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 ...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.展开更多
Cu nanoparticles supported on a variety of oxide supports, including SiO2, TiO2, ZrO2, Al2O3, MgO and ZnO, were investigated for the hydrogenolysis of biomass‐derived furfuryl alcohol to1,2‐pentanediol and 1,5‐pent...Cu nanoparticles supported on a variety of oxide supports, including SiO2, TiO2, ZrO2, Al2O3, MgO and ZnO, were investigated for the hydrogenolysis of biomass‐derived furfuryl alcohol to1,2‐pentanediol and 1,5‐pentanediol. A Cu‐Al2O3 catalyst with 10 wt% Cu loading prepared by a co‐precipitation method exhibited the best performance in terms of producing pentanediols compared with the other materials. This catalyst generated an 85.8% conversion and a 70.3% combined selectivity for the target pentanediols at 413 K and 8 MPa H2 over an 8‐h reaction. The catalyst could also be recycled over repeated reaction trials without any significant decrease in productivity. Characterizations with X‐ray diffraction, NH3/CO2‐temperature programmed desorption, N2 adsorption,transmission electron microscopy and N2 O chemisorption demonstrated that intimate and effective interactions between Cu particles and the acidic Al2O3 support in this material greatly enhanced its activity and selectivity. The promotion of the hydrogenolysis reaction was found to be especially sensitive to the Cu particle size, and the catalyst with Cu particles 1.9 to 2.4 nm in size showed the highest turnover frequency during the synthesis of pentanediols.展开更多
基金National Key Research and Development Program(Grant No.2023YFB3810600)National Natural Science Foundation of China(Grant No.2237081611)+1 种基金European Union’s Horizon 2020 Research and Innovation Program(Grant No.872102)Natural Science Foundation of Liaoning Province(Grant No.2022-MS-002).
文摘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.
基金supported by the National Natural Science Foundation of China(2113301121203221+1 种基金21473224)the Natural Science Foundation of Gansu Province(1308RJZA281)~~
文摘Cu nanoparticles supported on a variety of oxide supports, including SiO2, TiO2, ZrO2, Al2O3, MgO and ZnO, were investigated for the hydrogenolysis of biomass‐derived furfuryl alcohol to1,2‐pentanediol and 1,5‐pentanediol. A Cu‐Al2O3 catalyst with 10 wt% Cu loading prepared by a co‐precipitation method exhibited the best performance in terms of producing pentanediols compared with the other materials. This catalyst generated an 85.8% conversion and a 70.3% combined selectivity for the target pentanediols at 413 K and 8 MPa H2 over an 8‐h reaction. The catalyst could also be recycled over repeated reaction trials without any significant decrease in productivity. Characterizations with X‐ray diffraction, NH3/CO2‐temperature programmed desorption, N2 adsorption,transmission electron microscopy and N2 O chemisorption demonstrated that intimate and effective interactions between Cu particles and the acidic Al2O3 support in this material greatly enhanced its activity and selectivity. The promotion of the hydrogenolysis reaction was found to be especially sensitive to the Cu particle size, and the catalyst with Cu particles 1.9 to 2.4 nm in size showed the highest turnover frequency during the synthesis of pentanediols.
