PHOSPHOROUS ACID (VARIANTS) Russian patent published in 2002 - IPC

FIELD: manufacture of phosphorus-containing complexones, phosphorous acid salts, reducing agents, polymer stabilizers and biologically active polymers. SUBSTANCE: method comprises reacting elemental phosphorus (white, yellow), trimethyl amine, ethylene oxide with barium or calcium hydroxides and water at temperatures from 50 to 100 C and at ratios of reagents elemental phosphorus: trimethylamine: ethylene oxide: water:β- of 1:(5:25): (5-25): (5-20): (20-30): (5.5-7); or elemental phosphorus: beta-oxyethyltrimethyl ammonium hydroxide (choline):water: β- of (1:5-15):(20-30: 5.5.7, subsequently treating the resulting calcium or barium phosphite with diluted sulfuric acid in excessive amount to isolate phosphorous acid. Invention makes it possible to widen range of well-known methods for preparing phosphorous acid by treating new ecologically safe (no toxic phosphine is formed) method for preparing highly pure phosphorus acid using simple and inexpensive reagents with good yield (80-90 %). EFFECT: more efficient preparation method. 6 cl, 1 tbl