Abstract: Boron tris-(dialkyl-dithiocarbamate) of the general formula ##STR1## wherein R and R' represent the same or different branched-or straight-chain saturated or unsaturated alkyl radicals having from 1 to 16 carbon atoms and a process for preparing the same, comprising reacting 3 moles of an alkali dialkyl-dithiocarbamate of the general formula ##STR2## wherein R and R' are as defined in claim 1 and Me.sup.+ represents Na.sup.+, K.sup.+ or NH.sub.4.sup.+ with one mole boron tribromide, boron trichloride or boron trifluoride in an inert medium, separating the so-formed alkali metal or ammonium halide and isolating the boron tris-(dialkyl-dithiocarbamate). The new boron dithiocarbamates are suitable as additives for hydraulic oils or permanent gear lubricant oils.

Abstract: A direct method of preparing dialkyl-dithiocarbamates of multivalent metals by reacting the oxide of a multivalent metal with a secondary amine and carbon disulfide while simultaneously heating to 50.degree.-95.degree. C. and removing the so-formed water of the reaction.Suitable metal oxides are preferably lead oxide, zinc oxide, copper(II)oxide, iron(III)oxide, nickel(III)oxide, antimony(III)oxide and manganese dioxide. The reaction is preferably conducted in a solvent for the metal-dialkyl-dithiocarbamate which forms an azeotrope with water in order to remove the water of the reaction with the solvent.