A process for producing copper formate, which comprises subjecting methyl formate to a liquid-phase hydrolysis reaction at a temperature from 60 to 85.degree. C. in the presence of copper carbonate.

A process is described for recovering water soluble copper and manganese compounds from an aqueous solution by reacting the copper and manganese compounds with saturated aliphatic monocarboxylic acids containing 5 to 9 carbon atoms at elevated temperatures forming cupric and manganous alkanoates containing 5 to 9 carbon atoms, and simultaneously removing the water by distillation in the presence of sufficient oxygen-containing gas to prevent the copper from plating on the distillation equipment, recovering the cupric and manganese alkanoates.

A process is described for removing copper and manganese catalysts from an organic phase comprising a saturated aliphatic monocarboxylic acid containing 5 to 9 carbon atoms by extracting the catalysts with aqueous formic acid.

Organic copper salts having the formula I ##STR1## are used for the treatment of honeybees contaminated by various acarians and namely by the specific mite Varroa jacobsoni. These salts are utilized either as such, or in the form of compositions containing them, optionally in admixture with diluents, nutritive ingredients and other active principles. The compositions according to the invention are useful in the field of breeding and agriculture in restoring the sanitary condition in the hives.

A cuprous oxalate complex of the formula Cu.sub.2 (CO).sub.n L.sub.m C.sub.2 O.sub.4 wherein L is an unsaturated hydrocarbon containing at least one non-aromatic unsaturation and n and m are numbers from 0 to 2.