Solid-State-Sintered Silicon Carbide Reactor for High-Throughput Continuous-Flow Synthesis of Dodecylbenzene Sulfonic Acid

Abstract It is still a challenge to achieve a continuous-flow reactor with high heat transfer and corrosion resistance for sulfonation reactions. Herein, a solid-state-sintered silicon carbide (SiC) reactor has been developed and applied to the synthesis of dodecylbenzene sulfonic acid. In terms of heat transfer and corrosion resistance, SiC demonstrates advantages over other conventional materials used for manufacturing reactors, and the performance of SiC could be further improved through the solid-state sintering method. Through Computational Fluid Dynamics (CFD) simulations, the SiC reactor exhibited a high Nusselt number compared with reactors of other materials. Furthermore, the difference in thermal conductivity of the two SiC materials would lead to a more pronounced difference in the heat transfer capability of the reactor at high flow rates. The heat flux of solid-state-sintered SiC was 13.8 times that of polytetrafluoroethylene (PTFE), which could enable the SiC reactor to effectively avoid the accumulation of heat and control the reaction temperature. The solid-state-sintered SiC reactor was integrated into a reaction apparatus to explore the optimal reaction conditions for synthesizing dodecylbenzene sulfonic acid. The reaction afforded a 70.63% yield of dodecylbenzene sulfonic acid at 60 °C and a flow rate of 75 mL/min. Eventually, a response surface methodology was used to investigate the interactions among flow rate, sulfur trioxide mass ratio, and reaction temperature on dodecylbenzene sulfonic acid yields. This study advances the application of SiC in highly exothermic and corrosive reaction systems and elucidates the effects of microscopic material structure on macroscopic reactor performance.