Chemical modifications of carbon powders with aminophenyl and cyanophenyl groups and a study of their reactivity

A one-step method for the functionalization of carbon powder with 4-aminophenyl and 4-cyanophenyl. groups by reaction with the corresponding aryl amine in aqueous acidic solution is reported. This method is much more efficient than other procedures which commonly involved two steps in the case of the aminophenyl-modified carbon. Subsequently, the cyanophenyl-modified carbons were also chemically reduced to aminobenzyl groups. The presence of the grafted groups at the carbon surface was demonstrated by elemental analysis, thermogravimetric analysis and X-ray photoelectron spectroscopy. BET surface area measurements revealed a significant decrease of the carbon powder microporosity following the grafting of these substituted phenyl groups. Finally, the reactivity of these materials towards amino groups present at the surface of modified carbons was investigated with trifluoroacetic acid anhydride. (C) 2009 Elsevier Ltd. All rights reserved.