REVERSE-OSMOSIS FOR SEPARATION OF REACTION SOLUTIONS IN HOMOGENEOUS CATALYSIS

The potentials of reverse osmosis (RO) in separation of soluble homoge neous catalysts from reaction products were studied. Two environmental ly important liquid phase processes were considered: (A) detoxication of NO and H2S catalyzed by iron-containing phosphotungstenate heteropo ly anion PW11FeII(H2O)O-39(5-): 2NO+2O(2)+H2S-->2HNO(3)+S and (B) deto xication of the water soluble sulfides catalyzed by the sodium salt of tetra(sulfophthalocyanine)cobalt(II) : S2-+O-2-->(S, SO32-, SO42-, S2 O32-) For reaction (A), the RO retention of the NO3- product was found to decrease with the concentration of the heteropoly anion catalyst, reaching negative values, whereas the retention of the catalyst amount ed to 99 %. Due to the negative retention of the nitrate ions and high positive retention of the catalyst, their efficient separation was ac hieved. For reaction (B), RO allowed to retain the catalyst almost com pletely (retention exceeded 99.9 %), while the products (sulfur-contai ning anions) exhibited markedly lower retentions. For both reactions, the structure and activity of the catalysts remained unchanged after t he RO separation, thus enabling their multifold re-use.