Monohaloacetyl halides prodn - by halogenating ketenes in ester solvents, suppressing formation of polyhaloacetyl halides an

摘要

Monohaloacyl halides (I) are prepd. by reacting a ketene with a halogen in presence of a solvent which is either (a) an alicyclic carbonate of formula:- where R and R1-6 are H, halogen, CH3, chloromethyl or C2H5 and n = 0 or 1, (b) an alkoxyalkyl ester of formula R6-O-R7-O-CO-R8 where R6 and R8 are not 5C alkyl and R7 is not 5C alkylene, with the proviso that the total number of C number in R6, R7 and R8 is 3-10, (c) an ester of formula R9-COO-R1 R9-COO-R10 where R9 is 2-7C alkyl and R10 is 4C alkyl, or (d) a glycol ester of formula:- R20-COO-(CR12R13)a-(CR14R15)b-CR16R17-CR18R19-OOC-R11 where R11 and R20 are 4C alkyl, R12-19 are H, CH3 or C2H5 with the proviso that is not 3 of these gps. are CH3 or C2H5, and a and b 0 or 1. Formation of polyhaloacyl halides is inhibited and prodn. of acyl halides is reduced to a minimum. (I) are inters. for herbicidal alpha-haloacetanilides and other prods.