The distinct catalytic behaviours of calcium silicate hydrate for the high selectivity of 2,2′-isomer in reaction of phenol with formaldehyde

Abstract

The acidity and basicity of the catalyst have an important influence on the distribution of isomers. Herein, we prepared calcium silicate hydrate and used it for the reaction of phenol with formaldehyde to bisphenol F. The results showed that basic calcium silicate hydrate has a very high selectivity for 2,2′-isomer, which is not obvious in the presence of acidic catalysts. The highest selectivity to 2,2′-isomer (94.67%) and yield (51.33%) for bisphenol F were achieved over calcium silicate hydrate (Si/Ca = 3) catalyst at 383 K for 120 min. A possible mechanism was proposed in accordance with our examination. Changing the acidity and basicity of catalyst provides a way to improve the purity of isomers.