Study On Synthesis Of Tetrahydrothiophene

In recent years,the application of natural gas has become more and more common in industrial production and daily life,for the rapidly grown of the natural gas market,.With the improvement of gas safety performance,the warning industry has developed rapidly.Tetrahydrothiophene is widely used,for the advantages such as inoxidability,long retention time of its odor,less added,etc.Due to its high cost,the mercaptan warning agent with high toxicity still has many applications in China.the research on the synthesis of tetrahydrothiophene has very important practical significance.In this paper,1,4-dibromobutane was prepared from the hydrogen bromide which was recovered from the factory.The molar ratio?n?1,4-butanediol?:n?hydrobromic acid??,the dosage of catalyst?n?1,4-butanediol?:n?concentrated sulfuric acid??,the reaction temperature and the reaction time were optimized.The optimum yield was 88.20%.The purity of the product was 99.48% measured by gas chromatography.The final product was confirmed to be 1,4-dibromobutane by infrared spectrum,boiling point and shading rate.In this paper,SO₄^2-/ZrO₂-SiO₂ solid superacid was prepared to catalyze the synthesis of 1,4-dibromobutane.The influence of the aging time,the ratio of silicon-zirconium?n?Si?:n?Zr??,the concentration of H₂SO₄,the pro-calcination conditions,the calcination temperature and the calcination time on the catalytic activity of solid superacid was studied.The yield of 1,4-dibromobutane catalyzed by solid superacid prepared under the optimum conditions was 66.57%.The solid superacid and the 1,4-dibromobutane catalyzed by solid superacid were characterized by infrared spectrum,boiling point and shading rate.The purity of 1,4-dibromobutane was 98.95% measured by gas chromatography.1,4-dibromobutane synthesized in the first two steps was used to compound tetrahydrothiophene.The effects of the feed mode,the catalyst type,the molar ratio of the feed,the reaction temperature,the reaction time and the amount of the catalyst on the yield of tetrahydrothiophene were investigated.The yield of tetrahydrothiophene under the optimum conditions was 73.87%.Tetrahydrothiophene were characterized by infrared spectroscopy,boiling point.The purity of tetrahydrothiophene was97.20% measured by gas chromatography.In addition,the hydrogen bromide was recovered from the waste liquid of tetrahydrothiophene synthesis by a series of treatment,which was used for the synthesis of 1,4-dibromobutane.The yield of 1,4-dibromobutane was 38.72%.The purity of the 1,4-dibromobutane was 98.92 % measured by gas chromatography.