نتایج جستجو برای: epoxidation catalyst

تعداد نتایج: 45578  

Journal: :Organic & biomolecular chemistry 2013
Filipe J S Duarte A Gil Santos

The asymmetric synthesis of vicinal diols is a very important process in organic chemistry, as it allows the preparation of a large variety of useful derivatives. One of the most interesting methods to accomplish this synthesis is the asymmetric epoxidation of activated olefins, catalysed by chiral organic or organometallic catalysts. In this paper we study, with computational tools, two possib...

Journal: :Chemistry 2007
Lei Zhang Hendrikus C L Abbenhuis Gijsbert Gerritsen Nollaig Ní Bhriain Pieter C M M Magusin Brahim Mezari Wei Han Rutger A van Santen Qihua Yang Can Li

A novel interfacial hybrid epoxidation catalyst was designed with a new immobilization method for homogeneous catalysts by coating an inorganic support with an organic polymer film containing active sites. The titanium silsesquioxane (TiPOSS) complex, which contains a single-site titanium active center, was immobilized successfully by in-situ copolymerization on a mesoporous SBA-15-supported po...

2013
Mohd Bismillah Ansari Eun-Young Jeong Sang-Eon Park

Tirazine based microporous polymeric (TMP) network was found to be an efficient metal-free catalyst for the epoxidation of styrene. The reactions were performed in water as an environmentally benign medium using H2O2 as a green oxidant at ambient temperature. The reaction afforded higher yield with 90% conversion of styrene and 98% selectivity to styrene oxide in 6 h. The triazine based micropo...

Journal: :Organic & biomolecular chemistry 2012
Sajjad Ahmad Andrew Sutherland

A multi-bond forming, three-step tandem process involving a palladium(II)-catalysed Overman rearrangement and a ring closing metathesis reaction has been utilised for the efficient synthesis of a 2,3,6,7-tetrahydro-3-amidoazepine. Substrate directed epoxidation or dihydroxylation of this synthetic intermediate has allowed the diastereoselective synthesis of hydroxylated 3-aminoazepanes includin...

Journal: :Angewandte Chemie 2021

Designing a stable and selective catalyst with high H2 utilisation is of pivotal importance for the direct gas-phase epoxidation propylene. This work describes facile one-pot methodology to synthesise ligand-stabilised sub-nanometre gold clusters immobilised onto zeolitic support (TS-1) engineer Au/TS-1 catalyst. A non-thermal O2 plasma technique used quick removal ligands limited increase in p...

2007
Paola Gava Anton Kokalj

S ri e o l a re n d o i i z S a t n u r e d t i n A I v a a l n o z u a c t S i-m a a z p n e e r c s s o eg n u o i c r e v i e rtut Modeling the catalyst selectivity in the ethylene epoxidation reaction A first principles study Thesis submitted for the degree of

Journal: :Chemistry 2011
Łukasz Albrecht Lars Krogager Ransborg Anna Albrecht Lennart Lykke Karl Anker Jørgensen

This study demonstrates the first enantioselective synthesis of hydroxyalkyl- and aminoalkyl-substituted imidazoles, oxazoles, and thiazoles. The approach developed utilizes a highly effective one-pot reaction cascade that consists of either an organocatalytic epoxidation or aziridination of α,β-unsaturated aldehydes coupled with a [3+2]-annulation, in which amidines, ureas, or thioureas act as...

2014
Phillip A. Lichtor Scott J. Miller

We describe mechanistic investigations of a catalyst (1) that leads to selective epoxidation of farnesol at the 6,7-position, remote from the hydroxyl directing group. The experimental lineage of peptide 1 and a number of resin-bound peptide analogues were examined to reveal the importance of four N-terminal residues. We examined the selectivity of truncated analogues to find that a trimer is s...

2017
Xiaochuan Zou Cun Wang Yue Wang Kaiyun Shi Zhongming Wang Dongwei Li Xiangkai Fu Marinos Pitsikalis

Chiral MnIII (salen) complex supported on modified ZPS-PVPA (zirconium poly(styrenephenylvinylphosphonate)) and ZPS-IPPA (zirconium poly(styrene-isopropenyl phosphonate)) were prepared using –CH2Cl as a reactive surface modifier by a covalent grafting method. The supported catalysts showed higher chiral induction (ee: 72%–83%) compared with the corresponding homogeneous catalyst (ee: 54%) for a...

The acidic group (-CO2H) of MultiWall Carbon Nanotube (MWCNT) converted to acyl chloride group (-COCl) producing of MVCNT@COCl. Then the reaction of MVCNT@COCl and MoO2(acac)2 resulted in direct immobilization of the MoO2(acac)2 and the formation of MVCNT@CO(acac)MoO2(acac) catalyst. In addition, the MVCNT@COCl was esterified...

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