Improved method for preparing 4-phenyl-cyanophenyl

Abstract

The invention relates to a method for preparing 4-phenyl-cyanophenyl. The method mainly comprises the steps of: carrying out Friedel-Crafts acylation on biphenyl which is a starting material to obtain 1-chloroacetyl-4-phenyl-benzene; carrying out ammonolysis reaction on the 1-chloroacetyl-4-phenyl-benzene to obtain 4-phenyl-benzamide; and carrying out dehydration reaction on the 4-phenyl-benzamide in the presence of a dehydrating agent to obtain the target product. The method is characterized in that (1) a catalyst used in the Friedel-Crafts acylation reaction is imidazole ionic liquid; and (2) the dehydrating agent used in the dehydration reaction is a mixture of triphosgene and ammonium salt, the molar ratio of the triphosgene to the ammonium salt is 1:(0.05-0.1), and the ammonium salt is organic ammonium salt or / and inorganic ammonium salt. The method for preparing the 4-phenyl-cyanophenyl with better commercial value is provided by the invention.

Description

technical field [0001] The present invention relates to a method for preparing 4-phenyl-benzonitrile. Background technique [0002] 4-Phenyl-benzonitrile is an intermediate for the preparation of organic pigments. At present, the synthesis methods of aryl-p-phenylbenzonitrile mainly include ammoxidation method, catalytic coupling method, aldoxime dehydration method, Rosenmund-von Braun displacement method, benzoic acid method and Mettler method, etc. The raw material of the ammoxidation method is methyl aromatic hydrocarbon. This method not only needs to screen suitable catalysts, but also the equipment used needs high temperature and high pressure resistance and high energy consumption; the preparation of p-phenylbenzonitrile by coupling method not only has high raw material prices, but also has side effects in the reaction process. There are many products; the substitution method needs to use highly toxic nitrile salts, which is not conducive to safe production; the corre...

AI Technical Summary

Problems solved by technology

The deficiencies in the improved method are: 1. the catalyst used in the Friedel-Crafts acylation reaction is anhydrous aluminum trichloride, zinc chloride or iron trichloride

When using these catalysts, strict anhydrous conditions are required (difficult to operate), and difficult to handle; The purity of the crude product is 85%, which needs to be further purified (this increases the difficulty and equipment investment of large-scale preparation of 4-phenyl-benzonitrile)

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