JP4240191B2 - Process for producing aromatic nitrile and heterocyclic nitrile - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an aromatic nitrile or a heterocyclic nitrile by reacting a carbocyclic compound or a heterocyclic compound with a mixed gas containing ammonia and oxygen. Aromatic nitriles are useful as production raw materials for synthetic resins, agricultural chemicals, and the like, and as intermediate raw materials for amines, isocyanates, and the like. On the other hand, heterocyclic nitriles are used as intermediate raw materials for pharmaceuticals, feed additives, food additives and the like.
[0002]
[Prior art]
The ammoxidation reaction in which ammonia and oxygen are reacted with a carbocyclic compound or heterocyclic compound in the gas phase is extremely difficult to control the reaction temperature due to the generation of a large amount of reaction heat. The reactor is effective. JP-B-49-45860, which uses silica as a carrier for the catalyst, is an improvement of JP-B-45-19284 and exhibits excellent performance. Also, JP-B-51-15028, JP-A-1-275551, and JP-A-5-170724 can obtain preferable results using a fluidized bed reactor. However, all of these catalysts are subject to catalyst wear and pulverization in a fluid state, and it is difficult to continue a stable reaction. On the other hand, in the fixed bed type, a multi-tubular reactor is used, and generally a metal oxide catalyst in which an active ingredient is supported on alumina or titania is used. These catalysts have a practically durable strength in order to obtain the corresponding nitrile compound in a high yield, and at the same time, to prevent transformation in the reactor due to catalyst dusting during catalyst filling and reaction conditions. It is important to have.
[0003]
As a method for improving the catalyst strength, a strong support can be formed by sintering at 1000 ° C. or higher, and an effective metal oxide can be supported thereon. However, in a catalyst system that requires a large amount of effective metal oxide, It is difficult to obtain sufficient strength because defects such as peeling and cracking occur due to external impact and thermal stress between the support and the effective metal oxide, and the powder is pulverized. In order to increase the bonding force between the support and the effective metal oxide, the support and the effective metal oxide are mixed in the powder stage, and further a molding aid such as alumina or zirconia having a chemical bonding force is added. In this case as well, the strength is improved, but the decomposition reaction is accelerated at the chemically active sites of these oxides, and the desired nitrile product cannot be obtained in high yield.
[0004]
[Problems to be solved by the invention]
The object of the present invention is to provide a practical high-performance reactor in a fixed-bed multi-tubular reactor for ammoxidation of a carbocyclic compound or heterocyclic compound by a gas phase catalytic reaction to produce a corresponding aromatic nitrile or heterocyclic nitrile. It is to propose a catalyst having strength and obtaining the target product in high yield.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventor mixed a chromium compound treated with a specific chromium treating agent with a metal oxide containing vanadium, molybdenum or iron and alumina or titania. As a result, the inventors have found that a catalyst having a strength that can be practically endured and capable of obtaining the target product in a high yield can be obtained, and the present invention has been completed. That is, in the present invention, when a carbocyclic compound or a heterocyclic compound and a mixed gas containing ammonia and oxygen are contact-reacted on a catalyst to produce a corresponding nitrile compound, the chromium compound is converted into alcohols, sugars, organic oxy compounds and Prepared by mixing at least one kind of chromium treating agent selected from water-soluble aldehydes with heating and boiling treatment, one or more metal oxides selected from V, Mo and Fe, and alumina or titania. The present invention relates to a method for producing an aromatic nitrile or heterocyclic nitrile characterized by using a high-strength catalyst.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be specifically described.
The reaction in the present invention is a reaction (ammoxidation reaction) of a carbocyclic compound or a heterocyclic compound with an oxygen-containing gas and ammonia, and is carried out by contacting in a gas phase on a catalyst.
[0007]
The carbocyclic compound used as a raw material in the present invention is an aromatic compound and an alicyclic compound, and the alicyclic compound is simultaneously oxidized and dehydrogenated in this reaction (ammoxidation reaction) with an oxygen-containing gas and ammonia. Can be easily converted to an aromatic nitrile. Aromatic compounds and alicyclic compounds have a carbocyclic ring such as benzene, naphthalene, anthracene, cyclohexene, cyclohexane, dihydronaphthalene, tetralin, decalin, etc., and bonded methyl, ethyl, propyl, formyl, acetyl groups , A carbocyclic compound having at least one side chain (hereinafter referred to as a substituent) capable of generating a cyano group by an ammoxidation reaction, such as a hydroxymethyl group or a methoxycarbonyl group. The carbocyclic compound can be used even if it contains a halogen group, a hydroxyl group, an alkoxyl group, an amino group, a nitro group, or the like.
For example, toluene, xylene, trimethylbenzene, ethylbenzene, methylnaphthalene, dimethylnaphthalene, methyltetralin, dimethyltetralin, chlorotoluene, dichlorotoluene, methylamylin, cresol, methylanisole and the like can be mentioned.
These compounds can be used alone or in a mixture.
[0008]
The heterocyclic compound used in the present invention has a heterocyclic ring such as furan, pyrrole, indole, thiophene, pyrazole, imiazole, oxazole, pyran, pyridine, quinoline, isoquinoline, pyrroline, pyrrolidine, imidozoline, imidazolidine, pepyridine, and pepyrazine. It is a compound, and has a substituent in the side chain similarly to the said carbocyclic compound. Further, like the carbocyclic compound, it may contain a substituent such as a halogen group.
Examples thereof include furfural, 2-methylthiophene, 3-methylthiophene, 2-formylthiophene, 4-methylthiazole, methylpyridine, dimethylpyridine, trimethylpyridine, methylquinoline, methylpyrazine, dimethylpyrazine, methylpepyrazine and the like.
These compounds can be used alone or in a mixture.
[0009]
The raw material ammonia used in the present invention may be an industrial grade. The amount of ammonia used is in the range of 1 to 10 times mol, preferably 3 to 6 times mol for one substituent contained in 1 mol of the carbocyclic compound or heterocyclic compound. If the amount used is less than this, the yield of the target product is lowered, while if it is more than this, the space-time yield is reduced. In the method of the present invention, unreacted ammonia contained in the reaction gas can be recovered and returned to the reaction system for reuse. There are various methods for recovering unreacted ammonia from the reaction gas, but industrially, it is advantageous to absorb unreacted ammonia in water and then separate it from other by-products by distillation operation. . The amount of water in the ammonia recovered here varies depending on the distillation operating conditions, but is usually 5 to 20% by volume.
[0010]
The oxygen used in the present invention is supplied in the form of an oxygen-containing gas, and usually air is used. Alternatively, air or oxygen can be diluted with an inert gas such as nitrogen, carbon dioxide, exhaust gas or the like. The amount of oxygen used is 1.5 times mol or more, preferably 2 to 50 times mol for one substituent contained in 1 mol of the carbocyclic compound or heterocyclic compound. If the amount used is less than this, the yield of the target product is lowered, while if it is more than this, the space-time yield is reduced.
[0011]
The catalyst used in the present invention is basically composed of a composition containing at least one metal oxide selected from V, Mo and Fe and a chromium-treated product described later. The chromium-treated product is preferably in the range of 1.0 to 10.0% by weight based on the chromium metal oxide. When the chromium-treated product is less than this, the strength of the catalyst and the yield of the target product are obtained. Becomes worse. On the other hand, when the amount is larger than this, the yield is lowered by the diluting action and the catalyst cost is increased, which is disadvantageous in terms of economy. Further, an oxide of at least one metal selected from the group consisting of Mg, Ca, Ba, W, Co, Ni, B, Ge, Sn, Pb, P, Sb and Bi is added to the metal oxide. A modified composition system is preferable, and a metal oxide catalyst represented by the following composition formula is particularly preferable.
Composition formula: (Cr) a (V) b (Mo) c (Fe) d (X) e (O) f
(Where X is Mg, Ca, Ba, W, Co, Ni, B, Ge, Sn, Pb, P, Sb and Bi, subscripts a, b, c, d And e each represent an atomic ratio, a = 0.01 to 1 (preferably 0.1 to 0.7), b = 0.01 to 1 (preferably 0.1 to 0.7), c = 0 -1, d = 0 to 1 (preferably 0.05 to 0.7), e = 0 to 1 (preferably 0.05 to 0.7), and f is an oxide obtained by bonding the above elements Of oxygen).
These metal oxide catalysts can be used as high-strength catalysts in the present invention by using alumina or titania as a support.
[0012]
In the present invention, various metal oxide catalysts included in the above composition formula can be used. In particular, 50 to 99% by weight, preferably 65 to 95% by weight of alumina or titania as a support in Cr to V to B to Mo. A high-strength catalyst added with ˜97% by weight is preferably used.
[0013]
As the vanadium source in this catalyst, ammonium metavanadate, vanadyl sulfate, and vanadium salts of organic acids such as oxalic acid and tartaric acid are used, but ammonium metavanadate that can be easily decomposed into an oxide by subsequent calcination operation. , Vanadyl oxalate, vanadyl tartrate and the like are preferable.
As the boron source, boric acid, ammonium borate, or the like is used.
In addition, examples of the molybdenum source include ammonium paramolybdate, sodium molybdate, and potassium molybdate. Among these, metal cations such as sodium ions and potassium ions are easily decomposed in the subsequent calcination operation, and the catalyst contains metal cations such as sodium ions and potassium ions. Preference is given to ammonium paramolybdate which does not remain in the water.
[0014]
As the chromium source, chromium compounds such as chromic anhydride, ammonium chromate, sodium chromate, ammonium dichromate, potassium dichromate, sodium dichromate, etc. can be used. The salt containing is required to be removed (for example, an ion exchange method), and it is advantageous to use chromic anhydride, ammonium chromate, or ammonium dichromate that does not require this operation. Furthermore, chromic anhydride is most preferable in consideration of the price of the raw material.
[0015]
The chromium treating agent of the present invention can be selected from alcohols, sugars, organic oxy compounds and water-soluble aldehydes. Examples of alcohols include ethanol, propanol, butanol, propylene glycol, glycerin, pentaerythritol, xylol, sorbitol, and the like. Examples of sugars include galactose, mannitol, inosit, fructose, and starch. Moreover, as an organic oxy compound, an organic oxy acid and its ammonium salt are preferable, and specifically, glycolic acid, glyceric acid, oxalic acid, tartaric acid, and its ammonium salt are mentioned. Examples of water-soluble aldehydes include formaldehyde and glycol aldehyde.
Said compound can be used individually or in mixture of 2 or more types.
[0016]
In the method of treating the chromium compound, an aqueous solution of the chromium compound and an aqueous solution of the above-mentioned treatment agent are mixed and heated and boiled in a reactor equipped with a reflux. At that time, the concentration of the chromium compound and the concentration of the treatment agent are not critical and can vary widely depending on the type of the chromium compound and the treatment agent to be used, but generally both are 0.1 to 5.0 mol / liter. If the concentration is lower than this, the productivity will be poor, and it will be disadvantageous in terms of economy. In this case, a homogeneous catalyst cannot be obtained. The treatment time by heating is advantageously within 2 hours, preferably 30 minutes to 1 hour. By this treatment, the chromium aqueous solution becomes a sol-like substance (chromium treated product).
[0017]
The catalyst can be produced using a known method. For example, an aqueous boric acid solution is added to an aqueous solution in which vanadium oxide is dissolved in oxalic acid to obtain a uniform aqueous solution, and then a chromium-treated product and alumina or titania powder as a carrier are added and mixed. Thereafter, in order to sufficiently homogenize the catalyst, the mixture is kneaded by a mechanical operation and then extruded into an appropriate shape by a biaxial extruder. The obtained molded body is dried at 110 to 150 ° C. until a constant weight is obtained, and then calcined at 350 to 700 ° C., preferably 400 to 600 ° C., for several hours or more while circulating air. In addition, a more preferable result can be obtained when preliminary baking is performed at 200 to 350 ° C. prior to the baking.
[0018]
Although reaction temperature can be implemented in the wide range of 300-500 degreeC, it is preferable that it is 330-470 degreeC. When the temperature is lower than 300 ° C., the conversion rate of the raw material compound is small, and when the temperature is higher than 500 ° C., the production of carbon dioxide, hydrogen cyanide and the like increases and the yield of the nitrile compound decreases. Since the reaction temperature showing the highest yield varies depending on the type of raw material, the raw material concentration, the contact time, the calcination temperature of the catalyst, and the like, it is preferably selected within this range depending on these conditions. In general, the contact time between the reaction gas and the catalyst can be in a considerably wide range, but is preferably 0.5 to 30 seconds.
[0019]
The reaction of the present invention is usually carried out at normal pressure, but can be carried out under pressure or under reduced pressure. The reaction product can be collected by any appropriate method, for example, a method of cooling and collecting to a temperature sufficient to precipitate the product, a method of washing and collecting the reaction product gas with water or other suitable solvent Etc. are used.
[0020]
【Example】
Next, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited by these examples.
[0021]
Example 1
(Preparation of catalyst) After 19.6 g of CrO ₃ chromic acid was dissolved in 80 ml of water, 35.3 g of sorbitol was gradually added at 50 ° C., dissolved, reacted, and then boiled in a flask equipped with a reflux apparatus. The processing of was complete. On the other hand, 17.8 g of vanadium pentoxide V ₂ O ₅ was dissolved in 40 ml of water, heated to 80 to 90 ° C., 44.4 g of oxalic acid was added with good stirring, and the dissolved liquid was dissolved in 30 ml of water. 0.69 g of ammonium molybdate (NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O and 1.21 g of boric acid H ₃ BO ₃ were added. Next, after adding 300 g of aluminum oxide α-Al ₂ O ₃ powder and the previously prepared chromium-treated product to the mixed aqueous solution of V, Mo, and B, it takes 3 hours to homogenize with an Ishikawa-type cracker. Until kneaded. Thereafter, the obtained cake was molded by a twin screw extrusion molding machine, dried at 110 ° C. for 12 hours, pre-fired at 250 ° C., and finally fired at 450 ° C. for 15 hours. The atomic ratio of this catalyst is such that Cr: V: B: Mo is contained at a ratio of 1.0: 1.0: 0.1: 0.02, and the concentration of carrier alumina in the catalyst is 90 wt%.
[0022]
(Catalyst strength) The average diameter of this catalyst is 3.2 mm, and the crushing strength was measured. As a result, the strength was 113 (N) and the powdering rate was a good value of 1.0% by weight. Had.
[0023]
(Catalyst activity test) A reactor having an inner diameter of 23 mm heated with a molten salt was charged with 13 ml of this catalyst. From a metaxylene concentration of 0.6 vol%, ammonia of 3.8 vol%, and air of 95.6 vol% Was reacted at 400 ° C., the temperature at which this catalyst gave the highest isophthalonitrile yield, under the conditions of space-time rate SV2330Hr ⁻¹ . As a result, the yield of isophthalonitrile with respect to metaxylene was 83.8 mol%, the yield of methanitronitrile was 1.9 mol%, and the selectivity of isophthalonitrile with respect to the reacted metaxylene was 84. It was 1 mol%.
[0024]
Example 2
(Catalyst activity test) An activity test was conducted in the same manner as in Example 1 except that the catalyst prepared in Example 1 was used, and 3-methyl-pyridine was used instead of metaxylene. A gas consisting of 0.7% by volume of 3-methylpyridine, 2.0% by volume of ammonia and 97.3% by volume of air was converted to 390 ° C., SV2290Hr ⁻¹ , the temperature at which this catalyst gives the highest 3-cyanopyridine yield. It reacted on the conditions of. As a result, the yield of 3-cyanopyridine with respect to 3-methylpyridine was 90.5 mol%, and the selectivity for 3-cyanopyridine with respect to reacted 3-methylpyridine was 90.7 mol%.
[0025]
Example 3
(Preparation of catalyst) The same procedure as in Example 1 was conducted except that 29.4 g of tartaric acid was used instead of sorbitol.
[0026]
(Catalyst strength) The average diameter of this catalyst is 3.2 mm, and the crushing strength was measured. As a result, the strength was 126 (N), and the powdering rate was 0.8% by weight. Had.
[0027]
(Catalyst activity test) The activity test was conducted in the same manner as in Example 1. A gas consisting of a metaxylene concentration of 0.6% by volume, ammonia of 3.8% by volume, and air of 95.6% by volume at a temperature of 400 ° C., the temperature at which this catalyst gives the highest isophthalonitrile yield, is a space time rate SV2310Hr. ^The contact reaction was carried out under the condition of ^-1 . As a result, the yield of isophthalonitrile with respect to metaxylene was 82.5 mol%, and the yield of metatolunitrile was 1.6 mol%. The selectivity of isophthalonitrile with respect to the reacted metaxylene was 83. It was 0 mol%.
[0028]
Example 4
(Preparation of catalyst) The same procedure as in Example 1 was conducted except that 300 g of titanium oxide powder was used instead of carrier alumina.
[0029]
(Catalyst strength) The average diameter of this catalyst is 3.1 mm, and the crushing strength was measured. As a result, the strength was 103 (N), and the powdering rate was 1.5% by weight. Had.
[0030]
(Catalyst activity test) The activity test was conducted in the same manner as in Example 1. A gas consisting of a meta-xylene concentration of 0.7% by volume, ammonia of 3.9% by volume, and air of 95.4% by volume at a temperature of 375 ° C., the temperature at which this catalyst gives the highest isophthalonitrile yield, is a space time rate of SV2350Hr. ^The contact reaction was carried out under the condition of ^-1 . As a result, the yield of isophthalonitrile was 85.6 mol% with respect to metaxylene, and the yield of metatolunitrile was 1.2 mol%. The selectivity of isophthalonitrile with respect to the reacted metaxylene was 86. It was 1 mol%.
[0031]
Comparative Example 1
(Preparation of catalyst) 17.8 g of vanadium pentoxide V ₂ O ₅ was dissolved in 40 ml of water, heated to 80 to 90 ° C., 44.4 g of oxalic acid was added with good stirring, and 30 ml of water was added to the dissolved solution. 0.69 g of dissolved ammonium paramolybdate (NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O and 1.21 g of boric acid H ₃ BO ₃ were added. Next, 164 g of aluminum oxide α-Al ₂ O ₃ powder was added to the previously prepared mixed aqueous solution of V, Mo, and B, and then kneaded with an Ishikawa-type cracker until homogenous for 3 hours. . Thereafter, the obtained cake was molded by a twin screw extrusion molding machine, dried at 110 ° C. for 12 hours, pre-fired at 250 ° C., and finally fired at 450 ° C. for 15 hours. The atomic ratio of this catalyst is such that V: B: Mo is contained at a ratio of 1.0: 0.1: 0.02, and the concentration of carrier alumina in the catalyst is 90 wt%.
[0032]
(Catalyst strength) The average diameter of this catalyst was 3.3 mm, and the crushing strength was measured. As a result, the strength was 27 (N) and the powdering rate was 6.9% by weight, which was unacceptable in practical use. It was.
[0033]
(Catalyst activity test) A reactor having an inner diameter of 23 mm heated with molten salt was charged with 13 ml of this catalyst, and consisted of a metaxylene concentration of 0.6% by volume, ammonia of 3.8% by volume, and air of 95.6% by volume. The gas was catalytically reacted at 405 ° C., the temperature at which this catalyst gave the highest isophthalonitrile yield, at a space time rate of SV2250 Hr ⁻¹ . As a result, the yield of isophthalonitrile with respect to metaxylene was 72.8 mol%, and the yield of metatolunitrile was 1.0 mol%. The selectivity of isophthalonitrile with respect to the reacted metaxylene was 73. It was 0 mol%.
[0034]
Comparative Example 2
(Catalyst activity test) An activity test was conducted in the same manner as in Comparative Example 1 except that the catalyst prepared in Comparative Example 1 was used, and 3-methyl-pyridine was used instead of metaxylene. A gas consisting of 0.7% by volume of 3-methylpyridine, 1.9% by volume of ammonia, and 97.4% by volume of air was converted to 395 ° C., SV2310Hr ⁻¹ , the temperature at which this catalyst gives the highest 3-cyanopyridine yield. It reacted on the conditions of. As a result, the yield of 3-cyanopyridine with respect to 3-methylpyridine was 81.5 mol%, and the selectivity for 3-cyanopyridine with respect to reacted 3-methylpyridine was 81.8 mol%.
[0035]
Comparative Example 3
(Preparation of catalyst) The same procedure as in Comparative Example 1 was conducted except that 300 g of titanium oxide powder was used instead of carrier alumina.
[0036]
(Catalyst strength) The average diameter of this catalyst was 3.2 mm, and the crushing strength was measured. As a result, the strength was 22 (N) and the powdering rate was 7.5 wt%, which was unacceptable in practical use. It was.
[0037]
(Catalyst activity test) The activity test was conducted in the same manner as in Comparative Example 1. A gas consisting of a metaxylene concentration of 0.7% by volume, ammonia of 3.9% by volume, and air of 95.4% by volume at a temperature of 380 ° C., the temperature at which this catalyst gives the highest isophthalonitrile yield, is a space-time rate of SV2300Hr. ^The contact reaction was carried out under the condition of ^-1 . As a result, the yield of isophthalonitrile with respect to metaxylene was 72.2 mol%, and the yield of metatolunitrile was 1.5 mol%. The selectivity of isophthalonitrile with respect to the reacted metaxylene was 72. It was 9 mol%.
[0038]
【The invention's effect】
As described above, a chromium compound treated with at least one chromium treating agent selected from alcohols, saccharides, organic oxy compounds and water-soluble aldehydes, and one or more metals selected from V, Mo and Fe By mixing the oxide and alumina or titania, as shown in the examples, the carbocyclic compound or heterocyclic compound is ammoxidized to obtain the corresponding nitrile compound in a very high yield. A catalyst having high strength that can withstand practical use can be obtained. In general, the use of a multi-tube reactor is indispensable for carrying out an ammoxidation reaction with a large amount of heat generation in a fixed bed. It can be produced very advantageously industrially.

Claims (4)

When producing a corresponding nitrile compound by catalytically reacting a mixed gas containing ammonia and oxygen with a carbocyclic compound or heterocyclic compound, the chromium compound is converted from alcohols, sugars, organic oxy compounds and water-soluble aldehydes. A high-strength catalyst prepared by mixing at least one kind of chromium treatment agent selected by heating and boiling with one or more metal oxides selected from V, Mo and Fe, and alumina or titania is used. A process for producing an aromatic nitrile or heterocyclic nitrile, characterized in that The method for producing an aromatic nitrile or heterocyclic nitrile according to claim 1, wherein the chromium compound is chromic anhydride, ammonium chromate and / or ammonium dichromate. The high-strength catalyst further contains an oxide of at least one metal selected from the group consisting of Mg, Ca, Ba, W, Co, Ni, B, Ge, Sn, Pb, P, Sb and Bi. A process for producing an aromatic nitrile or heterocyclic nitrile according to 1 or 2. The method for producing an aromatic nitrile or heterocyclic nitrile according to claim 3, wherein the metal oxide contained in the high-strength catalyst is an oxide of V, Mo and B.