نتایج جستجو برای: Acidic catalyst

تعداد نتایج: 77393  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - دانشکده علوم 1390

abstract in first part of this project, the use of a new and biguanid-like catalyst supported on silica as a recyclable catalyst provides a new route for the synthesis of a variety of arylalkylidene rhodanine derivatives through knoevenagle reaction in at present of solvent at room temperature. rhodanine derivatives and especially arylalkylidene rhodanines have proven to be attractive compound...

Journal: :iranian journal of catalysis 2012
abdol r. hajipour fatemeh rafiee

a simple and mild method for tetrahydropyranylation of alcohols is reported at room temperature using a catalytic amount of 3-methylimidazolinium hydrogensulfate([hmim]hso4) as a green, efficient and reusable catalyst. using solvent-free conditions, non-toxic and inexpensive materials, modest and clean work-up, short reaction times and high yields of the products are the advantages of this method.

2014
Ga Vin Kim WoonYong Choi DoHyung Kang ShinYoung Lee HyeonYong Lee

The aim of this study was to increase the yield of biodiesel produced by Scenedesmus sp. through in situ transesterification by optimizing various process parameters. Based on the orthogonal matrix analysis for the acidic catalyst, the effects of the factors decreased in the order of reaction temperature (47.5%) > solvent quantity (26.7%) > reaction time (17.5%) > catalyst amount (8.3%). Based ...

Bijan Mombeni Goodajdar, Maryam Keshtibanian

In this study, a novel acidic magnetic dicationic ionic liquid was prepared in three steps to serve as a green  catalyst  in  organic  synthesis.  The  newly  synthesized  catalyst  was  characterized UV- VIS,  and  VSM  analysis.  Additionally,  the  decomposition  steps  acatalyst  were investigated by thermal  analysis  techniques  (TGA/DSC).  The  synthesized  acidic magnetic dication...

Journal: :The Journal of organic chemistry 2012
Lars P C Nielsen Stephan J Zuend David D Ford Eric N Jacobsen

The (salen)Co(III)-catalyzed hydrolytic kinetic resolution (HKR) of terminal epoxides is a bimetallic process with a rate controlled by partitioning between a nucleophilic (salen)Co-OH catalyst and a Lewis acidic (salen)Co-X catalyst. The commonly used (salen)Co-OAc and (salen)Co-Cl precatalysts undergo complete and irreversible counterion addition to epoxide during the course of the epoxide hy...

Journal: :caspian journal of chemistry 2014
moslem lakouraj zari fallah mahmood tajbakhsh vahid hasantabar

bifunctional acidic ionic liquids, having both h-imidazolium and -so3h groups as cation moieties (h-bfails) and cf3so3- as anion, were synthesized in high yields. these h-bfails showed significant hydrophilic properties, lower acidity and higher thermal stability relative to common ionic liquids, due to their unique structures. the (propyl or butyl-3-sulfonic) imidazolium trifluoromethane sulfo...

Journal: :Dalton transactions 2015
Lisong Chen Xiangzhi Cui Qingsong Wang Xiaohua Zhang Gang Wan Fangming Cui Chenyang Wei Jianlin Shi

The design of a non-precious metal oxygen reduction reaction (ORR) catalyst of high activity and long durability in acidic electrolyte is of great importance for the development and commercialization of low-temperature fuel cells, which remains a great challenge to date. Here, we demonstrate a facile, scalable protocol for the controlled synthesis of CoxC encapsulated in carbon nanotubes as a n...

2016
Ambreen Aslam Tahira Aziz Mughal

Microalgae have been receiving worldwide attention as promising feedstock for production of carbon neutral biodiesel. As an alternative fuel, biodiesel is very imperative for the sustainable development of mankind. Biodiesel production process is generally carried out through upstream and downstream processing to generate cellular biomass, extracted oil and finally transesterification reaction....

Journal: :Journal of the American Chemical Society 2006
Daisuke Nakashima Hisashi Yamamoto

A highly reactive and acidic chiral Brønsted acid catalyst, chiral N-triflyl phosphoramide, was developed. Highly enantioselective Diels-Alder reaction of alpha,beta-unsaturated ketone with silyloxydiene was demonstrated using this chiral Brønsted acid catalyst.

2015
Robin B Bedford Steven J Durrant Michelle Montgomery

The regiodivergent palladium-catalyzed C-H arylation of pyrazolo[1,5-a]pyrimidine has been achieved, wherein the switch in regioselectivity between positions C3 and C7 is under complete catalyst control. A phosphine-containing palladium catalyst promotes the direct arylation at the most acidic position (C7), whereas a phosphine-free catalyst targets the most electron-rich position (C3).

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