Heteropolyacid-Based Poly(ionic liquid)s for the Selective Oxidation of Cyclohexene to 2-Cyclohexene-1-one
Yuefeng Wu, Miaojun Su, Yahui Xiao, Binxiong Guang, Yong Liu
Abstract
Heteropolyacid-based poly(ionic liquid)s (PVDA1-PMo) were prepared as novel heterogeneous catalysts, and their texture and structure were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TG), N2-physisorption, and scanning electron microscopy (SEM). The catalytic performance of the as-prepared PVDA1-PMo was investigated for the selective oxidation of cyclohexene to 2-cyclohexene-1-one with molecular oxygen as oxidant. The results indicated that the phosphomolybdic anions were uniformly anchored on the surface of the PVAD1-PMo catalyst through a strong electrovalent bond. Moreover, the PVDA1-PMo catalyst inherited a certain amount of mesopores from PVAD1. Both were of great benefit to expose more active sites for the highly efficient oxidation of cyclohexene. The appropriate acidity endowed the PVAD1-PMo catalyst with superior selectivity to 2-cyclohexen-1-one. Therefore, the PVDA1-PMo catalyst displayed excellent activity and selectivity with the optimum cyclohexene conversion of 85.7% and selectivity to 2-cyclohexene-1-one of 51.9% as well as no significant activity and selectivity loss after five reusing times.