The catalytic activity of titania nanostructures in the synthesis of amides under solvent-free conditions

Abstract

Different shapes and phases of titania nanostructures with the uniform size distribution were synthesized by hydrothermal sol–gel technique. The influence of annealing temperature on the crystalline character, size and phase of the prepared nanomaterials were evidenced from the diffraction analysis. Infrared spectroscopic analysis ensured the structural confirmation of the sulfated titania nanostructures. Catalytic activity of the synthesized nanometric materials in direct amidation of aromatic and aliphatic carboxylic acids with aromatic amines was evaluated. Among the materials studied, sulfated titania nanotubes with the anatase phase exhibited excellent catalytic activity. The employed solvent-free protocol is greener and eradicates the drawbacks associated with the hazardous solvents employed in the prevailing solution phase methodologies.