Water-soluble heteropolyacid-based ionic liquids as effective catalysts for oxidation of benzyl alcohol in water with hydrogen peroxide

Green Processing and Synthesis

article

Ouyang Kai¹  Han Xiaoxiang¹  Xiong Chunhua¹  Tang Xiujuan²  Chen Qing¹ 

[1] Department of Applied Chemistry, Zhejiang Gongshang University;College of Environmental Science and Engineering, Zhejiang Gongshang University

关键词: ionic liquid;    optimization;    oxidation;    reaction engineering;    tungstophosphoric acid;   

DOI  :  10.1515/gps-2016-0237

来源: De Gruyter

【 摘 要 】

A series of organic-inorganic composite catalysts were prepared by modifying tungstophosphoric acid (H 3 PW 12 O 40 ) and propyl sulfonic acid-functionalized ionic complex. The obtained water-soluble catalysts were well characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and nuclear magnetic resonance, and investigated for their performance as homogeneous catalysts for selective oxidation of benzyl alcohol (BzOH) with hydrogen peroxide (H 2 O 2 ) in water. Among them, the [DMBPSH]H 2 PW 12 O 40 catalyst exhibited the best oxidative activity with a desirable benzaldehyde (BzH) selectivity of 97.0% and an excellent BzOH conversion of 98.5%. Further kinetic studies and model analysis by response surface methodology revealed that alcohols’ oxidation reaction followed an apparent order of 2.2 with an activation energy of 36.18 kJ/mol. And the optimal reaction conditions were established as follows: BzOH/H 2 O 2 molar ratio of 1:1.7, amount of catalyst 5.4 wt%, reaction time 3.9 h, amount of water 24 ml, and a maximum yield of BzH of 95.8%. Under optimum conditions, [DMBPSH]H 2 PW 12 O 40 catalyst showed a superior catalytic efficiency and reusability due to strong acidity and excellent surface activity.

【 授权许可】

CC BY