Green Synthsis Of Aromatic Ketones Catalyzed By Supported Tungstophosphoric Acid

In recent years，green synthesis of organic compounds catalyzed by new kinds ofcatalysts has attracted more and more attentions. Thus, a series of supportedtungstophosphoric acid (HPW) catalysts were prepared, and their catalytic performances wereinvestigated using the Friedel-Crafts acylation (F-C acylation) as a model reaction.Firstly, the catalytic performance of Hβ zeolite supported tungstophosphoric acid catalyst(HPW/Hβ) was studied via the F-C acylation of anisole with hexanoic acid. The conversion ofhexanoic acid was100%and the yield of4-methoxy phenyl hexyl ketone reached89.2%under the optimized reaction conditions. The catalysts were characterized by XRD, N2physisorption measurements, NH3-TPD and ICP. It was found that the highly dispersed HPWand large amounts of strongly acidic sites on HPW/Hβ accounted for its high catalyticactivity.Secondly, based on the special nature of chitosan, which is insoluble in acid andinsoluble in basic solution, a novel Fe3O4@CS@HPW catalyst was prepared free ofcrosslinking reagent. Its catalytic performance was then tested by the F-C acylation reactionof anisole with acetic anhydride and compared with that of a traditionalCR-Fe3O4@CS@HPW catalyst prepared using crosslinking reagent. The structures of thecatalysts were characterized by N2physisorption measurements, XRD, TEM, FT-IR, themagnetization test and correlated well with their catalytic performance.Finally, a magnetic core-shell structure material with a Fe3O4core, double SiO2shell andsupported HPW (Fe3O4@nSiO2@mSiO2@HPW) was prepared and tested by the F-Cacylation of anisole with acetic anhydride. Fe3O4@nSiO2@mSiO2@HPW showed bettercatalytic performance than both Fe3O4@nSiO2@HPW with only a dense shell andFe3O4@mSiO2@HPW with only a loose shell due to the combined effect of the double SiO2shell.