GB633239A - Production of thiophene - Google Patents

Abstract

Carbon disulphide is obtained as a by-product in the production of thiophene by separately preheating sulphur and a normal aliphatic paraffin or olefin of 4 carbon atoms to temperatures such that on admixture the temperature is 850-1400 DEG F., maintaining the mixture at said temperature for at least .01 second, and reducing rapidly to below 850 DEG F. Reaction times vary with temperature and, with the preferred ranges of 1000-1200 DEG F. for butane, and 900-1100 DEG F. for butenes, will be from .01 to several seconds. The hydrogen sulphide and tarry complex also formed may be treated to recover sulphur for re-use. Butadiene can be used only if admixed with predominant amounts of butane, butenes or inert diluents. A C4 refining gas is a suitable feed. The optimum ratio by weight of sulphur to hydrocarbon is about 0.5-4 or lower for butenes or butadiene. Pressure is generally atmospheric or sufficient to cause flow of reactants, and turbulent flow through a coil-type pipe reactor is preferred. Unreacted hydrocarbons may be recycled, if necessary after dilution. Reaction products may be quenched to about 300 DEG F. by spraying with thiophene or other liquid product, tar separated, stripped, and fractionated to recover thiophene and carbon disulphide. In examples, butane-butadiene in ratio by volume of 70 to 30, technical butene-2, and butane with recycled butene-butadiene are reacted with sulphur.ALSO:Thiophene is produced by separately preheating sulphur and a normal aliphatic paraffin or olefin of 4 carbon atoms to temperatures such that in admixture the temperature is 850-1400 DEG F., maintaining the mixture at said temperature for at least .01 sec., reducing rapidly to below 850 DEG F., and separating thiophene. Reaction times vary with temperature and, with the preferred ranges of 1000-1200 DEG F. for butane, and 900-1100 DEG F. for butenes, will be from .01 to several seconds. The hydrogen sulphide and tarry complex also formed may be treated to recover sulphur for re-use. Butadiene can be used only if admixed with predominant amounts of butane, butenes or inert diluents. A C4 refining gas is a suitable feed. The optimum ratio by weight of sulphur to hydrogen is about 0.5-4, or lower for butenes or butadiene. Pressure is generally atmospheric or sufficient to cause flow of reactants, and turbulent flow through a coil-type pipe reactor is preferred. Unreacted hydrocarbons may be recycled, if necessary, after dilution. Reaction products may be quenched to about 300 DEG F. by spraying with thiophene or other liquid product, tar separated, stripped, and fractionated to recover thiophene and carbon disulphide. In examples, butane-butadiene in ratio by volume of 70 to 30, technical butene-2, and butane with recycled butene-butadiene are reacted with sulphur.