Jacobsen's catalyst was immobilized onto SBA-15 by multi-step grafting, and this heterogenized catalyst exhibited comparable catalytic performance with the corresponding homogeneous counterpart for the epoxidation...Jacobsen's catalyst was immobilized onto SBA-15 by multi-step grafting, and this heterogenized catalyst exhibited comparable catalytic performance with the corresponding homogeneous counterpart for the epoxidation of alkenes, and the catalyst could be recycled effectively several times.展开更多
SalenMX has drawn much attention recently,because it is nonsensitive to moisture and effective for copolymerization of CO2 and epoxides.However,usually expensive organic metal compounds were used.A low cost procedure ...SalenMX has drawn much attention recently,because it is nonsensitive to moisture and effective for copolymerization of CO2 and epoxides.However,usually expensive organic metal compounds were used.A low cost procedure of SalenMX preparation is described that SalenAl（OPr） can be obtained by using aluminium iso-propoxide reacted with SalenH2 in tetrahydrofuran at room temperature overnight.The catalyst precursor Schiff-base SalenH2 （N,N′-Bis（salicylidene）-1,2-phenylenediamine） was synthesized by refluxing 2 equiv salicylaldehyde and 1 equiv of 1,2-phenylendiamine in methnol for a period of time.SalenH2 and SalenAl（OPr） were characterized by FT-IR,mass Spectroscopy,UV-Vis and 1H-NMR.The copolymerization of carbon dioxide and cyclohexene oxide（CHO） was carried out at 80℃ for a certain period time using 50 mg SalenAl（OPr） as catalyst.SalenAl（OPr） had been shown to be an effective catalyst for the copolymerization of CO2 and CHO along with a small quantity of byproduct cyclic carbonate.The addition of various cocatalysts,including DMAP,N-MeIm,DBU and Bu4NCl or Bu4NBr salts can greatly enhance the rate of copolymerization.The copolymers were produced with >95% carbonate linkages and <5% cyclic carbonates.The highest catalytic efficiency is 190 g copolymer per g catalyst.展开更多
A novel chiral Salen ligand with a glucose moiety was synthesized from the condensation of 1,2:5,6-di-O-isopropylidene-3-O-methylene-5-(3-tert-butyl-2-hydroxy benzaldehyde) -α-D-glucofuranose with (1R,2R)-1,2-diamino...A novel chiral Salen ligand with a glucose moiety was synthesized from the condensation of 1,2:5,6-di-O-isopropylidene-3-O-methylene-5-(3-tert-butyl-2-hydroxy benzaldehyde) -α-D-glucofuranose with (1R,2R)-1,2-diaminocyclohexane. Several chiral complexes of Mn3+, Fe3+, Co2+ and Cu2+ were prepared from this ligand. Both the ligand and the complexes were characterized by elemental analysis, NMR, IR, MS, and UV-Vis.展开更多
利用席佛碱催化体系催化二氧化碳(CO2)和环氧氯丙烷(ECH)共聚反应,合成出新型环状碳酸酯(ECHCO2)。利用红外光谱、核磁等方法对产物进行了表征。结果表明,最优化的试验温度是60℃,这一催化剂体系催化的活性高达920 polymer/(mol Co h),...利用席佛碱催化体系催化二氧化碳(CO2)和环氧氯丙烷(ECH)共聚反应,合成出新型环状碳酸酯(ECHCO2)。利用红外光谱、核磁等方法对产物进行了表征。结果表明,最优化的试验温度是60℃,这一催化剂体系催化的活性高达920 polymer/(mol Co h),并且有较高的选择性,高达99%。展开更多
文摘Jacobsen's catalyst was immobilized onto SBA-15 by multi-step grafting, and this heterogenized catalyst exhibited comparable catalytic performance with the corresponding homogeneous counterpart for the epoxidation of alkenes, and the catalyst could be recycled effectively several times.
文摘SalenMX has drawn much attention recently,because it is nonsensitive to moisture and effective for copolymerization of CO2 and epoxides.However,usually expensive organic metal compounds were used.A low cost procedure of SalenMX preparation is described that SalenAl（OPr） can be obtained by using aluminium iso-propoxide reacted with SalenH2 in tetrahydrofuran at room temperature overnight.The catalyst precursor Schiff-base SalenH2 （N,N′-Bis（salicylidene）-1,2-phenylenediamine） was synthesized by refluxing 2 equiv salicylaldehyde and 1 equiv of 1,2-phenylendiamine in methnol for a period of time.SalenH2 and SalenAl（OPr） were characterized by FT-IR,mass Spectroscopy,UV-Vis and 1H-NMR.The copolymerization of carbon dioxide and cyclohexene oxide（CHO） was carried out at 80℃ for a certain period time using 50 mg SalenAl（OPr） as catalyst.SalenAl（OPr） had been shown to be an effective catalyst for the copolymerization of CO2 and CHO along with a small quantity of byproduct cyclic carbonate.The addition of various cocatalysts,including DMAP,N-MeIm,DBU and Bu4NCl or Bu4NBr salts can greatly enhance the rate of copolymerization.The copolymers were produced with >95% carbonate linkages and <5% cyclic carbonates.The highest catalytic efficiency is 190 g copolymer per g catalyst.
文摘A novel chiral Salen ligand with a glucose moiety was synthesized from the condensation of 1,2:5,6-di-O-isopropylidene-3-O-methylene-5-(3-tert-butyl-2-hydroxy benzaldehyde) -α-D-glucofuranose with (1R,2R)-1,2-diaminocyclohexane. Several chiral complexes of Mn3+, Fe3+, Co2+ and Cu2+ were prepared from this ligand. Both the ligand and the complexes were characterized by elemental analysis, NMR, IR, MS, and UV-Vis.
