نتایج جستجو برای: metal free catalyst

تعداد نتایج: 733614  

2016
Sergey S. Zalesskiy Nikita S. Shlapakov Valentine P. Ananikov

The carbon-sulfur bond formation reaction is of paramount importance for functionalized materials design, as well as for biochemical applications. The use of expensive metal-based catalysts and the consequent contamination with trace metal impurities are challenging drawbacks of the existing methodologies. Here, we describe the first environmentally friendly metal-free photoredox pathway to the...

Journal: :Organic & biomolecular chemistry 2014
Liang Gong Li-Juan Xing Tong Xu Xue-Ping Zhu Wen Zhou Ning Kang Bin Wang

An oxidative olefination reaction between aliphatic primary amines and benzylic sp(3) C-H bonds has been achieved using N-bromosuccinimide as catalyst and tert-butyl hydroperoxide as oxidant. The olefination proceeds under mild metal-free conditions through direct deamination and benzylic C-H bond activation, and provides easy access to biologically active 2-styrylquinolines with (E)-configurat...

Journal: :Organic & biomolecular chemistry 2015
Wenbo Liu Chenjiang Liu Yonghong Zhang Yadong Sun Ablimit Abdukadera Bin Wang He Li Xuecheng Ma Zengpeng Zhang

The heterocyclic ionic liquid-catalyzed direct oxidative amination of benzylic sp(3) C-H bonds via intermolecular sp(3) C-N bond formation for the synthesis of N-alkylated azoles under metal-free conditions is reported for the first time. The catalyst 1-butylpyridinium iodide can be recycled and reused with similar efficacies for at least eight cycles.

Journal: :Chemical communications 2015
Jiangyong Diao Hongyang Liu Jia Wang Zhenbao Feng Tong Chen Changxi Miao Weimin Yang Dang Sheng Su

Reduced porous graphene oxide as a metal free catalyst was selected for the oxidative dehydrogenation of ethylbenzene to styrene. It showed the best catalytic performance compared with other carbon materials (routinely reduced graphene oxide, graphite powder and oxidized carbon nanotubes) and commercial iron oxide.

Journal: :Dalton transactions 2012
Ghazi Ghattas Dianjun Chen Fangfang Pan Jürgen Klankermayer

A camphor based chiral phosphonium hydrido borate zwitterion was synthesised and successfully applied in the enantioselective hydrogenation of imines with selectivities up to 76% ee. The high stability of the novel chiral FLP-system enables effective recycling of the metal-free catalyst.

Journal: :Journal of lipid research 1961
F W HEATON N URI

The connection between metal catalysis and the initiation step in autoxidation is emphasized. The formation of free radicals occurs in reactions involving not only various valency states, but also oxygen-complexes of the catalyst. The kinetics of the initial phase of the metal-catalyzed aerobic oxidation of linoleic acid are examined in detail, and a number of mechanisms postulated. The rate co...

Journal: :Chemical communications 2015
Ali Han Huanlin Chen Zijun Sun Jun Xu Pingwu Du

For the first time, noble-metal-free nickel phosphide (Ni2P) was used as an excellent catalyst precursor for water oxidation catalysis. The lowest onset potential was observed at ∼1.54 V (vs. RHE) and a Tafel slope of 60 mV dec(-1) was obtained in alkaline solution (pH = 13.6).

Journal: :Chemical communications 2013
Hongqi Sun Yuxian Wang Shizhen Liu Lei Ge Li Wang Zhonghua Zhu Shaobin Wang

Nitrogen (5.61 at%) doped reduced graphene oxide synthesized via a facile method was demonstrated as a superior metal-free catalyst for activation of peroxymonosulfate. Codoping with boron would further enhance the catalytic activity and the stability, providing a promising green material for environmental remediation.

2017
Andrea Guerrero-Corella Ana María Martinez-Gualda Fereshteh Ahmadi Enrique Ming Alberto Fraile José Alemán

The photocatalyzed synthesis of sulfoxides from alkenes and thiols has been carried out using Eosin Y. This is a metal-free method which uses a low catalyst loading, atmospheric oxygen as the oxidant, and visible light conditions (green light). A mechanism has been proposed that is consistent with the experimental results.

Journal: :Chemical communications 2014
Elias Feghali Thibault Cantat

The first metal-free reduction of lignin model compounds is described. Using inexpensive Et3SiH, PMHS and TMDS hydrosilanes as reductants, α-O-4 and β-O-4 linkages are reduced to primary alcohols and phenols under mild conditions using B(C6F5)3 as an efficient catalyst.

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