A highly efficient Pd\|BMImCl/TiO\-\%y\%\|SiO\-\%x\% catalyst system synthesized through sol\|gel method from palladium complex, ionic liquid, titanate and silicate esters was found for the oxidative carbonylation of ...A highly efficient Pd\|BMImCl/TiO\-\%y\%\|SiO\-\%x\% catalyst system synthesized through sol\|gel method from palladium complex, ionic liquid, titanate and silicate esters was found for the oxidative carbonylation of amines. The catalyst efficiency was much higher than that reported in previous papers and the TOF number reached to 10 372 when catalyst 0.05%Pd\|4.6%BMImCl/TiO\-\%y\%\|SiO\-\%x\% was used. The usability of ionic liquid was the key point for preparation of this catalyst system because of its high dissolvability to palladium complex and affording appropriate micro\|environment for the reaction. The synergism among palladium complex, ionic liquid, titanate and silicate was the main reason for the high catalytic activity of the catalyst system. BET, AES and XRD were used to characterized the catalysts in detail.展开更多
The TS-1 life in propylene epoxidation was studied in a continually slurry reactor under the condition of 40 ℃ and 0.4, 0.6 MPa. It is suggested that the single circle life of TS-1 was no less than 80 h, the conversa...The TS-1 life in propylene epoxidation was studied in a continually slurry reactor under the condition of 40 ℃ and 0.4, 0.6 MPa. It is suggested that the single circle life of TS-1 was no less than 80 h, the conversation of hydrogen peroxide was over 90%, the selectivity of propylene oxide and 1-methoxy-2-propanol was above 92.1%. The TS-1 catalyst can be regenerated in methanol, the initial activity of regenerative catalyst can’t change after the slightly deactivation in first regeneration. Element C and Ti were analyzed by XPS. The new the shift of electronic binding energy showed that Ti had been lost and deactivated in reaction, much carton deposited on the surface of TS-1, which are the main reasons of TS-1 deactivation, and the continual propylene epoxidation can be realized integrated with the thermodynamic reactor and the proper process.展开更多
Selective and durable fixed‐bed catalysts are highly desirable for developing eco‐efficient HPPO(hydrogen peroxide propylene oxide)process.The powder titanosilicate catalysts must be shaped before being applied in i...Selective and durable fixed‐bed catalysts are highly desirable for developing eco‐efficient HPPO(hydrogen peroxide propylene oxide)process.The powder titanosilicate catalysts must be shaped before being applied in industrial processes.As the essential additives for preparing formed catalysts,binders are usually the catalytically inert components,but they would cover the surface and pore mouth of zeolite,thereby declining the accessibility of active sites.By recrystallizing the binder(silica)/Ti‐MWW extrudates with the assistance of dual organic structure‐directing agents,the silica binder was converted into MWW zeolite phase to form a structured binder‐free Ti‐MWW zeolite with Si‐rich shell,which enhanced the diffusion efficiency and maintained the mechanical strength.Meanwhile,due to the partial dissolution of Si in the Ti‐MWW matrix,abundant silanol nests formed and part of framework TiO4 species were transferred into open TiO_(6)ones,improving the accumulation and activation ability of H_(2)O_(2)inside the monolith.Successive piperidine treatment and fluoridation of the binder‐free Ti‐MWW further enhanced the H_(2)O_(2)activation and oxygen transfer ability of the active Ti sites,and stabilized the Ti‐OOH intermediate through hydrogen bond formed between the end H in Ti‐OOH and the adjacent Si‐F species,thus achieving a more efficient epoxidation process.Additionally,the side reaction of PO hydrolysis was inhibited because the modification effectively quenched numerous Si‐OH groups.The lifetime of the modified binder‐free Ti‐MWW catalyst was 2400 h with the H_(2)O_(2)conversion and PO selectivity both above 99.5%.展开更多
文摘A highly efficient Pd\|BMImCl/TiO\-\%y\%\|SiO\-\%x\% catalyst system synthesized through sol\|gel method from palladium complex, ionic liquid, titanate and silicate esters was found for the oxidative carbonylation of amines. The catalyst efficiency was much higher than that reported in previous papers and the TOF number reached to 10 372 when catalyst 0.05%Pd\|4.6%BMImCl/TiO\-\%y\%\|SiO\-\%x\% was used. The usability of ionic liquid was the key point for preparation of this catalyst system because of its high dissolvability to palladium complex and affording appropriate micro\|environment for the reaction. The synergism among palladium complex, ionic liquid, titanate and silicate was the main reason for the high catalytic activity of the catalyst system. BET, AES and XRD were used to characterized the catalysts in detail.
文摘The TS-1 life in propylene epoxidation was studied in a continually slurry reactor under the condition of 40 ℃ and 0.4, 0.6 MPa. It is suggested that the single circle life of TS-1 was no less than 80 h, the conversation of hydrogen peroxide was over 90%, the selectivity of propylene oxide and 1-methoxy-2-propanol was above 92.1%. The TS-1 catalyst can be regenerated in methanol, the initial activity of regenerative catalyst can’t change after the slightly deactivation in first regeneration. Element C and Ti were analyzed by XPS. The new the shift of electronic binding energy showed that Ti had been lost and deactivated in reaction, much carton deposited on the surface of TS-1, which are the main reasons of TS-1 deactivation, and the continual propylene epoxidation can be realized integrated with the thermodynamic reactor and the proper process.
文摘Selective and durable fixed‐bed catalysts are highly desirable for developing eco‐efficient HPPO(hydrogen peroxide propylene oxide)process.The powder titanosilicate catalysts must be shaped before being applied in industrial processes.As the essential additives for preparing formed catalysts,binders are usually the catalytically inert components,but they would cover the surface and pore mouth of zeolite,thereby declining the accessibility of active sites.By recrystallizing the binder(silica)/Ti‐MWW extrudates with the assistance of dual organic structure‐directing agents,the silica binder was converted into MWW zeolite phase to form a structured binder‐free Ti‐MWW zeolite with Si‐rich shell,which enhanced the diffusion efficiency and maintained the mechanical strength.Meanwhile,due to the partial dissolution of Si in the Ti‐MWW matrix,abundant silanol nests formed and part of framework TiO4 species were transferred into open TiO_(6)ones,improving the accumulation and activation ability of H_(2)O_(2)inside the monolith.Successive piperidine treatment and fluoridation of the binder‐free Ti‐MWW further enhanced the H_(2)O_(2)activation and oxygen transfer ability of the active Ti sites,and stabilized the Ti‐OOH intermediate through hydrogen bond formed between the end H in Ti‐OOH and the adjacent Si‐F species,thus achieving a more efficient epoxidation process.Additionally,the side reaction of PO hydrolysis was inhibited because the modification effectively quenched numerous Si‐OH groups.The lifetime of the modified binder‐free Ti‐MWW catalyst was 2400 h with the H_(2)O_(2)conversion and PO selectivity both above 99.5%.
