Hydrogenation of propyne to propene over platinum/silica

Abstract

A Pt/silica catalyst was tested for use in propyne (methyl acetylene) hydrogenation over a range of temperatures (333–673 K) and gas ratios (C 3H 4:H 2, 2.5:1–1.3). The orders of reaction with respect to propyne, for propene formation, were determined to be −0.02 at 333 K, −0.04 at 373 K, and −0.13 at 423 K. Accurate values could not be determined at the higher temperatures due to the effect of catalyst deactivation. The order of reaction with respect to hydrogen was determined to be 0.60 at 333 K. No values were obtained at higher temperatures due to hydrogenation through to propane. At low temperatures the carbonaceous residue increased the turnover frequency but as the temperature was increased, increasing hydrogen pressure was required to maintain the residue in a form which did not act as a poison to the system.