共查询到20条相似文献,搜索用时 78 毫秒
1.
2.
Justin P. Gallivan 《Tetrahedron letters》2005,46(15):2577-2580
A water-soluble ruthenium-based olefin metathesis catalyst supported by a poly(ethylene glycol) conjugated N-heterocyclic carbene ligand is reported. The catalyst displays greater activity in aqueous ring-opening metathesis polymerization (ROMP) reactions than previously reported water-soluble metathesis catalysts. 相似文献
3.
A water-soluble and "self-assembled" polyoxometalate as a recyclable catalyst for oxidation of alcohols in water with hydrogen peroxide 总被引:1,自引:0,他引:1
Sloboda-Rozner D Alsters PL Neumann R 《Journal of the American Chemical Society》2003,125(18):5280-5281
We have demonstrated that a simply prepared water-soluble polyoxometalate, Na12[WZnZn2(H2O)2(ZnW9O34)2], synthesized from readily available zinc and tungsten salts in the presence of nitric acid, is an effective catalyst for selective alcohol oxidation with hydrogen peroxide in biphasic (water-alcohol) reaction media. Experiments have shown that the "self-assembled" catalyst in its mother liquor was as active as the isolated catalyst. The aqueous catalyst solution is easily separated from the water-insoluble products and can be recycled without loss in activity or selectivity. 相似文献
4.
Malhari D. Bhor 《Tetrahedron letters》2008,49(6):965-969
Direct reductive amination of aliphatic, aromatic and heterocyclic carbonyl compounds with primary/secondary amines is reported with water-soluble FeII/EDTA complex as a catalyst using low-pressure molecular hydrogen in a biphasic media. The catalyst is highly selective, recyclable and is an excellent replacement for expensive noble metal catalysts or stoichiometric reducing agents. 相似文献
5.
通过浸渍法将水溶性铑膦配合物(Rh-TPPTS)负载到由十六烷基三甲基溴化铵(CTAB)修饰的蒙脱土(MMT)上,制备出Rh-TPPTS/CTAB-MMT负载型催化剂.采用XRD,FTIR,TG,BET,31P CP-MAS NMR和分散性实验对催化剂进行了表征.结果表明:水溶性铑膦配合物成功地负载到有机MMT上,并且该催化剂在有机溶剂中具有很好的分散性.该催化剂对于1-癸烯的氢甲酰化反应具有好的催化活性.在100℃、4 MPa、甲苯为溶剂的条件下,催化1-癸烯氢甲酰化可获得93.0%的转化率,95.8%的醛的选择性,2.1的正异比,137 h-1的TOF值.并对不同链长烯烃底物进行了考察.随着烯烃碳链的增加,醛的选择性下降,但是正异比有所增加. 相似文献
6.
7.
采用商业WO3和Raney Ni为组合催化剂, 以菊芋秸秆为反应原料制备了乙二醇. 菊芋秸秆中含纤维素51.6 wt%、半纤维素10.3 wt%、木质素17.2 wt%、灰分1.7 wt%和水溶性物质19.2 wt%. 木质素对纤维素和半纤维素的转化影响较小, 而水溶性物质的存在抑制了乙二醇的生成, 因此由未经过预处理的菊芋秸秆得到的乙二醇收率只有29.9%. 而经简单的热水预处理可除掉其中的大部分水溶物, 因而乙二醇收率提高到37.6%. 此外, 组合催化剂在经过热水预处理的菊芋秸秆的转化中表现出了更好的循环使用性能. 同时考察了反应温度和时间对菊芋秸秆转化的影响. 相似文献
8.
9.
担载型水溶性膦铑配合物催化剂研究 总被引:5,自引:0,他引:5
烯类氢甲酰化反应包括了均相催化的某些重要应用。含贵金属和贵重配体的均相催化剂与产物的分离及制备高活性、高选择性、高稳定性催化剂,是均相催化及其多相化最活跃的研究领域之一。对于氢甲酰化催化剂多相化,在基础研究和技术上都仍存在如何解决好催化活性、反应选择性变化或金属流失等问题。将HRh(CO)[P(m-C_6H_4SO_33Na)_3]_3担载在亲水性 相似文献
10.
A novel TPPTS-Rh/SiO2 catalyst, prepared by directly modifying a heterogeneous highsurface-area Rh/SiO2 catalyst with water-soluble TPPTS ligands, could decrease the resistance of mass transfer in water/oil biphasic media for the hydroformylation of higher olefins. The catalytic performance for hydroformylation on this biphasic TPPTS-Rh/SiO2 catalyst system was higher than those of the traditional biphasic HRhCO(TPPTS)3 systems, owing to the chemical bonds between the highly dispersed Rh metal particles and the TPPTS ligands. The catalyst system is applicable for hydroformylation of higher olefins such as 1-dodecene. 相似文献
11.
A novel TPPTS-Rh/SiO2 catalyst, prepared by directly modifying a heterogeneous high-surface-area Rh/SiO2 catalyst with water-soluble TPPTS ligands, could decrease the resistance of masstransfer in water/oil biphasic media for the hydroformylation of higher olefins. The catalytic performancefor hydroformylation on this biphasic TPPTS-Rh/SiO2 catalyst system was higher than those of thetraditional biphasic HRhCO(TPPTS)3 systems, owing to the chemical bonds between the highly dispersedRh metal particles and the TPPTS ligands. The catalyst system is applicable for hydroformylation ofhigher olefins such as 1-dodecene. 相似文献
12.
Hejun Zhu Yunjie Ding Fu Yang Li Yan Jianmin Xiong Hongmei Yin Liwu LinNatural Gas Utilization Applied Catalysis Laboratory Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian China 《天然气化学杂志》2004,(2)
A novel TPPTS-Rh/SiO2 catalyst, prepared by directly modifying a heterogeneous high-surface-area Rh/SiO2 catalyst with water-soluble TPPTS ligands, could decrease the resistance of mass transfer in water/oil biphasic media for the hydroformylation of higher olefins. The catalytic performance for hydroformylation on this biphasic TPPTS-Rh/SiO2 catalyst system was higher than those of the traditional biphasic HRhCO(TPPTS)3 systems, owing to the chemical bonds between the highly dispersed Rh metal particles and the TPPTS ligands. The catalyst system is applicable for hydroformylation of higher olefins such as 1-dodecene. 相似文献
13.
Highly active water-soluble olefin metathesis catalyst 总被引:4,自引:0,他引:4
A novel water-soluble ruthenium olefin metathesis catalyst supported by a poly(ethylene glycol) conjugated saturated 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene ligand is reported. The catalyst displays improved activity in ring-opening metathesis polymerization, ring-closing metathesis, and cross-metathesis reactions in aqueous media. 相似文献
14.
Brown CJ Miller GM Johnson MW Bergman RG Raymond KN 《Journal of the American Chemical Society》2011,133(31):11964-11966
The design of a supramolecular catalyst capable of high-turnover catalysis is reported. A ruthenium(II) catalyst is incorporated into a water-soluble supramolecular assembly, imparting the ability to catalyze allyl alcohol isomerization. The catalyst is protected from decomposition by sequestration inside the host but retains its catalytic activity with scope governed by confinement within the host. This host-guest complex is a uniquely active supramolecular catalyst, capable of >1000 turnovers. 相似文献
15.
Chemoselective hydrogenation of substituted nitroaromatics using novel water-soluble iron complex catalysts 总被引:2,自引:0,他引:2
Deshpande RM Mahajan AN Diwakar MM Ozarde PS Chaudhari RV 《The Journal of organic chemistry》2004,69(14):4835-4838
Chemoselective hydrogenation of substituted nitroaromatic compounds by water-soluble iron complex catalysts with molecular hydrogen has been reported for the first time. This biphasic catalyst presents an opportunity for a solvent-free hydrogenation. This catalyst system provides a low-cost, efficient alternative to the selective but environmentally unacceptable stoichiometric reductions as well as the supported noble metal catalysts used for hydrogenation. An efficient recycling strategy has resulted in a cumulative turnover number above 6000. 相似文献
16.
A novel water-soluble NHC-Pd polymer with triethylene glycol legs was developed as a water soluble and highly recyclable catalyst that shows high catalytic activity in the Suzuki-Miyaura coupling of aryl chlorides in high yields in water at room temperature. 相似文献
17.
Novel water-soluble Cp*Ir-ammine complexes have been synthesized, and a new and highly atom-economical system for the synthesis of organic amines using aqueous ammonia as a nitrogen source has been developed. With a water-soluble and air-stable Cp*Ir-ammine catalyst, [Cp*Ir(NH(3))(3)][I](2), a variety of tertiary and secondary amines were synthesized by the multialkylation of aqueous ammonia with theoretical equivalents of primary and secondary alcohols. The catalyst could be recycled by a facile procedure maintaining high activity. A one-flask synthesis of quinolizidine starting with 1,5,9-nonanetriol was also demonstrated. This new catalytic system would provide a practical and environmentally benign methodology for the synthesis of various organic amines. 相似文献
18.
A new catalytic system for the dehydrogenative oxidation of alcohols using a water-soluble Cp*Ir complex bearing a bipyridine-based functional ligand as catalyst has been developed. With this catalytic system, a variety of primary and secondary alcohols have been efficiently converted to aldehydes and ketones, respectively, in aqueous media without using any oxidant. Reuse of the catalyst by a very simple procedure has been also accomplished. 相似文献
19.
A water-soluble and air-stable palladium(II)/cationic 2,2′-bipyridyl catalyst is proven to be a recyclable and extremely active catalyst for Suzuki reaction in aqueous and aerobic conditions. The conveniently prepared catalyst showed little loss in the catalytic process of the coupling between 4-bromoacetophenone and phenylboronic acid after five cycles. For the reactions of aryl chlorides, biaryls were formed in high yields under refluxing temperature in the presence of TBAB. 相似文献
20.
Eric Monflier Sbastien Tilloy Georges Fremy Yves Castanet Andr Mortreux 《Tetrahedron letters》1995,36(52):9481-9484
Solvent free biphasic hydroformylalion of various water-insoluble terminal olefins can be achieved in high yields and sclcctivitics by using a water-soluble rhodium/triphenylphosphine trisulfonate catalyst and per(2,6-di-o-mclhyl)-β-cyclodcxtrin as inverse phase transfer catalyst. The catalytic activities were up to ten times higher than those observed without pcr(2,6-di-o-methyl)-β-cyclodextrin. 相似文献