Synthesis of early-transition-metal carbide and nitride nanoparticles through the urea route and their use as alkylation catalysts.

The use of urea as either a carbon or a nitrogen source enabled the synthesis of various early-transition-metal nitride and carbide nanoparticles (TiN, NbN, Mo(2)N, W(2)N, NbC(x)N(1-x), Mo(2)C and WC). The ability of these particles to promote alkylation reactions with alcohols was tested on benzyl alcohol and acetophenone at 150 degrees C for 20 h in xylene. Group IV and V ceramics proved to be able to catalyse the formation of 1,3-diphenyl propenone, whereas group VI ceramics showed a tendency to promote the Friedel-Crafts-type reaction of benzyl alcohol on xylene (the solvent). TiN featured the highest activity for the alkylation of ketones and was further tested for more difficult alkylations. Group VI ceramics were further investigated as catalysts for the Friedel-Crafts-type alkylation of aromatics with activated alcohols. Interestingly, even hexanol could be effectively used for these reactions.