Thiophene exists in crude benzene fractions produced by coking, which is tar impurity. Because the boiling point of thiophene and benzene is close, it is difficult to separate the two by the general fractionation method. Solvent extraction.
The hydrogenation refining method has high cost, the investment is large, the industrialized production is not available, the sulfuric acid pollution is serious, the yield is low, after processing difficulty, also belongs to the backward craft, a few coking plants adopt this method to produce a small amount of thiophene; solvent extraction is a small investment, high yield, high purity, suitable for large-scale production
Our country has not yet been able to extract and refine thiophene, waste limited resources and cause serious pollution to the environment. In many chemical synthesis with benzene as solvent, the product quality and even scrap are seriously affected by the presence of trace thiophene.