A process for preparing environmentally safe dicofol and its formulations

摘要

The present invention provides for an improved practical process for producing DDTr-free p,p′-dicofol and its formulations substantially free of the practically inactive o-p′-dicofol comprising either directly recrystallizing technical dicofol from a suitable solvent such as acetic acid or alkanes, or alternat­ively preparing the p,p′-dicofol by the steps of (a) dehydrohalogenating technical DDT to give DDE; (b) chlorinating DDE to give Cl-DDT; and (c) hydrolyzing Cl-DDT to dicofol, wherein the technical DDT is initially recrystallized from a suitable solvent such as lower alkyl alcohols and then recrystallizing the resulting p,p′-dicofol from a suitable solvent such as acetic acid or alkanes.