Direct side-chain oxidation of ethylbenzene over supported Co4HP2Mo15V3O62 catalysts as a clean and highly efficient approach to producing acetophenone

The surface of acid-activated attapulgite (ATP) was modified by grafting 3-aminopropyltriethoxysilane (APTES) for the immobilization of heteropolyacid salt Co 4 HP 2 Mo 15 V 3 O 62 (CoHPAs). The samples were characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, specific surface area measurements, thermal analysis and field emission scanning electron microscopy. The catalytic activity was tested for the oxidation of ethylbenzene in the presence of 50 % H 2 O 2 for the first time in this work. It was found that the activity of the ATP supported CoHPAs catalyst is obviously influenced by APTES grafting. The CoHPAs/ATP APTES catalyst exhibits high activity owing to the silylation of ATP, with the conversion of ethylbenzene and selectivity of acetophenone up to 72.7 and 95.4 %, respectively. The results also show that the CoHPAs/ATP APTES catalyst can be reused at least five times without significant decrease of activity.