4-Substituted Benzoic Acids Functionalized Multi-Walled Carbon Nanotubes in Mild Polyphosphoric Acid/Phosphorous Pentoxide
Pristine multi-walled carbon nanotubes (P-MWNTs) were functionalized with 4-substituted benzoic acid via ‘‘direct’’ Friedel-Crafts acylation in mild reaction medium of polyphosphoric acid (PPA)/phosphorous pentoxide (P2O5). Raman spectroscopy, thermogravimetric analysis, transmission electron microscopy were applied in this paper to demonstrate that multi-walled carbon nanotubes inherently have functional groups on their surfaces as a result of the reaction. The overall evidence indicates that the 4-substituted benzoic acid functionalization of carbon nanotube can be achieved without oxidation as pre-treatment. Thus, aryl carbonyl moieties with different length of 4-substituted alkyl acyl amine functionalized MWNTs（F-MWNTs） can be synthesized simply, without disrupting the primary structures of the nanotubes.
H. H. Liu et al., "4-Substituted Benzoic Acids Functionalized Multi-Walled Carbon Nanotubes in Mild Polyphosphoric Acid/Phosphorous Pentoxide", Advanced Materials Research, Vols. 217-218, pp. 768-773, 2011