Green Oxidation of Cyclohexanone to Adipic Acid over Phosphotungstic Acid Encapsulated in UiO-66
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A very stable catalyst, phosphotungstic acid (PTA) encapsulated in metal–organic framework UiO-66, was prepared by a simple one-pot solvothermal method. Characterization results show that UiO-66 is quite stable in the catalyst preparation process, and PTA is encapsulated in the cavities of UiO-66 with good dispersity. The as-synthesized composite material exhibited good catalytic activity and excellent reusability for the green oxidation of cyclohexanone to adipic acid (AA). Under mild reaction conditions, the isolated yield of AA was as high as 80.3% without the introduction of any organic solvent or phase transfer agent. The excellent immobilization effect of UiO-66 for PTA is mainly because UiO-66 has a well matched window size to confine PTA molecule in its nanocages.
KeywordsPhosphotungstic acid Metal–organic frameworks Cyclohexanone Adipic acid
Fourier transform infrared spectroscopy
Inductively coupled plasma-atomic emission spectroscopy
Scanning electron microscope
Transmission electron microscopy
This work was supported by the National Natural Science Foundation of China (21302237, 51708075) and the Scientific and Technological Research Program of Chongqing Municipal Education Commission (KJ1713335, KJQN201801527).
Compliance with Ethical Standards
Conflict of interest
The authors declare no conflict of interest.
- 10.Xia CJ, Zhu B, Lin M, Shu XT (2012) A “green” cyclohexanone oxidation route catalyzed by hollow titanium silicate zeolite for preparing ε-caprolactone, 6-hydroxyhexanoic acid and adipic acid. China Pet Process Petrochem Technol 14:33–41Google Scholar
- 12.Ding ZB, Lian H, Wang QR, Tao FG (2004) Oxidation of cyclohexanone to adipic acid with 30% H2O2 and tungstate catalyst. Chin J Org Chem 24:319–321Google Scholar
- 14.Ye TX, Ma XN, Liu JY (2009) Catalytic oxidation of cyclohexanone to adipic acid catalysed by supported phosphotungstic acid. Ind Catal 17:46–48Google Scholar
- 25.Jiao L, Wang Y, Jiang HL, Xu Q (2017) Metal–organic frameworks as platforms for catalytic applications. Adv Mater 29:1703663Google Scholar