نتایج جستجو برای: acidic catalyst

تعداد نتایج: 77393  

Journal: :iranian journal of science and technology (sciences) 2015
s. rezayati

an efficient and chemoselective procedure for the preparation of 1, 1-diacatates (acylals) from various aldehydes with acetic anhydride in the presence of brønsted acidic ionic liquid [msei]cl as a reusable catalytic system under solvent-free condition at room temperature and short periods of times with excellent yields will be described. the catalyst was easily separated in simple work-up and ...

Journal: :Sustainable Energy and Fuels 2022

The valorisation of technical lignins by conversion is herein demonstrated using an acidic deep eutectic solvent in the absence or presence a co-catalyst (H 2 SO 4 H O ).

Ionic liquid 1,3-disulfonic acid imidazolium trifluoroacetate ([Dsim][TFA]) has been exploited as a highly efficient catalyst for the one-pot pseudo five-component reaction of phenylhydrazine (2 eq.) with ethyl acetoacetate (2 eq.) and arylaldehydes (1 eq.) in ethanol (reflux conditions). In this reaction, 4,4′‐(arylmethylene)‐bis(3‐methyl‐1‐phenyl‐1H‐ pyrazol‐5‐ol)s have been obtained in high ...

Journal: :Chemical communications 2011
Nagatoshi Nishiwaki Shotaro Hirao Jun Sawayama Kazuhiko Saigo Kazuya Kobiro

α-Nitro-δ-keto nitriles and α-nitro-δ-keto ester were readily converted to diazabicyclo compounds having vicinal functionality upon treatment with diamines. The keto nitrile attracts the diamine nearby to an acidic hydrogen to cause the pseudo-intramolecular imination which proceeds efficiently without any catalyst at room temperature.

Journal: :Chemical communications 2013
Xiujuan Sun Ping Song Tao Chen Jing Liu Weilin Xu

Fluorine-doped carbon blacks as inexpensive, high performance electrocatalysts for acidic oxygen reduction reaction were synthesized. The performance of the optimal catalyst (BP-18F) is close to the level of other reported best non-Pt electrocatalysts in acid, but with superlow H2O2 yield (<0.1%) ever. Their high performance is confirmed by quantum calculations.

Journal: :Chemical communications 2003
Ryoji Noyori Masao Aoki Kazuhiko Sato

Aqueous H2O2 is an ideal oxidant, when coupled with a tungstate complex and a quaternary ammonium hydrogensulfate as an acidic phase-transfer catalyst. It oxidizes alcohols, olefins, and sulfides under organic solvent- and halide-free conditions in an economically, technically, and environmentally satisfying manner.

Journal: :Journal of the American Chemical Society 2005
Stefan France Meha H Shah Anthony Weatherwax Harald Wack Justine P Roth Thomas Lectka

We report a mechanistically based study of bifunctional catalyst systems in which chiral nucleophiles work in conjunction with Lewis acids to produce beta-lactams in high chemical yield, diastereoselectivity, and enantioselectivity. Chiral cinchona alkaloid derivatives work best when paired with Lewis acids based on Al(III), Zn(II), Sc(III), and, most notably, In(III). Homogeneous bifunctional ...

2008
Yongkoo Seol Iraj Javandel

28 Fenton’s reagent, a solution of hydrogen peroxide and ferrous iron catalyst, is used for an 29 in-situ chemical oxidation of organic contaminants. Sulfuric acid is commonly used to 30 create an acidic condition needed for catalytic oxidation. Fenton’s reaction often involves 31 pressure buildup and precipitation of reaction products, which can cause safety hazards 32 and diminish efficiency....

Journal: :iranian journal of catalysis 2015
leila moradi gholam reza najafi hakimeh saeidiroshan

multiwalled carbon nanotubes (mwcnts) have been functionalized with -so3h groups using new three steps chemical routes. firstly, oh groups have been attached to cnt surfaces through a radical reaction. the second step involves converting the hydroxyl groups into the oxide one and last step included the attachment of –so3h groups on the mwcnts surfaces in the presence of 1-butyl-3-methyl imidazo...

Journal: :iranian journal of hydrogen & fuel cell 2015
mehdi kheirmand abolfath eshghi

reduced graphene oxide film was synthesized on a glassy carbon electrode by electro reduction of graphene oxide powders in aqueous solution. then platinum nano particles were deposited on reduced graphene oxide film that was deposited on the glassy carbon electrode via electro reduction of platinum salt. the physical morphology of the platinum on reduced graphene oxide film was evaluated by sca...

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