Composés herbicides dérivés d'acides phénoxybenzoïques et leurs procédés de préparation et d'utilisation

The invention provides herbicidal compounds, useful in soya and cereal crops, of the formula: in which: W is a group -CH= or -CX4= or the nitrogen atom, -N=; X1, X2, X3 and X4 represent a halogen atom; a polyhalogenoalkyl group; NO2; CN; or an alkyl, alkoxy, alkylsulphonyl, sulphonamide, nitroso or alkoxycarbonyl radical; R1 represents a group -OM, or -X-R ; M represents a hydrogen atom or a cation which is acceptable in agriculture; X is O or S; R and R represent a substituted or unsubstituted aliphatic, cycloaliphatic or aryl hydrocarbyl group or a substituted or unsubstituted heterocyclic group; R and R have one of the meanings given for R and can also represent the hydrogen atom or an alkoxy radical, or can together form a single, optionally substituted divalent hydrocarbon radical; and R has one of the meanings given for M and can also represent an alkyl group having 1 to 4 C.