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3045376 
Journal Article 
Carboxylation of Toluene with CO2 over Dimeric AlCl3 Immobilized on Alumina 
Gu, M; Cheng, Z 
2014 
Yes 
Industrial and Engineering Chemistry Research
ISSN: 0888-5885
EISSN: 1520-5045 
53 
24 
9992-9998 
WOS:000337720500004 
Carboxylation of toluene by CO2 over AlCl3 is providing a new approach for CO2 transformation as well as an improved synthetic method of p-toluic acid with less byproducts under mild condition. To prevent decomposition and corrosion of AlCl3 powder, AlCl3 was immobilized over gamma-Al2O3 support through reaction between dimer Al2Cl6 vapor and hydroxyl groups at the gamma-Al2O3 surface, and a high loading of AlCl (x = 2.5) up to 72.36 wt % was obtained. The composition of immobilized -O-Al2Cl5 group was detected by HRTEM/EDS and the structure was authenticated to be the same as that of Al2Cl6 by Al-27 MAS NMR. The Al valence in -O-Al2Cl5 was calculated to be 1.584, which is approximately the same as that in Al2Cl6. The above features of -O-Al2Cl5 guaranteed a high CO2 activation capacity in direct carboxylation of toluene with an isolated p-toluic acid yield of 73.34% with respect to AlCl3, which approaches that obtained by AlCl3 powder. Therefore, this work provides a more feasible way for carboxylation by CO2 in overcoming the instability of AlCl3 powder in the presence of moisture.