A green heterogeneous catalyst for Heck reaction-chitosan-immobilized palladium complex was prepared. The catalyst exhibits high activity and stereoselectivity under the moderate reaction conditions. The catalyst can ...A green heterogeneous catalyst for Heck reaction-chitosan-immobilized palladium complex was prepared. The catalyst exhibits high activity and stereoselectivity under the moderate reaction conditions. The catalyst can be separated easily from the reaction mixture and reused after washing. Under the suitable reaction conditions, the cross-coupling of iodobenzene (ArI) with acrylic acid (AA) or acrylate can be achieved 93.3% or 99% yield of trans-cinnamic acid or trans-cinnamic ester.展开更多
Methanol synthesis from hydrogenation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M（Cu,Zn）-ammonia complexes （DMAC） at various temperatures.The catalysts were characterized in d...Methanol synthesis from hydrogenation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M（Cu,Zn）-ammonia complexes （DMAC） at various temperatures.The catalysts were characterized in detail,including X-ray diffraction,N2 adsorption-desorption,N2O chemisorption,temperature-programmed reduction and evolved gas analyses.The influences of DMAC temperature,reaction temperature and specific Cu surface area on catalytic performance are investigated.It is considered that the aurichalcite phase in the precursor plays a key role in improving the physiochemical properties and activities of the final catalysts.The catalyst from rich-aurichalcite precursor exhibits large specific Cu surface area and high space time yield of methanol （212 g/（Lcat·h）;T=513 K,p=3MPa,SV=12000 h-1）.展开更多
Polymerization of 4-vinylpyridine by complex catalyst of neodymium chloride was studied. The influence of Al/Nd (molar ratio), concentration of catalyst, reaction time and temperature on polymerization of 4-vinylpyrid...Polymerization of 4-vinylpyridine by complex catalyst of neodymium chloride was studied. The influence of Al/Nd (molar ratio), concentration of catalyst, reaction time and temperature on polymerization of 4-vinylpyridine was investigated. The results show that different kinds of ligand in the rare earth complex have an effect on the catalytic activity of the complex. The catalytic activity of the rare earth complex is higher than that of simple rare earth chloride. The catalytic activity of polymer-supported catalyst is higher than those of the similar small molecular system.展开更多
An unbridged zirconocene complex bis(1,2-diphenylcyclopentadienyl)zirconium dichloride [(1,2-Ph2-C5H3)2ZrCl2] 1 has been synthesized and structurally characterized. When activated by MAO, 1 produces ultra-high molecul...An unbridged zirconocene complex bis(1,2-diphenylcyclopentadienyl)zirconium dichloride [(1,2-Ph2-C5H3)2ZrCl2] 1 has been synthesized and structurally characterized. When activated by MAO, 1 produces ultra-high molecular weight polyethylene with high melting transition temperature, as well as atactic oligopropylene with average molecular weight of ~1150 g mol-1.展开更多
Polymerization of styrene and 1,3-butadiene were performed by calix[4]arene-neodymium complexes using di-n-butylmagnesium and tri-iso-butylaluminum as cocatalyst respectively. The effect of the substituent groups in c...Polymerization of styrene and 1,3-butadiene were performed by calix[4]arene-neodymium complexes using di-n-butylmagnesium and tri-iso-butylaluminum as cocatalyst respectively. The effect of the substituent groups in calix[4]arene on the catalytic activity was first investigated.展开更多
1, 1'--Bis(benzylseleno)ferrocene and its platinum complex were synthesized. It was found that the platinum complex was efficient catalyst for the hydrosilylation of olefins with triethoxysilane.
Silica-bound 15-Crown-5, 18-Crown-6 with a spacer of propyloxymethyl and their platinum complexes have been synthesized. It was found that they were efficient catalysts for the hydrosilylation of olefms with triethoxy...Silica-bound 15-Crown-5, 18-Crown-6 with a spacer of propyloxymethyl and their platinum complexes have been synthesized. It was found that they were efficient catalysts for the hydrosilylation of olefms with triethoxysilane in the temperature range of 60 to 130 ℃.展开更多
Six kinds of polymer ligands, supported on SiO_2, containing coordinating atoms P, S and N respectively, have been synthesized. The Ru(Ⅲ)-Co(Ⅱ) bimetallic complexes of these polymer ligands have been obtained and ex...Six kinds of polymer ligands, supported on SiO_2, containing coordinating atoms P, S and N respectively, have been synthesized. The Ru(Ⅲ)-Co(Ⅱ) bimetallic complexes of these polymer ligands have been obtained and examined as catalysts for the hydroformylation of cyclohexene. The effects of reaction temperature, pressure and Co/Ru ratio etc. on the activities of catalysts were investigated in detail. The catalysts are all polymer-noncarbonyl-metal complexes, easily to be prepared, active and stable. From the experimental results it can be suggested that under reaction conditions such polymer-noncarbonyl-metal complexes convert 'in situ' to polymer-carbonyl-metal complexes, thus become active catalysts. The course of this conversion is supposed as a preliminary approach.展开更多
A modified method of preparing crown functionalized linear polysiloxane has been described.4'-allylbenzo-15-crown-5 was subjected to hydrosilylation with methyldichlorosilane,followed bypolycondensation with silan...A modified method of preparing crown functionalized linear polysiloxane has been described.4'-allylbenzo-15-crown-5 was subjected to hydrosilylation with methyldichlorosilane,followed bypolycondensation with silanol-terminated polydimethylsiloxane to give the title crownfunctionalized linear polysiloxane. It was found that the polysiloxane could be coordinated withplatinum salt to form platinum complex, which could catalyze the hydrosilylation of olefins withtriethoxysilane efficiently.展开更多
The reaction of a ruthenium carbide complex RuCl2（C：）（PCy3）2 with [H（Et2O）x]＋[BF4]- at a molar ratio of 1：2 produced a two-core ruthenium carbene complex, {[RuCl（=CHPCy3）（PCy3）]2（μ-Cl）3}＋·[BF4]-,...The reaction of a ruthenium carbide complex RuCl2（C：）（PCy3）2 with [H（Et2O）x]＋[BF4]- at a molar ratio of 1：2 produced a two-core ruthenium carbene complex, {[RuCl（=CHPCy3）（PCy3）]2（μ-Cl）3}＋·[BF4]-, in the form of a yellow-green crystalline solid in a yield of 94%. This two-core ruthenium complex is a selective catalyst for ring closing metathesis of unsubstituted terminal dienes. More importantly, no isomerized byproduct was observed for N-substrates when the two-core ruthenium complex was used as the catalyst at an elevated temperature（137 °C）, indicating that the complex is a chemo-selective catalyst for ring closing metathesis reactions.展开更多
The capability of the synthesized heteropoly complexes of rare earths {K10 [(O39W11Si) Ln(Gly)3Ln(SiW11O39)]?H2O (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy)} as the catalyst promoter in the synthesis of the ethyl acetate was ...The capability of the synthesized heteropoly complexes of rare earths {K10 [(O39W11Si) Ln(Gly)3Ln(SiW11O39)]?H2O (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy)} as the catalyst promoter in the synthesis of the ethyl acetate was studied. The results showed that the quantity of H2SO4 used for synthesizing the ethyl acetate can be reduced by 75% and the yield reached 98% at the optional condition.展开更多
Two multidentate ligands 2,9-di[6＇-（2″-hydroxyl-3″-methoxyphenyl）-n-2＇,5＇-diazahexyl]-1,10-phenanthroline（LA）and 2,9-di（6＇-α-phenol-n-2＇,5＇-diazahexyl）-1,10-phenanthroline（LB）were synthesized and full...Two multidentate ligands 2,9-di[6＇-（2″-hydroxyl-3″-methoxyphenyl）-n-2＇,5＇-diazahexyl]-1,10-phenanthroline（LA）and 2,9-di（6＇-α-phenol-n-2＇,5＇-diazahexyl）-1,10-phenanthroline（LB）were synthesized and fully characterized.Protonation of the ligands and the stability of the complexes of the ligands with divalent metal ions were investigated.The trinuclear metal complexes [Cu（Ⅱ）and Zn（Ⅱ）] of the ligands were studied,as catalysts,for the transphosphorylation of the RNA-model substrate 2-hydroxypropyl-p-nitrophenyl phosphate（HPNP）.The second-order rate constants of HPNP-hydrolysis catalyzed by M3L and M3LH-1 were obtained,which indicated that Zn3LBH-1 was the most efficient catalyst among them.The proposed mechanisms included the activation of the substrate via binding to the metal ions and intramolecular nucleophilic attack by the deprotonated C2-hydroxyl of HPNP.展开更多
Many catalysts were pcrpared by carbonization of ion exchange resin-PdCl_2 complexes at high temperature in nitrogen, hydrogen atmosphere. The rates for the hydrogenation of methyl acrylate and the amounts of Pd eluti...Many catalysts were pcrpared by carbonization of ion exchange resin-PdCl_2 complexes at high temperature in nitrogen, hydrogen atmosphere. The rates for the hydrogenation of methyl acrylate and the amounts of Pd elution of the carbonaceous products were measured and compared with those of commercial Pd/C catalyst. It indicates that the carbonaceous products are less active than Pd/C. However, the leaching of Pd from carbonaceous products is very small and much less than that from Pd/C.展开更多
In the practical use for the production of the α-olefins, it is highly desired to develop a novel heterogeneous catalyst system. The metal complexes immobilized into the clay interlayers show a great potential as het...In the practical use for the production of the α-olefins, it is highly desired to develop a novel heterogeneous catalyst system. The metal complexes immobilized into the clay interlayers show a great potential as heterogeneous catalysts due to their excellent processability. In this study, nine types of heterogeneous procatalyst Ln/Ni2+-micas were synthesized via a one-pot preparation method, which includes both the condensation reaction of the ligand derivatives and the intercalation of the ligands into the Ni2+ ion-exchanged fluorotetrasilicic mica interlayer. The ligand structures of the prepared procatalysts were [Ln: R-N = C(Nap)-C(Nap) = N-R] [(Nap = 1,8-naphthdiyl) (L1, R = 2-MePh;L2, R = 2-FPh;L3, R = 2-BrPh;L4, R = 4-MePh;L5, R = 4-FPh;L6, R = 4-BrPh;L7, R = 2,4-F2Ph;L8, R = 2,4-Br2Ph;L9, R = 2,6-F2Ph). At 50℃ and 0.7 MPaethylene pressure, the triisobutylaluminum-activated L1-L6/Ni2+-mica showed a catalytic activity for the ethylene oligo-/polymerization in the range of 334 - 549 g-ethylene•g-cat–1•h–1. A high catalyst activity was obtained when the substituent having a larger steric bulk than that of a methyl substituent was introduced at the ortho-position of the aryl rings. The introduction of the fluorine substituent as a strong electron-withdrawing group to the para-position also increased the catalytic activity. The L2, L4, L5, and L6/Ni2+-micas showed moderate selectivities to oligomers consisting of C4-C20 in the range of 19.9 - 41.6 wt% at 50℃. The calculated Schulz-Flory constants α based on the mole fraction of C12 and C14 were within 0.61 - 0.78.展开更多
文摘A green heterogeneous catalyst for Heck reaction-chitosan-immobilized palladium complex was prepared. The catalyst exhibits high activity and stereoselectivity under the moderate reaction conditions. The catalyst can be separated easily from the reaction mixture and reused after washing. Under the suitable reaction conditions, the cross-coupling of iodobenzene (ArI) with acrylic acid (AA) or acrylate can be achieved 93.3% or 99% yield of trans-cinnamic acid or trans-cinnamic ester.
基金supported by the National Basic Research Program of China (No. 2011CB201404)the financial support of the State Key Laboratory for Oxo Synthesis and Selective Oxidation (OSSO) of China
文摘Methanol synthesis from hydrogenation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M（Cu,Zn）-ammonia complexes （DMAC） at various temperatures.The catalysts were characterized in detail,including X-ray diffraction,N2 adsorption-desorption,N2O chemisorption,temperature-programmed reduction and evolved gas analyses.The influences of DMAC temperature,reaction temperature and specific Cu surface area on catalytic performance are investigated.It is considered that the aurichalcite phase in the precursor plays a key role in improving the physiochemical properties and activities of the final catalysts.The catalyst from rich-aurichalcite precursor exhibits large specific Cu surface area and high space time yield of methanol （212 g/（Lcat·h）;T=513 K,p=3MPa,SV=12000 h-1）.
文摘Polymerization of 4-vinylpyridine by complex catalyst of neodymium chloride was studied. The influence of Al/Nd (molar ratio), concentration of catalyst, reaction time and temperature on polymerization of 4-vinylpyridine was investigated. The results show that different kinds of ligand in the rare earth complex have an effect on the catalytic activity of the complex. The catalytic activity of the rare earth complex is higher than that of simple rare earth chloride. The catalytic activity of polymer-supported catalyst is higher than those of the similar small molecular system.
文摘An unbridged zirconocene complex bis(1,2-diphenylcyclopentadienyl)zirconium dichloride [(1,2-Ph2-C5H3)2ZrCl2] 1 has been synthesized and structurally characterized. When activated by MAO, 1 produces ultra-high molecular weight polyethylene with high melting transition temperature, as well as atactic oligopropylene with average molecular weight of ~1150 g mol-1.
文摘Polymerization of styrene and 1,3-butadiene were performed by calix[4]arene-neodymium complexes using di-n-butylmagnesium and tri-iso-butylaluminum as cocatalyst respectively. The effect of the substituent groups in calix[4]arene on the catalytic activity was first investigated.
文摘1, 1'--Bis(benzylseleno)ferrocene and its platinum complex were synthesized. It was found that the platinum complex was efficient catalyst for the hydrosilylation of olefins with triethoxysilane.
文摘Silica-bound 15-Crown-5, 18-Crown-6 with a spacer of propyloxymethyl and their platinum complexes have been synthesized. It was found that they were efficient catalysts for the hydrosilylation of olefms with triethoxysilane in the temperature range of 60 to 130 ℃.
文摘Six kinds of polymer ligands, supported on SiO_2, containing coordinating atoms P, S and N respectively, have been synthesized. The Ru(Ⅲ)-Co(Ⅱ) bimetallic complexes of these polymer ligands have been obtained and examined as catalysts for the hydroformylation of cyclohexene. The effects of reaction temperature, pressure and Co/Ru ratio etc. on the activities of catalysts were investigated in detail. The catalysts are all polymer-noncarbonyl-metal complexes, easily to be prepared, active and stable. From the experimental results it can be suggested that under reaction conditions such polymer-noncarbonyl-metal complexes convert 'in situ' to polymer-carbonyl-metal complexes, thus become active catalysts. The course of this conversion is supposed as a preliminary approach.
基金This work was supported by the National Natural Science Foundation of China and the Natural Science Foundation of Hubei Province
文摘A modified method of preparing crown functionalized linear polysiloxane has been described.4'-allylbenzo-15-crown-5 was subjected to hydrosilylation with methyldichlorosilane,followed bypolycondensation with silanol-terminated polydimethylsiloxane to give the title crownfunctionalized linear polysiloxane. It was found that the polysiloxane could be coordinated withplatinum salt to form platinum complex, which could catalyze the hydrosilylation of olefins withtriethoxysilane efficiently.
基金Supported by the National Natural Science Foundation of China(No.20872108)
文摘The reaction of a ruthenium carbide complex RuCl2（C：）（PCy3）2 with [H（Et2O）x]＋[BF4]- at a molar ratio of 1：2 produced a two-core ruthenium carbene complex, {[RuCl（=CHPCy3）（PCy3）]2（μ-Cl）3}＋·[BF4]-, in the form of a yellow-green crystalline solid in a yield of 94%. This two-core ruthenium complex is a selective catalyst for ring closing metathesis of unsubstituted terminal dienes. More importantly, no isomerized byproduct was observed for N-substrates when the two-core ruthenium complex was used as the catalyst at an elevated temperature（137 °C）, indicating that the complex is a chemo-selective catalyst for ring closing metathesis reactions.
文摘The capability of the synthesized heteropoly complexes of rare earths {K10 [(O39W11Si) Ln(Gly)3Ln(SiW11O39)]?H2O (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy)} as the catalyst promoter in the synthesis of the ethyl acetate was studied. The results showed that the quantity of H2SO4 used for synthesizing the ethyl acetate can be reduced by 75% and the yield reached 98% at the optional condition.
基金Supported by the National Natural Science Foundation of China(Nos.20371028and20671052).
文摘Two multidentate ligands 2,9-di[6＇-（2″-hydroxyl-3″-methoxyphenyl）-n-2＇,5＇-diazahexyl]-1,10-phenanthroline（LA）and 2,9-di（6＇-α-phenol-n-2＇,5＇-diazahexyl）-1,10-phenanthroline（LB）were synthesized and fully characterized.Protonation of the ligands and the stability of the complexes of the ligands with divalent metal ions were investigated.The trinuclear metal complexes [Cu（Ⅱ）and Zn（Ⅱ）] of the ligands were studied,as catalysts,for the transphosphorylation of the RNA-model substrate 2-hydroxypropyl-p-nitrophenyl phosphate（HPNP）.The second-order rate constants of HPNP-hydrolysis catalyzed by M3L and M3LH-1 were obtained,which indicated that Zn3LBH-1 was the most efficient catalyst among them.The proposed mechanisms included the activation of the substrate via binding to the metal ions and intramolecular nucleophilic attack by the deprotonated C2-hydroxyl of HPNP.
文摘Many catalysts were pcrpared by carbonization of ion exchange resin-PdCl_2 complexes at high temperature in nitrogen, hydrogen atmosphere. The rates for the hydrogenation of methyl acrylate and the amounts of Pd elution of the carbonaceous products were measured and compared with those of commercial Pd/C catalyst. It indicates that the carbonaceous products are less active than Pd/C. However, the leaching of Pd from carbonaceous products is very small and much less than that from Pd/C.
文摘In the practical use for the production of the α-olefins, it is highly desired to develop a novel heterogeneous catalyst system. The metal complexes immobilized into the clay interlayers show a great potential as heterogeneous catalysts due to their excellent processability. In this study, nine types of heterogeneous procatalyst Ln/Ni2+-micas were synthesized via a one-pot preparation method, which includes both the condensation reaction of the ligand derivatives and the intercalation of the ligands into the Ni2+ ion-exchanged fluorotetrasilicic mica interlayer. The ligand structures of the prepared procatalysts were [Ln: R-N = C(Nap)-C(Nap) = N-R] [(Nap = 1,8-naphthdiyl) (L1, R = 2-MePh;L2, R = 2-FPh;L3, R = 2-BrPh;L4, R = 4-MePh;L5, R = 4-FPh;L6, R = 4-BrPh;L7, R = 2,4-F2Ph;L8, R = 2,4-Br2Ph;L9, R = 2,6-F2Ph). At 50℃ and 0.7 MPaethylene pressure, the triisobutylaluminum-activated L1-L6/Ni2+-mica showed a catalytic activity for the ethylene oligo-/polymerization in the range of 334 - 549 g-ethylene•g-cat–1•h–1. A high catalyst activity was obtained when the substituent having a larger steric bulk than that of a methyl substituent was introduced at the ortho-position of the aryl rings. The introduction of the fluorine substituent as a strong electron-withdrawing group to the para-position also increased the catalytic activity. The L2, L4, L5, and L6/Ni2+-micas showed moderate selectivities to oligomers consisting of C4-C20 in the range of 19.9 - 41.6 wt% at 50℃. The calculated Schulz-Flory constants α based on the mole fraction of C12 and C14 were within 0.61 - 0.78.
