:1, 6.8:1, 7:1, 7.2:1, 7.4:1, 7.6:1, 7.8:1 or 8:1, but not limited to the listed values, other unlisted values within the range are also applicable, preferably (2-5):1.

Preferably, the concentration of the phosphoramidite ligand containing a carbazole group in the catalyst is 50-1800 ppm, for example, 50 ppm, 100 ppm, 150 ppm, 200 ppm, 250 ppm, 300 ppm, 350 ppm, 400 ppm, 450 ppm, 500 ppm, 550 ppm, 600 ppm, 650 ppm, 700 ppm, 750 ppm, 800 ppm, 850 ppm, 900 ppm, 950 ppm, 100 0ppm, 1050ppm, 1100ppm, 1150ppm, 1200ppm, 1250ppm, 1300ppm, 1350ppm, 1400ppm, 1450ppm, 1500ppm, 1550ppm, 1600ppm, 1650ppm, 1700ppm, 1750ppm or 1800ppm, but not limited to the listed values, other unlisted values within the range are also applicable, preferably 200-1200ppm.

Preferably, the concentration of the monosubstituted phosphite in the catalyst is 20-800ppm, for example, it can be 20ppm, 30ppm, 40ppm, 50ppm, 60ppm, 70ppm, 80ppm, 90ppm, 100ppm, 150ppm, 200ppm, 250ppm, 300ppm, 350ppm, 400ppm, 450ppm, 500ppm, 550ppm, 600ppm, 650ppm, 700ppm, 750ppm or 800ppm, but is not limited to the listed values, and other unlisted values within this range are equally applicable.

In a second aspect, an embodiment of the present application provides a method for preparing the catalyst as described in the first aspect, the preparation method comprising: mixing a metal precursor, a phosphoramidite ligand containing a carbazole group and a monosubstituted phosphite to obtain the catalyst.

In the present application, the metal precursor can be acetate of the corresponding metal element, acetylacetonato dicarbonyl rhodium (I), dodecacarbonyl tetrarhodium, [Rh(OAc)(COD)] ₂ , RhH(CO)(phosphoramidite) ₂ , Rhacac(CO)(phosphoramidite), etc., which are commonly used metal precursors in the art, and COD is 1,5-cyclooctadiene.

In a third aspect, an embodiment of the present application provides a use of the catalyst as described in the first aspect, wherein the use includes: subjecting olefins, synthesis gas and the catalyst to a hydroformylation reaction to prepare an aldehyde product.

As a preferred technical solution of the present application, the olefin includes propylene or butene;

Preferably, the butene includes one or a combination of at least two of 1-butene, 2-butene or isobutylene.

As a preferred technical solution of the present application, the molar ratio of carbon monoxide to hydrogen in the synthesis gas is (0.5-2):1, for example, it can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2:1, but is not limited to the listed values, and other unlisted values within the range are also applicable, preferably (0.9-1.3):1.

Preferably, the molar ratio of olefin to synthesis gas is (0.9-1.2):1, for example, it can be 0.9:1, 0.92:1, 0.94:1, 0.96:1, 0.98:1, 1:1, 1.01:1, 1.02:1, 1.03:1, 1.04:1, 1.05:1, 1.06:1, 1.07:1, 1.08:1, 1.09:1, 1.1:1, 1.11:1, 1.12:1, 1.14:1, 1.15:1, 1.16:1, 1.17:1, 1.18:1, 1.19:1 or 1.2:1, but is not limited to the listed values, and other unlisted values within the range are also applicable.

Preferably, the amount of the catalyst added is 0.0002-0.01 times the mass of the olefin, for example, 0.0002 times, 0.00021 times, 0.00022 times, 0.00023 times, 0.00024 times, 0.00025 times, 0.00026 times, 0.00027 times, 0.00028 times, 0.00029 times, 0.0003 ... .0004 times, 0.0005 times, 0.0006 times, 0.0007 times, 0.0008 times, 0.0009 times, 0.001 times, 0.002 times, 0.003 times, 0.004 times, 0.005 times, 0.006 times, 0.007 times, 0.008 times, 0.009 times or 0.01 times, but not limited to the listed values, other values not listed in this range are also applicable.

As a preferred technical solution of the present application, the temperature of the hydroformylation reaction is 65-120°C, for example, it can be 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, etc., but is not limited to the listed values, and other unlisted values within the range are also applicable.

As a preferred technical solution of the present application, the pressure of the hydroformylation reaction is 0.8-3.0 MPa, for example, it can be 0.8 MPa, 0.9 MPa, 1 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, 1.6 MPa, 1.7 MPa, 1.8 MPa, 1.9 MPa, 2.0 MPa, 2.1 MPa, 2.2 MPa, 2.3 MPa, 2.4 MPa, 2.5 MPa, 2.6 MPa, 2.7 MPa, 2.8 MPa, 2.9 MPa or 3.0 MPa, but is not limited to the listed values, and other values not listed within the range are equally applicable.

As a preferred technical solution of the present application, the use includes: carrying out a hydroformylation reaction of olefins, synthesis gas and the catalyst to prepare an aldehyde product;

The olefin includes propylene or butene; the butene includes one or a combination of at least two of 1-butene, 2-butene or isobutylene;

The molar ratio of carbon monoxide to hydrogen in the synthesis gas is (0.5-2):1; the molar ratio of olefin to synthesis gas is (0.9-1.2):1; the amount of the catalyst added is 0.0002-0.01 times the mass of the olefin;

The temperature of the hydroformylation reaction is 65-120° C. and the pressure is 0.8-3.0 MPa.

In the present application, when the catalyst system is used to carry out olefin hydroformylation reaction to produce aldehydes, different aldehyde products are obtained depending on the different olefins. Specifically, when propylene is used as the raw gas, a butyraldehyde product with a low normal-to-iso ratio is obtained. Butene can also be used to produce valeraldehyde, and the obtained valeraldehyde product also has a low normal-to-iso ratio. For example, 1-butene or 2-butene is used to increase the production of 2-methylbutyraldehyde through hydroformylation, and isobutylene is used to produce 3-methylbutyraldehyde through hydroformylation.

In the present application, the olefin hydroformylation method can be carried out in an intermittent or continuous manner. In the industrial method of the continuous manner, a pre-prepared metal catalyst and phosphoramidite derivative, an auxiliary agent phosphorous acid monosubstituted ester and a reaction solvent are added to a reactor to start a continuous synthesis method. After being heated to the required reaction temperature, olefin (propylene), carbon monoxide and hydrogen are introduced into the above-mentioned reaction mixture in a continuous or intermittent manner. The effluent of the reactor contains normal aldehyde and isomeric aldehyde, metal/phosphoramidite ligand containing carbazole group, by-products such as aldehyde condensation products, unreacted olefin, carbon monoxide, hydrogen and reaction solvent generated on site of the olefin hydroformylation reaction, which can be exported from the reactor to an evaporator/separator. By reducing pressure, the gaseous reactants carbon monoxide and hydrogen are separated from the mixture, and the aldehyde products of the product can be collected by distillation.

The remaining metal/phosphoramidite catalyst, auxiliary agent and all by-products not separated are recycled back to the olefin hydroformylation reactor and reused in the method of the present application. The aldehyde product can be separated from the reaction mixture by any separation technique known to professionals in the art, such as molecular distillation.

The method of the present application requires regular or continuous monitoring of the concentration of the phosphoramidite for a continuously running reaction system. If the concentration is found to be lower than the value, the compound may be lost due to degradation or the like. In this case, the phosphoramidite compound is added to the mixture of the reaction system.

In a fourth aspect, an embodiment of the present application provides a use of the catalyst as described in the first aspect, wherein the use comprises preparing an aldehyde product by using an olefin, synthesis gas and the catalyst in a reaction device;

The reaction device comprises a material feeding unit, a reactor, a separator and an evaporator which are connected in sequence;

The separator is provided with a tail gas outlet; the liquid phase outlet of the evaporator is connected to the reactor.

In the present application, in the hydroformylation of propylene, the reaction materials in the preparation device can be added to the reactor through the feeding device to carry out the hydroformylation reaction, the reacted materials are passed into the separator for gas-liquid separation, the unreacted gas and liquid materials are separated, and the separated liquid materials are sent to the evaporator for separation to obtain the product and the catalyst system, and the catalyst system is transported back to the reactor for secondary utilization.

Compared with the related technical solutions, the embodiments of the present application have the following beneficial effects:

(1) The catalyst provided in the embodiments of the present application, wherein the ligand is a phosphoramidite ligand containing a carbazole group, and the catalytic system composed of the ligand and rhodium has high reaction activity, good selectivity, and a small amount of metal catalyst. When the catalytic system is used for the hydroformylation of propylene to prepare butyraldehyde, the propylene conversion rate is high, and the propylene conversion rate is >99%. The normal-to-isobutyraldehyde ratio of the obtained butyraldehyde product can reach (1.3-1.8):1, which can achieve the purpose of increasing the production of isobutyraldehyde.

(2) The catalytic system can also be used for the hydroformylation of butene to prepare valeraldehyde. The n-to-isomer ratio of the valeraldehyde products obtained by hydroformylation of 1-butene and 2-butene can reach (0.5-1.8):1. The hydroformylation of isobutylene can produce 3-methylbutyraldehyde.

(3) This method can be used to upgrade and transform related 1,2-butanol industrial equipment to increase the production of isobutyraldehyde products.

Still other aspects will be apparent upon reading and understanding the detailed description.

Detailed ways

In order to better illustrate the present application and facilitate understanding of the technical solution of the present application, typical but non-limiting embodiments of the present application are as follows:

Example

In this example, the data reported are mainly based on the gas chromatography yield of aldehyde, that is, the percentage of valeraldehyde obtained by theoretical calculation based on olefin after the reaction is completed.

The carbazole group-containing phosphoramidite ligands L1-L10 used in the following examples have the following structures:

The catalyst used in the hydroformylation reaction can be prepared by mixing the transition metal with any one of the carbazole group-containing phosphoramidite ligands of L1-L12 and the monosubstituted phosphite, wherein the catalyst includes acetate of the corresponding metal element, acetylacetonato dicarbonyl rhodium (I), dodecacarbonyl tetrarhodium, [Rh(OAc)(COD)] ₂ , RhH(CO)(phosphoramidite) ₂ , Rhacac(CO)(phosphoramidite), etc.; wherein acac is acetylacetone and COD is 1,5-cyclooctadiene.

Example 1

In an air atmosphere, [Rh(acac)(CO) ₂ ] (0.01 mmol), the carbazole-containing phosphoramidite ligand (0.04 mmol) and monobutyl phosphite (0.01 mmol) selected in Table 1 and 25 mL of anhydrous toluene were added to a 500 mL stainless steel autoclave equipped with a pressure gauge, and the rhodium/phosphoramidite catalyst system was slowly stirred by a stirrer. The gas pipeline was connected, the gas in the autoclave was replaced with nitrogen three times, the amount of propylene specified in Table 1 was introduced, and a mixed gas of hydrogen and carbon monoxide (molar ratio of 1:1) was introduced until the total pressure was 1.8 MPa. The temperature was heated to the required temperature (80°C) under magnetic stirring, and gas was added several times during the reaction to maintain the total pressure at 1.8 MPa. After each gas addition, the reaction was carried out for 1 hour until the propylene was completely consumed and the reaction pressure no longer changed. The reactor was cooled, the residual gas was vented in a fume hood, weighed, the autoclave was opened, and a sample was taken to determine the normal-isobutyraldehyde ratio (molar ratio of normal-butyraldehyde/isobutyraldehyde) by gas chromatography (GC). The results are shown in Table 1.

Comparative Example 1

The only difference from Example 1 is that no phosphoramidite ligand containing a carbazole group is added to the catalyst system. The results are shown in Table 1. As can be seen from the table, only a small amount of butyraldehyde (n-butyraldehyde/isobutyraldehyde) product is detected in the product.

Comparative Example 2

The only difference from Example 1 is that monobutyl phosphite is not added. The ligand used in this case is L1. The results are shown in Table 1. It can be seen from the table that the propylene conversion rate is 82% and the product normal-to-iso ratio is 1.81.

Comparative Example 3

The only difference from Example 1 is that monobutyl phosphite is replaced by the L4 bidentate phosphite ligand in CN102266796A. The obtained results are shown in Table 1.

Table 1

As can be seen from the table, the ligand provided in this application is very important for improving the reaction activity and reducing the product iso-ratio. The iso-ratio of butyraldehyde given in the embodiment can be controlled between 1.4 and 1.5, and there is basically no reaction without the addition of ligand. The auxiliary agent monosubstituted phosphite also has a good promoting effect on the reaction. The propylene hydroformylation reaction involving diphosphite has good terminal selectivity, and the iso-ratio can reach 21.5, which is far less than the effect of this application.

Example 2

[Rh(acac)(CO) ₂ ] (0.01 mmol), carbazole-containing phosphoramidite ligand L3 (0.04 mmol), monobutyl phosphite (0.01 mmol), and 25 mL of anhydrous toluene were added to a 500 mL stainless steel autoclave equipped with a pressure gauge under air atmosphere, and the mixture was slowly stirred with a stirrer to generate a rhodium/phosphoramidite catalyst system. A gas pipeline was connected, and the gas in the autoclave was replaced with nitrogen three times. The olefins specified in Table 2 were added (the amount added was 20 g each), and a mixture of hydrogen and carbon monoxide (molar ratio of 1:1) was introduced until the total pressure reached 1.8 MPa. The reaction mixture was heated to the desired temperature (80°C) under magnetic stirring. Gas was added several times during the reaction to maintain the total pressure at 1.8 MPa. The reaction was carried out for 1 hour after each gas addition until the olefin was completely consumed and the reaction pressure no longer changed. The reactor was cooled and the residual gas was vented in a fume hood. The mixture was weighed, the reactor was opened, and samples were taken for determination of the normal-isomer ratio (molar ratio of normal-isomer aldehyde/isomer aldehyde) by gas chromatography (GC). The index results of the products corresponding to each butene are shown in Table 2.

Table 2

The Olefins Reaction temperature/℃ Time/h Positive difference ratio 1 1-Butene 80 6 1.78 2 2-Butene 85 6 0.57 3 Isobutylene 85 8 --

Example 3

Single-reactor simulation cycle test: [Rh(acac)(CO) ₂ ] (0.02 mmol), carbazole-containing phosphoramidite ligand L3 (0.07 mmol) and monobutyl phosphite (0.015 mmol), and 30 mL of anhydrous toluene were added to a 500 mL stainless steel autoclave equipped with a pressure gauge under air atmosphere, and the agitator was slowly stirred to generate a rhodium/phosphoramidite catalytic system. The gas pipeline was connected, and the gas in the autoclave was replaced with nitrogen three times, and a specified amount of propylene 20 g was introduced, and a mixed gas of hydrogen and carbon monoxide (molar ratio of 1:1) was introduced until the total pressure reached 1.8 MPa. The temperature was raised to the required temperature (80°C) under magnetic stirring, and the gas was supplemented several times in the middle of the reaction to maintain the total pressure of 1.8MPa. After 3 hours of reaction, the reactor was cooled, the residual gas was vented in the fume hood, and weighed; 10g of propylene, hydrogen and carbon monoxide were charged again to a total pressure of 1.8MPa, and the temperature was continued to rise to 80°C for reaction. This was repeated five times, and the normal-iso ratio of normal-butyraldehyde/isobutyraldehyde was 1.56 when the sampling was determined by gas chromatography (GC). The selectivity of the catalytic system was not affected after the reaction was run for 18 hours. The data of each time in the process are shown in Table 3. It can be seen from the table that the catalyst of the present application can still ensure a good catalytic effect after multiple cycles of use, and the increase in the production of isobutyraldehyde in the butyraldehyde product can be achieved.

table 3

frequency Positive difference ratio first 1.53 the second time 1.51 the third time 1.54 the fourth time 1.55 the fifth time 1.56

Example 4

The propylene hydroformylation reaction device of the present application is used, and the feed tower, hydroformylation reactor, separator and evaporator are replaced with nitrogen. Rh(acac)(CO) ₂ , phosphoramidite ligand L1 containing carbazole group and monobutyl phosphite are dissolved in 10L toluene in the feed tower, so that the concentration of Rh(I) is 80mg/L, the molar ratio of Rh/L1 is 1:3, and the concentration of monobutyl phosphite is 120mg/L. The 10L solution is pumped into the hydroformylation reactor with a volume of 15L through a pipeline; and the separator and evaporator are respectively kept with 2L of solution. Propylene is fed into the hydroformylation reactor at 4.2g/min, carbon monoxide and hydrogen at 2.85g/min and 0.21g/min, respectively. The temperature in the reactor is 80±1℃, and the total gas pressure of hydrogen, carbon monoxide and propylene is 1.8±0.1MPa. Propylene, carbon monoxide and hydrogen react under the catalysis of Rh/L3 to generate n-valeraldehyde and isovaleraldehyde. The mixed solution containing the reaction products and the catalyst flows from the hydroformylation reactor into the separator, and the pressure is reduced to 0.6MPa, and the solution and a small amount of unreacted tail gas are discharged. The solution after gas-liquid separation enters the evaporator for evaporation, and part of the n-butyraldehyde and isobutyraldehyde products are evaporated, and the remaining butyraldehyde and the catalyst system are returned to the hydroformylation reactor to continue to participate in the reaction.

In the feeding tower, the phosphoramidite ligand L1 containing a carbazole group is dissolved in toluene, and the concentration of the phosphoramidite ligand containing a carbazole group in the reactor is detected at regular intervals. When the ligand concentration is lower than 200 ppm, the feeding tower is opened, and the phosphoramidite ligand containing a carbazole group is pumped into the reactor, and the concentration of the phosphoramidite ligand containing a carbazole group is maintained in the range of 200-1200 ppm, specifically maintained within 1000±50 ppm in this embodiment, while the liquid level at the bottom of the hydroformylation reactor, the separator and the evaporator is kept constant.

The concentration of the phosphoramidite ligand L1 containing a carbazole group in the hydroformylation reactor was monitored by liquid chromatography, and the molar ratio of n-butyraldehyde to isobutyraldehyde was determined by gas chromatography (GC). The reaction was carried out continuously for 1000 hours, and the molar ratio of n-butyraldehyde/isovaleraldehyde received at the top of the evaporator fluctuated within a certain range, and the product n-isovaleraldehyde ratio was between 1.3 and 1.8.

It can be seen from the results of the above examples that the catalyst provided in the present application, by adopting a specific catalyst system, utilizes the specific coordination effect between the phosphoramidite ligand containing a carbazole group and the auxiliary monosubstituted phosphite to achieve an increase in the yield of the n-butyraldehyde product in the preparation process of propylene hydroformylation.

It is stated that the present application uses the above embodiments to illustrate the detailed structural features of the present application, but the present application is not limited to the above detailed structural features, that is, it does not mean that the present application must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement to the present application, equivalent replacement of the components selected by the present application, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present application.

The preferred embodiments of the present application are described in detail above; however, the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, a variety of simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the protection scope of the present application.

It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not further describe various possible combinations.

In addition, the various implementation modes of the present application may be arbitrarily combined, and as long as they do not violate the concept of the present application, they should also be regarded as the contents disclosed in the present application.

Claims (14)

A catalyst for olefin hydroformylation, wherein the catalyst comprises a metal center, a phosphoramidite ligand containing a carbazole group and a monosubstituted phosphite; The structural formula of the phosphoramidite ligand containing a carbazole group is as follows:

In the formula: R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ in the phosphoramidite compound are independently selected from one of hydrogen, halogen, C1-C4 alkyl, C1-C4 alkoxy, phenyl, trifluoromethyl or trimethylsilyl. The catalyst as claimed in claim 1, wherein the metal center comprises one or a combination of at least two of an iron compound, a cobalt compound, a nickel compound, a ruthenium compound, a rhodium compound, an iridium compound or a palladium compound, preferably a metal cobalt compound and/or a metal rhodium compound, more preferably a metal rhodium compound. The catalyst as claimed in claim 1 or 2, wherein the monosubstituted phosphite comprises one or a combination of at least two of monoethyl phosphite, monopropyl phosphite, monobutyl phosphite, monophenyl phosphite or mono(trimethylsilyl)phosphite. The catalyst according to any one of claims 1 to 3, wherein the molar ratio of the metal center to the phosphoramidite ligand containing a carbazole group is (1-8):1, preferably (2-5):1. The catalyst according to any one of claims 1 to 4, wherein the concentration of the phosphoramidite ligand containing a carbazole group in the catalyst is 50-1800 ppm, preferably 200-1200 ppm; Preferably, the concentration of the monosubstituted phosphite in the catalyst is 20-800 ppm. A method for preparing the catalyst according to any one of claims 1 to 5, wherein the preparation method comprises: The catalyst is obtained by mixing a metal precursor, a phosphoramidite ligand containing a carbazole group and a monosubstituted phosphite. A use of the catalyst according to any one of claims 1 to 5, wherein the use comprises: subjecting olefins, synthesis gas and the catalyst to a hydroformylation reaction to prepare an aldehyde product. The use according to claim 7, wherein the olefin comprises propylene or butene. The use according to claim 8, wherein the butene comprises one or a combination of at least two of 1-butene, 2-butene or isobutylene. The use according to any one of claims 7 to 9, wherein the molar ratio of carbon monoxide to hydrogen in the synthesis gas is (0.5-2):1, preferably (0.9-1.3):1. The use according to any one of claims 7 to 10, wherein the molar ratio of the olefin to the synthesis gas is (0.9-1.2):1; Preferably, the added amount of the catalyst is 0.0002-0.01 times the mass of the olefin. The use according to any one of claims 7 to 11, wherein the temperature of the hydroformylation reaction is 65 to 120° C.; Preferably, the pressure of the hydroformylation reaction is 0.8-3.0 MPa. The use according to any one of claims 7 to 12, wherein the use comprises: performing a hydroformylation reaction on olefins, synthesis gas and the catalyst to prepare an aldehyde product; The olefin includes propylene or butene; the butene includes one or a combination of at least two of 1-butene, 2-butene or isobutylene; The molar ratio of carbon monoxide to hydrogen in the synthesis gas is (0.5-2):1; the molar ratio of olefin to synthesis gas is (0.9-1.2):1; the amount of the catalyst added is 0.0002-0.01 times the mass of the olefin; The temperature of the hydroformylation reaction is 65-120° C. and the pressure is 0.8-3.0 MPa. The use of the catalyst according to any one of claims 1 to 5, wherein the use comprises preparing an aldehyde product by using an olefin, synthesis gas and the catalyst in a reaction device; The reaction device comprises a material feeding unit, a reactor, a separator and an evaporator which are connected in sequence; the separator is provided with a tail gas outlet; and the liquid phase outlet of the evaporator is connected to the reactor.