Aromatics acylation zirconia

Another important and well studied paramagnetic ion in the lattice of oxide semiconductors is Zr3+ in Zr02. Zirconia dioxide is widely used both as a catalyst of different chemical processes, and as a carrier for constructing supported metal-complex catalysts. In the last years, sulfated zirconia attracted significant interest as an active and selective catalyst in skeletal isomerization of normal alkanes at low temperatures, cracking of paraffins, alkylation and acylation of aromatics [42, 53 and Refs therein]. The appropriate experimental data are collected in the following Table 8.2. 

Patil, M. L., Jnaneshwara, G. K., Sabde, D. R, Dongare, M. K., Sudalai, A., and Deshpande, V. H. 1997. Regiospecific acylations of aromatics and selective reductions of azobenzenes over hydrated zirconia. Tetrahedron Lett., 38 2137-2140. 

H. 2000. Catalytic acylation of aromatics with carboxylic anhydrides over sulfated zirconia. Top. Catal. 13 281-285. 

Deutsch, J., Trunschke, A., Muller, D., Quaschning, V., Kemnitz, E., and Lieske, H. 2003. Different acylating agents in the synthesis of aromatic ketones on sulfated zirconia. Catal. Lett. 88 9-15. 

Tungstated zirconia (WZr) is known as stable solid superacid which demonstrates high catalytic activity in numerous reactions with a proton transfer, especially in the hydroisomerization of n-C4 - C alkanes and Friedal-Crafts acylation of aromatic compounds. Relatively low specific surface area (< 70 m /g ) is a certain disadvantage of WZr. Also, on today the synthesis of solid acids which occupy intermediate position between zeolites with their acidity function values (Ho > -8) and superacids (Ho < -12) is of interest. The data on synthesis and catalytic study of mesoporous W03-Zr02-Si02 (WZrSi) oxide are presented in this communication. 

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