Facile synthesis of acid mesoporous fluoropolymer as water-tolerant catalyst for esterification

• Acid mesoporous fluoropolymer with perfluoroalkyl sulfonyl imide was prepared.
• The polymers showed excellent hydrophobicity and acidity.
• The polymers acted as water-tolerant catalyst.
• The polymers could be used as reusable heterogeneous catalysts.

Mesoporous fluoropolymers with excellent hydrophobicity and acidity (H-PDVB-x-SSFAI) were solvothermally prepared by radical polymerization of perfluoroalkyl sulfonyl imide and divinylbenzene. The formation of mesopores depended on the synergy effect between nano-CaCO3 porogen and watered solvothermal media. The amount of doped water, and reactant ratio as well, was responsible for the textural properties. The fluoropolymers catalyzed the esterification of long-chain fatty acids with ethanol affording the conversion of 95%, along with TOF of 30.5 h−1 (31.9 h−1 reported for H2SO4). The high efficiency was attributed to its excellent hydrophobicity, wettability for ethanol, and acidity. Stability trial evinced that the fluoropolymers were sufferable to 24 h water-boiling with 86% acid groups remained. These are promising recyclable fluoropolymers, maintaining fairly stable catalytic activity for esterification of acetic acid with pentanol at least 7 runs.

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