Solvent-determined mechanistic pathways in zeolite-H-BEA-catalysed phenol alkylation

Yuanshuai Liu, Eszter Baráth, Hui Shi, Jianzhi Hu, Donald M. Camaioni, Johannes A. Lercher

Research output: Contribution to journalArticlepeer-review

78 Scopus citations

Abstract

Alkylation of phenolics is of great importance in synthetic chemistry and the valorization of lignocellulosic-biomass-derived streams. Here, we unravel how alkylating reactants and solvents significantly alter the reaction pathways of zeolite-catalysed alkylation of phenol in the liquid phase. The carbenium ion formed from the dehydration of cyclohexanol or from the adsorption and protonation of cyclohexene acts as the electrophile, inducing carbon-carbon bond formation. Cyclohexanol at Brønsted acid sites (BAS) forms hydrogen-bonded monomers and protonated dimers in apolar solvents. The dimer appears to generate a much lower concentration of carbenium ions compared with the monomer. Higher alkylation rates in apolar solvents than in water are caused by the energetically more-favourable carbenium ion formation from either alcohol or olefin on non-hydrated zeolite BAS than on hydronium ions produced by BAS in pores filled with water.

Original languageEnglish
Pages (from-to)141-147
Number of pages7
JournalNature Catalysis
Volume1
Issue number2
DOIs
StatePublished - 1 Feb 2018

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