Organic compounds -- part of the class 532-570 series – Organic compounds – Unsubstituted hydrocarbyl chain between the ring and the -c-...
Reexamination Certificate
2001-12-21
2002-12-03
Kumar, Shailendra (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Unsubstituted hydrocarbyl chain between the ring and the -c-...
C540S464000, C540S539000, C548S543000, C548S552000, C564S215000, C564S216000, C564S218000
Reexamination Certificate
active
06489474
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a process for producing an amide compound. More specifically, it relates to a process for producing an amide compound effectively by carrying out Beckmann rearrangement of an oxime in a liquid phase in the presence of a catalyst.
BACKGROUND OF THE INVENTION
Generally, as an industrial process for producing an amide compound, a process of converting an oxime compound into an amide compound through Beckmann rearrangement. For example, &egr;-caprolactam is produced through Beckmann rearrangement of cyclohexanone oxime. For such Beckmann rearrangement, currently a liquid-phase reaction has been adopted using a strong acid such as concentrated sulfuric acid or fuming sulfuric acid as the catalyst. However, in this known method, there are problems that, for separating the lactam compound formed, the sulfuric acid should be usually neutralized with ammonia to result in the formation of ammonium sulfate in an amount twice the amount of the above lactam compound as a by-product, and the reaction apparatus is corroded since a large amount of the strong acid is used. Therefore, the process is not necessarily economical and thus, it is expected to develop an effective catalyst for the rearrangement.
Therefore, Beckmann rearrangement in liquid phase has been variously investigated without using the sulfuric acid catalyst. For example, the following process are proposed for Beckmann rearrangement of cyclohexanone oxime in liquid phase using homogeneous catalysts: a process using an ion pair obtainable by reacting N,N-dimethylformamide with chlorosulfonic acid (a Vilsmeier complex), as the catalyst [M. A. Kira and Y. M. Shaker, Egypt. J. Chem., 16, 551 (1973)]; a process using a catalyst composed of an N,N-dialkylformamide and an alkylating agent obtainable from an epoxy compound and a strong acid (boron trifluoride-etherate or the like) [Y. Izumi, Chemistry Letters, pp. 2171 (1990)]; a process of rearranging cyclohexanone oxime with a phosphoric acid or a condensed phosphoric acid compound in a heptane solvent (Japanese Patent Laid-Open No. 149665/1987); a process using a catalyst composed of phosphorus pentoxide and a fluorine-containing strong acid or its derivative and a compound such as N,N-dialkylformamide (Japanese Patent Laid-Open No. 105654/1993; corresponding to U.S. Pat. No. 5,254,684); and the like.
However, the processes for producing &egr;-caprolactam by subjecting cyclohexanone oxime to Beckmann rearrangement in a liquid phase using these catalyst systems are not always satisfactory as industrial processes. Specifically, in the above Beckmann rearrangement of cyclohexanone oxime using a Vilsmeier complex as the catalyst, the lactam produced and the catalyst form a 1:1 complex, so that it is necessary to use the catalyst in an amount equimolar to the starting oxime. For this reason, the process cannot be said to be an economical industrial process. The process using a catalyst composed of an N,N-dialkylformamide and an alkylating agent obtained from an epoxy compound and a strong acid shows a novel method for the rearrangement, which is different from the conventional equimolar reaction using sulfuric acid as the catalyst. However, it is industrially not always satisfactory in view of operability because toxic compounds such as dimethyl sulfate and epichlorohydrin are sometimes used for producing the alkylating agent which is one of the rearrangement catalyst components. Further, in the process using phosphoric acid or a condensed phosphoric acid as the catalyst disclosed in Japanese Patent Laid-Open No. 149665/1987, the phosphoric acid catalyst is required in an amount as large as about 2 mol per 1 mol of the starting oxime, so that the process results in a large load on the catalyst-neutralizing step with ammonia after the reaction. Therefore, the process cannot be said to be economical industrial process.
In the process using a catalyst composed of phosphorus pentoxide and a fluorine-containing strong acid (e.g., a fluorine-containing sulfonic anhydride) or its derivative and a compound such as N,N-dialkylformamide disclosed in the above Japanese Patent Laid-Open No. 105654/1993 (U.S. Pat. No. 5,254,684), the catalyst shows a high catalytic activity but the specification describes that the catalytic activity is deactivated by the action of a trace amount of water, so that it is necessary to remove moisture strictly from the starting oxime, a reaction solvent, a reaction apparatus, and the like. In particular, the phosphorus pentoxide compound, a component of the catalyst, is known as a strong dehydrating agent by those skilled in the art, and thus, owing to the extremely high hygroscopicity, the handling is accompanied by a considerable care and troublesomeness. In addition, trifluoromethanesulfonic anhydride (a fluorine-containing strong acid compound) for use as a constituting component of the catalyst is effective as a highly active component of the catalyst, but is expensive and causes a problem of corrosion of the apparatus.
As described above, the catalyst systems heretofore proposed are not always satisfactory for the industrial production in view of catalyst efficiency, handling, and economical efficiency.
Object of the present invention is to provide a process for producing an amide compound with high efficiency through Beckmann rearrangement of an oxime compound in a liquid phase in the presence of an acid catalyst, by rearranging the oxime catalytically under a mild reaction conditions and using a small amount of catalyst, which is free from the above problems.
DISCLOSURE OF THE INVENTION
As a result of the extensive studies of catalysts for Beckmann rearrangement of an oxime compound into an amide compound, the present inventors have found that an amide compound can be obtained in a yield as high as in the case of the conventional process by carrying out the rearrangement using a catalyst comprising an aromatic sulfonic anhydride or non-fluorine-containing aliphatic sulfonic anhydride and an N,N-disubstituted amide compound without using an expensive fluorine-containing strong acid compound which is heretofore considered to be essential as a constituting component of the catalyst, and have attained the present invention.
Also, they have found that an amide compound can be obtained with higher efficiency by carrying out the rearrangement in the presence of at least one compound selected from the group consisting of sulfonic acids and anhydrides thereof, an N,N-disubstituted amide compound, and a carboxylic anhydride, and have attained the invention.
Namely, the first gist of the invention lies in a process for producing an amide compound by subjecting an oxime compound to Beckmann rearrangement in a liquid phase, characterized in that the reaction is carried out in the presence of a non-fluorine-containing sulfonic anhydride and an N,N-disubstituted amide compound.
The second gist of the invention lies in a process for producing an amide compound by subjecting an oxime compound to Beckmann rearrangement in a liquid phase, characterized in that the rearrangement is carried out in the presence of at least one compound selected from the group consisting of sulfonic acids and anhydrides thereof, an N,N-disubstituted amide compound, and an carboxylic anhydride.
As the preferred embodiments of the first gist of the invention, in the above process for producing an amide compound, it may be mentioned that the sulfonic anhydride is a non-fluorine-containing sulfonic anhydride, for example, a non-fluorine-containing benzenesulfonic anhydride or a non-fluorine-containing alkylsulfonic anhydride which may have a substituent, particularly p-toluenesulfonic anhydride or methanesulfonic anhydride, and the N,N-disubstituted amide compound is N,N-dimethylformamide, as well as the oxime compound is cyclohexanone oxime and the amide compound is &egr;-caprolactam.
As the preferred embodiments of the second gist of the invention, in the above process for producing an amide compound, it may be mentioned that the sulf
Kawaragi Yuuji
Setoyama Tohru
Kumar Shailendra
Mitsubishi Chemical Corporation
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