Popis: |
The hydrogenation and isomerization of 1-butene andcis-2-butene molecules are studied on platinum foil and single crystal (111), (100), and the stepped (755) surfaces at 300–350 K. In the presence of hydrogen, 1-butene andcis-2-butene are hydrogenated to butane. In addition, 1-butene is isomerized tocis- andtrans-2-butenes, whilecis-2-butene is converted totrans-2-butene. With a hydrogen pressure between 7 and 500 Torr, and a butene pressure of 3.5–70 Torr, both butene hydrogenation and isomerization rates exhibit a near-first-order dependence on the hydrogen pressure and a zero-order dependence on the hydrocarbon pressures. For both 1-butene andcis-2-butene molecules, the hydrogenation rates are insensitive to surface structures. The isomerization rate, however, is doubled forcis-2-butene molecules on the stepped platinum surface (Pt(755)). |