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Benzodioxole was monochloromethylated directly by aqueous formaldehyde and hydrogen chloride gas in CCl_4 in the presence of quaternary ammonium salts: C_16H_33-(CH_3)_3NX(X=Br,Cl), C_12H_25(CH_3)_3NCl,C_12H_25(CH_3)_2(C_6H_5CH_2)NCl and (C_4H_9)_4NBr. With hexadecyltrimethylammonium bromide at temperature 60~65 ℃ and for 15 hours of reaction, 1,3-benzodioxole was converted to piperonyl chloride with conversion more than 98% and selectivity up to 97%. The method has advantages of high selectivity, high conversion, negligible by-products and easy workup of the main product.
Benzodioxole was monochloromethylated directly by aqueous formaldehyde and hydrogen chloride gas in CCl_4 in the presence of quaternary ammonium salts: C_16H_33- (CH_3) _3NX (X = Br, Cl), C_12H_25 (CH_3) _3NCl, C_12H_25 (CH_3) _2 (C_6H_5CH_2) NCl and (C_4H_9) _4NBr. With hexadecyltrimethylammonium bromide at temperature 60-65 ° C and for 15 hours of reaction, 1,3-benzodioxole was converted to piperonyl chloride with conversion more than 98% and selectivity up to 97%. The method has advantages of high selectivity, high conversion, negligible by-products and easy workup of the main product.