Ionic Liquid Functionalized Polymer as an Efficient Solid Acid Catalyst for the Esterification Between Methanol and Methylacrylic Acid

Achieving esterification of methacrylic acid and methanol under mild conditions is challenging but cost-effective. It is important to develop a catalyst with high catalytic activity and stable structure. Therefore, a novel solid acid catalyst (PVD-ILs) with high acid density (1.56 mmol/g), rich mesoporous structure and good dispersion of active sites was synthesized. The copolymer of 4-vinylbenzyl and divinylbenzene was used as skeleton structure. After the amino-functionalization by polyethyleneimine and quaternization by 1,3-propanesultone and trifluoromethanesulfonic acid, the catalyst was gained. These brilliant properties give the catalyst with high activity compared with other catalysts. In the optimal reaction condition, the conversion of methyl methacrylate reached 77.8%. Moreover, the kinetics of the esterification between methacrylic acid and methanol was investigated under the presence of PVD-ILs. The catalytic activity of PVD-ILs did not show a distinct decline after 4-time cycles. And the structure of spent catalyst did not exhibit a significant difference from the fresh catalyst, confirming the synthesized catalyst had good stability. Graphical Abstract