Platinum catalyzed hydrogenation of 2-butyne-1,4-diol

Abstract

Hydrogenation of 2-butyne-1,4-diol (B₃D) using 1% Pt/CaCO₃ catalyst was carried out to give 2-butene-1,4-diol (B₂D) or butane-1,4-diol (B₁D) selectively or a mixture of two diols eliminating the formation of acetal, aldehyde, and alcohols as side products. In presence of ammonia, nearly complete selectivity to B₂D was obtained in a batch reactor while, in a fixed bed reactor total selectivity to B₁D was obtained. Effect of concentration of ammonia, metal loading and catalyst pre-treatment on catalyst activity and selectivity has been investigated in a batch reactor. The formation of B₁D and B₂D is explained on the basis of associative or dissociative adsorption of B₃D via carbene and carbyne type intermediates which react with adsorbed hydrogen to give the corresponding products. A kinetic model based on Langmuir-Hinshelwood (L-H) type mechanism has been proposed which shows a good agreement with experimental data.