نتایج جستجو برای: Basic heterogeneous catalysts

تعداد نتایج: 423845  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - پژوهشکده علوم 1388

heteropoly acids (hpa) and their salts have advantages as catalysts which make them both economically and environmentally attractive, strong br?nsted acidity, exhibiting fast reversible multi-electron redox transformations under rather mild conditions, very high solubility in polar solvents, fairly high thermal stability in the solid states, and efficient oxidizing ability, so that they are imp...

2011
Yogesh C. Sharma Bhaskar Singh John Korstad

Heterogeneous catalysts are now being tried extensively for biodiesel synthesis. These catalysts are poised to play an important role and are perspective catalysts in future for biodiesel production at industrial level. The review deals with a comprehensive list of these heterogeneous catalysts which has been reported recently. The mechanisms of these catalysts in the transesterification reacti...

2014
Ken Motokura Toshihide Baba Yasuhiro Iwasawa

This chapter deals with acid–base bifunctional heterogeneous catalyst surfaces with organofunctional groups. One of the most important issues for bifunctional heterogeneous catalysis is the coexistence of incompatible catalytic species, such as acid and base, nearby on a same solid particle surface. In nucleophilic reactions, acid–base bifunctional catalysts enable the activation of both nucleo...

Journal: :Modern chemistry 2022

The products of the reactions ethylene oxide with fatty alcohols, acids and amines are great industrial importance. They include surfactants, plasticizers insecticides. can be generally represented as oligomerization. Interaction between alcohols proceed in presence acidic well basic catalysts; main distinction being quantitative distribution reaction products. In catalysts rate increases molec...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1391

in this thesis, we exploit a simple and suitable method for immobilization of copper(ii) complex of 4?-phenyl-terpyridine on activated multi-walled carbon nanotubes [amwcnts-o-cu(ii)-phtpy]. this nanostructure was characterized by various physico-chemical techniques. to ensure the efficiency and fidelity of copper species, the implementation of three-component strategies in click-chemistry all...

Journal: :Chemistry 2008
Ken Motokura Mitsuru Tomita Mizuki Tada Yasuhiro Iwasawa

Acid-base bifunctional heterogeneous catalysts were prepared by the reaction of an acidic silica-alumina (SA) surface with silane-coupling reagents possessing amino functional groups. The obtained SA-supported amines (SA-NR2) were characterized by solid-state 13C and 29Si NMR spectroscopy, FT-IR spectroscopy, and elemental analysis. The solid-state NMR spectra revealed that the amines were immo...

2012
Feng Guo Zhen Fang

Biodiesel is usually produced by transesterification of vegetable oils or animal fats with chemical catalysts, especially in the presence of strong acidic or basic solutions, such as hydrochloric acid, sulphuric acid, sodium hydroxide, sodium methoxide and potassium hydroxide. Homogeneous alkali catalysts can convert triglycerides to their corresponding fatty acid methyl esters (FAMEs) with hig...

Journal: :Chemical communications 2016
Chengcheng Tian Xiang Zhu Carter W Abney Ziqi Tian De-En Jiang Kee Sung Han Shannon M Mahurin Nancy M Washton Sheng Dai

The design and synthesis of metal-free heterogeneous catalysts for efficient hydrogenation remains a great challenge. Here we report a novel approach to create conjugated nanoporous polymers with efficient hydrogenation activities toward unsaturated ketones by leveraging the innate steric encumbrance. The steric bulk of the framework as well as the local sterics of the Lewis basic sites within ...

Journal: :iranian journal of catalysis 2015
rajesh singh renu bala robita duvedi sahil kumar

amidoalkyl-2-naphthols as synthetic intermediates play an important role in medicinal chemistry due to their remarkable biological and many pharmacological properties. owing to the versatile biological activities, industrial and synthetic applications of these compounds, introduction of an alternative methodology is urgent in synthetic organic chemistry. low yield and harsh reaction conditions ...

2013
H. Hartati Mardi Santoso Sugeng Triwahyono Didik Prasetyoko

This paper reviews various types of heterogeneous acid-base catalysts for fragrances preparation. Catalytic activities of the various types of heterogeneous acid and base catalysts in fragrances preparation, i.e. nonzeolitic, zeolitic, and mesoporous molecular sieves, have been reported. Generally, heterogeneous acid catalysts are more commonly used in fragrance synthesis as compared to heterog...

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