JPH05170724A - Production of nitrile compound and catalyst therefor - Google Patents

Abstract

PURPOSE:To obtain a nitrile compound in high yield by catalytic reaction of an alkyl-substituted aromatic compound or alkyl-substituted heterocyclic compound with a mixed gas containing both ammonia and oxygen in the presence of a catalyst. CONSTITUTION:The objective nitrile compound can be obtained by the above- mentioned reaction using a catalyst prepared by allowing silica to support (A) both molybdenum oxide and phosphorus oxide prepared using phosphomolybdic acid or its salt, (B) vanadium oxide, (C) chromium oxide and (D) boron oxide.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention produces a corresponding nitrile compound from an alkyl-substituted aromatic compound or an alkyl-substituted heterocyclic compound (hereinafter collectively referred to as an alkyl-substituted compound), a mixed gas containing ammonia and oxygen. A method and its catalyst. Nitrile compounds are important intermediates in the organic chemical industry.For example, phthalonitrile is used as a synthetic resin, pesticide, and xylylenediamine raw material useful as a curing agent for diisocyanate and epoxy resins, and cyanopyridine is It is used as a raw material for nicotinic acid amide and nicotinic acid, which are useful substances in the fields of pharmaceuticals, feed additives, food additives, and the like.

[0002]

2. Description of the Related Art Various methods have been proposed for producing aromatic nitriles by ammoxidizing an alkyl-substituted aromatic compound with ammonia and oxygen. For example, Japanese Patent Publication 45-
It is described in 19284 that vanadium, chromium, and boron ternary catalysts show excellent performance. In JP-B-49-45860, silica is used as a carrier for this ternary catalyst, and vanadium is used. The atomic ratio of oxide, chromium oxide and boron oxide is 1: (0.5-2.0).
): (0.1-1.2), 30 with respect to silica
~ 60 wt% supported catalyst is described as excellent. In Japanese Patent Publication No. 51-15028, the atomic ratio of vanadium oxide, chromium oxide, boron oxide and phosphorous oxide is 1: (0.5-2.0) :( 0.1-
1.2): It is described that the catalyst of (0.01 to 0.3) can obtain high activity in a wide temperature range.
No. 275551 has an atomic ratio of vanadium oxide, chromium oxide, molybdenum oxide, and boron oxide of 1:
(0.5-2.0): (0.01-1.2): (0.0
It is described that the catalysts 1 to 1.2) have a small decrease in aromatic nitrile selectivity with time. As an example of producing a corresponding nitrile compound by ammoxidation of an alkyl-substituted heterocyclic compound, Japanese Patent Application Laid-Open No. 1-275564 discloses that when cyanopyridine is produced by reacting methylpyridine with ammonia and an oxygen-containing gas, silica is added. It is described that a high yield can be obtained by using a supported catalyst composed of vanadium oxide, chromium oxide and boron oxide.

[0003]

In the ammoxidation reaction in which an alkyl-substituted compound is reacted with ammonia and oxygen in a gas phase, it is extremely difficult to control the reaction temperature because a large amount of heat of reaction is generated. Is particularly effective. JP-B-49-45860, which uses silica as a carrier, is an improved version of JP-B-45-19284, and this catalyst is used in a fluidized bed reactor and exhibits excellent performance. Also, Japanese Patent Publication No. 51-15028, JP-A 1-275.
No. 551 also obtained favorable results using a fluidized bed reactor. However, these catalysts do not always have a sufficient yield of the nitrile compound, and further improvement thereof is desired.

[0004]

Means for Solving the Problems As a result of diligent studies for further improving the yield of a nitrile compound in an ammoxidation reaction of an alkyl-substituted compound, the present inventor has found that vanadium oxide, chromium oxide, boron supported on silica By using a five-component catalyst of a specific composition in which a phosphorus oxide and a molybdenum oxide prepared by using a compound of phosphomolybdic acid are added to a three-component catalyst composed of an oxide, the nitrile yield is remarkably increased. The present invention has been found by finding improvements.

That is, according to the present invention, when a nitrile compound is produced by catalytically reacting an alkyl-substituted aromatic compound or an alkyl-substituted heterocyclic compound with a mixed gas containing ammonia and oxygen on a catalyst, phosphomolybdic acid or a salt thereof is used. A method for producing a nitrile compound, which comprises using a catalyst prepared by using molybdenum oxide and phosphorus oxide, vanadium oxide, chromium oxide, and boron oxide supported on silica, and a catalyst thereof. ..

As the vanadium oxide, chromium oxide and boron oxide component raw materials used in the present catalyst, the respective oxides may be used as they are, or they may be easily treated by an appropriate treatment such as heating during catalyst preparation. Various compounds that become oxides are used. These compounds are
For example, vanadium includes ammonium metavanadate, vanadyl sulfate, and vanadium salts of organic acids such as oxalic acid and tartaric acid, and chromium includes chromic acid, chromium nitrate, chromium hydroxide, ammonium chromate, ammonium dichromate, and Boric acid, ammonium borate and the like are used as chromium salts and boron of organic acids such as oxalic acid and tartaric acid.

The present invention relates to molybdenum oxide and phosphorylation.
Phosphomolybdic acid or its salt is used as a raw material
It was found that
Of. This phosphomolybdic acid is a heteropoly acid compound
And is usually hydrothermally derived from phosphoric acid and molybdenum oxide.
Is synthesized. As phosphomolybdic acid, for example, H₃[PM
o₁₂O₄₀], H₇[PMo₁₁O₃₉], H₆[P₂Mo₁₈O
₆₂], Etc., and phosphorus molybdate is phosphorus molybdate.
Ammonium budenate (NH_Four)₃ [PMo ₁₂O₄₀]
There is a throat. Sources of molybdenum oxide and phosphorus oxide
For example, without using phosphomolybdic acid or its salt
As molybdenum, ammonium paramolybdate,
The remarkable effect is obtained when the catalyst is prepared using phosphoric acid as the catalyst.
The result is not exhibited.

The atomic ratio of vanadium, chromium, boron, molybdenum and phosphorus which are the catalyst components is 1: (0.5-2.
0): (0.01-1.2): (0.01-1.2)
): (0.001-0.1) is preferable. If the atomic ratio of each catalyst component is out of this range, the yield of the nitrile compound decreases. Examples of the silica carrying these catalyst components include, for example, Chemical Handbook, Applied Chemistry I.
The silica gel, colloidal silica, anhydrous silica and the like described on pages 256 to 258 (published by Maruzen 1986) are used. The concentration of the catalyst component was V ₂
As a weight% of the total oxide amount calculated as O ₅ , Cr ₂ O ₃ , B ₂ O ₃ , MoO ₃ , and P ₂ O _{5 in} the catalyst, 20 to 20
It is 80% by weight, preferably 30-60% by weight.

The catalyst can be produced by a known method. For example, a phosphomolybdic acid aqueous solution and a boric acid aqueous solution are added to a solution of vanadium oxide and chromium oxide dissolved in oxalic acid, and then silica sol is added to obtain a slurry mixture. In this case, if necessary, a solubilizing agent for boric acid is used. As the solubilizing agent for boric acid, polyhydric alcohol, α-monooxycarboxylic acid and dioxycarboxylic acid are used. In the case of a fluidized bed catalyst, this mixture is spray-dried, and if necessary, further dried at 110 to 150 ° C. and then calcined. For fixed bed catalysts, evaporate the mixture to dryness,
Then, it is baked. The firing is performed at 400 to 700 ° C., preferably 450 to 650 ° C. for several hours or more while circulating air. It should be noted that more preferable results can be obtained by performing preliminary firing at 200 to 400 ° C. prior to this firing.

Examples of the alkyl-substituted aromatic compound as a raw material to be ammoxidized include toluene, ethylbenzene, polymethylbenzene (xylene, mesitylene, cymene, durene, etc.), diethylbenzene, methylnaphthalene and the like. Further, as the alkyl-substituted heterocyclic compound,
Methyl pyridine, ethyl pyridine, dimethyl pyridine,
Methyl quinoline etc. are mentioned. The concentration of these starting alkyl compounds in the gas supplied to the reactor is preferably 0.5 to 5 vol% when air is used as the oxygen source.

The amount of ammonia used may be the theoretical amount (1 mol of ammonia per 1 mol of alkyl group) or more. The higher the molar ratio of the ammonia / alkyl-substituted compound in the raw material gas, the more advantageous it is to the nitrile yield from the raw material alkyl compound. However, the amount of ammonia used is not less than the theoretical amount because it requires recovery of unreacted ammonia. , And preferably about 2 to 10 times the theoretical amount. Air is usually used as the oxygen source, but it may be diluted with nitrogen, carbon dioxide, steam or the like as an inert diluent. The amount of oxygen to be supplied must be at least 1.5 times the theoretical amount or more, and preferably 2 to 50 times the theoretical amount.

The reaction temperature can be carried out in a wide range of 300 to 500 ° C, preferably 330 to 470 ° C. At a temperature lower than 300 ° C, the conversion rate of the raw material alkyl compound is small, and at a temperature higher than 500 ° C, carbon dioxide,
The production of hydrogen cyanide and the like increases and the yield of the nitrile compound decreases. The reaction temperature that gives the highest yield varies depending on the type of the starting alkyl-substituted compound, the starting material concentration, the contact time, the calcination conditions of the catalyst, and the like. Therefore, it is preferable to appropriately select within this range according to these conditions. The contact time between the reaction gas and the catalyst can be generally within a wide range, but it is preferably 0.5 to 30 seconds.

The reaction of the present invention is usually carried out at atmospheric pressure, but it can also be carried out under pressure or under reduced pressure. The reaction product can be collected by any appropriate method, for example, a method of collecting the reaction product by cooling it to a temperature sufficient for precipitating the product, or a method of washing and collecting the reaction product gas with water or another suitable solvent. Etc. are used. As mentioned above, since the reaction of the present invention is accompanied by intense heat generation, it is advantageous to carry out the reaction in a fluidized bed or a moving bed in the sense of removing the heat of reaction and preventing partial heating. Even if it is carried out, its characteristics are exhibited and excellent performance is maintained.

[0014]

EXAMPLES Next, the present invention will be described more specifically by way of Examples and Comparative Examples. However, the present invention is not limited to these examples.

Comparative Example 1 (Preparation of catalyst) To 229 g of vanadium pentoxide V ₂ O ₅ was added 500 ml of water, heated to 80 to 90 ° C., and 477 g of oxalic acid was added and dissolved while stirring well. Oxalic acid 9
To 63 g, 400 ml of water was added and heated to 50-60 ° C., and a solution of 252 g of CrO ₃ chromic anhydride in 200 ml of water was added and dissolved while stirring well. To the solution of vanadyl oxalate thus obtained, add 5 parts of the solution of chromium oxalate.
Mix at 0-60 ° C to obtain a vanadium-chromium solution. On the other hand, ammonium paramolybdate (NH ₄ ) ₆ M
oO ₂₄ · 4H ₂ O 44g water 300ml was added to this was added 85 wt% phosphoric acid H ₃ PO ₄ 3 g, mixed well at 30 to 40 ° C.. This molybdenum-phosphoric acid solution is added to the above vanadium-chromium solution, and 1667 g of 30 wt% aqueous silica sol is further added. To this slurry solution, 78 g of boric acid H ₃ BO ₃ was added and mixed well to obtain a liquid volume of about 3800.
Concentrate to g. The catalyst solution is heated to an inlet temperature of 250
Spray drying was carried out while maintaining the temperature at 130 ° C and the outlet temperature at 130 ° C. The spray-dried catalyst was dried in a dryer at 130 ° C for 12 hours and then 4
It was calcined at 00 ° C. for 0.5 hours, and then calcined at 550 ° C. for 8 hours under flowing air. This catalyst has an atomic ratio of V: C
r: B: Mo: P is 1: 1: 0.5: 5: 0.0: 1.0.01
And the catalyst concentration is 50 wt%.

(Catalyst activity test) A reactor having an inner diameter of 23 mm, which was heated in a molten salt bath, was charged with 40 ml of this catalyst, and metaxylene concentration was 3.0 vol% and ammonia was 21.0 vol.
%, Air at 76.0 vol%, the temperature at which this catalyst gives the highest isophthalonitrile yield 370
The fluidized contact reaction was carried out at a temperature of ℃ at a space velocity of SV750Hr ^-1 . As a result, the yield of isophthalonitrile was 76.9 mol% with respect to metaxylene, and the yield of metatolunitrile was 4.9 mol%, and the selectivity of isophthalonitrile with respect to the reacted metaxylene was high. Is 79.2
It was mol%.

Example 1 (Preparation of catalyst) Vanadium pentoxide V ₂ O ₅ 229 g of water 5
00 ml was added, the mixture was heated to 80 to 90 ° C., and 477 g of oxalic acid was added and dissolved while stirring well. Oxalic acid 9
To 63 g, 400 ml of water was added and heated to 50 to 60 ° C., and a solution of 252 g of CrO ₃ chromic anhydride in 200 ml of water was added and dissolved with good stirring. The solution of vanadyl oxalate thus obtained is mixed with the solution of chromium oxalate at 50 to 60 ° C. to obtain a vanadium-chromium solution. Phosphomolybdic acid H ₃ [PMo ₁₂ O ₄₀ ] was added to this solution.
Add a solution of 49.6 g of 30H ₂ O in 100 ml of water, and then add 1667 g of 30 wt% aqueous silica sol. To this slurry solution, 78 g of boric acid H ₃ BO ₃ was added and mixed well, and concentrated until the liquid amount became about 3800 g. This catalyst solution was supplied at an inlet temperature of 250 ° C. and an outlet temperature of 130.
It was spray-dried while keeping at ℃. 13 spray dried catalysts
After being dried in a dryer at 0 ° C. for 12 hours, it was calcined at 400 ° C. for 0.5 hours and then at 550 ° C. for 8 hours under air flow. This catalyst contains V: Cr: B: Mo: P in an atomic ratio of 1: 1: 0.5: 0.0: 1: 0.01.
The catalyst concentration is 50 wt%.

(Catalyst activity test) A catalyst activity test was conducted in the same manner as in Comparative Example 1 using the catalyst prepared as described above. Meta-xylene 3.0 vol%, ammonia 21.0 vol%,
A gas consisting of 76.0 vol% air was used at a temperature of 390 ° C, SV at which this catalyst gives the highest isophthalonitrile yield.
The reaction was carried out under the condition of 750 Hr ^-1 . The yield of isophthalonitrile with respect to metaxylene was 84.2 mol%, the yield of metatolunitrile was 2.2 mol%, and the selectivity of isophthalonitrile with respect to the reacted metaxylene was 84.2 mol%.
It was mol%.

Example 2 V: Cr: B: Mo: P in atomic ratio of 1: 1: 0.5:
A catalyst of 0.2: 0.02 was prepared in the same manner as in Example 1 and the activity test of the catalyst was conducted. Metaxylene 3.0 vol
% Ammonia, 21.0 vol% ammonia, 76.0 vol% air were reacted at SV 750 Hr ⁻¹ at 410 ° C., a temperature at which the catalyst gives the highest isophthalonitrile yield. The yield of isophthalonitrile with respect to metaxylene was 83.0 mol%, the yield of metatolunitrile was 2.8 mol%, and the selectivity of isophthalonitrile with respect to the reacted metaxylene was 83.4 mol%. ..

Example 3 Instead of the phosphomolybdic acid of Example 1, ammonium phosphomolybdate (NH ₄ ) ₃ [PMo ₁₂ O ₄₀ ] .3H ₂ O was used.
And V: Cr: B: Mo: P in an atomic ratio of 1: 1:
A 0.5: 0.1: 0.01 catalyst was prepared in the same manner as in Example 1 and the activity test of the catalyst was examined. Metaxylene 3.0
vol%, ammonia 21.0 vol%, air 76.0 vo
A gas consisting of 1% was reacted under the conditions of SV750Hr ^-1 at a temperature of 390 ° C at which the catalyst gives the highest yield of isophthalonitrile. The yield of isophthalonitrile with respect to meta-xylene was 84.1 mol%, the yield of metatolunitrile was 2.1 mol%, and the selectivity of isophthalonitrile with respect to the reacted meta-xylene was 84.5 mol%. It was

Example 4 Using the catalyst prepared in Example 1 and substituting paraxylene for metaxylene, an activity test of the catalyst was conducted in the same manner as in Example 1. A gas consisting of para-xylene 3.2 vol%, ammonia 19.5 vol% and air 77.3 vol%,
The catalyst was reacted with SV 800 Hr ^-1 at a temperature of 400 ° C., which gives the highest terephthalonitrile yield. The yield of terephthalonitrile based on paraxylene was 84.8.
The yield of paratolunitrile was 1.9 mol%, and the selectivity of terephthalonitrile to the reacted para-xylene was 85.2 mol%.

Example 5 Using the catalyst prepared in Example 1 and using toluene in place of metaxylene, an activity test of the catalyst was conducted in the same manner as in Example 1. Toluene 5.1 vol%, ammonia 25.0
A gas consisting of vol% and 69.9 vol% air was reacted under the conditions of SV840Hr ^-1 at 410 ° C, the temperature at which this catalyst gives the highest benzonitrile yield. The yield of benzonitrile with respect to toluene was 84.5 mol%, and the selectivity of benzonitrile with respect to the reacted toluene was 84.9 mol%.

Example 6 Using the catalyst prepared in Example 1, and using 3-methylpyridine in place of metaxylene, an activity test of the catalyst was conducted in the same manner as in Example 1. 3-methylpyridine 3.0 vol
% Ammonia, 12.0 vol% ammonia, 85.0 vol% air were reacted under the conditions of SV750 Hr ^-1 at 390 ° C. at a temperature where the catalyst gives the highest 3-cyanopyridine yield. The yield of 3-cyanopyridine with respect to 3-methylpyridine was 93.7 mol%, and the reaction of 3
The selectivity of 3-cyanopyridine with respect to -methylpyridine was 94.2 mol%.

[0024]

EFFECT OF THE INVENTION A catalyst in which molybdenum oxide and phosphorus oxide prepared by using the phosphomolybdic acid or its salt of the present invention and vanadium oxide, chromium oxide and boron oxide are supported on silica is used. As a result, the alkyl-substituted aromatic compound or alkyl-substituted heterocyclic compound is ammoxidized as shown in the examples, and the corresponding nitrile compound is obtained in an extremely high yield. The catalyst of the present invention is advantageously reacted in a fluidized bed or a moving bed, but even when used in a fixed bed reaction, its characteristics are exhibited and excellent performance is maintained, and a nitrile compound is industrially extremely advantageously produced. can do.

As mentioned above, the use of a catalyst composed of vanadium oxide, chromium oxide and boron oxide in such an ammoxidation reaction is disclosed in JP-B-51-15028.
The use of a catalyst composed of vanadium oxide, chromium oxide, boron oxide and molybdenum oxide is described in JP-A-1-275564. However, the use of phosphomolybdic acid or a salt thereof as a raw material in the preparation of these ammoxidation reaction catalysts is not described. In addition, vanadium oxide, chromium oxide, and boron oxide to which molybdenum oxide and phosphorus oxide are added are novel catalyst compositions in ammoxidation reaction. The extremely high yield of this nitrile compound is obtained only when the molybdenum oxide and the phosphorus oxide are prepared from phosphomolybdic acid or a salt thereof, as shown in Comparative Example 1, simply prepared from molybdate and phosphoric acid. In that case, the expected yield cannot be obtained. Therefore, the present invention is a novel invention which cannot be easily inferred by a person skilled in the art from the above-mentioned known documents.

Claims (3)

[Claims] 1. When a nitrile compound is produced by catalytically reacting an alkyl-substituted aromatic compound or an alkyl-substituted heterocyclic compound with a mixed gas containing ammonia and oxygen on a catalyst, phosphomolybdic acid or a salt thereof is used. Of a nitrile compound, characterized by using a catalyst comprising silica, which is supported molybdenum oxide and phosphorus oxide, and vanadium oxide, chromium oxide, and boron oxide. 2. A nitrile compound in which molybdenum oxide and phosphorus oxide prepared by using phosphomolybdic acid or a salt thereof, and vanadium oxide, chromium oxide, and boron oxide are supported on silica. Production catalyst 3. The atomic ratio of vanadium, chromium, boron, molybdenum and phosphorus is 1: (0.5-2.0) :( 0.
01-1.2): (0.01-1.2): (0.001
The catalyst for producing a nitrile compound according to claim 2, wherein