JPH04342551A - Production of amide by catalytic rearrangement of oxime - Google Patents

Abstract

PURPOSE:To provide a catalyst optimal for the rearrangement of an oxime to the corresponding amide in a liquid phase under mild conditions, prepared from an N,N-disubstituted formamide, chlorothiophosphoric diester and phosphorus oxytrichloride and/or phosphorus pentachloride. CONSTITUTION:In producing an amide by the rearrangement of the corresponding oxime, a catalyst prepared from (A) an N,N-disubstituted formamide of formula I (R1 and R2 are each 1-6C alkyl, 6-9C phenyl or substituted phenyl) (e.g. N,N-dimethylformamide), (B) a chlorothiophosphoric diester of formula II (R3 and R4 are each 1-8C alkyl, 6-9C phenyl or substituted phenyl) (e.g. dimethyl chlorothiophosphate) and (C) phosphorus oxytrichloride and/or phosphorus pentachloride, is used. For example, a mixture of a chlorothiophosphoric diester, phosphorus oxytrichloride or phosphorus pentachloride with an N,N- dialkylformamide is heated, if necessary, to prepared the present catalyst, which is then incorporated with an oxime to carry out rearrangement reaction.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing amides by rearrangement of oximes and a catalyst thereof.

0002

BACKGROUND OF THE INVENTION The rearrangement reaction of oxime to amide is known as Beckmann rearrangement reaction. For example, in the production of ε-caprolactam by rearrangement of cyclohexanone oxime, fuming sulfuric acid is used industrially as a catalyst. However, the method using fuming sulfuric acid has the essential drawback of producing a large amount of ammonium sulfate as a by-product, and there are also many process problems such as equipment corrosion, so there has been a desire to develop an efficient rearrangement catalyst.

For example, solid oxide catalysts in which boron oxide is supported on silica, alumina, or titania, and zeolite catalysts have been proposed, but when these solid catalysts are used for rearrangement reactions, high-temperature gas phase reaction conditions are required. This is problematic for industrial implementation, as it is accompanied by a decrease in ε-caprolactam yield, catalyst deterioration, and an increase in energy costs.

On the other hand, several methods are known in which ε-caprolactam is obtained by rearranging cyclohexanone oxime under relatively mild reaction conditions called liquid phase reaction. One is N
, a method using an ion pair (Vilsmeyer complex) obtained by the reaction of N-dimethylformamide and chlorosulfonic acid as a catalyst (M.A. Kira and Y.M.S.
haker, Egypt. J. Chem. , 16,
551 (1973)). However, this method is described as requiring an equimolar amount of catalyst to the oxime because the lactam formed and the catalyst form a 1:1 complex, and cannot be said to be economical.

[0005] The present inventor previously discovered that an epoxy compound and a strong acid (
reported a liquid-phase Beckmann rearrangement reaction using an alkylating agent obtained from boron trifluoride etherate, etc.) and a catalyst consisting of N,N-dialkylformamide (Y.Iz
umi, Chemistry Letters, p
p. 2171 (1990)). Although this method discloses an excellent new rearrangement method, it is not necessarily satisfactory industrially in terms of economy and operability, as it requires an epoxy compound and a strong acid as the alkylating agent used as components of the rearrangement catalyst. It's not something you get.

Furthermore, JP-A-62-149665 discloses a method for producing ε-caprolactam by rearranging cyclohexanone oxime in a heptane solvent using a phosphoric acid catalyst. However, it is necessary to use a large amount of phosphoric acid, approximately twice the mole amount, as a catalyst, and therefore it is described that after the reaction, ammonia is neutralized, and the phosphoric acid catalyst is recovered and reused through a complicated process.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a method for producing an amide by rearrangement of an oxime at a mild reaction temperature under liquid phase conditions, and a catalyst thereof. The purpose is to

[0008] As a result of extensive research into catalysts for rearranging oxime to amide, the present inventors found that N,N
-disubstituted formamide and chlorothiophosphoric acid diester,
It was discovered that a catalyst consisting of at least one phosphorus compound selected from the group consisting of phosphorus oxytrichloride and phosphorus pentachloride accelerates the rearrangement reaction, leading to the present invention.

[0009]

[Means for Solving the Problems] That is, the present invention provides the general formula (1), (wherein R1 and R2 are the same or different, and the number of carbon atoms is 1.
~6 alkyl group, or a phenyl group or substituted phenyl group having 6 to 9 carbon atoms. ) and the general formula (2), (wherein R3 and R4 are the same or different, an alkyl group having 1 to 8 carbon atoms, a phenyl group having 6 to 9 carbon atoms, or a substituted a chlorothiophosphoric acid diester represented by (representing a phenyl group), at least one phosphorus compound selected from the group consisting of phosphorus oxytrichloride, or phosphorus pentachloride; and the presence of the catalyst. This is a method for producing amides by catalytic rearrangement of oximes, characterized in that the reaction is carried out in a liquid phase.

The N,N-disubstituted formamide used in the present invention is represented by the above general formula (1),
R1 and R2 in the formula are the same or different and represent an alkyl group having 1 to 6 carbon atoms, or a phenyl group or substituted phenyl group having 6 to 9 carbon atoms, and the alkyl group having 1 to 6 carbon atoms includes a methyl group, Ethyl group, butyl group, pentyl group and hexyl group include phenyl group or substituted phenyl group having 6 to 9 carbon atoms, such as phenyl group, tolyl group, xylyl group, cumyl group and mesityl group.

More specifically, the N,N-disubstituted formamide includes N,N-dimethylformamide, N,N-diethylformamide, N,N-diisopropylformamide, N,N-dibutylformamide, N,N-dipentyl Formamide, N,N-dihexylformamide,
N,N-phenyl-N-methylformamide and the like are preferably used.

The chlorothiophosphate diester used in the present invention is represented by the above general formula (2), and specifically includes dimethyl chlorothiophosphate, diethyl chlorothiophosphate, dipropyl chlorothiophosphate, dibutyl chlorothiophosphate, and dipentyl chlorothiophosphate. , dihexyl chlorothiophosphate, dioctyl chlorothiophosphate, di-2-ethylhexyl chlorothiophosphate, and diphenyl chlorothiophosphate.

The amount of the above catalyst used is not particularly limited, but generally chlorothiophosphoric acid diester, phosphorus oxytrichloride or phosphorus pentachloride is used in an amount of about 0.0% of the oxime.
In the range of 1 to 50 mole %, preferably about 1 to 20 mole %, the N,N-disubstituted formamide is in the range of about 1 equivalent or more of chlorothiophosphoric acid diester, phosphorus oxytrichloride or phosphorus pentachloride.

The present invention applies without any limitation to known oxime compounds. Specific examples of the oxime compound include cyclohexanone oxime, cyclopentanone oxime, cyclododecanone oxime, acetaldoxime, acetone oxime, 2-butanone oxime, benzaldehyde oxime, acetophenone oxime, and benzophenone oxime. Among them, it is preferably applied to cyclic oximes such as cyclohexanone oxime, cyclopentanone oxime, and cyclododecanone oxime.

The oxime rearrangement reaction of the present invention is usually carried out in the presence of a solvent. The solvent is not particularly limited, but N,N-dialkylformamides, such as N,N-dimethylformamide, N,N-diethylformamide, and N,N-dipropylformamide, which are one component of the catalyst, are preferably used.

In the present invention, after preparing the catalyst by pre-mixing the catalyst components chlorothiophosphoric acid diester, phosphorus oxytrichloride or phosphorus pentachloride with N,N-dialkylformamide and heating as necessary, the oxime The rearrangement reaction may be carried out by adding and mixing oxime, or the rearrangement reaction may be carried out by mixing chlorothiophosphoric acid diester, phosphorus oxytrichloride or phosphorus pentachloride with N,N-dialkylformamide in the presence of an oxime. The method of addition is not particularly limited. The reaction usually takes about 20 to
It is carried out at 150°C, preferably about 30-100°C.

[0017]

EXAMPLES The present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 After purging a 200 ml round bottom flask with nitrogen, dry N,
45 ml of N-dimethylformamide and 10 mmol of dimethyl chlorothiophosphate were added, and the mixture was stirred at 65°C for 1 hour. Next, 70.7 mmol of cyclohexanone oxime was added to N
, N-dimethylformamide (46 ml) was dissolved in 6 ml of N-dimethylformamide.
After dropping at 5° C. over 30 minutes, the reaction was continued for an additional 1.5 hours. After the reaction was completed, the results of gas chromatograph analysis showed that the conversion rate of cyclohexanone oxime was 53.2.
%, the yield of ε-caprolactam was 48.9% (selectivity was 92.0%). The catalytic turnover of produced ε-caprolactam based on dimethyl chlorothiophosphate is 3.
．． 5 (mol/mol).

Example 2 After purging a 200 ml round bottom flask with nitrogen, dry N,
45 ml of N-dimethylformamide and 10 mmol of phosphorus oxytrichloride were added, and the mixture was stirred at 95°C for 10 minutes. Next, 70.7 mmol of cyclohexanone oxime was added to N,
65 mL of a solution dissolved in 45 ml of N-dimethylformamide
After the dropwise addition over 30 minutes at °C, the reaction was continued for an additional 1.5 hours. After the reaction was completed, the results of gas chromatographic analysis showed that the conversion rate of cyclohexanone oxime was 98.7%.
, the yield of ε-caprolactam was 67.8% (selectivity was 6
8.7%). The catalytic turnover of produced ε-caprolactam based on phosphorus oxytrichloride was 4.8 (mo
l/mol).

Example 3 A reaction was carried out in the same manner as in Example 2, except that the amount of phosphorus oxytrichloride was changed to 5 mmol. After the reaction was completed, the results of gas chromatographic analysis showed that the conversion rate of cyclohexanone oxime was 69.7%, and the yield of ε-caprolactam was 45.0% (selectivity was 64.6%). The catalytic turnover of the produced ε-caprolactam based on phosphorus oxytrichloride was 6.4 (mol/mol).

Example 4 The amount of phosphorus oxychloride in Example 2 was changed to 5.5 mmol.
The reaction was carried out according to Example 2 except that the reaction temperature was 95°C. After the reaction was completed, the results of gas chromatographic analysis showed that the conversion rate of cyclohexanone oxime was 92.9%, and the yield of ε-caprolactam was 62.3% (
The selectivity was 67.1%). The catalytic turnover of produced ε-caprolactam based on phosphorus oxytrichloride is 8.
．． It was 0 (mol/mol).

Comparative Example 1 A reaction was carried out in the same manner as in Example 2, except that 10 mmol of phosgene was used in place of phosphorus oxytrichloride. After the reaction was completed, the results of gas chromatograph analysis showed that the conversion rate of cyclohexanone oxime was 16.5.
%, the yield of ε-caprolactam is 4.9% (selectivity is 2
9.7%). Catalytic turnover of produced ε-caprolactam based on phosgene is 0.3 (mol/mol
l).

Example 5 A reaction was carried out in accordance with Example 2, except that 5 mmol of phosphorus pentachloride was used in place of phosphorus oxytrichloride. After the reaction was completed, analysis by gas chromatography showed that the conversion rate of cyclohexanone oxime was 85.7.
%, the yield of ε-caprolactam was 55.4% (selectivity was 64.7%). Catalytic turnover of produced ε-caprolactam based on phosphorus pentachloride is 7.8 (mol/
mol).

Example 6 A reaction was carried out in the same manner as in Example 2, except that 5 mmol of phosphorus pentachloride was used in place of phosphorus oxytrichloride in Example 2, and the reaction temperature was 95°C. After the reaction was completed, analysis by gas chromatography showed that the conversion rate of cyclohexanone oxime was 98.9%, and the yield of ε-caprolactam was 65.4% (selectivity was 66.2%). The catalytic turnover of the produced ε-caprolactam based on phosphorus pentachloride was 9.4 (mol/mol).

Claims (4)

[Claims] Claim 1: General formula (1), where R1 and R2 are the same or different and represent an alkyl group having 1 to 6 carbon atoms, or a phenyl group or substituted phenyl group having 6 to 9 carbon atoms. The N,N-disubstituted formamide represented by the general formula (2), (wherein R3 and R4 are the same or different, an alkyl group having 1 to 8 carbon atoms, a phenyl group or substituted phenyl group having 6 to 9 carbon atoms) A catalyst for a rearrangement reaction of an oxime to an amide, which comprises a chlorothiophosphoric acid diester represented by the following formula, at least one phosphorus compound selected from the group consisting of phosphorus oxytrichloride and phosphorus pentachloride. 2. The N,N-disubstituted formamide is N,N-dimethylformamide, N,N-diethylformamide,
N,N-diisopropylformamide, N,N-dibutylformamide, N,N-dipentylformamide, N
, N-dihexylformamide or N-phenyl-N-
The catalyst for the rearrangement reaction of oxime to amide according to claim 1, which is methylformamide. 3. The chlorothiophosphate diester is dimethyl chlorothiophosphate, diethyl chlorothiophosphate, dipropyl chlorothiophosphate, dibutyl chlorothiophosphate, dipentyl chlorothiophosphate, dihexyl chlorothiophosphate, dioctyl chlorothiophosphate, di-chlorothiophosphate.
The catalyst for the rearrangement reaction of oxime to amide according to claim 1, which is 2-ethylhexyl or diphenyl chlorothiophosphate. 4. A method for producing an amide by catalytic rearrangement of an oxime, which comprises carrying out the reaction in a liquid phase in the presence of the catalyst according to claim 1.