焦化苯中噻吩的卤化新反应

A new reaction for the halogenation of thiophene in the coking benzene was investigated. The method was designed to occur in a water-benzene two-phase mixtures solution containing both the permanganate and the chloride. A partial of thiophene will react with chlorine to generate the 2-chlorothiophene or 2,5-dichlorothiophene. The total sulfur and the thiophene contents in the benzene were determined by micro coulometer and GC-FPD respectively. The chloro-thiophenes produced were characterized by GCMS analysis. The preliminary results show that the thiophene in the benzene can not be oxidized by alone potassium permanganate solution even at pH 2—3. When the chlorides were used as the co-reactant the thiophene can be converted to chloro-thiophene. The process could be explained as follow: the chloride was oxidized by permanganate to generate chlorine in the suitable acidic solution, then the chlorine produced react immediately with thiophene to form chloro-thiophenes. The thiophene in the coking benzene could be completely converted by using the new method if the suitable reaction conditions are selected such as the pH value of aqueous solution and the molar concentration of both the permanganate and chloride.