JP2001302602A - Method for producing amide compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an amide compound in high efficiency by Beckmann rearrangement of an oxime compound in a liquid phase, under a mild reaction condition and in the presence of a small amount of acid catalyst. SOLUTION: This method for producing an amide compound comprises Beckmann rearrangement of an oxime compound in a liquid phase and is characterized by making the reaction in the presence of a condensed phosphoric acid compound, an N,N-disubstituted amide compound and, optionally, a fluorine- containing strong acid or its derivative.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Generally, as a method of producing an amide compound which is industrially performed, a method of converting an oxime compound to 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. At present, such a Beckmann rearrangement reaction is industrially adopted as a liquid phase reaction using a strong acid such as concentrated sulfuric acid or fuming sulfuric acid as a catalyst. However, in this known method, it is usually necessary to neutralize sulfuric acid with ammonia in order to separate the produced lactam compound, and ammonium sulfate (ammonium sulfate) is by-produced in an amount about twice that of the lactam compound; Since a large amount of a strong acid is used, there are problems such as corrosion of the reaction apparatus, and the method is not always economical. Therefore, development of an efficient catalyst for rearrangement reaction is expected.

[0003] Various studies have been made on the Beckmann rearrangement reaction in a liquid phase without using a sulfuric acid catalyst. For example, in a Beckmann rearrangement reaction of cyclohexanone oxime in a liquid phase using a homogeneous catalyst, a method using an ion pair (bismeier complex) obtained by a reaction between N, N-dimethylformamide and chlorosulfonic acid as a catalyst (M.
A. Kira and Y. M. Shaker, Egy
pt. J. Chem. , 16, 551 (1973)),
A method using an alkylating agent formed from an epoxy compound and a strong acid (boron trifluoride / etherate, etc.) and a catalyst comprising N, N-dialkylformamide (Y. Izum)
i, Chemistry Letters, pp. 21
71 (1990)), a method of rearranging cyclohexanone oxime using a condensable phosphoric acid compound in a heptane solvent (Japanese Patent Laid-Open No. 62-149665); Using a catalyst comprising a compound such as -dialkylformamide (JP-A-5-105654, Y. Izumi,
Journal of Molecular Catal
ysis A: Chemical 149 (1999) p
p. 25-32) and the like have been proposed.

However, a method of producing ε-caprolactam by performing Beckmann rearrangement reaction of cyclohexanone oxime in a liquid phase using these catalyst systems is not always satisfactory as an industrial production method. Specifically, in the above-described Beckmann rearrangement reaction of cyclohexanone oxime using a bismeyer complex as a catalyst, since a formed lactam and a catalyst form a 1: 1 complex, an equimolar amount of a catalyst is required for the starting oxime. It is not an economical industrial manufacturing method. The method using an alkylating agent formed from an epoxy compound and a strong acid and a catalyst comprising N, N-dialkylformamide is different from the conventional equimolar reaction using sulfuric acid as a catalyst. Although a method is disclosed, a toxic compound such as dimethyl sulfate or epichlorohydrin may be used in order to produce an alkylating agent, so that this method is not necessarily industrially satisfactory from the viewpoint of operability. Further, JP-A-62-2
In the method using a condensed phosphoric acid compound as a catalyst disclosed in Japanese Patent No. 149665, it is necessary to use a phosphoric acid catalyst as large as about twice as much as 1 mol of the starting oxime. Since a large load is applied to the neutralization step, it cannot be said to be an economical industrial production method.

The method using a catalyst comprising phosphorus pentoxide and a fluorinated strong acid or a derivative thereof and a compound such as N, N-dialkylformamide disclosed in the above-mentioned JP-A-5-105654 exhibits high catalytic activity. However, it is also described in the specification that the catalytic activity is deactivated by a very small amount of water, which requires strict removal of water from the raw material oxime, reaction solvent, reaction apparatus and the like. Particularly, as can be seen from the fact that those skilled in the art know that phosphorus pentoxide compounds as catalyst components are strong dehydrating agents, they have extremely high hygroscopicity, and therefore require great care and complicated handling. Thus, conventionally proposed catalyst systems are not always satisfactory for industrial implementation in terms of catalyst efficiency, handleability, and economic efficiency.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a method for performing the Beckmann rearrangement reaction of an oxime compound in a liquid phase in the presence of an acid catalyst, which does not have the above-mentioned problems. An object of the present invention is to provide a method for producing an amide compound with high efficiency by catalytically rearranging an oxime compound with a catalytic amount.

[0007]

The inventors of the present invention have conducted intensive studies on a catalyst for Beckmann rearrangement of an oxime compound to an amide compound. The present invention has been found that an amide compound can be obtained with higher efficiency when a rearrangement reaction is carried out in a catalyst system composed of an amide compound, and further, a catalyst system in which a fluorinated strong acid or a derivative thereof coexists with these catalyst compounds. did. That is, the gist of the present invention is a method for producing an amide compound by performing a Beckmann rearrangement reaction of an oxime compound in a liquid phase,
A method for producing an amide compound, characterized in that the reaction is performed in the presence of a condensed phosphoric acid compound and an N, N-disubstituted amide compound.

In a preferred embodiment of the present invention, in the method for producing an amide compound, the reaction is carried out in the presence of a strong fluorinated acid or a derivative thereof, and the N, N-disubstituted amide compound is N, N-dimethylformamide. Wherein the fluorinated strong acid or derivative thereof is a compound selected from the group consisting of trifluoroacetic anhydride, trifluoromethanesulfonic acid, trifluoromethanesulfonic anhydride and boron trifluoride etherate complex, and the oxime compound is cyclohexanone Oxime, and the amide compound is ε-caprolactam.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below. The oxime compound used as a raw material in the Beckmann rearrangement reaction of the present invention is not particularly limited, 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. Among them, cyclic oxime compounds such as cyclohexanone oxime, cyclopentanone oxime and cyclododecanone oxime are preferably used.

[0010] The condensed phosphate compound is a component of the catalyst used in the present invention, linear polymer phosphate produced by dehydration condensation of orthophosphoric acid of the general formula Hn + 2P _n O3n + 1
(N = 2 to 15). Two or more PO ₄ tetrahedra have a structure in which the oxygen atoms at the vertices are shared and linearly connected, and in the general formula, n = 2 (pyrophosphate), n
= 3 (triphosphoric acid), n = 4 (tetraphosphoric acid) and the like are known. The structure of a typical condensed phosphoric acid compound is shown below.

[0011]

Embedded image

As described above, the condensed phosphoric acid compound used in the present invention is phosphorus pentoxide (P ₂ O ₅ ) which is a metal oxide.
Is a phosphorus compound having a hydroxyl group (-OH) in the molecule. These condensed phosphoric acid compounds are generally prepared by heating and dehydrating orthophosphoric acid (O = P (OH) ₃ ) at a high temperature of 300 ° C. or higher for a long time, or by mixing phosphorus pentoxide and orthophosphoric acid in arbitrary amounts. Can be easily obtained by, for example, a method of producing by mixing and heating, and in this case, it is generally obtained as a mixture of various linear condensed phosphoric acid compounds as described above. As the condensed phosphoric acid compound used in the present invention, any of the above-described various linear condensed phosphoric acid compounds alone or a mixture thereof can be used, and the composition thereof is not particularly limited. The mixture is more preferably used from the viewpoint of the production of the phosphate compound.

As the condensed phosphoric acid compound used in the present invention, it is usually preferable that the condensed phosphoric acid compound has a high degree of condensation in order to obtain high activity. On the other hand, if the degree of condensation is too high, the viscosity increases. Therefore, it may be difficult to handle in a process, and it is therefore preferable to use a condensed phosphoric acid compound having an appropriate degree of condensation. Specifically, the above-mentioned general formula _{Hn + 2P n O3n + 1 (} n = 2~15) n with condensed phosphoric acid compound represented by 2-15, preferably 2-10,
More preferably, 2 to 4, especially 3 or 4, condensed phosphoric acid compounds or mixtures thereof are used. Orthophosphoric acid or the like may be mixed in the condensation reaction product. The composition of these condensed phosphoric acid compounds is, for example, anion-
exchange chromatographic method and molybdenum-blue colorimetry
y method (Ohashi, Bull. Chem. Soc. J
Apan, 30.864 (1957)).

Degree of condensation (n) of the condensed phosphoric acid compound of the present invention
, When condensed phosphoric acid compound is one single item, the following relationship between the condensed phosphoric acid _{(Hn + 2P n O3n + 1} ) of P ₂ O ₅ is satisfied, is calculated from the expression. nP ₂ O ₅ + (n + 2) H ₂ O → H _{n + 2} P _n O _{3n + 1}

数 n × (141.94) / [n × (141.94) + (n + 2) × (1
8)]｝ 100 = P ₂ O ₅ (wt%) [P ₂ O ₅ MW = 141.94 H ₂ O MW = 18] For example, in the case of polyphosphoric acid having a P ₂ O ₅ content of 82.55 wt%, the above formula is used. Thus, n = 3 (degree of condensation) is calculated. When the condensed phosphoric acid compound is a mixture, it is determined from the P ₂ O ₅ content in the mixture as an average degree of condensation (provided that it is a single product) by the above formula. For example, if the P ₂ O ₅ content is
In the case of a polyphosphoric acid mixture of 83.9 wt%, n
= 4 (average degree of condensation).

Although the condensed phosphoric acid compound has relatively high hygroscopicity, it has a low hygroscopicity as compared with P ₂ O _5. It also has the advantages of reducing the load of water removal on raw materials and equipment and of being a viscous liquid, so that it can be handled by a relatively easy operation method. The benefits in terms of aspect are great. The amount of the condensed phosphoric acid compound used (in terms of P ₂ O ₅ ) in the present invention is not particularly limited, but is generally about 0.05 to 20 mol%, preferably 0.1 to 20 mol%, based on the starting oxime compound. 1 to 10 mol%, more preferably 0.5 to 5 mol%
Used in the range. If the amount is less than this range, sufficient catalytic activity cannot be obtained. On the other hand, if the amount is too large, the alkali required for the catalyst treatment after the rearrangement reaction increases, which is not preferable.

The N, N-disubstituted amide compound used in the present invention generally has the same or different substituents having 1 to 18 carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms. Carboxamides, especially formamides, on the nitrogen atom. 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 having the same two alkyl groups are preferable, and N, N-dimethylformamide is particularly preferable.

The amount of the N, N-disubstituted amide compound used is not particularly limited, and varies depending on the range of the starting oxime compound and the range of the condensed phosphoric acid compound, and is not uniformly defined. However, the amount can be usually 1 to 1000 times, preferably 10 to 100 times the weight of the oxime compound. The N, N-disubstituted amide compound used in the present invention is
Since it acts as a solvent at the same time as being a component of the catalyst, it can be used by mixing with an appropriate solvent when a suitable solvent is used for smoothly proceeding the rearrangement reaction. The solvent is 4 to the N, N-disubstituted amide compound.
It is possible to mix up to 0 times by volume, preferably up to 20 times by volume, more preferably up to 10 times by volume. Examples of the solvent that can be used in the rearrangement reaction of the present invention include aliphatic hydrocarbon compounds such as n-hexane, n-heptane, n-octane, and n-dodecane; benzene, toluene, xylene, mesitylene, and monochlorobenzene. , Aromatic hydrocarbon compounds such as methoxybenzene,
Acetonitrile, propanenitrile, capronitrile,
Adiponitrile, benzonitrile, nitrile compounds such as tolunitrile, dimethyl phthalate, dibutyl phthalate,
Examples thereof include ester compounds such as dimethyl malonate and dimethyl succinate, and these can be used alone or in combination.

In the present invention, the rearrangement reaction of the oxime compound to the amide compound can proceed catalytically only with the catalyst formed from the above-mentioned condensed phosphoric acid compound and N, N-disubstituted amide. Fluorinated carboxylic acid, fluorinated carboxylic anhydride, fluorinated carboxylic acid ester, fluorinated sulfonic acid, fluorinated sulfonic anhydride,
The catalytic activity can be further increased by using a fluorinated strong acid such as a fluorinated sulfonic acid ester or a fluorinated acid / ether complex or a derivative thereof in combination. Specific compounds include trifluoroacetic acid, trifluoroacetic anhydride, trifluoromethanesulfonic acid, trifluoromethanesulfonic anhydride, ethyl trifluoromethanesulfonic acid, boron trifluoride, boron trifluoride ether complex and the like. Among them, fluorinated sulfonic acids such as trifluoromethanesulfonic acid, trifluoromethanesulfonic acid ester and trifluoromethanesulfonic anhydride and derivatives thereof are preferable, and trifluoromethanesulfonic anhydride is particularly preferable. The amount of the fluorinated strong acid and the derivative thereof used in the present invention is not particularly limited, but is generally about 0.1 to 20 in molar ratio with respect to the condensed phosphoric acid compound (in terms of P ₂ O ₅ ). Preferably 0.2 to
It is used in a molar ratio of 10 mol, more preferably in a range of 0.5 to 5 molar ratio.

The conditions for carrying out the method of the present invention are not particularly limited, but the reaction is carried out usually at a temperature of 30 ° C. to 200 ° C., preferably 60 ° C. to 150 ° C., more preferably 80 ° C. to 130 ° C. The reaction pressure is not particularly limited, and the reaction is carried out under normal pressure to pressurized conditions. In the present invention, the rearrangement reaction proceeds regardless of the order in which the catalyst components of the condensed phosphoric acid compound and the N, N-disubstituted amide compound, and furthermore, the fluorinated strong acid or its derivative and the starting oxime compound are mixed in any order. It is not preferable that the phosphoric acid compound and the oxime compound, or the fluorinated strong acid or a derivative thereof and the oxime compound are heated for a long time and then mixed with other catalyst components to react with each other. After the formation, it is preferable to start the reaction by supplying the starting oxime compound. In this case, the starting oxime compound can be dissolved in a part of the N, N-disubstituted amide compound and used for the reaction.

The reaction mode for carrying out the reaction of the present invention is not particularly limited, and any of a batch reaction and a continuous flow reaction can be carried out. However, it is industrially preferable to use the continuous flow reaction mode. . The raw material oxime compound, catalyst component and reaction solvent used in the reaction are preferably subjected to sufficient water removal in advance and then subjected to the reaction in order to obtain high catalytic activity and high selectivity to the amide compound.
The resulting amide compound can be separated, purified and obtained from the reaction solution by a usual method such as an extraction operation or a distillation operation after deactivating the catalyst by a small amount of an alkaline compound such as an aqueous ammonium solution after the reaction is completed.

[0021]

EXAMPLES The present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist. In the following examples, the lactam yield is represented by mol% based on the charged oxime compound, and the TON value (Turn Over Number) is represented by the number of moles of the lactam generated relative to the charged condensed phosphoric acid compound (P ₂ O ₅ conversion: mol). . The used condensed phosphoric acid compound (P ₂ O
₅ content 83.9wt%) is a mixture of monophosphoric acid, pyrophosphoric acid, triphosphoric acid and tetraphosphoric acid, and the average degree of condensation is about 4
It is.

Example 1 After replacing a 50 ml round bottom flask dried by a dryer at 100 ° C. with dry nitrogen treated with Molecular Sieve-4A,
10 ml of N, N-dimethylformamide previously dried with molecular sieve-4A and condensed phosphoric acid compound 8
8.6 mg (about 0.52 mmol in terms of P ₂ O ₅ ) was added, and the mixture was heated and stirred at 110 ° C. for 10 minutes. Next, 1.01 g (8.9 mmol) of cyclohexanone oxime was added to N, N-
A solution dissolved in 10 ml of dimethylformamide was added and reacted at 110 ° C. for 15 minutes. After completion of the reaction, the reaction solution was treated with a commercially available 28% -NH ₃ aqueous solution to deactivate the catalyst, and the reaction solution was analyzed by gas chromatography. As a result, the yield of ε-caprolactam was 26.7.
%, TON value was 4.6.

Comparative Example 1 A Beckmann rearrangement reaction of cyclohexanone oxime was carried out in the same manner as in Example 1, except that N, N-dimethylformamide was changed to chlorobenzene or benzonitrile. As a result, the yield and TON value of ε-caprolactam were as follows. Lactam yield (%) TON value Chlorobenzene 4.6% 0.8 Benzonitrile 5.8% 1.0

Examples 2 to 5 After replacing a 50 ml round bottom flask dried by a dryer at 100 ° C. with dry nitrogen treated with Molecular Sieve-4A,
N, N-dimethylformamide 10 ml, condensed phosphoric acid compound 88.6 mg (about 0.52 mmol in terms of P ₂ O ₅ )
Was added and the mixture was heated and stirred at 110 ° C. for 10 minutes. Next, 0.3 mmol of various fluorinated strong acids shown in Table 1 were added, and 1
The mixture was heated and stirred at 10 ° C. for 5 minutes. Next, a solution prepared by dissolving 1.01 g (8.9 mmol) of cyclohexanone oxime in 10 ml of N, N-dimethylformamide was added.
The reaction was performed at 110 ° C. for 15 minutes. After completion of the reaction,
After deactivating the catalyst by treatment with an 8% -NH ₃ aqueous solution, the reaction solution was analyzed by gas chromatography. Table 1 shows the results
Shown in

Comparative Example 2 A Beckmann rearrangement reaction of cyclohexanone oxime was carried out in the same manner as in Example 2 except that the operation was carried out without adding a condensed phosphoric acid compound. The results are shown in Table 1.

[0026]

[Table 1]

Examples 6 and 7 In Example 2, the amounts of the condensed phosphoric acid compounds used are shown in Table 2.
The Beckmann rearrangement reaction of cyclohexanone oxime was carried out in the same manner except that the reaction was carried out in the amounts shown in (1). The results are shown in Table-2.

[0028]

[Table 2]

Examples 8 to 9 The Beckmann rearrangement of cyclohexanone oxime was carried out in the same manner as in Example 6, except that the pretreatment (formation of the catalyst species) and the reaction temperature were carried out at the temperatures shown in Table 3. did. The results are shown in Table-3.

[0030]

[Table 3]

Examples 10 to 11 The Beckmann rearrangement reaction of cyclohexanone oxime was carried out in the same manner as in Example 8, except that N, N-dimethylformamide was used as an N, N-dimethylformamide / acetonitrile mixed solution. Was carried out.
The results are shown in Table-4.

[0032]

[Table 4]

[0033]

According to the method of the present invention, an amide compound can be produced from an oxime compound under a mild reaction condition in a high yield, and a conventionally known catalyst system using P ₂ O ₅ can be produced. Since a catalyst system with improved water resistance is used, it is possible to reduce the load of storing the catalyst and removing water in the equipment, which is an industrially advantageous method.

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // C07B 61/00 300 C07B 61/00 300 F term (reference) 4C034 DE03 4H006 AA02 AC53 BA31 BA35 BA37 BA45 BA50 BA51 BA52 BC14 4H039 CA71 CH90 CJ90

Claims (5)

[Claims] 1. A method for producing an amide compound by carrying out a Beckmann rearrangement reaction of an oxime compound in a liquid phase, wherein the reaction is carried out in the presence of a condensed phosphoric acid compound and an N, N-disubstituted amide compound. The method for producing an amide compound described above. 2. The method for producing an amide compound according to claim 1, wherein the reaction is carried out in the presence of a strong fluorinated acid or a derivative thereof. 3. The method for producing an amide compound according to claim 1, wherein the N, N-disubstituted amide compound is N, N-dimethylformamide. 4. A fluorinated strong acid or a derivative thereof is trifluoroacetic anhydride, trifluoromethanesulfonic acid,
The method for producing an amide compound according to claim 2, which is a compound selected from the group consisting of trifluoromethanesulfonic anhydride and a boron trifluoride etherate complex. 5. 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.