Synthesis Of Conductive Polymer Monomer3,4-ethylene Dioxide Thiophene Process

A reasonable and feasible synthetic route was designed on the basis of readinga lot of literature in order to prepare3,4-ethylene dioxide thiophene (EDOT), themonomer of conductive polymer, was synthesized by methyl chloroacetate throughthe nucleophilic substitution reaction, the Claisen ester-condensation reaction,O-alkyl-ation reaction, hydrolysis reaction and decarboxylation. The new synthesisprocess for EDOT on the basis of the original process to improve and optimize toacquire, which was low cost, high conversion, simple to operate, less environmentalpollution and worth to the industrial production.The optimum conditions of nucleophilic substitution reaction as follows:themolar ratio n[methyl chloroacetate]:n[sodium sulfide]=1:0.7, the amount of phasetransfer catalyst is in mass fraction of3%, reaction temperature at30°C,reactiontime10h. The optimum process conditions of Claisen ester-condensation reaction:the amount of dimethyl2,2’-thiobisacetate is35.6g (0.2mol),molar ratio n[dimethyl2,2’-thiobisacetate]: n[diethyl oxalate]=1:1.1, the amount of solid sodium methoxideis0.8mol,100ml of methanol, reaction time4h. The optimum conditions ofO-alkylation:the quality ratio of raw material m[2,5-thiophenedicarboxylate-3,4-dihydroxy-thiophene]:m[1,2-dichloroethane]=1:6,100ml of the solvent DMF, theamount of catalyst is4%(mass fraction), reaction time6h. The optimum conditionsof the hydrolysis reaction: the dosage of2,5-thiophenedicarboxylate-3,4-ethylenedioxide thiophene is46g (0.2mol), the amount of sodium hydroxide solution (massfraction of10%) is250ml, reaction temperature at80℃, reaction time2h. Theoptimum conditions of the decarboxylation reaction: the quality ratio of raw material m[2,5-dicarboxylic acid-3,4-ethylene dioxide thiophene]:m[DMSO]=1:5,the amountof the catalyst of copper powder is8%(mass fraction),reaction temperature at160℃,reaction time9h. In this conditions of process, the total yield of product is32%.Quantitative analysis and structural characterization of intermediates and finalproduct were determined by HPLC, GC-MS, IR,1H-NMR.