In this paper,a series of optically active MeO-BIPHEP-type ligands,（S）-6,6′-dimethoxy-2,2’-bis（di-p-alkoxyphenylphosphine）- 1,1′-biphenyl were synthesized and used to prepare the ruthenium complex.The effects o...In this paper,a series of optically active MeO-BIPHEP-type ligands,（S）-6,6′-dimethoxy-2,2’-bis（di-p-alkoxyphenylphosphine）- 1,1′-biphenyl were synthesized and used to prepare the ruthenium complex.The effects of para-substituted were observed,the results showed that the ruthenium catalysts[diphosphine RuCl;diamine]containing both t-Bu and i-Pr substitutions have better activities and enantioselectivities than the non-substituted ruthenium catalysts in the asymmetric hydrogenation of acetophenone.展开更多
A variety of secondary amines were obtained in high isolated yields in the reductive amination of aldehydes and ketones by using lithium amidoborane as reducing agent. Compared to ammonia borane, lithium amidoborane h...A variety of secondary amines were obtained in high isolated yields in the reductive amination of aldehydes and ketones by using lithium amidoborane as reducing agent. Compared to ammonia borane, lithium amidoborane has higher reducibility, and thus, exhibits faster reaction rate.展开更多
Chiral N,N＇-dialkylated cyclohexanediamine derived ligands have been synthesized and used in the asymmetric hydrogenation of aryl ketones.Optically active alcohols with up to 90%enantiomeric excess were obtained in h...Chiral N,N＇-dialkylated cyclohexanediamine derived ligands have been synthesized and used in the asymmetric hydrogenation of aryl ketones.Optically active alcohols with up to 90%enantiomeric excess were obtained in high yields.展开更多
Ru-La/γ-Al2O3 catalyst was prepared by impregnation method and characterized by temperature pro- grammed reduction（TPR）, transmission electron microscopy（TEM）, X-ray photoelectron spectra（XPS）, Brunauer- Emmett...Ru-La/γ-Al2O3 catalyst was prepared by impregnation method and characterized by temperature pro- grammed reduction（TPR）, transmission electron microscopy（TEM）, X-ray photoelectron spectra（XPS）, Brunauer- Emmett-Teller（BET）, X-ray diffraction（XRD）, and NH3-temperature programmed desorption（NH3-TPD）. NH3-TPD revealed that the strong acidic centers in γ-Al2O3 are not the major factor to cause the hydrolysis of esters to acids in the hydrogenation of esters. The results of TPR and TEM indicate that the appropriately added lanthanum results in the good dispersion of ruthenium and the easy reduction of ruthenium oxide on Ru-Laγ-Al2O3, which could promote the catalytic activity of Ru-La/γ-Al2O3 for the hydrogenation of methyl propionate to propanol. When the amount of lanthanum added in the catalyst was up to 9%（mass fraction）, 4%Ru-9%La/γ-Al2O3 catalyst gave a conversion of methyl propionate of 98.1% and a selectivity of 94.8% to propanol at a reaction temperature of 180℃ and a hydro- gen pressure of 5.0 MPa.展开更多
Amide,which is derived from proline and is inexpensive and air-stable,has been synthesized and characterized by ~1H NMR,^（13）C NMR,and MS.It was found to be an efficient ligand in the palladium-catalyzed Suzuki cros...Amide,which is derived from proline and is inexpensive and air-stable,has been synthesized and characterized by ~1H NMR,^（13）C NMR,and MS.It was found to be an efficient ligand in the palladium-catalyzed Suzuki cross-coupling reaction.In the Pd/amide catalytic system,aryl bromides can be coupled with phenylboronic acid in ethanol/water（1：2;v/v） in excellent yields even with a low Pd loading of 0.01 mol%.Moreover,the scope of the reaction is broad,and a wide variety of functional groups are tolerant.展开更多
The commercially available diphosphane ligand MeO-BIPHEP was first investigated in the palladium-catalyzed Sonogashira reaction in the absence of copper and amine.The coupling of various aryl bromides and aryl chlorid...The commercially available diphosphane ligand MeO-BIPHEP was first investigated in the palladium-catalyzed Sonogashira reaction in the absence of copper and amine.The coupling of various aryl bromides and aryl chlorides with phenylacetylene gave moderate to excellent yields.展开更多
The hydrogen desorption properties of Li 2 BNH 6 were improved by doping with cobalt. With the addition of CoCl 2 (7 wt%), more than 8 wt% of hydrogen was released from Li 2 BNH 6 at temperatures below 210°C, whi...The hydrogen desorption properties of Li 2 BNH 6 were improved by doping with cobalt. With the addition of CoCl 2 (7 wt%), more than 8 wt% of hydrogen was released from Li 2 BNH 6 at temperatures below 210°C, which is approximately 90°C lower than that of pristine Li 2 BNH 6 . X-ray diffraction, Fourier transform-infrared and Raman characterizations revealed that the dehydrogenation was a stepwise process with the formation of intermediates Li 4 BN 3 H 10 and LiBH 4 and final products of Li 3 BN 2 and LiH. The introduction of Co greatly accelerated the dehydrogenation of Li 4 BN 3 H 10 . X-ray absorption near-edge structure measurements revealed that Co and CoB species formed during ball milling of CoCl 2 with LiBH 4 and LiNH 2 , which may function as catalyst in the subsequent dehydrogenation.展开更多
Hydrous zirconia supported ruthenium catalyst Ru/ZrO2 xH2O, prepared by co-precipitating ruthenium trichloride and zirconium oxychloride with ammonia, was able to catalyze efficiently methyl propionate to propanol und...Hydrous zirconia supported ruthenium catalyst Ru/ZrO2 xH2O, prepared by co-precipitating ruthenium trichloride and zirconium oxychloride with ammonia, was able to catalyze efficiently methyl propionate to propanol under the mild conditions. In aqueous system, the propanol yield of 〉99% was achieved under the conditions of reaction temperature of 150 ℃ and hydrogen pressure of 5.0 MPa, while in non-aqueous system the maximum propanol yield was only 47.0%. FTIR spectra and hydrogenation results indicated that the high catalytic performance of Ru/ZrO2 xH2O in aqueous phase results from the cooperation effect between water as a solvent and hydroxyl groups on the surtace of carrier.展开更多
基金the NSFC(No.20272037),the Doctor's Foundation of Education Ministry of China(No.20030610022)Foundation of Xihua University(No.R0723315) and(No.07ZA109) for the financial support of this work.
文摘In this paper,a series of optically active MeO-BIPHEP-type ligands,（S）-6,6′-dimethoxy-2,2’-bis（di-p-alkoxyphenylphosphine）- 1,1′-biphenyl were synthesized and used to prepare the ruthenium complex.The effects of para-substituted were observed,the results showed that the ruthenium catalysts[diphosphine RuCl;diamine]containing both t-Bu and i-Pr substitutions have better activities and enantioselectivities than the non-substituted ruthenium catalysts in the asymmetric hydrogenation of acetophenone.
文摘A variety of secondary amines were obtained in high isolated yields in the reductive amination of aldehydes and ketones by using lithium amidoborane as reducing agent. Compared to ammonia borane, lithium amidoborane has higher reducibility, and thus, exhibits faster reaction rate.
基金the NSFC(No.20272037)the NSF of Sichuan(No.07ZA109)the foundation of Xihua University(No. R0723315) and(No.XZD0912-09) for the financial support of this work
文摘Chiral N,N＇-dialkylated cyclohexanediamine derived ligands have been synthesized and used in the asymmetric hydrogenation of aryl ketones.Optically active alcohols with up to 90%enantiomeric excess were obtained in high yields.
基金Supported by the National Natural Science Foundation of China（No.21072138）.
文摘Ru-La/γ-Al2O3 catalyst was prepared by impregnation method and characterized by temperature pro- grammed reduction（TPR）, transmission electron microscopy（TEM）, X-ray photoelectron spectra（XPS）, Brunauer- Emmett-Teller（BET）, X-ray diffraction（XRD）, and NH3-temperature programmed desorption（NH3-TPD）. NH3-TPD revealed that the strong acidic centers in γ-Al2O3 are not the major factor to cause the hydrolysis of esters to acids in the hydrogenation of esters. The results of TPR and TEM indicate that the appropriately added lanthanum results in the good dispersion of ruthenium and the easy reduction of ruthenium oxide on Ru-Laγ-Al2O3, which could promote the catalytic activity of Ru-La/γ-Al2O3 for the hydrogenation of methyl propionate to propanol. When the amount of lanthanum added in the catalyst was up to 9%（mass fraction）, 4%Ru-9%La/γ-Al2O3 catalyst gave a conversion of methyl propionate of 98.1% and a selectivity of 94.8% to propanol at a reaction temperature of 180℃ and a hydro- gen pressure of 5.0 MPa.
文摘Amide,which is derived from proline and is inexpensive and air-stable,has been synthesized and characterized by ~1H NMR,^（13）C NMR,and MS.It was found to be an efficient ligand in the palladium-catalyzed Suzuki cross-coupling reaction.In the Pd/amide catalytic system,aryl bromides can be coupled with phenylboronic acid in ethanol/water（1：2;v/v） in excellent yields even with a low Pd loading of 0.01 mol%.Moreover,the scope of the reaction is broad,and a wide variety of functional groups are tolerant.
文摘The commercially available diphosphane ligand MeO-BIPHEP was first investigated in the palladium-catalyzed Sonogashira reaction in the absence of copper and amine.The coupling of various aryl bromides and aryl chlorides with phenylacetylene gave moderate to excellent yields.
基金supported by the Hundred Talents Project of Chinese Academy of Sciences (KGCX2-YW-806)the Knowledge Innovation Program of Chinese Academy of Sciences (KJCX2-YW-H21)+1 种基金the National Hi-Tech Research & Development Project of China (2009AA05Z108)the National Natural Science Foundation of China (10979051, 20971120, 20973162)
文摘The hydrogen desorption properties of Li 2 BNH 6 were improved by doping with cobalt. With the addition of CoCl 2 (7 wt%), more than 8 wt% of hydrogen was released from Li 2 BNH 6 at temperatures below 210°C, which is approximately 90°C lower than that of pristine Li 2 BNH 6 . X-ray diffraction, Fourier transform-infrared and Raman characterizations revealed that the dehydrogenation was a stepwise process with the formation of intermediates Li 4 BN 3 H 10 and LiBH 4 and final products of Li 3 BN 2 and LiH. The introduction of Co greatly accelerated the dehydrogenation of Li 4 BN 3 H 10 . X-ray absorption near-edge structure measurements revealed that Co and CoB species formed during ball milling of CoCl 2 with LiBH 4 and LiNH 2 , which may function as catalyst in the subsequent dehydrogenation.
基金Project supported by the National Natural Science Foundation of China （No. 21072138）, Key Project of Chinese Ministry of Education （No. 307023）, the State Key Laboratory of Surface Science of Xiamen University, and the Innovation Foundation of Sichuan University.
文摘Hydrous zirconia supported ruthenium catalyst Ru/ZrO2 xH2O, prepared by co-precipitating ruthenium trichloride and zirconium oxychloride with ammonia, was able to catalyze efficiently methyl propionate to propanol under the mild conditions. In aqueous system, the propanol yield of 〉99% was achieved under the conditions of reaction temperature of 150 ℃ and hydrogen pressure of 5.0 MPa, while in non-aqueous system the maximum propanol yield was only 47.0%. FTIR spectra and hydrogenation results indicated that the high catalytic performance of Ru/ZrO2 xH2O in aqueous phase results from the cooperation effect between water as a solvent and hydroxyl groups on the surtace of carrier.
