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.

酚类的烷基化在合成化学和木质纤维素生物质来源的物流的增值中非常重要。在这里，我们揭示了烷基化反应物和溶剂如何显着改变液相催化沸石催化苯酚烷基化的反应途径。由环己醇的脱水或环己烯的吸附和质子化形成的碳正离子充当亲电子试剂，诱导形成碳-碳键。布朗斯台德酸位点处的环己醇（BAS）在非极性溶剂中形成氢键键合的单体和质子化的二聚体。与单体相比，二聚体似乎产生了低得多的碳正离子。