Polymerization of aniline derivatives by K2 Cr2 O7 and production of Cr2 O3 nanoparticles

Abstract

Oxidative polymerization of aniline, anthranilic acid, and aniline-co-anthranilic acid by potassium dichromate Cr(VI) as an oxidant in acidic medium was investigated. In this study, the polymerization process of aniline, o-anthranilic acid as well as aniline/o-anthranlic acid using K2Cr2O7 produced, coordinated Cr(III)/polyaniline (PANI), Cr(III)/polyanthranilic acid (PAA) and Cr(III)/poly aniline-co-anthranilic acid (PANAA). The mechanism of polymerization reaction in the presence of dichromate was hypothesized. The precursor chromium doped polymers were characterized by TGA, FT-IR, UV-visible, XRD analyses. Cr2O3 nanoparticles size were determined using TEM analysis. The calcinations process of synthesized chromium doped PANI, PAA and PANAA yields Cr2O3 nanoparticles 26%, 31%, and 34% wt. respectively. Rhombohedral phase of Cr2O3 particles in the range from 33 to 61 nm was produced from chromium/polyanthranilic acid (PAA) and chromium/poly(aniline-co-anthranilic acid) PANAA. UV- visible analysis showed that optical band gaps (Eg) of doped poly aniline and its derivatives are in the range from1.55 to 1.80 using Tacu's law. The band gap values reveal that the doped chromium emeraldine base can be used as semiconductor materials. Copyright © 2016 John Wiley & Sons, Ltd.