Benzodioxole was monochloromethylated directly by aqueous formaldehyde and hydrogen chloride gas in CCl4 in the presence of quaternary ammonium salts: C16H33-(CH3)3NX(X=Br,Cl), C12H25(CH3)3NCl,C12H25(CH3)2(C6...Benzodioxole was monochloromethylated directly by aqueous formaldehyde and hydrogen chloride gas in CCl4 in the presence of quaternary ammonium salts: C16H33-(CH3)3NX(X=Br,Cl), C12H25(CH3)3NCl,C12H25(CH3)2(C6H5CH2)NCl and (C4H9)4NBr. With hexadecyltrimethylammonium bromide at temperature 6065 ℃ 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.展开更多
文摘Benzodioxole was monochloromethylated directly by aqueous formaldehyde and hydrogen chloride gas in CCl4 in the presence of quaternary ammonium salts: C16H33-(CH3)3NX(X=Br,Cl), C12H25(CH3)3NCl,C12H25(CH3)2(C6H5CH2)NCl and (C4H9)4NBr. With hexadecyltrimethylammonium bromide at temperature 6065 ℃ 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.