Effect of the Composition of the Medium on the Selectivity of Deactivation of Skeletal Nickel Catalyst

The effect of the composition of the catalytic system (the nature and composition of the solvent, specifically, aqueous solutions of sodium hydroxide and their mixtures with aliphatic alcohols with the alcohol concentration of 0.11 mole fractions) and additions of a catalyst poison (sodium sulfide) on the catalytic activity of skeletal nickel in the liquid-phase hydrogenation of the carbon‒carbon double bond in sodium maleate was studied. The assumption was made on the decisive role of the solvent in changing the activity of skeletal nickel in the hydrogenation reaction of sodium maleate, which is primarily associated with the redistribution of individual forms of adsorbed hydrogen. In was found that in the water‒sodium hydroxide‒monohydric alcohol solvent skeletal nickel undergoes selective deactivation at the NaOH concentration of 0.01 M, antiselective deactivation at the NaOH concentration of 0.10 M, and variable deactivation at the NaOH concentration of 1.0 M. It is shown that in some cases sodium sulfide additions exert a promoting effect on skeletal nickel in the hydrogenation of sodium maleate.