Abstrakt
Aluminosilicate and gallosilicate MTW zeolites were prepared in the bulk and nanosponge form by direct hydrothermal synthesis. Designed materials were tested in acylation of p-xylene with benzoyl chloride and compared with large pore zeolite *BEA and medium pore zeolite MFI.
Nanosponge MTW exhibited generally better performance than bulk MTW zeolites due to higher accessibility of the catalyst's active sites in nanosponge zeolite. Selective transformation of benzoyl chloride towards target 2,5-dimethylbenzophenone was achievable over nanosponge MTW zeolites.
The gallosilicate nanosponge MTW exhibited significantly higher conversion (61%) of benzoyl chloride than its aluminosilicate counterpart (27%) with the same concentration of Bronsted acid sites (0.04 mmol/g). This result is clearly caused by the suitable strength of acid centres in Ga-MTW, which enables the sufficient activation of BzCl molecules as well as efficient desorption of formed polar products.
Additionally, the gallosilicate MTW outperformed both conventional zeolites *BEA and MFI used as reference materials.