Kinetics of hydroxylation of phenol with SiC foam supported TS-1 structured catalyst

Abstract

In light of the challenges associated with catalyst separation and recovery, as well as the low production efficiency resulting from intermittent operation for titanium silicalite-1 (TS-1) catalyzed phenol hydroxylation to dihydroxybenzene in the slurry bed, researchers keep on exploring the use of a continuous fixed bed to replace the slurry bed process in recent years. This study focuses on preparing a TS-1 coated structured catalyst on SiC foam, which exhibits significant process intensification in performance. We investigated the kinetics of this structured catalyst and compared it with those of extruded TS-1 catalyst; the dynamic equations of the two catalysts were obtained. It was observed that both catalysts followed E-R adsorption mechanism model, with an effective internal diffusion factor ratio between structured and extruded TS-1 of approximately 7.71. It was confirmed that the foamed SiC-based structured TS-1 catalyst exhibited significant improvements in phenol hydroxylation in fixed-bed reactor due to its well-developed pore structure, good thermal conductivity, excellent internal mass transfer performance, and short reactant diffusion distance, leading to higher utilization efficiency of active components. This finding also provides a foundation for designing and developing phenol hydroxylation processes in fixed-bed using structured catalysts through computational fluid dynamics calculations.