JPH11246505A - Production of unsaturated nitrile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently obtain an unsaturated nitrite without adding a halogen promoter to a reaction system, by carrying out ammoxidation in the presence of a specific metal oxide. SOLUTION: Propane or isobutane is subjected to an ammoxidation reaction by using an oxide catalytic composition of the empirical formula Sba Qb Vc Md Ox (Q is niobium or tantalum; V is vanadium; M is one or more selected from the group consisting of molybdenum, tungsten, iron, chromium, manganese, titanium, tin and serum; when (a) is 1, (b) is 0.1-1.5, (c) is 0.001-1, (d) is 0-1 and (x) is a number determined by the oxidation state of each element) having values of lattice spacing (d) (Å) of at least 3.49-3.52, 3.09-3.13 and 2.95-2.98 in the X-ray diffraction to give acrylonitrile or methacrylonitrile. Preferably the oxide catalytic composition is obtained by reducing a pentavalent vanadium compound, mixing the reduced compound with a niobium antimony compound and baking the mixed compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an unsaturated nitrile. More specifically, the present invention relates to a method for producing acrylonitrile or methacrylonitrile from a saturated aliphatic hydrocarbon, propane or isobutane.

[0002]

2. Description of the Related Art Nitriles such as acrylonitrile and methacrylonitrile are industrially produced as important intermediates such as synthetic fibers, synthetic resins and synthetic rubbers. Conventionally, acrylonitrile has been produced by ammoxidation of propylene, and methacrylonitrile has been produced by ammoxidation of isobutene. However, in recent years, attention has been paid to a method for producing propane or isobutane by ammoxidation, which is cheaper than propylene and isobutene, and various catalysts have been proposed.

For example, Sb-V catalysts (GB1, 36
6,135), Sb-UW catalysts (USP 3,67)
0,006), Fe-U-Sb based catalyst (USP 3,68
6,295), VP catalyst (JP-B-58-5188).
No.), Bi-V-based catalyst (JP-A-63-295545),
Mixture of V-Sb-based catalyst and Fe-Sb-based catalyst
3-295546), a mixture of a V-Sb-based catalyst and a Bi-Mo-based catalyst (JP-A-64-38051), Mo-V
-Te-Nb-based catalyst (JP-A-2-257), Ag-B
i-V-Mo based catalyst (JP-A-3-58961), Mo
-V-Sb-based catalyst (JP-A-9-157241), V-
Sb-Sn-based catalyst (JP-A-8-996), V-Sb-T
i-based catalyst (JP-A-8-238428), V-Sb-Li
System catalyst (JP-A-8-290058), Nb-Sb-Cr
(JP-A-10-1465) and the like have been reported.

[0004]

In the production of unsaturated nitriles by ammoxidation of saturated hydrocarbons, despite the many studies described above, the target yield is still low. Attempts have also been made to increase the yield of nitriles by adding small amounts of organic halides, inorganic halides, and sulfur compounds to the reaction system, but these additions cause corrosion problems in the reactor, which has led to industrialization. Have difficulty. Development of a catalyst for efficiently performing ammoxidation of propane or isobutane without using a corrosive halogen promoter or the like has been an important issue in the art.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies on a novel catalyst for producing acrylonitrile or methacrylonitrile by ammoxidation using propane or isobutane as a raw material. Q
Have found that the target nitrile can be efficiently produced by ammoxidation in the presence of a metal oxide of Nb and / or Ta) without the presence of a halogen promoter in the reaction system, and completed the present invention.

Namely, the present invention provides a process for preparing ammoxidation by propane or acrylonitrile or methacrylonitrile from isobutane, the following general formula _{Sb a Q b V c M d} O x ( wherein Sb is antimony, Q is Niobium and / or tantalum, V is vanadium, M is at least one element selected from the group consisting of molybdenum, tungsten, iron, chromium, manganese, titanium, tin and cerium; O represents oxygen;
When a is 1, b = 0.1 to 1.5, c = 0.001 to 1, d = 0 to 1, and x is a numerical value determined by the oxidation state of each element. The present invention relates to a method for producing an unsaturated nitrile, characterized by using an oxide catalyst composition represented by the formula (1) and having at least the following value of lattice spacing d (Å) in X-ray diffraction. Lattice spacing d (Å) 3.49 to 3.52 3.09 to 3.13 2.95 to 2.98

[0007]

Embodiments of the present invention will be described below in detail. In producing the vanadium-niobium and / or tantalum-antimony-containing oxide catalyst used in the present invention, the pentavalent vanadium compound is reduced, then mixed with a compound of niobium and antimony, and calcined.

Examples of the pentavalent vanadium compound include vanadium pentoxide, ammonium metavanadate, and vanadium oxytrichloride. Preferably, vanadium pentoxide and ammonium metavanadate are used.

As a method for reducing a pentavalent vanadium compound, a method using an acid such as hydrochloric acid or oxalic acid as a reducing agent,
Examples include a method using hydrazine or hydroxylamine, and a method using alcohol or aldehyde. Preferably, a method using an alcohol or an aldehyde is used.

[0010] Alcohols and aldehydes used for reduction include ethanol, isopropyl alcohol, isobutyl alcohol, allyl alcohol, benzyl alcohol,
Formaldehyde, acetaldehyde and the like are used.
If vanadium is not reduced, the yield of the desired product decreases.

As a raw material of the antimony component, antimony trioxide or the like can be used. As a raw material of niobium, niobate, niobium pentoxide, niobium oxalate, niobium ammonium oxalate, or the like can be used.

The catalyst can be used as it is, but a carrier can be used to increase the surface area of the catalyst or to improve physical properties such as mechanical strength. As a preferable carrier, silica, alumina, titania, and zirconia may be used alone or a mixture thereof. Carrier is 10 to 90% by weight of the total catalyst weight
Can be arbitrarily changed within the range. As a raw material, sol, gel, oxide powder, or the like can be used.

The drying may be carried out by any method such as evaporation to dryness, spray drying and vacuum drying. Firing is 200 ~
Perform at 900 ° C. for 0.5 to 20 hours. The firing is performed in an atmosphere of air, oxygen, nitrogen, carbon dioxide, or the like, or a mixed gas atmosphere thereof, depending on the purpose.

The form of these catalysts is not particularly limited. It may be used as it is after firing, or after drying or firing, tableting, extrusion molding, molding by a method such as granulation,
The shape may be a pellet, ring, sphere, or the like.

The reaction gas composition used in the reaction is preferably 0.3 to 5 mol of ammonia and 1 to 5 mol of oxygen per 1 mol of propane or isobutane. Good. The reaction can be carried out under normal pressure near atmospheric pressure, or under slightly increased or reduced pressure.

The reaction temperature ranges from 400 ° C. to 550 ° C., preferably from 420 ° C. to 500 ° C. Contact times range from 0.1 to 30 seconds. In addition, a fixed bed,
Either a fluidized bed or a moving bed may be used.

[0017]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. The activity test used a fixed-bed reactor. The contact time, the conversion of propane or isobutane and the yield of the desired product (acrylonitrile or methacrylonitrile) are defined as follows: Space velocity (ml / h · g) = [feed gas flow rate under reaction conditions (ml / h)] / [catalyst volume (g)] Conversion of propane or isobutane (%) = [mol of propane or isobutane consumed] Number] / [moles of propane or isobutane supplied] × 100 Selectivity (%) of target product = [moles of target product generated] / [moles of propane or isobutane consumed] × 100 target generation Product yield (%) = [moles of target product formed] / [moles of propane or isobutane supplied]
× 100

Example 1 A catalyst having a composition represented by SbNb _0.95 V _0.05 O _X was prepared by the following method. 1.6 g of vanadium pentoxide was added to a mixed solution of benzyl alcohol and toluene, and the mixture was heated and stirred to reduce the color to black. After reduction, niobic acid was added to 58.1.
g and antimony trioxide were added, and benzyl alcohol and toluene were evaporated with good stirring. The paste-like solid was taken out and dried at 350 ° C. for 6 hours.
Thereafter, it was baked at 600 ° C. for 4 hours. This catalyst was charged into a reactor, the reaction temperature was 500 ° C., and the space velocity was 1600 ml /
h · g, propane: ammonia: oxygen: helium = 1:
An ammoxidation reaction of propane was performed at a molar ratio of 1: 2: 2. Table 1 shows the results.

Example 2 A catalyst having a composition represented by SbNb _0.9 V _0.1 O _X was prepared in the same manner as in Example 1 except that 3.3 g of vanadium pentoxide and 55.0 g of niobic acid were added. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Example 3 A catalyst having a composition represented by SbNb _0.8 V _0.2 O _X was prepared in the same manner as in Example 1 except that 6.5 g of vanadium pentoxide and 48.9 g of niobic acid were added. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Example 4 A catalyst having a composition represented by SbNb _0.5 V _0.5 O _X was prepared in the same manner as in Example 1 except that 16.3 g of vanadium pentoxide and 30.6 g of niobic acid were added. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Example 5 A catalyst having a composition represented by SbNb _0.2 V _0.8 O _X was prepared in the same manner as in Example 1 except that 26.1 g of vanadium pentoxide and 12.2 g of niobic acid were added. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Example 6 A catalyst having a composition represented by SbTa _0.9 V _0.1 O _X was prepared in the same manner as in Example 2 except that 68.7 g of tantalum pentoxide was added instead of niobic acid. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Example 7 A catalyst having a composition represented by SbNb _0.6 V _0.1 Fe _0.3 O _X was prepared by the following method. Isobutyl alcohol 300m
3.2 g of vanadium pentoxide was added to the 1 solution, and the mixture was heated and stirred to be reduced to black. After reduction, 3
6.7 g and 52.3 g of antimony trioxide were added, and isobutyl alcohol was evaporated with good stirring. The obtained solid was dried at 350 ° C. for 6 hours. This solid was thoroughly mixed with iron hydroxide obtained by adding 43.6 g of iron nitrate to a distillation and adding ammonia water, dried at 200 ° C., then at 400 ° C. for 2 hours, and further at 750 ° C. for 4 hours. Fired. An ammoxidation reaction of propane was performed in the same manner as in Example 1. Table 1 shows the results.

Example 8 A catalyst having a composition represented by SbNb _0.6 V _0.1 Sn _0.3 O _X was prepared by the following method. The solid consisting SbNb _0.6 V _0.1 O _X was prepared in the same manner as in Example 7, tin chloride 32.0
g was added to an aqueous solution of 3M hydrochloric acid, mixed well with iron hydroxide obtained by adding aqueous ammonia, and dried at 200 ° C.
Baking was performed at 0 ° C. for 2 hours and further at 750 ° C. for 4 hours. An ammoxidation reaction of propane was performed in the same manner as in Example 1. Table 1 shows the results.

[0026] A catalyst was prepared to Example 9 composition represented by SbNb _0.6 V _0.1 Ti _0.3 O _X in the following manner. The solid consisting SbNb _0.6 V _0.1 O _X was prepared in the same manner as in Example 7, the titanium chloride 2
A solution obtained by adding 4.3 g to a 3 M hydrochloric acid aqueous solution and then adding ammonia water was mixed well with titanium hydroxide, dried at 200 ° C, and calcined at 400 ° C for 2 hours and further at 750 ° C for 4 hours. An ammoxidation reaction of propane was performed in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 1 A catalyst whose composition was represented by SbNbO ₄
It was prepared in the same manner as in Example 1 except that 1.1 g was added and vanadium pentoxide was not added. Using this catalyst,
An ammoxidation reaction of propane was performed in the same manner as in Example 1.
Table 1 shows the results.

Comparative Example 2 A catalyst having a composition represented by SbVO ₄ was prepared in the same manner as in Example 1 except that 32.6 g of vanadium pentoxide was added and no niobic acid was added. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 3 A catalyst having a composition represented by SbV _0.1 Fe _0.3 O _X was prepared in the same manner as in Example 7 except that no niobate was added. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 4 A catalyst having a composition of SbV _0.1 Sn _0.3 O _X was prepared in the same manner as in Example 8, except that no niobate was added. Using this catalyst, propane ammoxidation was carried out in the same manner as in Example 1. Table 1 shows the results.

[0031]

[Table 1]

[0032]

According to the catalyst produced by the method of the present invention,
The target nitrile can be produced in high yield from propane or isobutane as a raw material.

Claims (3)

[Claims] 1. A process for producing acrylonitrile or methacrylonitrile from propane or isobutane by ammoxidation, the following general formula _{Sb a Q b V c M d} O x ( wherein Sb is antimony, Q is niobium and / or T is tantalum, V is vanadium, M is at least one element selected from the group consisting of molybdenum, tungsten, iron, chromium, manganese, titanium, tin and cerium, O represents oxygen, and when a is 1, b = 0 .1 to 1.5, c = 0.001 to 1, d = 0 to 1, and x is a value determined by the oxidation state of each element.) And at least the following in X-ray diffraction: A method for producing an unsaturated nitrile, comprising using an oxide catalyst composition having a lattice spacing d (Å).
Lattice spacing d (Å) 3.49 to 3.52 3.09 to 3.13 2.95 to 2.98 2. The oxide catalyst composition is obtained by reducing a pentavalent vanadium compound, mixing a compound of niobium and antimony, and calcining the mixture.
Production method as described. 3. The method according to claim 2, wherein an alcohol and / or an aldehyde is used as a reducing agent in the reduction of the pentavalent vanadium compound.