Highly selective synthesis for 4,4′-bisphenol F from phenol and formaldehyde catalyzed with [C4mim][HSO4] ionic liquid

The effects of N-methylimidazole cation [C(n)mim] with different alkyl chain lengths, the types of cations and anions of ionic liquids and the reaction parameters on the catalytic activity and the selectivity for 4,4'-bisphenol F were investigated. The hydrogen bonding between the hydroxyl of phenol and the C2-position hydrogen of imidazole moiety in hydrophilic imidazole-based ionic liquid has important influence on the selectivity for 4,4'-bisphenol F, and under the conditions of the molar ratio of phenol/[C(4)mim][HSO4] 1:1, reaction temperature 65 degrees C and the theoretical molar ratio of phenol/formaldehyde 2:1, the selectivity for 4,4'-bisphenol F reached 69.1%. Compared with the high phenol/formaldehyde ratio reported in literatures, the low molar ratio of phenol/formaldehyde and the low reaction temperature can greatly reduce energy consumption, and has important significance for industrial application. (C) 2016 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.