METHOD FOR PREPARING AND PURIFICATION OF 1,1-DIFLUOROETHANE AND PRODUCT PREPARED BY METHOD THEREOF Russian patent published in 2003 - IPC

FIELD: chemical technology. SUBSTANCE: invention relates to preparing and purification of 1,1-difluoroethane that is used for foam-formation of plastics or as propellant in aerosols. Purification method is carried out by treatment of crude 1,1-difluoro- ethane with content of hydrogen chloride less 1 mole per 1 mole of 1,1-difluoroethane with hydrogen fluoride. Treatment is carried out under conditions close to conditions for synthesis of 1,1-difluoroethane by fluorination of chlorine-containing hydrocarbon. Preferably, treatment is carried out in liquid phase in reaction medium containing 500 g of HF per 1 kg of 1,1-difluoroethane, not less, in the presence of catalyst. Derivatives of metals of groups IIIa, IVa, IVb, Va, Vb and VIb of Periodic system of elements or their mixtures are used as catalyst. Invention proposes method for preparing 1,1-difluoroethane by interaction of hydrogen fluoride with chlorine-containing precursor of 1,1-difluoroethane in the presence of catalyst, if necessary. Crude product containing 1,1-difluoroethane and hydrogen chloride is obtained that is separated. Prepared product containing 1 mole of HCl per 1 mole 1,1-difluoroethane, not less, is treated with hydrogen fluoride and purified 1,1-difluoroethane is obtained. Invention proposes also the mixture containing 1,1- difluoroethane with purity above 99.8 weight% obtained by fluorination of chlorine-containing hydrocarbon and containing vinyl chloride in the concentration below 10 mg/kg. EFFECT: improved preparing method, enhanced purity of end product. 10 cl, 3 tbl, 2 dwg, 6 ex