Hydroformylation of propylene to butyraldehyde using dichloro-bis(salicylaldehyde)-o-phenylenediiminato ruthenate(III)

Abstract

Butyraldehyde is obtained by the hydroformylation of propylene in aqueous medium catalysed by Ru^III-saloph-CO complex at 27 atm CO + H₂ (1:1) syn gas with C₃H₆:syn gas ratio 1:5 and 120°C with a turnover rate of 17 mol product per mol catalyst per hour. Synthesis of aldehydes by the hydroformylation of olefins under milder conditions has been of great interest in recent years [1-5]. The usual catalysts involve the metal complexes of cobalt such as cobalt carbonyl [6,7] and phosphine-coordinated cobalt carbonyl [8], which act at ~130-160°C and 100-200 atm CO + H₂ (1:1). The commercial preparation of butyraldehyde by the hydroformylation of propylene uses rhodium complexes as catalysts [9, 10]. The advantages [10] of the rhodium complex are low temperature (80-120°C), low pressure of CO + H₂ (7-30 atm) and the higher selectivity for the more valuable hydroformylation product butyraldehyde. There are reports in the literature in which hydroformylation of propylene to butyraldehyde was achieved using ruthenium complexes as catalysts at 150°C and 150 atm CO + H₂ (1:1) [11]. In the present paper we report the hydroformylation of propylene to butyraldehyde using [Ru^III(saloph)CO] complex at 120°C and 27 atm CO + H₂ (1:1).