Isomerization

Abstract

The sections in this article are Introduction Mechanism of Skeletal Isomerization of C 5+ Alkanes with Acid Catalysts Reaction Cycle in Isomerization of Alkanes The Isomerization Reaction: Rearrangement of the Intermediate Carbenium Ion Supporting Evidence for the Protonated Cyclopropane ( PCP ) Isomerization Mechanism Reactions with n ‐Butane Effect of Chain Length on the Relative Rates of Isomerization of n ‐Alkanes Location of Branching in Isomerized Alkanes Chain Termination Reactions: Catalyst Deactivation Acid‐catalyzed Cracking and Isomerization: Effect of Chain Length on Selectivity for Isomerization Mechanism of C 4 Alkane Isomerization Isomerization Catalysts Monofunctional Acidic Catalysts Bifunctional Catalysts Isomerization of Pentanes and Hexanes for Octane Enhancement Octane Numbers and Thermodynamic Equilibrium Concentrations of Isomeric Pentanes and Hexanes Processes for Isomerization of Pentanes and Hexanes Processes Using Aluminum Chloride/Hydrochloric Acid as Monofunctional Catalyst Processes Using Bifunctional Catalysts Consisting of Pt Supported on Chlorinated Alumina Processes Using a Noble Metal on Amorphous Silica–Alumina as Bifunctional Catalyst Processes Using a Noble Metal on Zeolite as Bifunctional Catalyst Combining C 5 and C 6 Alkane Isomerization with Physical Separations Processes for Isomerization of Higher Alkanes Processes for Conversion of n ‐Butane to Isobutane Role of Alkane Isomerization in the Hydrocarbon Processing Industry

Carbocation Branching Observed in a Simulation

“…Reference 4 correctly noted difficulties in equating this first step with the traditionally cited mechanism of Brouwer. 2,23,24 Instead, the mechanism of Edwards and Lesage 25 (their A f E f B for the branching of a cyclohexanone cation) is the best of the early predictions: not only is it entirely composed of PCP + structures, but the two C-C bonds they draw as stretched in each of their structures (A, E, and B) are the correct ones, according to the DFT-optimized structures. We felt that drawing only one C-C bond as dotted, instead of two as in Edwards and Lesage, would allow a more comforting description of these intermediate and transition-state structures as "closed secondary" and "closed primary" carbenium ions, respectively.…”