The exploration of highly efficient catalysts based on nano-sized Ti-rich titanosilicate zeolites with controllable active titanium species is of great importance in zeolite catalytic reactions.Herein,we reported an e...The exploration of highly efficient catalysts based on nano-sized Ti-rich titanosilicate zeolites with controllable active titanium species is of great importance in zeolite catalytic reactions.Herein,we reported an efficient and facile synthesis of nano-sized Ti-rich TS-1(MFI)zeolites by replacing tetrabutyl orthotitanate(TBOT)with tetrabutyl orthotitanate tetramer(TBOT-tetramer)as the titanium source.The introduced TBOT-tetramer slowed down the zeolite crystallization process,and accordingly balanced the rate of incorporating Ti and the crystal growth and inhibited the massive formation of anatase species.Notably,the prepared Ti-rich TS-1 zeolite sample had a Si/Ti as low as 27.6 in contrast to conventional one with a molar ratio of 40.The TBOT-tetramer endowed the titanosilicate zeolites with enriched active titanium species and enlarged external surface area.It also impeded the formation of anatase species,resulting in superior catalytic behavior toward the oxidative desulfurization of dibenzothiophene compared with the conventional TS-1 zeolite counterpart prepared with TBOT.展开更多
With the increasingly stringent standards for limiting sulfide content in liquid fuels,oxidative desulfurization(ODS)has become a promising ultra-deep desulfurization process in fuel desulfurization.TS-1 zeolites show...With the increasingly stringent standards for limiting sulfide content in liquid fuels,oxidative desulfurization(ODS)has become a promising ultra-deep desulfurization process in fuel desulfurization.TS-1 zeolites show great potential as catalysts for ODS reactions,due to its remarkable oxidation activity at low temperatures and pressure.However,the inherent microporous structure of conventional TS-1 zeolites restricts the mass transportation and renders the active sites in the microporous space of TS-1 zeolites inaccessible for bulky aromatic organosulfur compounds.Fabrication of hierarchical TS-1 zeolites by incorporating meso-/macropores into microporous TS-1 zeolites is an effective strategy to improve mass transportability.In recent years,abundant efforts have been dedicated to developing synthetic strategies of hierarchical TS-1 zeolite,thereby improving its catalytic performance in the ODS process.This mini-review addresses the synthetic methods of hierarchical TS-1 catalysts and their catalytic performance in the ODS reactions.In addition,some current problems and prospects of synthesis routes for constructing hierarchical TS-1 catalysts have also been revised.We expect this mini-review to shed light on the more efficient preparation strategies of hierarchical TS-1 zeolites for the ODS process.展开更多
A novel composite material(TD)composed of TS-1 microcrystalline and dendritic mesoporous silica nanospheres(DMSNs)was successfully prepared.The TD composite material had open pore structure and large specific surface ...A novel composite material(TD)composed of TS-1 microcrystalline and dendritic mesoporous silica nanospheres(DMSNs)was successfully prepared.The TD composite material had open pore structure and large specific surface area,which was conducive to the mass transfer of reactants and products.The Ti element in TS-1 could be used as an electron assistant,and the spillover d-electrons were conducive to the improvement of the sulfidation and dispersion of MoS_(2),thereby forming more type II MoS_(2) active phases.The incorporation of Ti could bring more Brønsted(B)and Lewis(L)acid,which was conducive to the hydrogenation pathway(HYD)selectivity(41.2%)of dibenzothiophene(DBT)hydrodesulfurization(HDS)and isomerization(ISO)route selectivity(21.9%)of 4,6-dimethyldibenzothiophene(4,6-DMDBT)HDS,thus improve the HDS activity of DBT and 4,6-DMDBT.NiMo/TD-70(Aging temperature=70℃)had the best HDS activities of DBT(99.0%)and 4,6-DMDBT(93.7%)due to its large open pore structure,good acidity,suitable metal-support interaction(MSI)and perfect dispersion of the metallic active sites.展开更多
We substituted several environmentally friendly catalysts which included HY and H- β zeolites, various cation-exchanged β zeolites, and solid-supported ferric chloride for conventional catalysts for the synth...We substituted several environmentally friendly catalysts which included HY and H- β zeolites, various cation-exchanged β zeolites, and solid-supported ferric chloride for conventional catalysts for the synthesis of 3-(1-cyclohexenyl)-2-butanone from the reaction of ethylidenecyclohexane with acetic anhydride at room temperature. HY zeolite was found to be the most effective for this reaction, and gave the acylated product in a 72% yield under the conditions of n (ethylidenecyclohexane)/ n (acetic anhydride)/ m (HY zeolite)=1 mmol/10 mmol/0 100 g, reaction temperature 25 ℃ and reaction time 2 h. The used HY zeolite can be recovered, regenerated and gave almost the same yield as the fresh one. The lifetime of the HY zeolite is over 80 h. The effect of different factors on the reaction has also been investigated.展开更多
TS-1/SiO_2 extrudate was post-treated with mixed solution of tetrapropyl ammonium hydroxide(TPAOH)and various ammonium salts solution(NH_4F,(NH_4)_3PO_4,(NH_4)_2CO_3,(NH_4)_2SO_4,NH_4CH_3CO_2,NH_4NO_3,NH_4Cl and(NH_4)...TS-1/SiO_2 extrudate was post-treated with mixed solution of tetrapropyl ammonium hydroxide(TPAOH)and various ammonium salts solution(NH_4F,(NH_4)_3PO_4,(NH_4)_2CO_3,(NH_4)_2SO_4,NH_4CH_3CO_2,NH_4NO_3,NH_4Cl and(NH_4)_2TiF_6).The obtained hierarchical TS-1 catalysts were characterized by many techniques and tested for propylene epoxidation using hydrogen peroxide as an oxidant in a fixed-bed reactor.It was shown that the physicochemical and catalytic properties of the treated TS-1/SiO_2 extrudate depended on the types of ammonium salts added.Compared to the treatment with TPAOH alone,the treatment with a mixed solution of TPAOH and some ammonium salts can greatly improve the catalytic properties of the treated TS-1/SiO_2 extrudate.Some of these ammonium salts were favorable for the incorporation of titanium in the framework,and the beneficial effect depended on the types of ammonium salt.TS-1/SiO_2 extrudate treated with a mixed solution of TPAOH and(NH_4)_3PO_4 exhibited the highest catalyst stability in propylene epoxidation.Such catalytic property can be correlated to high crystallinity,more framework titanium,large specific surface area and large external surface area.展开更多
Simultaneous achievement of constructing mesopores and eliminating anatase is a long-term pursuit for enhancing the catalytic performance of TS-1.Here,we developed an aromatic compounds-mediated synthesis method to pr...Simultaneous achievement of constructing mesopores and eliminating anatase is a long-term pursuit for enhancing the catalytic performance of TS-1.Here,we developed an aromatic compounds-mediated synthesis method to prepare anatase-free and hierarchical TS-1 for olefin epoxidation.A series of hierarchical TS-1 zeolites were prepared by introducing aromatic compounds containing different functional groups via the crystallization process.The formation of intercrystalline mesopores and insertion of titanium into framework were facilitated at different extent.The synergistic coordination of carboxyl and hydroxyl in aromatic compounds with Ti(OH)4 realizes the uniform distribution of titanium species and eliminates the generation of anatase.Noteworthily,eight machine learning models were trained to reveal the mechanism of additive functional groups and preparation conditions on anatase formation and microstructure optimization.The prediction accuracy of most models can reach more than 80%.Benefiting from the larger mesopore volumes(0.37 cm3⋅g−1)and higher content of framework Ti species,TS-DHBDC-48h samples exhibit a higher catalytic performance than other zeolites,giving 1-hexene conversion of 49.3%and 1,2-epoxyhenane selectivity of 99.9%.The paper provides a facile aromatic compounds-mediated synthesis strategy and promotes the application of machine learning toward the design and optimization of new zeolites.展开更多
The exploration of high-efficient catalysts based on hierarchical Ti-containing zeolites with optimized active titanium species distribution is of great value in enhancing the epoxidation of bulky olefins. Herein, hie...The exploration of high-efficient catalysts based on hierarchical Ti-containing zeolites with optimized active titanium species distribution is of great value in enhancing the epoxidation of bulky olefins. Herein, hierarchical TS-1(MFI) zeolite with an extra-large external surface area(210 m2/g) and highly active octahedral- coordinated Ti species was prepared via organic base-assisted sequential post-treatment. Such a catalyst afforded a high turnover number value(TON, 114) in 1-octene epoxidation reaction, which was over twice than that(53) of the untreated conventional microporous TS-1 parent. According to the detailed characterization results, we revealed the hierarchical porosity construction effect of tetrapropylamonium hydroxide(TPAOH) treatment(first step) and the octahedral-coordinated Ti species fabrication effect of ethylamine(EA) treatment(second step) under hydrothermal condition. Such a facile post-treatment strategy reported in this work may provide guidance for the rational synthesis of TS-1 zeolite with enhanced catalytic activity.展开更多
基金the National Natural Science Foundation of China, China (Grant 21920102005, 22288101, and 21835002)the 111 Project, China (B17020)+2 种基金the European Union through the European Research Council, European Union (grant ERC-AdG-2014-671093, SynCatMatch)the Spanish Government through “Severo Ochoa”, Spain (SEV2016-0683, MINECO) for supporting this workthe financial support from China Scholarship Council, China
文摘The exploration of highly efficient catalysts based on nano-sized Ti-rich titanosilicate zeolites with controllable active titanium species is of great importance in zeolite catalytic reactions.Herein,we reported an efficient and facile synthesis of nano-sized Ti-rich TS-1(MFI)zeolites by replacing tetrabutyl orthotitanate(TBOT)with tetrabutyl orthotitanate tetramer(TBOT-tetramer)as the titanium source.The introduced TBOT-tetramer slowed down the zeolite crystallization process,and accordingly balanced the rate of incorporating Ti and the crystal growth and inhibited the massive formation of anatase species.Notably,the prepared Ti-rich TS-1 zeolite sample had a Si/Ti as low as 27.6 in contrast to conventional one with a molar ratio of 40.The TBOT-tetramer endowed the titanosilicate zeolites with enriched active titanium species and enlarged external surface area.It also impeded the formation of anatase species,resulting in superior catalytic behavior toward the oxidative desulfurization of dibenzothiophene compared with the conventional TS-1 zeolite counterpart prepared with TBOT.
基金supported by the National Natural Science Foundation of China(21971082)the Jilin Province Science and Technology Development Plan(20200201096JC and 20190201229JC)+1 种基金the China Postdoctoral Science Foundation(2019T120235 and 2018M640280)for supporting this workthe 111 Project(B17020)。
文摘With the increasingly stringent standards for limiting sulfide content in liquid fuels,oxidative desulfurization(ODS)has become a promising ultra-deep desulfurization process in fuel desulfurization.TS-1 zeolites show great potential as catalysts for ODS reactions,due to its remarkable oxidation activity at low temperatures and pressure.However,the inherent microporous structure of conventional TS-1 zeolites restricts the mass transportation and renders the active sites in the microporous space of TS-1 zeolites inaccessible for bulky aromatic organosulfur compounds.Fabrication of hierarchical TS-1 zeolites by incorporating meso-/macropores into microporous TS-1 zeolites is an effective strategy to improve mass transportability.In recent years,abundant efforts have been dedicated to developing synthetic strategies of hierarchical TS-1 zeolite,thereby improving its catalytic performance in the ODS process.This mini-review addresses the synthetic methods of hierarchical TS-1 catalysts and their catalytic performance in the ODS reactions.In addition,some current problems and prospects of synthesis routes for constructing hierarchical TS-1 catalysts have also been revised.We expect this mini-review to shed light on the more efficient preparation strategies of hierarchical TS-1 zeolites for the ODS process.
基金This research was supported by the Science Foundation of China University of Petroleum-Beijing(No.2462023QNXZ002)the National Key R&D Program of China(2021YFA1501201)+2 种基金the National Natural Science Foundation of China(No.22278174)Independent research project of State Key Laboratory of heavy oil(2021–01)Shandong Excellent Young Scientists Fund Program(Overseas,2022HWYQ-082).
文摘A novel composite material(TD)composed of TS-1 microcrystalline and dendritic mesoporous silica nanospheres(DMSNs)was successfully prepared.The TD composite material had open pore structure and large specific surface area,which was conducive to the mass transfer of reactants and products.The Ti element in TS-1 could be used as an electron assistant,and the spillover d-electrons were conducive to the improvement of the sulfidation and dispersion of MoS_(2),thereby forming more type II MoS_(2) active phases.The incorporation of Ti could bring more Brønsted(B)and Lewis(L)acid,which was conducive to the hydrogenation pathway(HYD)selectivity(41.2%)of dibenzothiophene(DBT)hydrodesulfurization(HDS)and isomerization(ISO)route selectivity(21.9%)of 4,6-dimethyldibenzothiophene(4,6-DMDBT)HDS,thus improve the HDS activity of DBT and 4,6-DMDBT.NiMo/TD-70(Aging temperature=70℃)had the best HDS activities of DBT(99.0%)and 4,6-DMDBT(93.7%)due to its large open pore structure,good acidity,suitable metal-support interaction(MSI)and perfect dispersion of the metallic active sites.
基金supported by the National Natural Science Foundation of China (220925310, U1162102)the Specialized Research Fund for the Doc-toral of Higher Education (2012007613000)+1 种基金the National Basic Research Program of China (973 Program, 2012BAE05B02)the Shanghai Lead-ing Academic Discipline Project (B409)~~
基金Supported by the National Natural Science Foundation of China( No.2 0 1730 14 )
文摘We substituted several environmentally friendly catalysts which included HY and H- β zeolites, various cation-exchanged β zeolites, and solid-supported ferric chloride for conventional catalysts for the synthesis of 3-(1-cyclohexenyl)-2-butanone from the reaction of ethylidenecyclohexane with acetic anhydride at room temperature. HY zeolite was found to be the most effective for this reaction, and gave the acylated product in a 72% yield under the conditions of n (ethylidenecyclohexane)/ n (acetic anhydride)/ m (HY zeolite)=1 mmol/10 mmol/0 100 g, reaction temperature 25 ℃ and reaction time 2 h. The used HY zeolite can be recovered, regenerated and gave almost the same yield as the fresh one. The lifetime of the HY zeolite is over 80 h. The effect of different factors on the reaction has also been investigated.
基金supported by National Natural Science Foundation of China (No. 21276183)
文摘TS-1/SiO_2 extrudate was post-treated with mixed solution of tetrapropyl ammonium hydroxide(TPAOH)and various ammonium salts solution(NH_4F,(NH_4)_3PO_4,(NH_4)_2CO_3,(NH_4)_2SO_4,NH_4CH_3CO_2,NH_4NO_3,NH_4Cl and(NH_4)_2TiF_6).The obtained hierarchical TS-1 catalysts were characterized by many techniques and tested for propylene epoxidation using hydrogen peroxide as an oxidant in a fixed-bed reactor.It was shown that the physicochemical and catalytic properties of the treated TS-1/SiO_2 extrudate depended on the types of ammonium salts added.Compared to the treatment with TPAOH alone,the treatment with a mixed solution of TPAOH and some ammonium salts can greatly improve the catalytic properties of the treated TS-1/SiO_2 extrudate.Some of these ammonium salts were favorable for the incorporation of titanium in the framework,and the beneficial effect depended on the types of ammonium salt.TS-1/SiO_2 extrudate treated with a mixed solution of TPAOH and(NH_4)_3PO_4 exhibited the highest catalyst stability in propylene epoxidation.Such catalytic property can be correlated to high crystallinity,more framework titanium,large specific surface area and large external surface area.
基金National Key Research and Development Program of China,Grant/Award Number:2021YFB3500700SINOPEC Research Institute of Petroleum Processing+3 种基金Natural Science Foundation of Guangdong Province of China,Grant/Award Number:2022A1515011918Scientific and Technological Innovation Foundation of Shunde Graduate SchoolUniversity of Science and Technology Beijing,Grant/Award Number:BK20AE003Fundamental Research Funds for the Central Universities,Grant/Award Number:FRF-IDRY-20-004。
文摘Simultaneous achievement of constructing mesopores and eliminating anatase is a long-term pursuit for enhancing the catalytic performance of TS-1.Here,we developed an aromatic compounds-mediated synthesis method to prepare anatase-free and hierarchical TS-1 for olefin epoxidation.A series of hierarchical TS-1 zeolites were prepared by introducing aromatic compounds containing different functional groups via the crystallization process.The formation of intercrystalline mesopores and insertion of titanium into framework were facilitated at different extent.The synergistic coordination of carboxyl and hydroxyl in aromatic compounds with Ti(OH)4 realizes the uniform distribution of titanium species and eliminates the generation of anatase.Noteworthily,eight machine learning models were trained to reveal the mechanism of additive functional groups and preparation conditions on anatase formation and microstructure optimization.The prediction accuracy of most models can reach more than 80%.Benefiting from the larger mesopore volumes(0.37 cm3⋅g−1)and higher content of framework Ti species,TS-DHBDC-48h samples exhibit a higher catalytic performance than other zeolites,giving 1-hexene conversion of 49.3%and 1,2-epoxyhenane selectivity of 99.9%.The paper provides a facile aromatic compounds-mediated synthesis strategy and promotes the application of machine learning toward the design and optimization of new zeolites.
基金This work was supported by the National Natural Science Foundation of China (Nos.21835002,21621001,22001090)the "111" Project of China(No.B17020)the China Postdoctoral Science Foundation(No.2021T140259).
文摘The exploration of high-efficient catalysts based on hierarchical Ti-containing zeolites with optimized active titanium species distribution is of great value in enhancing the epoxidation of bulky olefins. Herein, hierarchical TS-1(MFI) zeolite with an extra-large external surface area(210 m2/g) and highly active octahedral- coordinated Ti species was prepared via organic base-assisted sequential post-treatment. Such a catalyst afforded a high turnover number value(TON, 114) in 1-octene epoxidation reaction, which was over twice than that(53) of the untreated conventional microporous TS-1 parent. According to the detailed characterization results, we revealed the hierarchical porosity construction effect of tetrapropylamonium hydroxide(TPAOH) treatment(first step) and the octahedral-coordinated Ti species fabrication effect of ethylamine(EA) treatment(second step) under hydrothermal condition. Such a facile post-treatment strategy reported in this work may provide guidance for the rational synthesis of TS-1 zeolite with enhanced catalytic activity.