GB923051A - Esters of chlorinated carboxylic acids and herbicidal compositions containing same - Google Patents

Abstract

The invention comprises compounds of the general formulae <FORM:0923051/IV(a)/1> in which R denotes an a -a -dichloropropyl or a ,a -dichloroethyl radical, X denotes a halogen atom or a cyano group, and R1, R2, R3 and R4 may be identical or different, each representing a hydrogen atom or an alkyl or alkoxyalkyl radical. The compounds may be prepared by reaction of the acid chlorides of a ,a -dichloropropionic acid or a ,a -dichlorobutyric acid with the appropriate alcohols, or by esterification of the free acids with the alcohols in the presence of a catalyst and a hydrocarbon capable of azeotropic distillation with water. A list of suitable alcohols is given. The preparation of the b -cyanoethyl, b -chloroethyl and a -methyl-b -chloroethyl esters of both acids is described. The compounds may be used as herbicides (see Group VI).ALSO:Compounds of the general formul <FORM:0923051/VI/1> in which R denotes an a ,a -dichloropropyl or a ,a -dichloroethyl radical, X denotes a halogen atom or a cyano group, and R1, R2, R3 and R4 may be identical or different, each representing a hydrogen atom or an alkyl or alkoxyalkyl radical (see Group IV (b)) are suitable for combating weeds, especially monocotyledonous weed plants in dicotyledonous crops. The esters may, for example, be used as sprays in the form of dispersions or emulsions, and may be mixed with known herbicides. Examples are given illustrating the use as herbicides of aqueous emulsions of the b -chloroethyl, b -cyanoethyl, and 1-methyl-2-chloroethyl esters of a ,a -dichloropropionic and a ,a -dichlorobutyric acids.