Catalytic properties of the metal-organic framework Cr-MIL-101 in solvent-free cycloaddition of CO2 to epoxides to produce cyclic carbon- ates using tetrabutylammonium bromide as co-catalyst have been explored under m...Catalytic properties of the metal-organic framework Cr-MIL-101 in solvent-free cycloaddition of CO2 to epoxides to produce cyclic carbon- ates using tetrabutylammonium bromide as co-catalyst have been explored under mild reaction conditions （8 bar CO2, 25 ~C）. Styrene and propylene carbonates were formed with high yields （95% and 82%, respectively）. Catalytic performance of Cr-MIL-101 was compared with other MOFs： Fe-MIL-101, Zn-MOF-5 and HKUST-1, The catalytic properties of different quaternary ammonium bromides, Cr-MIL-101 as well as PW12/Cr-MIL-101 composite material have been assessed in oxidative carboxylation of styrene in the presence of both tert-butyl hydroperoxide and H202 as oxidants at 8-100bar CO2 and 25-80 ~C with selectivity to styrene carbonate up to 44% at 57% substrate conversion.展开更多
The flotation behaviors of decyltrimethylammonium (103C), dodecyltrimethylammonium chloride (DTAC), tetradecyltrimethylammonium chloride (TTAC) and cetyltrimethylammonium chloride (CTAC) on kaolinite of different part...The flotation behaviors of decyltrimethylammonium (103C), dodecyltrimethylammonium chloride (DTAC), tetradecyltrimethylammonium chloride (TTAC) and cetyltrimethylammonium chloride (CTAC) on kaolinite of different particle size fraction were studied. The adsorbed amount and adsorption isotherms of collectors on kaolinite were determined for painstaking investigation into the adsorption of quaternary amines at kaolinite-water interface by ultraviolet spectrophotometer methods. The flotation results show that the flotation recovery of kaolinite of different particle fraction increases with an increase in pH when 103C, DTAC, TTAC and CTAC are used as collectors. As the concentration of collectors increases, the flotation recovery increases. Particle size of kaolinite has a strong effect on flotation. The flotation recovery of fine kaolinite decreases with the carbon chain of quaternary ammonium salts collectors increasing, while coarse kaolinite is on the contrary. The adsorbed amount tests and adsorption isotherms show that adsorbed amount increases when the particle size of kaolinite increases or when the carbon chain length of quaternary ammonium salts increases. Within the range of flotation collector concentration, the longer the hydrocarbon chain, the more probable to be absolutely adsorbed by fine kaolinite particles and then the lower the collector concentration in the bulk, which leds to lower flotation recovery.展开更多
Wettability is an important surface property that deserves to further explore the factors on its alteration.Series of bis-N-heterocyclic quaternary ammonium salts with different spacer length and N-heterocyclic headgr...Wettability is an important surface property that deserves to further explore the factors on its alteration.Series of bis-N-heterocyclic quaternary ammonium salts with different spacer length and N-heterocyclic headgroups(morpholinium(BMMB,BMMD and BMMH),piperidinium(BPMH)and piperazinium(BMPMH))have been synthesized and employed for altering the wettability of vermiculite and its derivates(Vts)treated by Li^(+)-saturated heating method.The results of X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),thermogravimetric analysis(TG-DTG),scanning electron microscopy(SEM)and N_(2)adsorption/desorption isotherms indicate that all of the bis-N-heterocyclic quaternary ammonium salts have been successfully inserted into the vermiculite layers,leading to the organic monolayer.The results of capillary rise tests combined with Lipophilic to Hydrophilic Ratio(LHR)values unveil the wettability alteration of the organo-Vts.As the layer charge decreases,the hydrophilicity of the organo-Vts gradually increases,which is probably caused by the decline in binding sites.As the result of the change in spacer length of modifier,the wetting properties of morpholinium-based organo-Vts change in order of BMMD-Vts>BMMH-Vts>BMMB-Vts,and difference in N-heterocyclic headgroups leads to the sequence of wettability:BMPMH-Vts>BPMH-Vts>BMMH-Vts.Layer charge of Vt,spacer length and the type of the N-heterocyclic headgroup of modifier have the synergistic effect on the regulation of the wettability.展开更多
Quaternary phosphonium salts （QPS） with reactive groups used as antibacterial agents are promising which could be covalently linked to inert polymer surfaces by in situ polymerization. In this work, two kinds of qua...Quaternary phosphonium salts （QPS） with reactive groups used as antibacterial agents are promising which could be covalently linked to inert polymer surfaces by in situ polymerization. In this work, two kinds of quaternary phosphonium salts with hydroxyl groups were synthesized successfully. Characterization of these two quaternary phosphonium salts was performed by the Fourier transform infrared spectroscopy （FT-IR） and nuclear magnetic resonance （NMR） spectrometry. The thermal stability and antibacterial activity of antibacterial agents were also investigated by using thermo-gravimetric analysis, differential scanning calorimetry （TG-DSC） and agar diffusion method. The test results showed that these two QPS exhibited good thermal stability and excellent antibacterial activity against both bacteria： Staphylococcus aureus and Escherichia coll.展开更多
基金the Russian Foundation for Basic Research(RFBR grant12-03-31537)
文摘Catalytic properties of the metal-organic framework Cr-MIL-101 in solvent-free cycloaddition of CO2 to epoxides to produce cyclic carbon- ates using tetrabutylammonium bromide as co-catalyst have been explored under mild reaction conditions （8 bar CO2, 25 ~C）. Styrene and propylene carbonates were formed with high yields （95% and 82%, respectively）. Catalytic performance of Cr-MIL-101 was compared with other MOFs： Fe-MIL-101, Zn-MOF-5 and HKUST-1, The catalytic properties of different quaternary ammonium bromides, Cr-MIL-101 as well as PW12/Cr-MIL-101 composite material have been assessed in oxidative carboxylation of styrene in the presence of both tert-butyl hydroperoxide and H202 as oxidants at 8-100bar CO2 and 25-80 ~C with selectivity to styrene carbonate up to 44% at 57% substrate conversion.
基金the National Natural Science Foundation of China (No.50974134)the National Basic Research Program of China (No.2005CB623701)
文摘The flotation behaviors of decyltrimethylammonium (103C), dodecyltrimethylammonium chloride (DTAC), tetradecyltrimethylammonium chloride (TTAC) and cetyltrimethylammonium chloride (CTAC) on kaolinite of different particle size fraction were studied. The adsorbed amount and adsorption isotherms of collectors on kaolinite were determined for painstaking investigation into the adsorption of quaternary amines at kaolinite-water interface by ultraviolet spectrophotometer methods. The flotation results show that the flotation recovery of kaolinite of different particle fraction increases with an increase in pH when 103C, DTAC, TTAC and CTAC are used as collectors. As the concentration of collectors increases, the flotation recovery increases. Particle size of kaolinite has a strong effect on flotation. The flotation recovery of fine kaolinite decreases with the carbon chain of quaternary ammonium salts collectors increasing, while coarse kaolinite is on the contrary. The adsorbed amount tests and adsorption isotherms show that adsorbed amount increases when the particle size of kaolinite increases or when the carbon chain length of quaternary ammonium salts increases. Within the range of flotation collector concentration, the longer the hydrocarbon chain, the more probable to be absolutely adsorbed by fine kaolinite particles and then the lower the collector concentration in the bulk, which leds to lower flotation recovery.
基金This work is funded by the National Natural Science Foundation of China(Grant No.21776306).
文摘Wettability is an important surface property that deserves to further explore the factors on its alteration.Series of bis-N-heterocyclic quaternary ammonium salts with different spacer length and N-heterocyclic headgroups(morpholinium(BMMB,BMMD and BMMH),piperidinium(BPMH)and piperazinium(BMPMH))have been synthesized and employed for altering the wettability of vermiculite and its derivates(Vts)treated by Li^(+)-saturated heating method.The results of X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),thermogravimetric analysis(TG-DTG),scanning electron microscopy(SEM)and N_(2)adsorption/desorption isotherms indicate that all of the bis-N-heterocyclic quaternary ammonium salts have been successfully inserted into the vermiculite layers,leading to the organic monolayer.The results of capillary rise tests combined with Lipophilic to Hydrophilic Ratio(LHR)values unveil the wettability alteration of the organo-Vts.As the layer charge decreases,the hydrophilicity of the organo-Vts gradually increases,which is probably caused by the decline in binding sites.As the result of the change in spacer length of modifier,the wetting properties of morpholinium-based organo-Vts change in order of BMMD-Vts>BMMH-Vts>BMMB-Vts,and difference in N-heterocyclic headgroups leads to the sequence of wettability:BMPMH-Vts>BPMH-Vts>BMMH-Vts.Layer charge of Vt,spacer length and the type of the N-heterocyclic headgroup of modifier have the synergistic effect on the regulation of the wettability.
文摘Quaternary phosphonium salts （QPS） with reactive groups used as antibacterial agents are promising which could be covalently linked to inert polymer surfaces by in situ polymerization. In this work, two kinds of quaternary phosphonium salts with hydroxyl groups were synthesized successfully. Characterization of these two quaternary phosphonium salts was performed by the Fourier transform infrared spectroscopy （FT-IR） and nuclear magnetic resonance （NMR） spectrometry. The thermal stability and antibacterial activity of antibacterial agents were also investigated by using thermo-gravimetric analysis, differential scanning calorimetry （TG-DSC） and agar diffusion method. The test results showed that these two QPS exhibited good thermal stability and excellent antibacterial activity against both bacteria： Staphylococcus aureus and Escherichia coll.
