New media in homogeneous catalysis: wet sodium or tetrabutylammonium hydrogensulfate salts for reppe syntheses catalyzed by a ru(ii) carbonyl complex

The ruthenium(II) complex fac-[Ru(CO)2(H2O)3(C(O)C2H5)][CF3SO3] dissolved in aqueous tetrabutylammonium hydrogensulfate ([(CH3(CH2)3)4N][HSO4]) or sodium hydrogensulfate (NaHSO4) catalyzes the hydrocarboxylation of ethylene to propionic acid and additionally produces minor amounts of hydrocarbonylation products (diethyl ketone and propanal), under water-gas shift reaction conditions. This system is stable with a selectivity of 90% to propionic acid for high ethylene conversion. A turnover frequency of propionic acid, TOF(C2H5CO2H)/24 h = 5 × 103 (TOF (C2H5CO2H) = ([(moles of C2H5CO2H)/(moles of Ru) × rt)] × 24 h) was achieved for Ru = 7.45 × 10−4 mol, [(CH3(CH2)3)4N][HSO4] = 80 g (2.36 × 10−2 mol); H2O = 40 g (2.22 mol); CO = C2H4 = 20 g (total pressure = 88 atm); T = 150°C by a reaction time (rt) of 2.87 h. The countercation (sodium or tetrabutylammonium), the ruthenium concentration and the hydrogensulfate/H2O ratio of the medium affect the catalytic reaction. A nonlinear dependence on total ruthenium c...