Study on Mechanism of the Hydrogenation of Maleic Anhydride to Succinic Anhydride Catalyzed by RuCl_3/PPh_3

In this paper, \{\}\+\{31\}P NMR and IR were used in situ techniques to characterize RuCl\-3/PPh\-3 catalyst, the effect of acids and bases on the hydrogenation of maleic anhydride to succinic anhydride was also studied. Based on the results, the catalytic cycle on the hydrogenaton of maleic anhydride to succinic anhydride catalysed by RuCl\-3/PPh\-3 has been proposed. (1) The active species RuHCl(PPh\-3)\-3 was formed by \{RuCl\-3/\}PPh\-3 in situ characterization; (2) The carbon carbon double bond of maleic anhydride coordinated with the active species to form coordination compound; (3) The metallic alkyl compound was formed by the hydrogen transfer; (4) The metallic alkyl compound reacted with hydrogen to yield succinic anhydride and to restore the active species RuHCl(PPh\-3)\-3.