A NEW METHOD TO PREPARE 3-OCTYLTHIOPHENE AND POLY-(3-OCTYLTHIOPHENE)

A new method has been developed for the synthesis of 3-octylthiophene starting from dipotassium salt of octylsuccinic anhydride, phosphorus pentasulfide and phosphorus. The yield of the reaction is about 70 %. The inorganic waste formed can be converted back to phosphorus pentasulfide with sulphur at 550 degrees C. The method reduces substantially the production cost and the amount of waste. 3-Octylthiophene obtained via this method was polymerized using FeCl3 as the oxidant. The polymer yield was about 70 %. The characterized polymer consists of 84 % regular head-to-tail linkages. The polymer has Fe content less than 100 ppm, chlorine content 0.5 %, Mw approximate to 70000 and Mn approximate to 29000. The 4-point conductivity of a doped film is 47 S/cm.