Hydroformylation of Synthetic Naphtha Catalyzed by a Dinuclear gem-Dithiolato-Bridged Rhodium(I) Complex

Abstract

This work focuses on the use of a gem-dithiolato-bridged rhodium(I) (Rh2(μ-S2CBn2)(cod)2) complex (cod = 1,5-cyclooctadiene, Bn2CS2 2� = 1,3-diphenyl-2,2-dithiolatopropane) dissolved in toluene in the presence of monodentate phosphite P-donor ligand (P(OPh)3) under carbon monoxide/hydrogen (1:1, syngas) atmosphere as an effective catalyst for hydroformylation of some olefins (oxo-reactions). The capability of this system to catalyze the hydroformylation of hex-1-ene, cyclohexene, 2,3-dimethyl-but-1-ene and 2-methyl-pent-2-ene and their quaternary mixture (synthetic naphtha) has been demonstrated. This innovative method to perform the in situ hydroformylation of the olefins present in naphthas to oxygenated products would be a promissory work for a future industrial catalytic process applicable to gasoline improving based on oxo-reactions. An important observation is that variation of CO/H2 pressure (6.8  34.0 atm), temperature (60  80 oC), reaction time (2  10 h), rhodium concentration ((1.0  1.8)x10 -3 mol/L) affect hydroformy- lation reaction rates. Optimal conversion to oxygenated products were achieved under (Rh) = 1.8 x10 -2 mol/L, P(CO/H2) = 34 atm (CO/H2 = 1:1) at 80 oC for 10 h.