JPH09165361A - Method for producing methacrylonitrile - Google Patents

Abstract

(57) Abstract: It is intended to provide a method for producing methacrylonitrile at a high yield by accelerating a reaction between an alkyl methacrylic acid ester and ammonia. A method for producing methacrylonitrile, which comprises reacting an alkyl methacrylic acid ester with ammonia in a gas phase in the presence of a phosphorus-containing oxide composition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel method for producing methacrylonitrile. More particularly, it relates to a method for producing methacrylonitrile by reacting an alkyl methacrylic acid ester with ammonia in the gas phase in the presence of a phosphorus-containing oxide catalyst. Methacrylonitrile is a compound useful as a raw material for copolymers and fiber processing agents.

[0002]

As a method for producing methacrylonitrile, a method involving ammoxidation of isobutylene is well known. However, there is no known method for producing methacrylonitrile by reacting methacrylic acid alkyl ester as a raw material with ammonia.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to
It is an object of the present invention to provide a novel method capable of promoting the reaction between an alkyl methacrylic acid ester and ammonia to produce methacrylonitrile at a high yield.

[0004]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in order to achieve the above object, the specific phosphorus-containing oxide composition produced methacrylonitrile from alkyl methacrylate and ammonia. It has been found that it exhibits an excellent catalytic action for the reaction. The present invention has been made based on such findings.

That is, the present invention relates to a method for producing methacrylonitrile, which comprises subjecting a methacrylic acid alkyl ester and ammonia to a gas phase reaction in the presence of an oxide composition represented by the following empirical formula. Empirical formula PaXbYcOd [In the formula, X is Ti, Zr, V, Nb, Ta, Cr, M
o, W, Mn, Fe, Co, Ni, Cu, Ag, Zn,
At least one element selected from the group consisting of B, Al, Sn, Sb, Bi and Te, Y is Li, Na, K,
Rb, Cs, Mg, Ca, Sr, Ba, La and Ce
Indicating at least one element selected from the group consisting of
The subscripts a, b, c, d represent the atomic ratio of each element, and a = 1
, B = 0.about.100, c = 0.about.20, and d
Indicates the number corresponding to the oxide formed by combining the above elements. ]

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. The important point in the reaction of the alkyl methacrylate of the present invention with ammonia is the catalyst used. As the catalyst, the oxide composition represented by the above empirical formula PaXbYcOd is used. Preferred ratio of each component (atomic ratio)
When a = 1, b = 0.1-50 (more preferably b = 0.2-20) and c = 0-20. As a result, methacrylonitrile can be effectively produced.
It is not clear what kind of complex oxide each of P, X, Y and O constituting the catalyst of the present invention becomes in the constituting catalyst and contributes to the manifestation of the effect on the activity and selectivity. However, if the ratio of the components of the catalyst deviates from the range, the yield of production of the target methacrylonitrile may decrease or the physical properties of the catalyst may deteriorate. Therefore, with this catalyst,
In order for each component in the catalyst to exert its effect effectively,
It is presumed that they are closely related to each other.

As the method for preparing the catalyst, any method known in the technical field of this kind such as a mixing method, a precipitation method and an impregnation method can be used. Catalyst Raw Material The starting raw material for each component constituting the catalyst can be selected from many types such as metal, oxide, hydroxide, chloride and nitrate of each component. Also,
It is also possible to use a substance that can be converted into an oxide by subjecting it to a chemical treatment or a firing treatment. As the raw material of P component,
Although it is convenient to use orthophosphoric acid, condensed phosphoric acid,
Phosphorus pentoxide, various ammonium phosphates and the like are used. X component (Ti, Zr, V, Nb, Ta, Cr, M
o, W, Mn, Fe, Co, Ni, Cu, Ag, Zn,
(B, Al, Sn, Sb, Bi and Te components) as raw materials, metals, oxides, chlorides of the respective components,
Nitrate or the like is used. Y component (Li, Na, K, R
As the raw material of (b, Cs, Mg, Ca, Sr, Ba, La and Ce components), oxides, hydroxides, chlorides, nitrates and the like of the respective components are used.

Preparation of catalyst A catalyst can be prepared by mixing, coprecipitating or impregnating these catalyst raw materials so as to have a desired composition ratio, drying and then calcining. For example, in the case of producing a fixed bed catalyst, it can be produced by drying a slurry prepared from each component, kneading, molding into a columnar shape or a spherical shape, and calcining this. Baking is 300-900
℃, preferably in the range of 450 ~ 850 ℃, 0.5 ~ 1
It is good to do it for 0 hours. Further, in the case of producing a fluidized bed catalyst, the slurry prepared from each component raw material is spray-dried by an appropriate means to be formed into fine particles, and then produced by firing at the temperature as described above. You can

Although the catalyst can be used without a carrier, it may be supported on various carriers such as silica, alumina, silica-alumina, silica-titania and titania. In that case, it is preferable to use a carrier of 5 to 95 wt% of the whole catalyst.

Reaction raw materials The alkyl methacrylates used in the present invention include methyl, ethyl, n-propyl, isopropyl,
n-butyl, isobutyl, sec-butyl, tert-
Various methacrylic acid alkyl esters such as butyl, 2-ethylhexyl, cyclohexyl, lauryl, tridecyl and stearyl are used. Particularly, methyl methacrylate is preferred. Also, these alkyl methacrylates can be used in a mixture. Ammonia for industrial use can be used.

Reaction Method In carrying out the reaction, either a fixed bed or fluidized bed reactor commonly used for gas phase catalytic reactions can be used. From the viewpoint of strictly controlling the reaction temperature, it is preferable to use a fluidized bed reactor. The reaction is carried out by supplying alkyl methacrylate and ammonia to a reactor filled with the catalyst prepared as described above.

The composition of the gas supplied to the reactor is such that the molar ratio of ammonia / methacrylic acid alkyl ester is 0.2 to
The range is 10, preferably 0.3 to 4. It is also possible to introduce an inert gas into the supply gas. This makes the reaction thermodynamically favorable. Examples of the inert gas include nitrogen, water vapor, carbon dioxide gas, helium and the like. Further, an oxidizing gas such as oxygen can be added to the supply gas in order to maintain the activity of the catalyst and remove the thermodynamic restriction of the reaction. In that case, it can be expected that the conversion rate of the alkyl methacrylate is increased and the yield is improved.

The reaction temperature is in the range of 200 to 500 ° C, preferably 250 to 460 ° C. The reaction pressure may be atmospheric pressure, pressurization or reduced pressure, but atmospheric pressure to 2 kg / c
A range of m ² is suitable. The contact time is 0.1 to 20 seconds based on the gas volume at the reaction temperature and the reaction pressure,
The range of 0.5 to 10 seconds is preferable.

[0014]

EXAMPLES The embodiments and effects of the present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Catalyst Activity Test Method A catalyst was packed in a fluidized bed reactor having an inner diameter of a catalyst fluidized portion of 2.5 cm and a height of 40 cm, and a raw material gas having the composition shown below was supplied to the reactor. The reaction pressure is normal pressure. Source gas composition (molar ratio) Condition 1 Methyl methacrylate: Ammonia: Nitrogen = 1: 1: 12 Condition 2 Methyl methacrylate: Ammonia: Air: Nitrogen = 1:
1: 1: 11

The methyl methacrylate conversion rate, methacrylonitrile yield and methacrylonitrile selectivity are defined as follows.

Catalyst 1 A fluidized bed catalyst having an empirical formula of P ₁ B _0.91 O _0.36 (SiO ₂ ) _3.65 was prepared as follows. 972 g of silica hydrogel (50 wt% as SiO ₂ ) prepared by reacting sodium silicate and nitric acid and 418 g of boric acid are taken and added to 1600 g of pure water while stirring. The pH of the obtained aqueous slurry was adjusted to 2 with 10% nitric acid, and then wet-milled. Silica sol (20 wt% as SiO ₂ ) 5
670 g and phosphoric acid 855 g are added. The aqueous slurry thus obtained is spray-dried using a rotary disk type spray dryer. 200 fine spherical particles obtained
Firing was performed at 2 ° C for 2 hours and then at 400 ° C for 3 hours. The final firing was performed at 500 ° C. for 3 hours.

Catalyst 2 A fluid bed catalyst having an empirical formula of P ₁ B _1.25 O _4.37 (SiO ₂ ) _8.75 was prepared in the same manner as Catalyst 1. However, the final firing was performed at 600 ° C. for 3 hours.

Catalyst 3 A fluidized bed catalyst having an empirical formula of P ₁ B _0.24 O _2.86 (SiO ₂ ) _2.14 was prepared in the same manner as Catalyst 1. However, the final firing was 650 ° C. for 3 hours.

Catalyst 4 A fluidized bed catalyst having an empirical formula of P ₁ B _3.33 O _7.5 (SiO ₂ ) _43.3 was prepared in the same manner as Catalyst 1. However, the final baking was performed at 600 ° C. for 4 hours.

Catalyst 5 A fluidized bed catalyst having an empirical formula of P ₁ Zr ₁₅ K _0.4 O _32.7 (SiO ₂ ) ₉₀ was prepared in the same manner as Catalyst 1. However, Zr
An aqueous zirconyl nitrate solution was used as a raw material, and potassium nitrate was used as a K raw material. The final firing was performed at 500 ° C. for 5 hours.

Catalyst 6 The empirical formula is P ₁ V ₅ Fe ₅ Ni _0.5 Zn _0.5 O _23.5 (Si
A fluidized bed catalyst with O ₂ ) ₁₀ was prepared as follows. 585 g of ammonium metavanadate and 12.4 kg of pure water
Dissolved in, then 2020g iron nitrate, nickel nitrate 2
9.1 g and zinc nitrate 29.7 g are added and dissolved. After adding 115 g of phosphoric acid, 1500 g of silica sol (20 wt% as SiO ₂ ) is added. The aqueous slurry thus obtained is spray-dried using a rotary disk type spray dryer. The obtained fine spherical particles were fired at 250 ° C. for 2 hours and then at 400 ° C. for 3 hours. The final firing was performed at 700 ° C. for 3 hours.

Catalyst 7 A fluidized bed catalyst having an empirical formula of P ₁ Fe ₁ Mg _0.2 O _4.2 (SiO ₂ ) ₂₅ was prepared as follows. Iron nitrate 1338
g and 170 g of magnesium nitrate are dissolved in 1500 g of pure water. Subsequently, 382 g of phosphoric acid was added, and then 2500 g of silica sol (20 wt% as SiO ₂ ) was added.
The aqueous slurry thus obtained is spray-dried using a rotary disk type spray dryer. The obtained fine spherical particles were fired at 250 ° C. for 2 hours and then at 400 ° C. for 3 hours. The final baking was performed at 650 ° C. for 4 hours.

Catalyst 8 A fluidized bed catalyst having an empirical formula of P ₁ Al ₁₁ La ₂ O ₂₂ (SiO ₂ ) _7.5 was prepared in the same manner as Catalyst 1. However, Al
Aluminum nitrate was used as a raw material, and lanthanum nitrate was used as a La raw material. The final firing was 750 ° C. for 3 hours.

Catalyst 9 A fluidized bed catalyst having an empirical formula of Fe ₁ O _1.5 (SiO ₂ ) ₃ was prepared in the same manner as Catalyst 7. The final calcination of the catalyst is 65
It was carried out at 0 ° C. for 4 hours.

Table 1 shows the results of an activity test conducted on the above catalysts 1-9.

[0027] MMA; methyl methacrylate, MAN; methacrylonitrile

[0028]

EFFECT OF THE INVENTION The phosphorus-containing oxide composition used in the present invention exhibits an excellent catalytic action for the reaction of producing methacrylonitrile from alkyl methacrylate and ammonia, and produces methacrylonitrile in good yield. It can be done.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location // C07B 61/00 300 C07B 61/00 300

Claims (2)

[Claims] 1. A method for producing methacrylonitrile, which comprises reacting an alkyl methacrylic acid ester with ammonia in a gas phase reaction in the presence of an oxide composition represented by the following empirical formula. Empirical formula PaXbYcOd [In the formula, X is Ti, Zr, V, Nb, Ta, Cr, M
o, W, Mn, Fe, Co, Ni, Cu, Ag, Zn,
At least one element selected from the group consisting of B, Al, Sn, Sb, Bi and Te, Y is Li, Na, K,
Rb, Cs, Mg, Ca, Sr, Ba, La and Ce
Indicating at least one element selected from the group consisting of
The subscripts a, b, c, d represent the atomic ratio of each element, and a = 1
, B = 0.about.100, c = 0.about.20, and d
Indicates the number corresponding to the oxide formed by combining the above elements. ] 2. The method according to claim 1, wherein the reaction is carried out in the presence of oxygen.