Alkyl chloride prodn. from alkyl chloroformates - by thermal decarboxylation in aprotic solvent

摘要

Prodn. of alkyl chlorides comprises decarboxylating alkyl chloroformates at 80-200 degrees C (pref. 110-140 degrees C) in an aprotic solvent. The solvent is pref. an amide, esp. an N-alkylated cyclic amide of formula (I): (where x = 2-12; R = 1-18C alkyl). The prefd. cpd. (I) is N-methylpyrrolidone. The starting material can be a chloroformate derived from a 1-30C alkanol or a 2-30 di- or polyhydric alcohol. Process gives high yields (e.g. 97-98%) of high purity prods. without the use of catalysts. In an example, MeCl is prepd. continuously in 98% yield by pumping methyl chloroformate into a pressurised reactor contg. N-methylpyrrolidone at 120-130 degrees C.