نتایج جستجو برای: homogeneous catalyst

تعداد نتایج: 113196  

2017
Xiaochuan Zou Cun Wang Yue Wang Kaiyun Shi Zhongming Wang Dongwei Li Xiangkai Fu Marinos Pitsikalis

Chiral MnIII (salen) complex supported on modified ZPS-PVPA (zirconium poly(styrenephenylvinylphosphonate)) and ZPS-IPPA (zirconium poly(styrene-isopropenyl phosphonate)) were prepared using –CH2Cl as a reactive surface modifier by a covalent grafting method. The supported catalysts showed higher chiral induction (ee: 72%–83%) compared with the corresponding homogeneous catalyst (ee: 54%) for a...

In this work, the ionic liquid triethylamine-bonded sulfonic acid {[Et3N–SO3H]Cl}, N,N-diethyl-N-sulfoethanammonium chloride was used as a green acidic homogeneous catalyst to synthesis of 3,4-dihydropyrimidin-2(1H)-ones and 3,4-dihydropyrimidin-2(1H)-thiones as two categories of heterocycles, from aldehyde, dicarbonyl compound and urea or thiourea throughout the one-pot three components cycloc...

Journal: :Acta Crystallographica Section A Foundations of Crystallography 2009

2015
Giancarlo Franciò Ulrich Hintermair Walter Leitner

Solution-phase catalysis using molecular transition metal complexes is an extremely powerful tool for chemical synthesis and a key technology for sustainable manufacturing. However, as the reaction complexity and thermal sensitivity of the catalytic system increase, engineering challenges associated with product separation and catalyst recovery can override the value of the product. This persis...

ramin rezaei, sara ahmadi sedigheh abdollahi

A green methodology for the development of the synthesis of dihydropyrimidinones via a clean multi-component Biginelli reaction by using cyclohexane-1,4-diyl bis (hydrogen sulfate) (CDBH) as an effective catalyst in water and solvent-free conditions was reported. This sulfonated catalyst is an efficient and environmentally benign homogeneous catalysts which characterized by using different tech...

2014
Catharina Paukner Krzysztof K. K. Koziol

We report a new strategy towards the control of carbon nanotube (CNT) structure and continuous fibre formation using a floating catalyst direct spinning CVD process. In the procedures used to date, a sulphur promoter precursor is added to significantly enhance the rate of CNT formation in the floating catalyst synthesis. Within the reaction zone, the rapidly grown nanotubes self-assemble into b...

A homogeneous ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate doped with LiCl ([BMIm]BF4-LiCl) was found as catalyst solvents for the synthesis of dicoumarols by the condensation of 4-hydroxycoumarin and aldehyde at 80 ˚C. In this field, several types of aromatic aldehyde, containing electron-withdrawing groups as well as electron-donating groups, were rapidly changed to the correspo...

Journal: :Angewandte Chemie 2013
Chang-Bin Yu Yong-Gui Zhou

Hydrogenolysis is an important synthetic method in organic chemistry, and has been widely applied in industrial processes, natural product synthesis, and the removal of waste materials. In practice, most hydrogenolysis reactions have been used for the synthesis of racemic or achiral compounds. Very few studies on asymmetric homogeneous hydrogenolysis have been reported. The first example, repor...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان همدان - دانشگاه پیام نور مرکز همدان (واحد فامنین) - دانشکده علوم پایه 1389

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