Study On Catalysis Of AlCl₃ To Synthsis Branched Benzophenone By Acidylation

Benzophenones, with a strong absorption of ultraviolet radiation, are important organic intermediates, which are widely used in commodity chemicals, pharmaceutical synthesis, pesticide, plastic, dope and other fields. In traditional process of production, phosgene, benzoyl chloride, benzotrichloride, benzoic acid, 2-methyl benzylmethane are used as reagents. At the beginning, we provide a comparison to these methods and summarize advantages and disadvantages. Then, the synthesis technics of some important benzophenones are introduced. After that,we report the path of preparation of 2,2'-dihydroxy-4,4'-dimethoxybenzophenone.In the process of the preparation, we choose triphosgene as a substitute of phosgene that is used in traditional preparation. Phosgene is toxic gas, so it is dangerous to use it in the experiment and its conveyance and storage is not convenient. With the development of green chemistry, scientists have been seeking for the ideal substitute of phosgene. Triphosgene is a new acyl reagent, which is usually stable, and its conveyance storage is convenient.In the Friedel-Crafts reaction, Lewis acids were often used as the catalyst. different kinds of Lewis acids catalysts were selected and tested for F-C reaction, the results showed that anhydrous AlCl3 is the best catalyst for the syntheses of BP-6, the yield of 2,2'-dihydroxy-4,4'-dimethoxybenzophenone arrived at 60 percent.On the basis of synthesizing 2,2'-dihydroxy-4,4'-dimethoxybenzophenone. The optimization condition to synthesis BP-6 is as follows: in the presence of anhydrous AlCl3, DMF as the 1,3-Dimethoxybenzene reacted with phosgene released by BTC at 30℃in the solvent of C2H4Cl2, after 10 hours,distilled water and strong hydrochloric aic were added into the solution one by one, followed by the reaction at 80℃for 12 hours , added water and HCl (32%). Hydrolyzation at normal temperature for 48 hours. At last, we got 2,2'-dihydroxy-4,4'-dimethoxybenzophenone with a yield 60 % . The new method introduced owns the following anvantages: simple and safe opertation, less pollution, proveding a novel friendly-environment method for the synthesis of benzophenones.