Amino benzoic acid modified silica--an improved catalyst for the mono-substituted product in the benzylation of toluene with benzyl chloride.

Iron and 4-(methylamino)benzoic acid have been successfully incorporated into silica extracted from rice husk. The silica/Fe/amine complex, RH-Fe(5% amine), showed a ca. 24% increase in specific surface area compared to RH-Fe. This increase was attributed to the templated formation of regular pores. The XRD showed the RH-Fe(5% amine) to be amorphous. The Friedel-Crafts benzylation reaction with toluene using RH-Fe(5% amine) showed a drastic reduction in the di-substituted products to ca. 1.0%.