JP2003128648A - Method for producing amide compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently converting into amide compound, an inert catalytic species composed of a dehydrated dimer of the amide compound and sulfonic acid in a reaction mixture after a catalytic liquid-phase Beckmann rearrangement reaction. SOLUTION: The method produces the amide compound through the Beckmann rearrangement of oxime compound in a liquid phase containing a catalyst containing an acid component selected from at least an acid anhydride and a catalyst prepared from an N,N-bisubstituted amide compound. The resultant mixture containing the inert catalytic seed composed of the dehydrated dimer of the generated amide compound and an acid derived from the acid component is treated with a proton compound of >=0.1 and <=1,000 mol, based on the dehydrated dimer of the reaction mixture.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an amide compound. More specifically, it relates to a method for efficiently producing an amide compound by performing a Beckmann rearrangement reaction of an oxime in the presence of a catalyst in a liquid phase.

[0002]

2. Description of the Related Art Generally, as a method of industrially producing an amide compound, a method of converting an oxime compound into an amide compound by a Beckmann rearrangement reaction is known. For example, ε-caprolactam is It is produced by the Beckmann rearrangement reaction of cyclohexanone oxime. As the Beckmann rearrangement reaction, a liquid phase reaction using a strong acid such as concentrated sulfuric acid or fuming sulfuric acid as a catalyst is industrially adopted at present. However, in this known method, it is usually necessary to neutralize sulfuric acid with ammonia in order to separate the produced lactam compound, and about twice as much ammonium sulfate (ammonium sulfate) as the by-product of the lactam compound is produced as a by-product. Further, since a large amount of strong acid is used, there is a problem such as corrosion of a reaction device, which is not always an economical method, and development of an efficient rearrangement reaction catalyst is expected.

Therefore, various studies have been conducted on the Beckmann rearrangement reaction in a liquid phase which does not use a sulfuric acid catalyst. For example, in the Beckmann rearrangement reaction of cyclohexanone oxime in a liquid phase using a homogeneous catalyst, a method using an ion pair (bismeier complex) obtained by the reaction of N, N-dimethylformamide and chlorosulfonic acid as a catalyst (MAKi
ra and YMShaker, Egypt. J. Chem., 16,551 (1973)),
Method using a catalyst consisting of an alkylating agent formed from an epoxy compound and a strong acid (boron trifluoride, etherate, etc.) and N, N-dialkylformamide (Y. Izumi, Chemis
Try Letters, pp. 2171 (1990)), a method of rearrangement of cyclohexanone oxime using a phosphoric acid or a condensable phosphoric acid compound in a heptane solvent (JP-A-62-149665), phosphorus pentoxide and N, N -A method using a catalyst composed of a compound such as dialkylformamide (Patent 265
2280), a phosphorus pentoxide and a fluorine-containing strong acid or a derivative thereof and a compound such as N, N-dialkylformamide and the like (JP-A-5-105654).
No. publication) is proposed.

However, the method for producing ε-caprolactam by subjecting cyclohexanone oxime to a Beckmann rearrangement reaction in a liquid phase using these catalyst systems is not always satisfactory as an industrial production method. Specifically, in the Beckmann rearrangement reaction of cyclohexanone oxime using the above-mentioned bismeier complex as a catalyst, the produced lactam and the catalyst form a 1: 1 complex, and therefore, a catalyst in an equimolar amount to the raw material oxime is required. It cannot be said that it is an economical industrial manufacturing method. Further, the method using a catalyst composed of an alkylating agent produced from an epoxy compound and a strong acid and an N, N-dialkylformamide is different from the conventional equivalent reaction using sulfuric acid as a catalyst, and a new rearrangement in which the reaction catalytically proceeds. Although a method is disclosed, since a toxic compound such as dimethylsulfate or epichlorohydrin may be used for producing an alkylating agent, it is not necessarily a method industrially satisfactory from the viewpoint of operability. Furthermore, JP-A-62-1
In the method using phosphoric acid or condensed phosphoric acid as a catalyst disclosed in Japanese Patent No. 149665, it is necessary to use a large amount of phosphoric acid catalyst, which is about twice as much as 1 mol of the starting oxime, and therefore ammonia after reaction is used. Since it imposes a great load on the step of neutralizing the catalyst, it cannot be said to be an economical industrial manufacturing method.

Further, in the method using a catalyst composed of phosphorus pentoxide and a fluorine-containing strong acid or its derivative and a compound such as N, N-dialkylformamide disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 5-105654 (corresponding to USP5254684). , Although having a relatively high catalytic activity, the number of moles of caprolactam produced per mole of catalyst (Turn Over Numbe
(r: TON) uses an expensive strong fluorine-containing acid or its derivative, so its performance was not industrially satisfactory. On the other hand, the present inventors have previously proposed a catalyst system having a high catalytic activity, which contains an acid component containing a compound selected from sulfonic acid or sulfonic anhydride and an N, N-disubstituted amide compound. It has been found that in the reaction product when such a catalyst system is used, an inactive catalyst species composed of an amide compound dimer and a sulfonic acid, which are formed by dehydration condensation of a part of the formed amide compound, is produced, It has been found that the formation of such an inert catalyst species results in a decrease in the yield of the desired amide compound.

[0006]

DISCLOSURE OF THE INVENTION The present invention is directed to an inert catalyst species consisting of a dehydrated dimer of the amide compound formed in the reaction mixture after the catalytic Beckmann rearrangement reaction of the oxime compound and an acid of the catalytic acid component. It is an object of the present invention to provide a method for increasing the yield of a target amide compound by efficiently converting the dehydrated dimer of the amide compound of 1 to the amide compound.

[0007]

In view of the above problems, the present inventor has considered the behavior of an inert catalyst species consisting of dehydrated dimer of amide compound and acid in the reaction mixture after catalytic Beckmann rearrangement reaction and the behavior of the amide. The present invention has been achieved as a result of intensive studies on a method for efficiently converting a dehydrated dimer of a compound into an amide compound. That is, the gist of the present invention is a method for producing an amide compound by rearranging an oxime compound in a liquid phase containing at least an acid component selected from an acid anhydride and a catalyst prepared from an N, N-disubstituted amide compound. In, the reaction mixture containing the inert catalyst species consisting of the dehydrated dimer of the produced amide compound and the acid derived from the acid component is added in an amount of 1000 mol or less to 0.1 mol with respect to the dehydrated dimer of the amide compound in the reaction mixture. The method for producing an amide compound is characterized by treating with the above-mentioned protic compound.

In a preferred embodiment of the present invention, in the above method for producing an amide compound, the protic compound is used in an amount of not more than 100 mol 0.5 with respect to the dehydrated dimer of the inactive catalyst species of the amide compound in the reaction mixture. Use at least 1 mol, the protic compound is water, and the treatment is from 30 ° C to 150 ° C.
It may be carried out at ° C. Further, in the method for producing the amide compound, the acid anhydride which is the rearrangement reaction catalyst is a strong acid anhydride and is a sulfonic acid anhydride, for example, an aromatic sulfonic acid anhydride or an aliphatic sulfonic acid anhydride, among which fluorine-free. Examples thereof include sulfonic acid anhydride, particularly p-toluenesulfonic acid anhydride or methanesulfonic acid anhydride, and the acid component contains carboxylic acid anhydride and sulfonic acid and / or its anhydride. You can also do it. Treatment with a protic compound treats the reaction mixture with N,
It is also possible to perform the reaction residual liquid obtained by distilling and separating the N-disubstituted amide compound. Further, it can be mentioned that the N, N-disubstituted amide compound is an N, N-dimethylformamide compound, and that the oxime compound is cyclohexanone oxime and the amide compound is ε-caprolactam.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described below. << Oxime Compound >> The oxime compound as a raw material used in the Beckmann rearrangement reaction of the present invention is not limited at all and a known oxime compound is applied. Specific examples of the oxime compound include cyclohexanone oxime, cyclopentanone oxime, cyclododecanone oxime, acetone oxime, 2-butanone oxime, acetophenone oxime, benzophenone oxime, 4'-hydroxyacetophenone oxime, and the like, preferably 2 to 20 carbon atoms. Include 3 to 13 oximes. Among them, cyclohexanone oxime, cyclopentanone oxime, cyclododecanone oxime and the like having 4 to 20 carbon atoms, preferably 5 to 5 carbon atoms.
Thirteen cyclic oxime compounds are preferably applied.

<< Catalyst Component >> The Beckmann rearrangement reaction catalyst of the present invention contains an acidic component and an N, N-disubstituted amide compound, and the acid anhydride used as the acidic component is not particularly limited. A strong acid anhydride having high reactivity with water and easily hydrolyzed to form a strong acid is preferable. Examples of strong acid anhydrides include sulfonic acid anhydrides such as aromatic sulfonic acid anhydrides and aliphatic sulfonic acid anhydrides, fluorinated acid anhydrides such as trifluoromethanesulfonic acid anhydrides, and phosphoric acid anhydrides of 5 oxidation. More preferred examples are phosphorus and rhenium heptoxide which is an anhydride of perrhenic acid. Among these, non-fluorine-containing sulfonic acid anhydrides, phosphorus pentoxide, and the like are preferable because they are industrially inexpensive and easily available. Other suitable acidic components include the combined use of a carboxylic acid anhydride, preferably acetic anhydride, with a strong acid, preferably a compound selected from sulfonic acid and its anhydride.

The rearrangement reaction catalyst component preferably used in the present invention is an acid component containing at least one acid anhydride and N, N.
-Containing at least one compound selected from the group consisting of (I) sulfonic acid and its acid anhydride as a more preferable catalyst component system containing a disubstituted amide compound, a carboxylic acid anhydride and N, N-disubstituted Amide compound, or (I
I) Consists of non-fluorine-containing sulfonic anhydride and N, N-disubstituted amide compound. The form of catalytically active species produced from these catalyst components is not clear at present, but since the oxime compound as a raw material acts and the reaction proceeds, the raw material oxime compound also becomes a catalyst constituent component. Can be considered as a component of.

<Acid component><Catalyst component system (I): sulfonic acid and its acid anhydride-carboxylic acid anhydride><Sulfonic acid and its anhydride> Catalyst component system (I) of the present invention
The at least one compound selected from the group consisting of sulfonic acid and its acid anhydride used as one component is not particularly limited, and may have a substituent having 6 to 20 carbon atoms, preferably Aromatic sulfonic acids of 6 to 10, aliphatic sulfonic acids of 1 to 20 carbon atoms which may have a substituent, preferably 1 to 10 and their acid anhydrides can be used (here, The substituent is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 4 carbon atoms,
It represents an acyl group having 2 to 4 carbon atoms and a halogen atom such as Cl, Br and F). Among these, non-fluorine-containing sulfonic acid and its anhydride are more preferable.

Specific compounds include benzenesulfonic acid, p-toluenesulfonic acid, p-toluenesulfonic acid monohydrate, p-dodecylbenzenesulfonic acid and 2,4.
-Dimethylbenzenesulfonic acid, 2,5-dimethylbenzenesulfonic acid, 4-chlorobenzenesulfonic acid, 4-
Fluorobenzenesulfonic acid, α-naphthylsulfonic acid, β-naphthylsulfonic acid, biphenylsulfonic acid,
Methanesulfonic acid, trifluoromethanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, 1-hexanesulfonic acid, 1-octanesulfonic acid and their anhydrides, and the like, among them, methanesulfonic acid, trifluoromethanesulfonic acid, Ethanesulfonic acid, propanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, p
-Dodecylbenzenesulfonic acid and their anhydrides are preferred, and methanesulfonic acid, p-toluenesulfonic acid and their anhydrides are particularly preferred. Fluorine-containing strong acid compounds such as trifluoromethanesulfonic acid and its acid anhydride are also compounds that favorably advance the rearrangement reaction, but since the fluorine-containing strong acid compound is extremely expensive, an economical industrial manufacturing method is established. In order to do so, it is required to establish an advanced recovery technology and reuse technology of the fluorine-containing strong acid compound.

The amount of at least one compound selected from the group consisting of sulfonic acids and their anhydrides in the catalyst component system (I) of the present invention is not particularly limited, but in general, the starting oxime compound is used. About 0.2 ~
It is used in an amount of 20 mol%, preferably 1.0 to 15 mol%, and more preferably 2.0 to 12 mol%. If the amount is less than this range and the amount is too small, sufficient catalytic activity cannot be obtained. On the other hand, if the amount is too large, the load required for the catalytic treatment after the rearrangement reaction becomes large, which is not preferable.

<Carboxylic Anhydride> Catalyst Component System of the Present Invention
The carboxylic acid anhydride used as one component of (I) is not particularly limited, and may have a substituent and has 1 to 20 carbon atoms, preferably 1 to 8 aliphatic carboxylic acid anhydrides. Thing, carbon number 6 to 1 which may have a substituent
Aromatic carboxylic acid anhydride of 2 can be used (here, the substituent is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an acyl group having 2 to 4 carbon atoms,
Represents a halogen atom such as Cl, Br, F). Although the valence of the carboxylic acid is not particularly limited, it is preferably monovalent.
Specific compounds include acetic anhydride, propionic anhydride, n-butyric anhydride, n-valeric anhydride, n-caproic anhydride, n-heptanoic anhydride, 2-ethylhexanoic anhydride, Examples thereof include benzoic anhydride, phthalic anhydride, maleic anhydride, and succinic anhydride. Among them, acetic anhydride and propionic anhydride, which are low boiling point compounds, are preferable.

The amount of the carvone anhydride used in the present invention is not particularly limited, but generally it is at least one compound selected from the group consisting of the above-mentioned sulfonic acids and these acid anhydrides. About 0.5-20
It is used in an amount of 0 mol times, preferably 1.0 to 100 mol times, and more preferably 2.0 to 50 mol times. If the amount exceeds this range and the amount is too small, sufficient catalytic activity cannot be obtained. On the other hand, if the amount is too large, the load required for catalyst separation after the rearrangement reaction becomes large, which is not preferable.

<Catalyst component system (II): non-fluorine-containing sulfonic acid anhydride> The non-fluorine-containing sulfonic acid anhydride used as the catalyst component system (II) of the present invention is not particularly limited, and may be aromatic or Examples thereof include linear or cyclic aliphatic sulfonic acid anhydrides, which may have one or more substituents on the aromatic ring and have 6 to 20 carbon atoms, preferably 6 to 10 carbon atoms. Alternatively, an aliphatic sulfonic acid anhydride having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, which may have a substituent can be used (here, the substituent has 1 to 8 carbon atoms. Represents an alkyl group, an alkoxy group having 1 to 4 carbon atoms, an acyl group having 2 to 4 carbon atoms, or a halogen atom such as Cl or Br).

Specific compounds include benzenesulfonic anhydride, p-toluenesulfonic anhydride, m-xylene-4-sulfonic anhydride, p-dodecylbenzenesulfonic anhydride and 2,4-dimethylbenzenesulfone. Acid anhydride, 2,5-dimethylbenzenesulfonic acid anhydride, 4
-Chlorobenzenesulfonic anhydride, α-naphthylsulfonic anhydride, β-naphthylsulfonic anhydride, biphenylsulfonic anhydride, methanesulfonic anhydride, ethanesulfonic anhydride, propanesulfonic anhydride, 1-
Hexanesulfonic anhydride, 1-octanesulfonic anhydride, etc. are mentioned, Especially, p-toluenesulfonic anhydride and methanesulfonic anhydride are preferable.

The amount of the non-fluorine-containing sulfonic acid anhydride used in the catalyst component system (II) of the present invention is not particularly limited, but generally about 0.2 to 20 mol relative to the starting oxime compound. %, Preferably 1.0 to 15 mol%,
It is more preferably used in the range of 2.0 to 12 mol%. If the amount exceeds the above range and the amount is too small, sufficient catalytic activity cannot be obtained. On the other hand, if the amount is too large, the load required for the catalytic treatment after the rearrangement reaction becomes large, which is not preferable.

<N, N-Disubstituted Amide Compound> The N, N used in the catalyst system of the present invention, for example, the above catalyst systems (I) and (II).
-The disubstituted amide compound usually has 1 to 1 carbon atoms.
8, preferably 1 to 8 carbon atoms, more preferably 1 carbon atom
Carboxylic acid amides having up to 4 identical or different alkyl substituents on the nitrogen atom, especially formamide. Examples of the substituent on the nitrogen atom include an alkyl group, an alkoxy group, and an aryl group. Among them, an alkyl group is preferable, and an amide compound having no nitrogen atom-containing cyclic structure is preferable. Specific compounds include N, N-dimethylformamide, N, N-diethylformamide,
N, N-di-i-propylformamide, N, N-dibutylformamide, N, N-dipentylformamide, N,
N-dioctylformamide, N-methyl, N-stearylformamide and the like can be mentioned. Among them, those in which two alkyl groups are the same are preferable, and N, N-dimethylformamide is particularly preferable.

The use amount of the above N, N-disubstituted amide compound is not particularly limited, and the use amount range of the raw material oxime compound and the use range of at least one compound selected from the group consisting of sulfonic acid and acid anhydride are used. Further, the amount of carboxylic acid anhydride varies depending on the usage amount range and is not specified in a uniform manner, but it is usually 1 to 1000 times by weight, preferably 10 to 100 times by weight with respect to the oxime compound. Can be used. Moreover, with respect to the total amount of the sulfonic acid and the sulfonic anhydride, a molar ratio of usually 10 to 2000, preferably 25 to 1000, and more preferably 50 to 500 is used. The N, N-disubstituted amide compound used in the present invention is a component of the catalyst and at the same time acts as a solvent. Therefore, when an appropriate solvent is used to smoothly proceed the rearrangement reaction, It can be used as a mixture with the solvent.

Examples of the solvent other than the N, N-disubstituted amide compound that can be used in the rearrangement reaction of the present invention include, for example, n-hexane, n-heptane, n-octane and n-octane.
Aliphatic hydrocarbon compounds such as dodecane, aromatic hydrocarbon compounds such as benzene, toluene, xylene, mesitylene, monochlorobenzene, methoxybenzene, nitrile compounds such as acetonitrile, propanenitrile, capronitrile, adiponitrile, benzonitrile, tolunitrile, phthalic acid Examples thereof include ester compounds such as dimethyl, dibutyl phthalate, dimethyl malonate, and dimethyl succinate. These can be used alone or in a mixture. When a solvent other than the N, N-disubstituted amide compound is used, for the N, N-disubstituted amide compound,
It can be mixed in a volume of 0.01 to 20 times, preferably 0.1 to 10 times, and more preferably 0.5 to 1 times. By mixing in such a range, the load when distilling and separating the N, N-disubstituted amide compound after the reaction can be reduced.

In the method for producing an amide compound by rearrangement of an oxime compound according to the present invention, the water content of an acid component including an acid and an acid anhydride in a rearrangement reaction liquid phase is reduced to a specific value or less, and in the liquid phase. Water content of 2000ppm
The following are effective for improving the selectivity of the target amide compound and improving the reaction rate. As a specific method for this, the oxime compound, the N, N-disubstituted amide compound and / or the reaction solvent used in the reaction, and further the rearrangement reactor and the receiver, piping and the like associated with the reactor are previously dried. It is possible to use it. Further, in order to keep the water concentration in the reaction system constant, it is preferable to carry out the reaction in a dry gas atmosphere, and it is preferable to avoid mixing of air containing water. Usually, it is carried out in an inert gas atmosphere such as nitrogen, argon or helium. Dry air can also be used. A water absorbing agent may be present in the reaction solution in order to remove water in the reaction solution.

The above-mentioned oxime compound, N, N-disubstituted amide compound, reaction solvent and reaction atmosphere gas are preferably dried by the following steps. In general industrial production method of oxime compound,
Hydroxylamine sulfate and ammonia are allowed to act on ketones, and the oxime compound obtained through such a production method generally contains about 5 to 10% by weight of water. This is combined with a dried N, N-disubstituted amide compound and / or a reaction solvent described below, and used by reducing the water content in the reaction liquid phase to such an extent that a predetermined value is satisfied. Specific methods for drying the oxime compound include general distillation, distillation using a thin film evaporator, crystallization, vacuum drying of solid oxime, and the like, and these may be appropriately combined. As the raw material oxime compound for the method of the present invention, it is preferable to use a compound having a reduced water content of usually 1% by weight or less, preferably 0.1% by weight or less, more preferably 0.01% by weight or less.

Further, in the present invention, it is desirable to dry the N, N-dialkylamide compound, the reaction solvent and the gas in the reaction atmosphere. Examples of specific drying methods include general distillation, distillation using a thin film evaporator, drying using molecular sieves, a method using metallic sodium, etc., and drying using salts such as sodium sulfate and magnesium sulfate. And the like can be used. It is also possible to combine these. If the N, N-dialkylamide compound and the reaction solvent that have been sufficiently dried are available, this step may not be necessarily included.

In the method of the present invention, it is desirable to carry out the reaction by controlling the molar ratio of water to the total of the acid components including the acid and the acid anhydride in the reaction liquid phase to be 1 or less. For that purpose, in carrying out the rearrangement reaction of the present invention, the drying degree of the oxime compound, the N, N-disubstituted amide compound and / or the reaction solvent obtained through the above-mentioned drying step is appropriately combined and the It is preferable to control the water content to a predetermined state. In the present invention, the water molar ratio to the total of the acid components including the acid and the acid anhydride in the reaction liquid phase is 1 or less, preferably 0.6 or less, and more preferably 0.2 or less. The water content may be measured by a known method, for example, the Karl Fischer method.

In the present invention, as described above, the water content of the acid component in the reaction liquid phase is reduced, and the water content in the liquid phase is set to 2000 ppm or less, whereby the selectivity of the target amide compound is remarkably increased. In addition to the improvement, the reaction rate is also improved. The improved selectivity is particularly useful from an industrial point of view. Although the reason why the selectivity is improved by controlling the water concentration is not clear, it is presumed that it is due to suppression of deactivation of the catalytically active species by water and suppression of hydrolysis of the oxime compound by water.

(Aspect of Rearrangement Reaction) In the method of the present invention, the reaction proceeds even if the catalyst component and the starting oxime compound are added in any order. For example, a strong acid anhydride and an N, N-disubstituted amide compound are mixed in advance. Examples include a method of adding an oxime compound to the liquid to start the reaction. In particular, as a preferred embodiment of the present invention, a method in which a strong acid anhydride and an N, N-disubstituted amide compound are mixed in advance with an amide compound of an object, and then an oxime compound is added to carry out a rearrangement reaction. In this way, by mixing the strong acid anhydride, the N, N-disubstituted amide compound and the target amide compound and then adding the oxime compound to carry out the rearrangement reaction, It is possible to improve the production amount of the amide compound.

The details of the form of the catalytically active species formed from the above catalyst components in the rearrangement reaction of the present invention are not necessarily clear, but the step of forming the active species is carried out by combining a strong acid anhydride and an N, N-disubstituted amide compound. Is shown below as an example.
As a result of the detailed study of the catalytic reaction mechanism of the present reaction by the present inventors, the active species of the rearrangement reaction are strong acid anhydride and N, N-
The active species can be produced by any of a method of producing from a combination of a disubstituted amide compound and an oxime compound and a method of producing from a combination of a strong acid anhydride or an N, N-disubstituted amide compound and a target amide compound. After the formation, it was found that the oxime compound could be catalytically rearranged to the amide compound by any method. Furthermore, as a result of detailed examination of the above-mentioned two active species forming reactions, the latter method, that is, the target amide compound was previously mixed with the strong acid anhydride and the N, N-disubstituted amide compound, and then the oxime compound was mixed, the catalyst was added. It was found that the number of moles of the target amide compound produced per the number of moles of the strong acid anhydride used (the number of moles of the amide compound newly produced by the reaction) was improved by carrying out the dynamic rearrangement reaction. From this, it is presumed that the method of forming an active species from a combination of a strong acid anhydride and an N, N-disubstituted amide compound and an objective amide compound forms an active species with higher selectivity. Therefore, in the present invention, the target amide compound is mixed in advance with the strong acid anhydride and the N, N-disubstituted amide compound, and then the oxime compound is mixed, and the catalytic rearrangement reaction is carried out to reduce the amount of the strong acid anhydride used. The amount can be reduced and the amide compound can be efficiently produced.

The amount of the target amide compound, which is preliminarily mixed with the strong acid anhydride and the N, N-disubstituted amide compound, is usually 0.1 to 10 times the molar amount of the strong acid anhydride, preferably,
It is 0.3 to 3 mole times, more preferably 0.5 to 1.5 mole culture. Since the active species formation reaction proceeds very quickly, there is no particular limitation on the temperature during mixing, and it is usually -50 ° C.
To 200 ° C, preferably -20 ° C to 100 ° C, more preferably 0 ° C to 50 ° C. There is no particular restriction on the mixing time, and the operation may be such that only momentary contact is made before introduction into the reactor, or the mixing may be carried out in a storage tank or the like for a long period of time. It is possible to select. It is usually 0.1 second to 1000 hours, preferably 1 second to 100 hours.

(Rearrangement Reaction Conditions) The conditions for carrying out the method of the present invention are not particularly limited, but the reaction temperature is usually 0 ° C. to 200 ° C., preferably 40 ° C. to 150 ° C., more preferably 60 ° C. to 130 ° C. It is carried out in. The reaction pressure is also not particularly limited, and the reaction is carried out under normal pressure to increased pressure. The reaction time or residence time is usually 1
Second to 10 hours, preferably 30 seconds to 7 hours. In the present invention, the rearrangement reaction proceeds even if the catalyst components of the strong acid or the strong acid anhydride thereof, the N, N-disubstituted amide compound and the carboxylic acid anhydride and the starting oxime compound are mixed in any order. In the case of (I), sulfonic acid or acid anhydride and carboxylic acid anhydride, the catalyst component system (II)
In the case of, non-fluorine containing sulfonic acid anhydride is
A mixture of the N-disubstituted amide compound or a mixture of these mixtures further containing a small amount of the starting oxime compound or the target amide compound is heated to a predetermined temperature, and then the starting solution in which the starting oxime compound is dissolved is sequentially added. It is preferable to start the reaction by supplying the reaction mixture. In that case, the raw material oxime compound can also be supplied under the condition that the oxime compound that can be dissolved in a part of the N, N-disubstituted amide compound and used for the reaction is melted. If the raw material oxime compound is supplied all at once and the reaction is started from the state where a high concentration of the oxime compound is present in the catalyst component liquid, it may cause early deactivation of the catalyst and increase of by-products. Not preferable.

<< Rearrangement Reaction Format >> The reaction format for carrying out the rearrangement reaction of the present invention is not particularly limited, and either batch reaction or continuous flow reaction can be carried out, but industrially, continuous flow reaction is possible. It is preferable to use the format. The type of the reactor is not particularly limited, and a general reactor such as a reactor composed of one tank or two or more continuous stirring tanks and a tubular reactor can be used. Further, in the present invention, since an acid catalyst is used, it is preferable to use a corrosion resistant material for the reactor material, for example, stainless steel, Hastelloy, Monel, Inconel, titanium, titanium alloy, zirconium, zirconium alloy,
Nickel, nickel alloy, tantalum, or fluororesin,
Examples thereof include materials coated with various types of glass on the inside.

The reaction mode of the present invention will be specifically described below with reference to an example of the continuous flow reaction of the present invention. N, N- in which a catalyst solution of the present invention, that is, a strong acid or its strong acid anhydride, which is one component of the catalyst, and a carboxylic acid anhydride (in the case of the catalyst system (I)) were dissolved in a sufficiently dried reactor. The disubstituted amide compound liquid is supplied and maintained at a predetermined temperature. An N, N-disubstituted amide solution in which a raw material oxime compound is dissolved is continuously supplied together with an inert solvent, if necessary, and reacted for a desired residence time. At the same time, an amide compound and an unreacted oxime are produced. The reaction mixture containing the compound and the catalyst as well as the solvent is taken off continuously.

<< Treatment of Reaction Mixture with Protic Compound >> The reaction mixture taken out from the reactor in which the rearrangement reaction has been carried out is usually a light boiling by-product, a solvent, a carboxylic acid (a carboxylic acid anhydride with a catalyst system (I)). When using objects), N, N-
Includes disubstituted amide compounds, target amide compounds, unreacted oximes, and other catalytic acid components. As a result of detailed analysis by the inventors of this reaction mixture by a spectroscopic method,
It was revealed that the amide compound produced was dehydrated and dimerized, and the dimer of the amide compound and the strong acid as the acid component produced an inert catalyst species forming an ion pair. This is
This means that a part of the target amide compound produced by the rearrangement reaction is consumed by the inert catalyst species, so that the yield of the target amide compound decreases. In the present invention, an inactive catalyst species composed of a dehydrated dimer of this amide compound and a strong acid is decomposed by treating with a protic compound, and the amide compound dimer is selectively converted into the target amide compound. Is.

<Protic compound> The protic compound used in the present invention for decomposing the above-mentioned inert catalyst species includes water and alcohol compounds. The alcohol compound is not particularly limited, and an aliphatic alcohol compound having 1 to 8 carbon atoms, which may have a substituent, preferably 1 to 4 can be used (here, the substituent Represents an alkyl group having 1 to 2 carbon atoms). Specific compounds include methyl alcohol, ethyl alcohol, n-butyl alcohol, i-butyl alcohol, and n.
-Hexanol, n-octanol and the like can be mentioned, and among them, methyl alcohol and ethyl alcohol are preferable. Among the above-mentioned protic compounds, water is most preferable in order to convert the amide compound dimer into the target amide compound in one step.

The amount of the above-mentioned protic compound to be used is not particularly limited, but it is usually from 0.1 mol times to 100 times the dimer of the above-mentioned inert catalyst species.
An amount of 0 mol times, preferably 0.5 mol times to 100 mol times, and more preferably 1 mol time to 10 mol times can be used. If the amount is too small beyond this range, sufficient decomposition activity from the amide compound dimer to the target amide compound cannot be obtained. On the other hand, if the amount is too large, a large amount of conversion of the target amide compound itself into an amino acid (for example, amide compound) is performed. Is ε−
In the case of caprolactam, unfavorable side reactions such as aminocaproic acid) are by-produced and are not preferable.

<Treatment Conditions> The treatment conditions with the protic compound in the method of the present invention are not particularly specified, but the treatment temperature is usually 0 ° C. to 200 ° C., preferably 30 ° C. to 150 ° C., more preferably 60 ° C. It is carried out in the range of 120 ° C. The treatment pressure is also not particularly limited, and the treatment is performed under normal pressure to increased pressure. The treatment time or residence time is usually 1 minute to 40 hours, preferably 10 minutes to 7 hours. For efficient processing,
Preference is given to working under stirring or shaking.

The treatment of the Beckmann rearrangement reaction mixture with a protic compound may be carried out by allowing the protic compound to act directly on the mixture after the reaction, or by treating the reaction mixture with a light boiling by-product, N, It may be carried out by reacting the reaction residual liquid after removing the N-disubstituted amide compound and the reaction solvent with a protic compound. In the latter case, it is advantageous that the decomposition reaction can be smoothly proceeded and the amount of the protic compound used can be reduced by mixing the reaction residual liquid with a solvent which has been subjected to an appropriate dry treatment and allowing it to act. . Examples of the solvent that can be used in this case include aliphatic hydrocarbon compounds such as n-hexane, n-heptane, n-octane, and n-dodecane, benzene, toluene, xylene, mesitylene, monochlorobenzene, and methoxybenzene. Aromatic hydrocarbon compounds such as acetonitrile, nitrile compounds such as acetonitrile, propanenitrile, capronitrile, adiponitrile, benzonitrile and tolunitrile, and ester compounds such as dimethyl phthalate, dibutyl phthalate, dimethyl malonate and dimethyl succinate. These can be used alone or in combination. When these solvents are used, for example, they can be mixed with the reaction residual liquid after distillation in an amount of 0.5 to 50 times by volume, preferably 1 to 10 times by volume, and more preferably 1 to 5 times by volume. Can be mixed with. By mixing and treating in such a range, the load at the time of distilling and separating the solvent after the treatment can be reduced.

The treatment liquid after the treatment with the above-mentioned protic compound is then neutralized with, for example, an acidic sulfonic acid catalyst with a small amount of an alkaline compound such as an aqueous ammonium solution, and then extracted or distilled. The target amide compound can be separated and purified by a usual method such as operation, but the desired amide compound can be isolated by a known method such as distillation, crystallization and extraction without performing neutralization treatment. It is also possible to obtain it by performing a separation operation. The treatment liquid after the treatment with the protic compound is NH
_{3. When} neutralizing the strong acid catalyst by adding an aqueous solution of an alkaline compound such as NaOH, the salt of the strong acid catalyst can be solid-precipitated by adding a solvent such as toluene as a poor solvent. The product amide compound and the catalyst can be separated. Next, the mixture of the solvent and the target amide compound is separated into the solvent and the target amide compound by various separation operations such as distillation separation, extraction separation or crystallization separation. The recovered solvent is recycled to the alkali treatment step of the catalyst, and in that case, unnecessary by-products are separately separated by a separation means such as distillation. The target amide compound can be further purified by introducing it to a distillation column for purification.

A strong acid catalyst salt neutralized and separated by adding an alkaline compound such as NH ₃ or NaOH, for example, an inorganic salt of sulfonic acid is a strong acid such as sulfuric acid, hydrochloric acid or nitric acid, or a solid acid or an acid type ion exchange salt. It can be easily returned to sulfonic acid using a resin or the like. The regenerated sulfonic acid compound can be recycled to the reaction system as it is in a state of being dissolved in an inert solvent. However, when it is necessary to convert it into an acid anhydride, under mild operating conditions, for example, fuming sulfuric acid. , It can be easily dehydrated by contact with a dehydrating agent such as diphosphorus pentoxide, condensed phosphoric acid, etc. and converted into sulfonic acid anhydride. The regenerated sulfonic acid anhydride can be transferred to a reactor together with an inert solvent. It is possible to recycle with.

[0041]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded. In addition, the calculation method of the conversion rate of the compound (1) and the selectivity of the product by the conversion in the following Examples and Comparative Examples is as follows.

[0042]

[Equation 1] {Conversion rate (%) of compound (1)} =   (Number of moles of converted compound (1)) x 100 / (number of moles of compound (1) before decomposition)   (Number of moles of converted compound (1)) = {(number of moles of compound (1) before decomposition)-(after decomposition Remaining number of moles of compound (1))}

[Equation 2] {Ε-caprolactam or 6-amino-n-caproic acid selectivity (%)} =   (Number of moles of formed ε-caprolactam or 6-amino-n-caproic acid) × 2 × 100 / (conversion Number of moles of compound (1))

[Equation 3] {Selectivity (%) of compound (3)} =   (Number of moles of compound (3) formed) x 100 / (number of moles of converted compound (1))

Example 1 0.2700 g of para-toluenesulfonic anhydride (0.8
27 mmol), N, N-dimethylformamide 14.
175 g was charged into a 50 ml three-necked flask in a dry box, and the three-necked flask was heated with an oil bath under a dry nitrogen stream while stirring to bring the internal temperature to 75.5 ° C.
Cyclohexanone oxime 1.65 in dry box
A solution prepared by dissolving 9 g of 3.100 g of N, N-dimethylformamide in the above 3 at a constant rate for 18 minutes.
Beckmann rearrangement reaction of cyclohexanone oxime was performed by supplying to a one-necked flask. After 18 minutes, 1 more
After keeping the internal temperature of the flask at 75 ° C. for 0 minutes, the three-necked flask was cooled. The following operations were also performed in the dry box. When a part of the reaction liquid was taken out and 1 H-NMR was measured, all of the paratoluenesulfonic acid anhydride was changed to paratoluenesulfonic acid. Further, a compound (1) (an amide compound dehydrated dimer) having the following structure, which is formed by dehydration condensation of 2 molecules of ε-caprolactam, is produced, and an ion pair compound (2) with paratoluenesulfonic acid is produced in the solution. Was confirmed. The structural formulas of the compounds (1) and (2) are shown below.
Compound (2) is a resonance structure.

Structural formula of compound (1)

[Chemical 1]

Structural formula of compound (2)

[Chemical 2]

At this time, the ratio of the compound (1) to para-toluenesulfonic acid was determined from the comparison of the integral values of protons in 1 H-NMR, and when converted to the ratio to the charged paratoluenesulfonic acid anhydride, 43 mol%
Met. Based on this, the number of moles of compound (1) was converted from the number of moles of p-toluenesulfonic acid anhydride charged.
0.8128 g of this rearrangement reaction solution was charged into a 30 ml eggplant-shaped flask, and the amount of water in the reaction solution was the amount of the compound (1) in the reaction solution.
Water was added so as to be 5.3 times equivalent of the number of moles of, and the temperature of the oil bath was set to 100 ° C. under an argon atmosphere,
Heated for 1 hour. After cooling, 1H-NMR was measured, and it was found that the compound (1) (present in the solution in the structure of compound (2)) was 84% converted. At this time,
With respect to the converted compound (1), ε-caprolactam is produced with a selectivity of 95%, and a ring-opening compound of a compound obtained by dehydration-condensation of two molecules of ε-caprolactam (in a solution, an ion pair with paratoluenesulfonic acid ( 3) was produced) with a selectivity of 5%. Structural formula of compound (3) (resonance structure)
Is shown below.

[0047]

[Chemical 3]

Immediately after the Beckmann rearrangement reaction, 15.1 mol of ε-caprolactam was produced per mol of paratoluenesulfonic acid anhydride, but the compound (2) was 84% by heat treatment at 100 ° C. for 1 hour. After conversion, ε-caprolactam was found to have increased to 15.8 mol.

Example 2 0.559 g (1.71) of paratoluenesulfonic acid anhydride
3 mmol), 0.207 g of ε-caprolactam (1.
829 mmol), N, N-dimethylformamide 2
7.608g (30ml) 50m in the dry box
In a 3-neck flask of 1 l, the 3-neck flask was heated in an oil bath under a stream of dry nitrogen while stirring to adjust the internal temperature to 7
It was kept at 5 ° C. In a dry box, cyclohexanone oxime (4.876 g, 43.086 mmol) was added to N, N
-A solution prepared by dissolving 9.111 g of dimethylformamide was prepared and fed to the above-described three-necked flask at a constant rate for 51 minutes to carry out the Beckmann rearrangement reaction of cyclohexanone oxime. After 51 minutes, the three-necked flask was cooled. Of this Beckmann rearrangement reaction solution, 3
While leaving 9.090 g in a three-necked flask, N, N-dimethylformamide and light-boiling components were heated at an oil bath temperature of 70 ° C. for 2 minutes.
The residue was distilled off under reduced pressure at 0 to 15 mmHg to obtain 4.941 g of a residue.

The following operation was also performed in the dry box.
4.01 g of dehydrated toluene (water content concentration 4 ppm) was added to the thus obtained kettle residue to form a uniform solution.
When 1 H-NMR was measured by sampling a part thereof, it was found that the compound (1) was contained in the form of the compound (2). Further, all of the paratoluenesulfonic acid anhydride was changed to paratoluenesulfonic acid. At this time, the ratio of the compound (1) to the charged paratoluenesulfonic anhydride was 77 mol%.
Based on this, the number of moles of compound (1) was converted from the number of moles of p-toluenesulfonic acid anhydride charged. 5.5563 g of the toluene solution remaining in the kettle was charged into a 30 ml eggplant-shaped flask, and 8.6453 g of dehydrated toluene was additionally added. Then, with respect to the compound (1), the water content in the reaction solution was After adding water so that the molar ratio was 1.3 times the molar number of 1), the temperature of the oil bath was set to 90 ° C. in an argon atmosphere, and heating was performed for 1 hour.

After cooling, 1 H-NMR was measured,
The compound (1) has disappeared. At this time, the converted compound
In contrast to (1), ε-caprolactam was produced with a selectivity of 94%, and compound (3) was produced with a selectivity of 6%. Immediately after the Beckmann rearrangement reaction, 19.9 mol of ε-caprolactam was formed per mol of paratoluenesulfonic anhydride, but it was found that the amount increased to 21.3 mol after decomposition of the compound (1). (However, excluding the initially added ε-caprolactam)

Comparative Example 1 2.5 g of a toluene solution prepared by adding toluene to the kettle residue obtained by distilling the light-boiling fraction and N, N-dimethylformamide from the rearrangement reaction solution in Example 2 was used, and further dehydrated toluene was added. The heat treatment was performed in the same manner as in Example 2 except that the amount added was 3.88 g and that water was not added. The water content at this time was 0.057 equivalent to the compound (1). It was found that the compound (1) was converted by 6% after the heat treatment. The amount of increase in ε-caprolactam before and after the heat treatment was very small, and almost no increase was observed in 1 H-NMR. Capillary column (HR20M 0.25φ × 50m, Shinwa chemical
As a result of Beckmann rearrangement reaction, 19.9 mol of ε-caprolactam was produced per mol of paratoluenesulfonic acid anhydride, but after heating at 90 ° C. for 1 hour, 20. 0 mol (excluding ε-caprolactam initially added), and ε-
Caprolactam increased only 0.1 mole per mole of paratoluene sulfonic anhydride.

Example 3 0.280 g (0.85) of paratoluenesulfonic acid anhydride
8 mmol), 0.101 g of ε-caprolactam (0.
893 mmol), N, N-dimethylformamide 1
50 g of 3.802 g (15 ml) in a dry box
In a 3-neck flask of 1 l, the 3-neck flask was heated in an oil bath under a stream of dry nitrogen while stirring to adjust the internal temperature to 7
It was kept at 5 ° C. Cyclohexanone oxime (2.440 g, 21.562 mmol) was added to N, N in a dry box.
A solution prepared by dissolving 4.555 g of dimethylformamide was prepared and fed to the above-mentioned three-necked flask at a constant rate for 51 minutes to carry out the Beckmann rearrangement reaction of cyclohexanone oxime. After 51 minutes, the three-necked flask was cooled. 1 out of this Beckmann rearrangement reaction solution
While leaving 9.545 g in the three-necked flask, N, N-dimethylformamide and the light-boiling component were heated at an oil bath temperature of 70 ° C. for 2 minutes.
The residue was distilled off under reduced pressure at 0 to 15 mmHg to obtain 2.471 g of residue in the kettle.

2.835 g of water was added to the obtained kettle residue. When 1 H-NMR was measured by sampling a part of the compound, the compound (1) was in the form of the compound (2). Further, all of the paratoluenesulfonic acid anhydride was changed to paratoluenesulfonic acid. At this time, the ratio of the compound (1) to the charged paratoluenesulfonic acid anhydride was 70 mol%. Based on this, the number of moles of compound (1) was converted from the number of moles of p-toluenesulfonic acid anhydride charged. This pot residue aqueous solution 4.000
g in a 30 ml eggplant flask, and under a nitrogen atmosphere,
The temperature of the oil bath was set to 80 ° C., and heating was performed for 2 hours.

The amount of water in the reaction solution before the heating operation was 859 times the molar amount of the compound (1) in the reaction solution. After cooling, 1 H-NMR was measured to find that compound (1) was 8
It had been converted by 8%. At this time, 50% of ε-caprolactam, 16% of compound (3) and 27% of 6-amino-n-caproic acid were formed with respect to the converted compound (1). Immediately after the Beckmann rearrangement reaction, 18.0 mol of ε-caprolactam was produced per mol of paratoluenesulfonic acid anhydride, but it was 1 after decomposition of the compound (1).
It was found to have increased to 8.6 mol. (Excluding initially added ε-caprolactam)

[0056]

According to the method of the present invention, the desired amide compound can be produced in high yield by heating the reaction mixture after the Beckmann rearrangement reaction by a simple method.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsushi Fujii             1000 Kamoshida-cho, Aoba-ku, Yokohama-shi, Kanagawa             Within Mitsubishi Chemical Corporation (72) Inventor Toru Seto             1000 Kamoshida-cho, Aoba-ku, Yokohama-shi, Kanagawa             Within Mitsubishi Chemical Corporation F-term (reference) 4C034 DE03                 4H006 AA02 AC53 BA51 BA66 BC10                       BC19 BC34 BV22                 4H039 CA71 CJ90

Claims (13)

[Claims] 1. A method for producing an amide compound by rearrangement of an oxime compound in a liquid phase containing at least an acid component selected from an acid anhydride and a catalyst prepared from an N, N-disubstituted amide compound. A reaction mixture containing an inert catalyst species consisting of a dehydrated dimer of an amide compound and an acid derived from an acid component is used in an amount of 1,000 mol or less and 0.1 mol or more of proton based on the dehydrated dimer of the amide compound in the reaction mixture. A method for producing an amide compound, which comprises treating with an acidic compound. 2. The method according to claim 1, wherein the protic compound is used in an amount of 100 mol or less and 0.5 mol or more based on the dehydrated dimer of the amide compound of the inert catalyst species in the reaction mixture. Method for producing amide compound. 3. A reaction residual liquid obtained by distillative separation of an N, N-disubstituted amide compound from a reaction mixture containing an inert catalyst species consisting of a dehydrated dimer of an amide compound formed and an acid, is a protic compound. The method for producing an amide compound according to claim 1 or 2, wherein the amide compound is treated. 4. The method for producing an amide compound according to claim 1, wherein the protic compound is water. 5. The method for producing an amide compound according to claim 1, wherein the acid anhydride is a strong acid anhydride. 6. The method for producing an amide compound according to claim 1, wherein the acid anhydride is a sulfonic acid anhydride. 7. The method for producing an amide compound according to any one of claims 1 to 6, wherein the acid anhydride is an aromatic sulfonic acid anhydride or an aliphatic sulfonic acid anhydride. 8. The method for producing an amide compound according to claim 1, wherein the acid anhydride is a non-fluorine-containing sulfonic acid anhydride. 9. The method for producing an amide compound according to claim 1, wherein the acid anhydride is p-toluenesulfonic acid anhydride or methanesulfonic acid anhydride. 10. An N, N-disubstituted amide compound is N, N-
The compound is a dialkylformamide.
10. The method for producing the amide compound according to any one of 1 to 9. 11. The method for producing an amide compound according to claim 1, wherein the oxime compound is cyclohexanone oxime and the amide compound is ε-caprolactam. 12. The method for producing an amide compound according to claim 6, wherein the acidic component contains a carboxylic acid anhydride and a sulfonic acid and / or an acid anhydride thereof. 13. The protic compound is water, and the treatment is 3
It is performed at 0 ° C to 150 ° C.
13. The method for producing the amide compound according to any one of 12.