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12 Jul 12:26

Stretchable supramolecular hydrogels with triple shape memory effect

Chem. Sci., 2016, 7,6715-6720
DOI: 10.1039/C6SC02354A, Edge Article
Open Access Open Access
Creative Commons Licence&nbsp This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Xiaoxia Le, Wei Lu, Jing Zheng, Dingyi Tong, Ning Zhao, Chunxin Ma, He Xiao, Jiawei Zhang, Youju Huang, Tao Chen
Here, we present a novel mechanical stretchable supramolecular hydrogel with a triple shape memory effect at the macro/micro scale.
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05 Jul 11:27

NHPI/tert-butyl nitrite: A highly efficient metal-free catalytic system for aerobic oxidation of alcohols to carbonyl compounds using molecular oxygen as the terminal oxidant

Publication date: 5 August 2016
Source:Catalysis Communications, Volume 83
Author(s): Yongke Hu, Lei Chen, Bindong Li
A highly practical metal-free catalytic system has been developed for aerobic oxidation of alcohols to corresponding ketones and aldehydes using catalytic amount of N-hydroxyphthalimide (NHPI) and tert-butyl nitrite (TBN) with molecular oxygen serving as the terminal oxidant. A variety of aliphatic, aromatic, allylic, and heterocyclic alcohols were smoothly converted to desired products with moderate to excellent yields. Moreover, a possible radical mechanism was proposed.

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25 May 00:39

Organic radical functionalized SBA-15 as a heterogeneous catalyst for facile oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

Publication date: August 2015
Source:Journal of Molecular Catalysis A: Chemical, Volumes 404–405
Author(s): Neha Mittal , Grace M. Nisola , Jeong Gil Seo , Seong-Poong Lee , Wook-Jin Chung
Organic radical functionalized mesoporous silica was prepared by the immobilization of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) on ordered mesoporous silica (SBA-15) and applied as a heterogeneous catalyst (TEMPO-SBA-15) for the synthesis of 2,5-diformylfuran (2,5-DFF) from 5-hydroxymethylfurfural (5-HMF). A 73 % 2,5-DFF yield was obtained from 5-HMF oxidation under mild reaction conditions in ethyl acetate with the addition of [bis(acetoxy) iodo]benzene (BAIB) and acetic acid as co-oxidants in an oxygen-rich environment. The presence of BAIB and oxygen facilitated the in-situ regeneration of TEMPO (the hydroxylamine form) whereas acetic acid addition aided in the initial formation of oxoammonium form of TEMPO, which was responsible for facile 5-HMF oxidation. All reaction components were found critical in maximizing the 2,5-DFF yield. The pore size distribution and architecture of SBA-15 played essential roles for the diffusive transport of reactants and products and resulted in improved reaction selectivity. Aside from these advantages, TEMPO-SBA-15 catalyst was easily separated and re-used several times with negligible loss in its catalytic activity. The prepared heterogeneous TEMPO-SBA-15 is an efficient catalyst that offers a sustainable route for 2,5-DFF production.

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