Reactions of 2-octanol on Amberlyst® 15: concurrent Eley–Rideal and Langmuir–Hinshelwood reactions on two different types of active sites

Not all acid sites are created equal: Alkene isomerization and dimerization occur on separate sites on Amberlyst®15 catalyst

“…One proposal for the origin of two different types of acid sites on Amberlyst®15 catalyst relates to the stereochemistry of the polystyrene chain. [ 1 ] If the stereochemistry of the asymmetric carbons is random, 74% of the phenyl rings have at least one other neighboring phenyl ring on the same side of the polymer backbone, whereas 26% do not (Scheme 2). p ‐Sulfonic acid groups on these rings can therefore experience different environments.…”

“…Dehydration of 2‐octanol on Amberlyst®15 catalyst requires interaction of adsorbed 2‐octanol with a vacant site. [ 1 ] The adsorption coefficient for 2‐octanol on the site(s) where dehydration occurs must therefore be small enough to avoid saturation of those sites. Similarly, alkene adsorption may be weaker on the closely spaced acid sites than it is on the isolated acid sites that have no nearby neighboring acid group.…”

“…Kinetic investigations have shown that two different types of acidic sites likely exist on the surface of dry Amberlyst®15 catalyst. [ 1–3 ] For example, during addition of p ‐xylene to 1‐dodecene to make dodecyl p ‐xylenes, double bond isomerization of 1‐dodecene appears to occur on a site that is different than the site where the addition reaction occurs. [ 2 ] Similarly, for addition of heptanoic or nonanoic acid to 1‐tetradecene to make secondary esters, the esterification reaction occurs on a different site than the double bond isomerization.…”

How substituent effects influence the thermodynamics and kinetics of gas-phase transesterification of alkyl lactates to lactide using TiO2/SiO2

“…Contrarily, initial ML 2 A formation rate increased linearly with MLA partial pressure. The non-linear plateauing shape of the LD formation curve is a strong indication that the transesterification rate is controlled by a dualsite surface reaction, that is to say a Langmuir-Hinshelwood type reaction mechanism [40,41].…”

Kinetics of the esterification between lactic acid and isoamyl alcohol in the presence of silica gel‐supported sodium hydrogen sulphate

“…In this work, a supported catalyst (NaHSO 4 · Silica) was prepared by loading sodium hydrogen sulphate on silica gel. The kinetic data of the esterification between isoamyl alcohol and lactic acid over NaHSO 4 · Silica were measured within 343–378 K. Three kinds of dynamic models, including the pseudo‐homogeneous (PH) model, Eley‐Rideal (ER) model, and Langmuir‐Hinshelwood (LH) model, were employed to correlate the experimental data. Considering the non‐ideality of reactants and products, the mole fractions of species were replaced by activities and the UNIFAC method was applied to predict the activity coefficients .…”