CATALYTIC SYNTHESES OF AROMATIC CONDUCTING POLYMERS

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1) Polypyrrole is a stable and heat-resisting polymer. We have already developed a novel method to prepare polypyrrole from pyrrole by using molecular oxygen as an oxidant and copper (I) chloride-aluminum chloride complex as a catalyst, respectively. However, sine this catalyst is sensitive to water, the catalyst can be deactivate by the water bye-produced by the reduction of molecular oxygen. Thus, in this project, we have developed a new catalytic system which does not contain aluminum chloride. Among various metal salts, we found that iron (III) salts like iron (III) chloride are effective for this purpose. In addition, the solvent used for this reaction was found effective in the reaction yield and the conductivity of the polymer produced. In fact, propylene carbonate was found the best among the solvents examined. The catalytic oxidative polymerization was carried out in the presence of anions, which work as the dopant, to improve the conductivity of the produced polymer.2) The copper (II) chloride-oxygen system was found effective in the catalytic oxidative polymerization of aniline and its derivatives. However, the polyaniline thus prepared has a disadvantage, i.e., a bad processability. In order to cover this disadvantage, a novel method was investigated to prepare polyaniline from precursor polymers. Poly (o-aminobenzoic acid) is soluble in some organic solvents and alkaline solutions, being one of the candidates for the precursor polymer. However, the yield is very low when it is prepared by a conventional method. We have develop a new method to prepare poly (o-aminobenzoic acid) at high yield by oxidative polymerization in an alkaline solution. Heat treatment of poly (o-aminobenzoic acid) gives polyaniline with loss of carbon dioxide. We have also developed a new method to prepare sulfonated polyaniline from aminobezenesulfonic acid as a raw materials.