Using DFT calculations, we have investigated the cycloaddition of thiophene with ethylene, followed by desulfurization of the produced heterobicyclic molecules at 373 K. The whole reaction process has been modeled in three steps: (i) the molecule adsorption on tungsten sulfide acting as a catalyst, (ii) the cycloaddition of the adsorbed molecule with ethylene, (iii) the elimination of the sulfur atom by hydrogenation of the cycloaddition products. Cycloaddition, in the presence or in the absence of catalyst, produced a bicyclic compound including a C–S bond. Its reaction with hydrogen led to the hydrogenolysis of C–S bonds. Without catalyst, the reaction of bicyclic compounds with hydrogen led to a double hydrogenolysis producing cyclohexa-1,2-diene and hydrogen sulfur. In the presence of catalyst, the reaction took place in two steps, leading to cyclohexene. With increasing the molecular weight of compounds, cycloaddition can allow the separation between light hydrocarbons from alkyl-thiophenic molecules with distillation, knowing that boiling temperature increases with the molecular weight. Although consuming more hydrogen, the reaction with catalysts led to an unsaturated cyclic product which can improve the octane number of fuels containing them.

使用DFT计算，我们研究了噻吩与乙烯的环加成反应，然后在373 K下对生成的杂双环分子进行脱硫。整个反应过程分三个步骤进行建模：（i）分子在硫化钨上的吸附作为催化剂；（ii）吸附的分子与乙烯的环加成，（iii）通过环加成产物的氢化消除硫原子。在催化剂存在或不存在的情况下，环加成反应都会生成包含C–S键的双环化合物。它与氢的反应导致了C–S键的氢解。在没有催化剂的情况下，双环化合物与氢的反应导致了两次氢解反应，从而生成了环六-1,2-二烯和氢硫。在催化剂存在下，反应分两步进行：导致环己烯。随着化合物分子量的增加，已知沸腾温度随分子量的增加而增加，环加成反应可通过蒸馏将轻烃与烷基噻吩分子分离。尽管消耗更多的氢，但与催化剂的反应产生了不饱和环状产物，其可以提高含有它们的燃料的辛烷值。