ABSTRACT
Cyclohexene and (-)-apopinene were hydrogenated over various Pt/Si02 catalysts, and their turnover frequencies (TOFs) and numbers of active sites, from CS2 titration (CSrsites), are reported.
Introduction
Historically, stereochemistry has contributed much to understanding organic reaction mechanisms in solution; similarly, during the past forty-five years, stereochemistry has made contributions to understanding organic reaction mechanisms on surfaces ( 1 ). An important goal is to understand mechanisms of selectivity on surfaces, especially on metal surfaces, which catalyze much of the fme chemicals and specialty chemicals processes. In this study we examine the differences in hydrogenation and deuteriumation between two different molecular probes, cyclohexene and (-)-apopinene. Cyclohexene is a relatively flat and flexible molecule with both sides of its double bond able to adsorb on the surface, while (-)-apopinene is a rigid, inflexible molecule with one side of its double bond blocked from adsorption by a gem-dimethyl group.
