| Thiophenol compounds are important fine chemicals which have wide applications in pharmaceutical intermediates, pesticides, dyes and polymers. Thiophenol was synthesized with halogenated benzene and hydrogen sulfide by high temperature gas-phase reaction in tubular reactor. Effects of reactor structure, temperature, reactants molar ratio and residence time on production of thiophenol compounds were studied and the structure of products were characterized by IR and 1HNMR. What’s more, The effects of H-donor RH were also investigated in this research. The results showed the optimal reaction conditions of Chlorobenzene and hydrogen sulfide were at 600℃,n(hydrogen sulfide):n(Chlorobenzene)=2.5:1, reactants residence time was 45s, under this condition, the yield of thiophenol was 50.31%; the optimal reaction conditions of Bromobenzene and hydrogen sulfide were obtained at 580℃, n (hydrogen sulfide):n(Bromobenzene)=2:1, reactants residence time was 40s, under this condition, the yield of thiophenol was 62.39%; the optimal reaction conditions of 4-Chlorotoluene and hydrogen sulfide were obtained at 640℃,n(hydrogen sulfide): n(4-Chlorotoluene)=3:1, residence time was 55s, the yield of 4-Tolyl mercaptan was 65.63%. In addition, some certain RH could improve the selectivity of yield of thiophenol and reduce the yield of phenyl sulfide in side reaction. The best results were obtained at the use of 15mol% of RH for reaction of Chlorobenzene and hydrogen sulfide, and the yield of thiophenol was increased to 60.83%; For reaction of 4-Chlorotoluene and hydrogen sulfide, the appropriate amount of RH was 20mol%, and yield of 4-tolyl mercaptan reached to 78.82%. The effects of the structure of reactor on the reaction were studied by the experiment combined with simulation. ANSYS software was used to simulate the flow field in reactor.The results indicated the control of diffusion and mixing could improve the chemical reaction rate. The conversion rate and yield could be further improved by optimizing the structure of the reactor. The research provided theoretical supports for design of tubular reactor in industrialization. |
