JP2013155133A - Method for producing cyanopyrrole compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new method for producing a pyrrole compound having a cyano group from a pyrrole compound having an aldehyde group by vapor-phase catalytic reaction.SOLUTION: There is provided a method for producing a pyrrole compound having a cyano group by vapor-phase catalytic reaction of a pyrrole compound having an aldehyde group with ammonia in the presence of a tin-containing catalyst.

Description

  The present invention relates to a method for producing a pyrrole compound having a cyano group, characterized by reacting a pyrrole compound having an aldehyde group with ammonia in a gas phase in the presence of a catalyst containing tin. A pyrrole compound having a cyano group is very useful as an intermediate for pharmaceuticals, agricultural chemicals or various organic synthesis.

  As a method for producing an aromatic nitrile by reacting an aromatic aldehyde with ammonia in the gas phase in the presence of a catalyst, 4-benzonitrile is produced from 4-phenylbenzaldehyde with a yield of 98% using an alumina catalyst containing copper. Example (see, for example, Patent Document 1), using a catalyst containing copper oxide, zinc oxide and alumina, yield of benzonitrile from benzaldehyde was 96%, and yield of p-tolunitrile from p-tolualdehyde was 92%. There is an example obtained in% (see, for example, Patent Document 2).

JP 2000-239247 A JP 2002-179636 A

As described above, several methods have been reported for producing an aromatic nitrile by reacting an aromatic aldehyde with ammonia in the gas phase in the presence of a catalyst. There is no method for producing a pyrrole compound having a cyano group from a compound, and development of this production method has been desired.

  As a result of intensive studies in view of such circumstances, the present inventors have found that when a catalyst containing tin is used, a pyrrole compound having a cyano group can be produced from a pyrrole compound having an aldehyde group by a gas phase contact reaction, and the present invention is completed. It came to do.

  That is, the present invention relates to a method for producing a pyrrole compound having a cyano group, characterized by reacting a pyrrole compound having an aldehyde group with ammonia in a gas phase in the presence of a catalyst containing tin.

  According to the present invention, a pyrrole compound having a cyano group can be obtained by a novel gas phase catalytic reaction. Therefore, since the method of the present invention contributes to the enrichment of technology, it can contribute to industrial development.

  The present invention will be described in detail below.

  As a pyrrole compound having an aldehyde group, the general formula (1):

（式中、Ｒはアルキル基を示し、ｎは０〜３の整数である。）で示される化合物が挙げられる。一般式（１）において、アルデヒド基及び置換基Ｒはピロール環の炭素に結合する基である。Ｒで表されるアルキル基は、炭素数１〜８の直鎖状のアルキル基、炭素数３〜８の側鎖を有したアルキル基又は炭素数５〜８の環状アルキル基である。好ましくは炭素数１〜４の直鎖状のアルキル基又は炭素数３〜４の側鎖を有したアルキル基である。ｎが２以上の整数のとき複数の置換基Ｒは互いに同じアルキル基であっても異なるアルキル基であっても良い。

(Wherein R represents an alkyl group, and n is an integer of 0 to 3). In the general formula (1), the aldehyde group and the substituent R are groups bonded to carbon of the pyrrole ring. The alkyl group represented by R is a linear alkyl group having 1 to 8 carbon atoms, an alkyl group having a side chain having 3 to 8 carbon atoms, or a cyclic alkyl group having 5 to 8 carbon atoms. A linear alkyl group having 1 to 4 carbon atoms or an alkyl group having a side chain having 3 to 4 carbon atoms is preferable. When n is an integer of 2 or more, the plurality of substituents R may be the same alkyl group or different alkyl groups.

Examples of the compound represented by the general formula (1) include pyrrole-2-carbaldehyde, pyrrole-3-carbaldehyde, 3-methyl-pyrrole-2-carbaldehyde, 5-methyl-pyrrole-2-carbaldehyde, 4- Examples include ethyl-pyrrole-2-carbaldehyde, 2,4-dimethyl-pyrrole-3-carbaldehyde and the like.

  As a pyrrole compound having a cyano group, which is an object of the present invention, general formula (2):

（式中、Ｒ及びｎは前記に同じ。）で示される化合物が挙げられる。一般式（２）において、シアノ基及び置換基Ｒはピロール環の炭素に結合する基である。

(Wherein, R and n are as defined above). In the general formula (2), the cyano group and the substituent R are groups bonded to carbon of the pyrrole ring.

  Examples of the compound represented by the general formula (2) include pyrrole-2-carbonitrile, pyrrole-3-carbonitrile, 3-methyl-pyrrole-2-carbonitrile, 5-methyl-pyrrole-2-carbonitrile, 4 -Ethyl-pyrrole-2-carbonitrile, 2,4-dimethyl-pyrrole-3-carbonitrile and the like.

The catalyst used in the present invention is a catalyst containing tin. The catalyst containing tin means a catalyst containing metallic tin and / or tin oxide as a catalytic active component. Examples of tin oxide include stannous oxide and stannic oxide. Examples of the tin-containing catalyst include those composed of metallic tin and / or tin oxide, and those obtained by supporting metallic tin or / and tin oxide on a carrier.
The carrier is not particularly limited as long as it is industrially available, and includes various zeolites, alumina, silica, titania, zirconia and the like. The amount of metal tin or / and tin oxide supported on the carrier is usually 0.1 to 25 parts by weight per 100 parts by weight of the carrier.

  Metal tin and tin oxide that are commercially available as catalysts can be used as they are as the catalyst of the present invention. In addition, any catalyst prepared by a kneading method, impregnation method, coprecipitation method, concentration drying method or the like using a raw material for catalyst preparation and, if desired, a carrier can be used as the catalyst of the present invention.

As a raw material used in preparing the catalyst of the present invention, any compound that is usually used in the preparation of a catalyst can be used. Examples include complexes, acetates, carbonates, halides, hydroxides, nitrates, ammonium salts, phosphates, sulfates, oxalates, lactates and / or formates containing the metal constituting the catalyst of the present invention. be able to.

  The catalyst of the present invention is formed into a desired shape such as powder, columnar, cylindrical, spherical or granular and used for the gas phase reaction of the present invention.

The present invention is usually carried out at a temperature in the range of 100 to 500 ° C., preferably at a temperature in the range of 150 to 470 ° C., under normal pressure or under pressure. The reaction method is not particularly limited, and the reaction is performed in a fixed bed, a fluidized bed, or a moving bed, and any of a batch method and a continuous method can be adopted.

The ammonia used in the present invention is not particularly limited as long as it is industrially available.
The amount of the raw material used may be within the range of 1: 0.1 to 50.0 in the molar ratio of pyrrole compound having aldehyde group: ammonia, but is preferably in the range of 1: 0.5 to 30.0. It is.

  The space velocity of the pyrrole compound having an aldehyde group is usually 0.01 to 2 (g / cc-catalyst · h) in terms of LHSV (liquid space velocity), preferably 0.1 to 1 (g / cc-catalyst · h).

  The reaction is carried out in the presence or absence of a diluent. The diluent is not particularly limited as long as it is inert to the reaction, and any diluent can be used. Specifically, inert gases such as nitrogen and argon, aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, undecane, tetralin and decahydronaphthalene, and halogenated fats such as dichloromethane and 1,2-dichloroethane. A solvent inert to the reaction of nitrile compounds such as aromatic hydrocarbons, acetonitrile and propionitrile can be used, and acetonitrile is preferred. You may use these individually or in mixture of 2 or more types. When a solvent inert to the reaction is used as a diluent, the pyrrole compound having an aldehyde group is usually subjected to the reaction by previously dissolving the pyrrole compound having an aldehyde group in the solvent.

  After completion of the reaction, the product is collected by an appropriate means such as absorption of the reaction gas into a solvent, and then the pyrrole compound having a target cyano group can be obtained by an ordinary means such as distillation.

Next, the present invention will be specifically described based on examples, but the present invention is not limited thereto. In addition, the analysis by the gas chromatography in an Example was performed on condition of the following. The conversion rate and yield were calculated according to the following definitions.
Conversion (%) = reacted pyrrole having aldehyde group (mol) / provided pyrrole having aldehyde group (mol) × 100
Yield (%) = pyrrole having cyano group produced by reaction (mole) / pyrrole having aldehyde group supplied (mole) × 100

Gas chromatographic analysis conditions Gas chromatograph: GC-17A manufactured by Shimadzu Corporation
Column: J & W, DB-1, 30 m, inner diameter 0.32 mm, film thickness 1.0 μm
Temperature: 50 ° C. (2 min) → (10 ° C./min)→70° C. (10 min) → (15 ° C./min)→250° C. (5 min)

Example 1
Pyrex (registered trademark) glass tube having an inner diameter of 19 mm was filled with 10 ml of a solid material obtained by pressing a tin (IV) oxide catalyst (manufactured by Nippon Chemical Industry Co., Ltd.) at a pressure of 60 MPa, and classified into 10 to 16 mesh. Carborundum was filled up and down by 20 cm and 12 cm, respectively. The catalyst was kept at 400 ° C., and a mixture of pyrrole-2-carbaldehyde: ammonia: nitrogen: acetonitrile (solvent) = 1: 10: 3: 4 (molar ratio) was added on a pyrrole-2-carbaldehyde basis. It was made to pass from the upper part of the glass tube by LHSV = 0.1 (g / cc-cat * h). The product was collected by bubbling in 100 ml of water. As a result of gas chromatography analysis of the product after 1.5 hours had passed since the start of the reaction, the conversion of pyrrole-2-carbaldehyde was 96%, and the yield of pyrrole-2-carbonitrile was 19%. there were.

Example 2
(Influence of reaction temperature)
The reaction was carried out in the same manner as in Example 1 except that the reaction temperature was changed to 450 ° C. The conversion of pyrrole-2-carbaldehyde was 94%, and the yield of pyrrole-2-carbonitrile was 18%.

Example 3
(Influence of ammonia usage)
The reaction was carried out in the same manner as in Example 2 except that the amount of ammonia used for the reaction was changed to 17 mol times with respect to pyrrole-2-carbaldehyde. The conversion of pyrrole-2-carbaldehyde was 91%, and the pyrrole-2-carbonitrile yield was 10%.

Comparative Example 1
The reaction was carried out in the same manner as in Example 1 except that the catalyst was copper oxide / zinc oxide (weight ratio) = 28/53 (product name “MDC-1” manufactured by Zude Chemie Catalysts) Carried out. The conversion of pyrrole-2-carbaldehyde was 90%, and the pyrrole-2-carbonitrile yield was 4%.

Comparative Example 2
The reaction was carried out in the same manner as in Example 1 except that the catalyst was changed to copper oxide / zinc oxide (weight ratio) = 28/53 (manufactured by Zude Chemie Catalyst, trade name “MDC-1”). The conversion of pyrrole-2-carbaldehyde was 100%, and the pyrrole-2-carbonitrile yield was 0%.

Comparative Example 3
The catalyst contains 88% by weight of zinc oxide (made by Zude Chemie Catalysts, trade name “N748”), the reaction temperature is 450 ° C., and the amounts of ammonia and nitrogen used are 17 mol times each of pyrrole-2-carbaldehyde. The reaction was carried out in the same manner as in Example 1 except that the amount was changed to 4 mol times. The conversion of pyrrole-2-carbaldehyde was 100%, and the pyrrole-2-carbonitrile yield was 2%.

Claims (4)

A method for producing a pyrrole compound having a cyano group, comprising subjecting a pyrrole compound having an aldehyde group to a gas phase contact reaction with ammonia in the presence of a catalyst containing tin. The method for producing a pyrrole compound having a cyano group according to claim 1, wherein a pyrrole compound having an aldehyde group dissolved in a solvent inert to the reaction is used. A pyrrole compound having an aldehyde group is represented by the formula (1):

(Wherein R represents an alkyl group and n is an integer of 0 to 3), and a pyrrole compound having a cyano group has the formula (2):

(Wherein R and n are the same as defined above). The method for producing a pyrrole compound having a cyano group according to claim 1 or 2. The method for producing a pyrrole compound having a cyano group according to any one of claims 1 to 3, wherein the pyrrole compound having an aldehyde group is pyrrole-2-carbaldehyde.