نتایج جستجو برای: base catalyst

تعداد نتایج: 299630  

A new dimeric orthopalladated complex was synthesized via reaction of 2,3-dimethoxy benzaldehyde oxime with palladium chloride and lithium chloride in methanol as solvent and sodium acetate as base at room temperature. The catalytic activity of this dimeric [Pd{C6H2(-CH=NOH)-(OMe)2-2,3}(µ-Cl)]2 complex as an efficient, air, and moisture tolerant catalyst was investigated in Mizoroki–Heck cross ...

Mir Abdullah S. Sadiadi Saved Mojtaba Moosavi Shokofe Aghabevzi

The transesterification process of trimethylphosphate with ethanol and isopropanol is examined. It is found that the reaction does not proceed in the absence of base even at temperature up to 100°C, whereas in the presence of sodium alkoxide as a catalyst it takes place at room temperature leading to a mixture of mono-,bi-, tri-substitute esters as well as the minor by-products resulting from t...

Journal: :journal of chemical and petroleum engineering 2015
kambiz tahvildari tahereh hajy heidar

due to the high price of virgin vegetable oils and the drawbacks of the homogeneous catalytic transesterification, in this work an economically profitable alternative process was proposed for biodiesel synthesis in which transesterification of the low-cost waste cooking oil (wco) with methanol in a heterogeneous system was done. alumina impregnated with sodium hydroxide was utilized as a solid ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2010
Hongming Li Xiaofeng Liu Fanghui Wu Liang Tang Li Deng

Complementary to enantioselective transformations of planar functionalities, catalytic desymmetrization of meso compounds is another fundamentally important strategy for asymmetric synthesis. However, experimentally established stereochemical models on how a chiral catalyst discriminates between two enantiotopic functional groups in the desymmetrization of a meso substrate are particularly lack...

Journal: :The Journal of organic chemistry 2017
Pengcheng Liu Ran Liang Lei Lu Zhentao Yu Feng Li

A cyclometalated iridium(III) complex containing a N∧C∧N-coordinating terdentate ligand [Ir(dpyx-N,C,N)Cl(μ-Cl)]2 was found to be a general and highly effective catalyst for the α-alkylation of ketones and N-alkylation of amines with alcohols. In the presence of catalyst (1 mol % Ir) and base (0.2-0.5 equiv), a variety of desirable products were obtained in good yields under an air atmosphere. ...

2011
Dragos Tutunea

In this paper the transesterification of palm oil with methanol in the presence of NaOH as a catalyst was conducted in an experimental biodiesel installation. The kinetics of base-catalyzed transesterification of palm oil based on parameters such as oil and alcohol ratio, catalyst concentration and temperature were investigated to optimize the biodiesel production rate. Although, transesterific...

Journal: :Forensic science international 2002
S Klemenc

In this paper, we describe an acetylating method for fast synthesis of heroin from morphine in the presence of 4-dimethylaminopyridine (4-DMAP) as a catalyst. In the reaction which led to heroin formation, the morphine base was subjected to a solution made up of 4-DMAP (catalyst), methylene chloride (solvent) and acetic anhydride (acetylating agent). We showed that in comparison with classic ac...

An organosuperbase (N,N-dimethylbiguanide) immobilized on mesoporous and magnetically separable silica supports, was found for the first time, to act as a highly-stable, scalable and efficient heterogeneous catalyst for the Henry reaction under mild and neutral condition. Several factors such as catalyst amount, solvent and reaction time concerning the reactivity were also discussed. The proced...

Journal: :Dalton transactions 2012
Yilin Sun Guangming Wu Dinghai Cen Yaofeng Chen Limin Wang

Four multitopic Schiff-base ligand precursors were synthesized via condensation of 4,4'-diol-3,3'-diformyl-1,1'-diphenyl or 1,3,5-tris(4-hydroxy-5-formylphenyl)benzene with 2,6-diisopropylaniline or 2,6-dimethylaniline. Amine elimination reactions of Ln[N(SiMe(3))(2)](3) (Ln = La, Nd, Sm or Y) with these multitopic ligand precursors gave ten heterogeneous rare-earth metal catalysts. These heter...

Journal: :Dalton transactions 2013
Daniel Canseco-Gonzalez Martin Albrecht

A series of Ru(II) (η(6)-arene) complexes with 1,2,3-triazolylidene ligands comprising different aryl and alkyl wingtip groups have been prepared and characterized by NMR spectroscopy, microanalysis, and in one case by X-ray diffraction. All complexes are active catalyst precursors for the oxidation of alcohols to the corresponding aldehydes/ketones without the need of an oxidant or base as add...

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