A double active center system, namely Salen-Cu（Ⅱ）@MIL-101（Cr）, was successfully synthesized via the"ship in a bottle" approach, which acted as a bifunctional material for both capture and conversion of ...A double active center system, namely Salen-Cu（Ⅱ）@MIL-101（Cr）, was successfully synthesized via the"ship in a bottle" approach, which acted as a bifunctional material for both capture and conversion of COin a single process. For the first time, Salen-Cu（Ⅱ）@MIL-101（Cr） catalyst was developed for the synthesis of propylene carbonate from COand propylene oxide under room temperature and ambient pressure with a yield of 87.8% over 60 h. Furthermore, the reaction mechanism was also discussed.展开更多
Calixarene compounds are widely used in molecular recognition,complexation,extraction,catalysis,medicine,etc.,and these properties are closely related to the bonded metal ions.Although the metal clusters constructed u...Calixarene compounds are widely used in molecular recognition,complexation,extraction,catalysis,medicine,etc.,and these properties are closely related to the bonded metal ions.Although the metal clusters constructed using calixarene and its derivatives have achieved great progress,Al clusters based on these macrocyclic ligands are still in the preliminary research stage due to the obvious hydrolysis of Al^(3+)ions in solution.It is a great challenge to obtain high-quality measurable single crystals of aluminum oxo clusters(AlOCs).Herein,we used an oxygen-rich organic macrocyclic ligand of p-tertbutylsulfonylcalix[4]arene(H_(4)BTC4A-SO_(2))to synthesize three Al_(4) clusters with formulas Al_(4)(OH)_(2)(BTC4A-SO_(2))_(2)(MeO)_(2)(DMA)_(2)(MeOH)_(2)(Al_(4)-DMA·MeOH),Al_(4)(OH)_(4)(BTC4A-SO_(2))_(2)(DMA)_(4)(Al_(4)-DMA),and Al_(4)(OH)_(4)(BTC4A-SO_(2))_(2)(DMF)_(4)(Al_(4)-DMF)which are combined by different solvents.Interestingly,the cycloaddition of carbon dioxide proves that the three AlOCs with different coordinated solvents exhibit different catalytic activities and Al_(4)-DMF shows the highest catalytic yield up to 99%.This work not only reveals three interesting calixarene-based Al cluster structures,but also realizes the regulation of catalytic activities for the reaction of the cycloaddition of carbon dioxide.This provides insights into the assembly of AlOCs and their study as catalysts.展开更多
Atmospheric CO_(2)concentrations are soaring due to the continued use of fossil fuels in energy production,an anthropogenic activity that is playing a leading role in global warming.Thus,research aimed at the capture ...Atmospheric CO_(2)concentrations are soaring due to the continued use of fossil fuels in energy production,an anthropogenic activity that is playing a leading role in global warming.Thus,research aimed at the capture and conversion of CO_(2)into value-added products,such as cyclic carbonates,is booming.While CO_(2)is an abundant,cheap,non-toxic,and readily accessible Cl feedstock,its thermodynamic stability necessitates the development of highly efficient catalysts that are able to promote chemical reactions under mild conditions.In this work,a novel mesoporous poly(ionic liquid)with dual active sites was synthesized through a facile method that involves co-polymerization,post-synthetic metalation,and supercritical CO_(2)drying.Due to a high density of nucleophilic and electrophilic sites,the as-prepared poly(ionic liquid),denoted as P2D-4BrBQA-Zn,offers excellent performance in a CO_(2)cycloaddition reaction using epichlorohydrin as the substrate(98.9%conversion and 96.9%selectivity).Moreover the reaction is carried out under mild,solvent-free,and additive-free conditions.Notably,P2D-4BrBQA-Zn also efficiently promotes the conversion of various other epoxide substrates into cyclic carbonates.Overall,the catalyst is found to have excellent substrate compatibility,stability,and recyclability.展开更多
Thiamine derivatives that are cheap, readily available, non-toxic and green are used as heterogeneous catalyst for the generation of cyclic carbonates through cycloaddition of CO_2 to epoxides without the need of co-c...Thiamine derivatives that are cheap, readily available, non-toxic and green are used as heterogeneous catalyst for the generation of cyclic carbonates through cycloaddition of CO_2 to epoxides without the need of co-catalyst and solvent. The interaction between thiamine hydrochloride(VB_1-Cl) and substrates(CO_2 and propylene oxide) was proven by ultraviolet-visible spectroscopy and ~1H nuclear magnetic resonance analysis, and it is deduced that the synergistic action among multi-functional groups(hydroxyl, halide anion and amine) is a favorable factor for cycloaddition reaction. A series of VB_1/GO aerogels were facilely prepared through the addition of aqueous VB_1 derivatives to a suspension of GO in ethanol at room temperature. It was found that the aerogel generated through the interaction of VB_1-Cl with GO shows catalytic activity and stability higher than those of VB_1-Cl. It is because the electrostatic interaction between GO and VB_1-Cl enhances the nucleophilicity and leaving ability of anion. The effects of reaction temperature, catalyst loading, CO_2 pressure and reaction time on CO_2 cycloaddition to propylene oxide were thoroughly studied.展开更多
基金supported by the National Key Projects for Fundamental R&D Program of China(2016YFB0600902)the NFSC of Tianjin(16JCZDJC36700 and 14JCQNJC03000)
文摘A double active center system, namely Salen-Cu（Ⅱ）@MIL-101（Cr）, was successfully synthesized via the"ship in a bottle" approach, which acted as a bifunctional material for both capture and conversion of COin a single process. For the first time, Salen-Cu（Ⅱ）@MIL-101（Cr） catalyst was developed for the synthesis of propylene carbonate from COand propylene oxide under room temperature and ambient pressure with a yield of 87.8% over 60 h. Furthermore, the reaction mechanism was also discussed.
基金the financial support from the National Natural Science Foundation of China(No.22071125 and No.22101148)the Natural Science Foundation of Shandong Province(No.ZR2021QB008)the College Students’Innovation and Entrepreneurship Training Program Projects of Shandong Province(No.S202311065219)。
文摘Calixarene compounds are widely used in molecular recognition,complexation,extraction,catalysis,medicine,etc.,and these properties are closely related to the bonded metal ions.Although the metal clusters constructed using calixarene and its derivatives have achieved great progress,Al clusters based on these macrocyclic ligands are still in the preliminary research stage due to the obvious hydrolysis of Al^(3+)ions in solution.It is a great challenge to obtain high-quality measurable single crystals of aluminum oxo clusters(AlOCs).Herein,we used an oxygen-rich organic macrocyclic ligand of p-tertbutylsulfonylcalix[4]arene(H_(4)BTC4A-SO_(2))to synthesize three Al_(4) clusters with formulas Al_(4)(OH)_(2)(BTC4A-SO_(2))_(2)(MeO)_(2)(DMA)_(2)(MeOH)_(2)(Al_(4)-DMA·MeOH),Al_(4)(OH)_(4)(BTC4A-SO_(2))_(2)(DMA)_(4)(Al_(4)-DMA),and Al_(4)(OH)_(4)(BTC4A-SO_(2))_(2)(DMF)_(4)(Al_(4)-DMF)which are combined by different solvents.Interestingly,the cycloaddition of carbon dioxide proves that the three AlOCs with different coordinated solvents exhibit different catalytic activities and Al_(4)-DMF shows the highest catalytic yield up to 99%.This work not only reveals three interesting calixarene-based Al cluster structures,but also realizes the regulation of catalytic activities for the reaction of the cycloaddition of carbon dioxide.This provides insights into the assembly of AlOCs and their study as catalysts.
基金financial support from the National Natural Science Foundation of China(22078274,21903066)。
文摘Atmospheric CO_(2)concentrations are soaring due to the continued use of fossil fuels in energy production,an anthropogenic activity that is playing a leading role in global warming.Thus,research aimed at the capture and conversion of CO_(2)into value-added products,such as cyclic carbonates,is booming.While CO_(2)is an abundant,cheap,non-toxic,and readily accessible Cl feedstock,its thermodynamic stability necessitates the development of highly efficient catalysts that are able to promote chemical reactions under mild conditions.In this work,a novel mesoporous poly(ionic liquid)with dual active sites was synthesized through a facile method that involves co-polymerization,post-synthetic metalation,and supercritical CO_(2)drying.Due to a high density of nucleophilic and electrophilic sites,the as-prepared poly(ionic liquid),denoted as P2D-4BrBQA-Zn,offers excellent performance in a CO_(2)cycloaddition reaction using epichlorohydrin as the substrate(98.9%conversion and 96.9%selectivity).Moreover the reaction is carried out under mild,solvent-free,and additive-free conditions.Notably,P2D-4BrBQA-Zn also efficiently promotes the conversion of various other epoxide substrates into cyclic carbonates.Overall,the catalyst is found to have excellent substrate compatibility,stability,and recyclability.
文摘Thiamine derivatives that are cheap, readily available, non-toxic and green are used as heterogeneous catalyst for the generation of cyclic carbonates through cycloaddition of CO_2 to epoxides without the need of co-catalyst and solvent. The interaction between thiamine hydrochloride(VB_1-Cl) and substrates(CO_2 and propylene oxide) was proven by ultraviolet-visible spectroscopy and ~1H nuclear magnetic resonance analysis, and it is deduced that the synergistic action among multi-functional groups(hydroxyl, halide anion and amine) is a favorable factor for cycloaddition reaction. A series of VB_1/GO aerogels were facilely prepared through the addition of aqueous VB_1 derivatives to a suspension of GO in ethanol at room temperature. It was found that the aerogel generated through the interaction of VB_1-Cl with GO shows catalytic activity and stability higher than those of VB_1-Cl. It is because the electrostatic interaction between GO and VB_1-Cl enhances the nucleophilicity and leaving ability of anion. The effects of reaction temperature, catalyst loading, CO_2 pressure and reaction time on CO_2 cycloaddition to propylene oxide were thoroughly studied.
