نتایج جستجو برای: basic heterogeneous catalysts

تعداد نتایج: 423845  

Journal: :Reactive & functional polymers 2010
Lev Bromberg Ezio Fasoli Michael Alvarez T Alan Hatton Gabriel L Barletta

Polycationic systems based on poly(hexamethylene biguanide) (PHMBG), branched polyethyleneimine (PEI) and poly(N-vinylguanidine) (PVG) have been evaluated as heterogeneous catalysts for the transesterification of sunflower oil by methanol. Insoluble networks are synthesized via crosslinking of PHMBG by either 4,4'-methylenebis(N,N-diglycidylaniline) or polyisocyanate prepolymer, PEI with sebaco...

Journal: :iranian chemical communication 2015
hadi jabbari jabbar khalafy peyman najafi moghadam

a most effective and less energy demanding method of producing fatty esters, diol esters, by esterifying fatty acids, with neopentyl and ethylenglycol alcohols in the presence of an acidic ion exchange resin catalyst(polyestyrendivinylbenzensulfated) was investigated at elevated temperature. in this process an azeotroping agent, toluene, was used to facilitate continuous removal of water by dis...

Journal: :polyolefins journal 2015
helmut g. alt

eethylene polymerization catalysts became available in an enormous variety. the challenge in this research is to find catalysts that are able to connect ethylene molecules in such a way that not only linear chains are produced but variations like branched materials that possess very interesting mechanical properties like linear low density polyethylene (lldpe). in this contribution, three diffe...

Journal: :Nature chemistry 2012
Elad Gross Jack Hung-Chang Liu F Dean Toste Gabor A Somorjai

A combination of the advantages of homogeneous and heterogeneous catalysis could enable the development of sustainable catalysts with novel reactivity and selectivity. Although heterogeneous catalysts are often recycled more easily than their homogeneous counterparts, they can be difficult to apply in traditional organic reactions and modification of their properties towards a desired reactivit...

Journal: :Molecules 2010
Kiyotomi Kaneda Takato Mitsudome Tomoo Mizugaki Koichiro Jitsukawa

In this review, we describe the development by our research group of highly functionalized heterogeneous Olympic medal metal (gold, silver, and copper) nanoparticle catalysts using hydrotalcite as a support, aimed towards Green and Sustainable Chemistry. Olympic medal metal nanoparticles can cooperate with the basic sites on the hydrotalcite surface, providing unique and high performance cataly...

Journal: :Journal of the American Chemical Society 2012
Fujian Liu Liang Wang Qi Sun Longfeng Zhu Xiangju Meng Feng-Shou Xiao

Homogeneous catalysts usually show higher catalytic activities than heterogeneous catalysts because of their high dispersion of catalytically active sites. We demonstrate here that heterogeneous catalysts of ionic liquids functionalized on superhydrophobic mesoporous polymers exhibit much higher activities in transesterification to form biodiesel than homogeneous catalysts of the ionic liquids ...

Journal: :Angewandte Chemie International Edition 2005

Journal: :Angewandte Chemie 2005
John Meurig Thomas Robert Raja Dewi W Lewis

Intellectually, the advantages that flow from the availability of single-site heterogeneous catalysts (SSHC) are many. They facilitate the determination of the kinetics and mechanism of catalytic turnover-both experimentally and computationally-and make accessible the energetics of various intermediates (including short-lived transition states). These facts in turn offer a rational strategic pr...

A. Esmaeilzadeh A. Shojaeian M. Hatami M. Qandalee, P. Biparva

Two-component reaction of 2-aminobenzophenones with acetylenic esters in the presence of γ-Al2O3 and Cu/ZnO as suitable heterogeneous catalysts has been studied. Nano γ-Al2O3 and Cu/ZnO showed high activities when used as surface catalysts for the synthesis of quinoline derivatives. After completion of the reaction, the catalyst was ...

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