The reaction of CO with H2O to give CO2 and H2 is catalyzed at low temps. and pressures in aq. alc. solns. by catalysts formed in situ from Ni 2,6-bis(diphenylphosphinomethyl)pyridine (L) complexes. Thus, NiLX+ (X = Cl, Br) reacts at room temp. or just above with CO and H2O to give Ni(HL)(CO)2+, CO2, H+, and X-; the Ni(HL)(CO)2+ reacts with H+ and X- at higher temps. to regenerate NiLX+ and CO and produce H. The intermediates were identified by IR spectroscopy. A BuOH-8% H2O soln. of NiLCl2 gave a max. turnover no. of ∼6/h when circulated through a glass bead-filled column at 30° under 0.94 atm CO and through a flask at 90°. The pseudo-1st-order rate const. for the reaction of NiLCl2 with CO at 0.94 atm in the above soln. was 0.31/min at 22°.
Homogeneous catalysis of the water-gas shift reaction using 2,6-bis(diphenylphosphinomethyl)pyridine complexes of nickel
VASAPOLLO, Giuseppe;
1980-01-01
Abstract
The reaction of CO with H2O to give CO2 and H2 is catalyzed at low temps. and pressures in aq. alc. solns. by catalysts formed in situ from Ni 2,6-bis(diphenylphosphinomethyl)pyridine (L) complexes. Thus, NiLX+ (X = Cl, Br) reacts at room temp. or just above with CO and H2O to give Ni(HL)(CO)2+, CO2, H+, and X-; the Ni(HL)(CO)2+ reacts with H+ and X- at higher temps. to regenerate NiLX+ and CO and produce H. The intermediates were identified by IR spectroscopy. A BuOH-8% H2O soln. of NiLCl2 gave a max. turnover no. of ∼6/h when circulated through a glass bead-filled column at 30° under 0.94 atm CO and through a flask at 90°. The pseudo-1st-order rate const. for the reaction of NiLCl2 with CO at 0.94 atm in the above soln. was 0.31/min at 22°.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
