METHOD OF SYNTHESIS OF O,O-DIALKYLDITHIOPHOSPHATES Russian patent published in 2002 - IPC

FIELD: organic chemistry, chemical technology. SUBSTANCE: invention relates to the improved method of synthesis O, O-dialkyldithio-phosphates that are widely used as floating agents in enrichment of nonferrous, rare and precious metal ores. Method of synthesis of O, O-dialkyldithiophosphates involves synthesis of O, O- dialkyldithiophosphoric acid by interaction of phosphorus pentasulfide with aliphatic alcohol followed by treatment with alkali. Synthesis of O, O-dialkyldithiophosphoric acid is carried out for two steps: firstly, 15-25 wt. -% of alcohol reacts with 30-35 wt. - % of phosphorus pentasulfide of measured amount maintaining the mole ratio of phosphorus pentasulfide and alcohol = 1: (2.69-5.0) at temperature of reaction mixture 75 C, not above; the second stage involves interaction of the remained part of reagents in medium of reaction product (in reaction mixture) obtained in the first stage at the same temperature. At the second stage phosphorus pentasulfide is added firstly to reaction mixture obtained at the first stage followed by gradual addition of alcohol. Mother liquor from production of alkaline metal alkylxanthogenate with the same alcohol radical synthesized by interaction of alcohol excess, alkali and carbon disulfide is used as an alcohol component. EFFECT: improved method of synthesis, simplified process, increased yield of end product, decreased wastes, elimination of additional use of solvents from technological process. 3 cl, 13 ex