6485-57-0Relevant articles and documents
Activation of Molecular Oxygen Using Durable Cobalt Encapsulated with Nitrogen-Doped Graphitic Carbon Shells for Aerobic Oxidation of Lignin-Derived Alcohols
Sun, Yuxia,Ma, Hong,Luo, Yang,Zhang, Shujing,Gao, Jin,Xu, Jie
, p. 4653 - 4661 (2018)
It has long been a challenge for activating O2 by transition-metal nanocatalysts, which might lose activity due to strong tendency for oxidation. Herein, O2 could be activated by durable encapsulated cobalt nanoparticles (NPs) with N-doped graphitic carbon shells (Co@N-C), but not by encapsulated cobalt NPs with graphitic carbon, exposed cobalt NPs supported on activated carbon, or N-doped carbon. Electron paramagnetic resonance, real-time in situ FTIR spectroscopy, and mass spectrometry measurements demonstrated the generation of the highly active superoxide radical, O2.?. This unique ability enables Co@N-C to afford an excellent catalytic performance in model aerobic oxidation of monomeric lignin-derived alcohols. Further analysis elucidated that encapsulated cobalt and nitrogen-doped graphitic carbon might contribute to the capacity through influencing the electronic properties of outer layers. Moreover, through isolation by N-doped graphitic carbon shells, the inner metallic cobalt NPs are inaccessible in term of either alcohols or oxygenated products, and a distinctive resistance to leaching and agglomeration has been achieved.
Radical-scavenging activity of butylated hydroxytoluene (BHT) and its metabolites
Fujisawa, Seiichiro,Kadoma, Yoshinori,Yokoe, Ichiro
, p. 189 - 195 (2004)
To clarify the radical-scavenging activity of butylated hydroxytoluene (BHT), a food additive, stoichiometric factors (n) and inhibition rate constants (kinh) were determined for 2,6-di-tert-butyl-4-methylphenol (BHT) and its metabolites 2,6-di-tert-butyl-p-benzoquinone (BHT-Q), 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHA-CHO) and 3,5-di-tert-butyl-4- hydroperoxy-4-methyl-2,5-cyclohexadiene-1-one (BHT-OOH). Values of n and k inh were determined from differential scanning calorimetry (DSC) monitoring of the polymerization of methyl methacrylate (MMA) initiated by 2,2′-azobis(isobutyronitrile) (AIBN) or benzoyl peroxide (BPO) at 70°C in the presence or absence of antioxidants (BHT-related compounds). The n values declined in the order BHT (1-2) > BHT-CHO, BHT-OOH (0.1-0.3) > BHT-Q (~0). The n value for BHT with AIBN was approximately 1.0, suggesting dimerization of BHT. The kinh values declined in the order BHT-Q ((3.5-4.6)×104 M-1 s-1) > BHT-OOH (0.7-1.9×104 M-1 s-1) > BHT-CHO ((0.4-1.7)×104 M-1 s-1) > BHT ((0.1-0.2)×104 M-1 s-1). The k inh for metabolites was greater than that for the parent BHT. Growing MMA radicals initiated by BPO were suppressed much more efficiently by BHT or BHT-Q compared with those initiated by AIBN. BHT was effective as a chain-breaking antioxidant.
Visible-Light-Mediated Additive-Free Decarboxylative Ketonization Reaction of Acrylic Acids: An Access to α-Thiocyanate Ketones
Wang, Zhi-Lv,Chen, Jie,He, Yan-Hong,Guan, Zhi
supporting information, p. 3741 - 3749 (2021/03/09)
Visible-light-mediated additive-free decarboxylative functionalization of acrylic acids has been developed. The reaction uses inexpensive organic dye 9,10-dicyanoanthracene as a photocatalyst and uses the ubiquitous dioxygen as both an oxygen source and an oxidant. Through this mild and environmentally friendly method, a series of important α-thiocyanate ketones can be generated from easily available acrylic acids and ammonium thiocyanate. In addition, the facile transformation of product α-thiocyanate ketones makes this method have great potential for application in organic and pharmaceutical chemistry.
Photo-Mediated Decarboxylative Ketonization of Atropic Acids with Sulfonyl Hydrazides: Direct Access to β-Ketosulfones
Chen, Jie,Allyson, Zoe G.,Xin, Jing-Rui,Guan, Zhi,He, Yan-Hong
supporting information, p. 2045 - 2051 (2020/02/11)
An efficient formation of synthetically and biologically relevant β-ketosulfones via a photo-mediated decarboxylative ketonization of atropic acids was disclosed. The approach features metal-free conditions, good functional group compatibility, readily available starting materials and the use of ubiquitous dioxygen as both oxygen source and oxidant. Furthermore, mechanistic studies reveal that the decarboxylative ketonization reaction proceeds via a radical mechanism and may involve a radical chain reaction. (Figure presented.).