Method for preparing p-chlorodiphenyl ketone

Abstract

The invention discloses a method for preparing p-chlorodiphenyl ketone. According to the method, p-chlorotrichloromethyl benzene, p-chlorobenzoic acid and benzene are subjected to Friedel-Crafts reaction in the presence of a catalytic amount of Lewis acid, such as FeCl3 to prepare p-chlorodiphenyl ketone. The method is performed under the conditions of a heating temperature of 150 DEG C-180 DEG C and a pressure of 0.5-0.8MPa, the molar ratio of p-chlorotrichloromethyl benzene to benzene is 1: (2-5), the molar ratio of p-chlorobenzoic acid to p-chlorotrichloromethyl benzene is 1: 1, the yield of p-chlorodiphenyl ketone is 90%, the disadvantage of aluminum-salt-containing wastewater pollution caused by catalysis of equimolar anhydrous AlCl3 used in the conventional acylation method is eliminated, the multi-step reaction of firstly preparing acyl chloride and then carrying out acylation in the traditional method is avoided, no isomer is generated and the product is high in quality.

Description

technical field [0001] The invention relates to a preparation method of p-chlorobenzophenone, which belongs to the field of chemical preparation. Background technique [0002] 4-Chlorobenzophenone is an important intermediate in organic synthesis, used as a photoinitiator and ultraviolet absorber, and can be used to make UV-curable coatings and inks. It is often used in the preparation of p-chlorobenzhydrylamine in the pharmaceutical industry, which is an important intermediate for the synthesis of levocetirizine for the treatment of allergic diseases. Because the chlorine atom on the p-chlorobenzophenone molecule is affected by the carbonyl group, it is easy to react with nucleophiles, and they are all raw materials for the manufacture of drugs and pesticides. The most important preparation method of p-chlorobenzophenone is: (1) Friedel-Crafts acylation reaction method of p-chlorobenzoyl chloride and benzene, this method is simple and easy, and the yield is as high as more...

AI Technical Summary

Problems solved by technology

The most important preparation method of p-chlorobenzophenone is: (1) Friedel-Crafts acylation reaction method of p-chlorobenzoyl chloride and benzene, this method is simple and easy, and the yield is as high as more than 90%, and the disadvantage is that 1 mol of Chlorobenzoyl chloride needs to use more than 2mol of anhydrous AlCl3 as a catalyst. After the reaction, it must be hydrolyzed with an acidic aqueous solution to obtain p-chlorobenzophenone, which produces a large amount of aluminum-containing salt Waste acid is unfavorable in terms of economic cost and environmental protection

(2) Benzoyl chloride and chlorobenzene are condensed under the catalysis of anhydrous AlCl3 to obtain p-chlorobenzophenone [Journal of Shanxi University (Natural Science Edition), 1999, 22(3): 247-250], the yield is very high, the disadvantage is that the amount of catalyst is large, and there are many three wastes; and the product contains certain ortho isomers, which can only be purified by repeated recrystallization with organic solvents

(3) Wu Chun [Journal of Harbin University of Commerce (Natural Science Edition), 2003, 19 (3): 329-331] reported a supported palladium catalyst for the cross-coupling of tributylphenyltin and p-chlorobenzoyl chloride Combined preparation of p-chlorobenzophenone, the highest yield reaches 92%, but the process uses the precious palladium catalyst of the organometallic kit, and the industrial application value needs to be further explored

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