16812-36-5Relevant articles and documents
Phenol-based lipophilic fluorescent antioxidant indicators: A rational approach
Krumova, Katerina,Oleynik, Paul,Karam, Pierre,Cosa, Gonzalo
, p. 3641 - 3651 (2009)
(Chemical Equation Presented) The reactivity, electrochemistry, and photophysics of the novel antioxidant indicator B-TOH, a BODIPY-α- tocopherol adduct, were investigated. We also studied a newly prepared BODIPY-3,5-di-tert-butyl-4-hydroxybenzoic acid ad
Thermally recyclable polylactic acid/cellulose nanocrystal films through reactive extrusion process
Dhar, Prodyut,Tarafder, Debashis,Kumar, Amit,Katiyar, Vimal
, p. 268 - 282 (2016)
This paper reports a single step reactive extrusion process for fabrication of thermally stable, polylactic acid grafted cellulose nanocrystal(PLA-g-CNC) nanocomposite films using dicumyl peroxide as crosslinking agent. PLA-g-CNC nanocomposites were recycled without significant breakage in the molecular structure of PLA. The grafted PLA chains shields the sulfate and hydroxyl groups of CNCs, thereby enhancing the compatibilization with PLA matrix and preventing thermal degradation during extrusion. NMR and FTIR spectroscopy studies showed that amorphous PLA chains grafted on CNC surface through C-C bonds formation. Presence of such chemical crosslinks led to efficient transfer of modulus of CNCs to PLA matrix, thereby improving the tensile strength and young's modulus by～40% and～490%,respectively. Recycling of PLA-g-CNC doesn't alter the molecular weight, thermal, crystallization and mechanical properties of the nanocomposites significantly. Therefore, the current study provides a novel approach for fabricating CNC-reinforced-PLA nanocomposites which can be easily recycled and reused for multiple cycles.
Cumene hydroperoxide decomposition in the presence of organic zinc salts
Nurullina,Batyrshin,Kharlampidi
, p. 349 - 352 (2006)
Cumene hydroperoxide degradation in chlorobenzene in the presence of zinc naphthenate was studied. It was found and kinetically corroborated that the degradation is preceded by the formation of an intermediate complex of the hydroperoxide with the catalys
Radical scavenging reactivity of catecholamine neurotransmitters and the inhibition effect for DNA cleavage
Kawashima, Tomonori,Ohkubo, Kei,Fukuzumi, Shunichi
, p. 675 - 680 (2010)
Neurotransmitters such as catecholamines (dopamine, L-dopa, epinephrine, norepinephrine) have phenol structure and scavenge reactive oxygen species (ROS) by hydrogen atom transfer (HAT) to ROS. Radical scavenging reactivity of neurotransmitters with galvinoxyl radical (G?) and cumyloxyl radical (R?)in acetonitrile at 298 K was determined by the UV-vis spectral change. The UV-vis spectral change for HAT from catecholamine neurotransmitters to G? was measured by a photodiode array spectrophotometer, whereas HAT to much more reactive cumylperoxyl radical, which was produced by photoirradiation of dicumyl peroxide, was measured by laser flash photolysis. The second-order rate constants (kGO) were determined from the slopes of linear plots of the pseudo-first-order rate constants vs concentrations of neurotransmitters. The kGO value of hydrogen transfer from dopamine to G? was determined to be 23 M-1 s-1, which is the largest among examined catecholamine neurotransmitters. This value is comparable to the value of a well-known antioxidant: (+)-catechine (27 M-1 s-1). The kGO value of hydrogen transfer from dopamine to GO* increased in the presence of Mg2+ with increasing concentration of Mg2+. Such enhancement of the radical scavenging reactivity may result from the metal ion-promoted electron transfer from dopamine to the galvinoxyl radical. Inhibition of DNA cleavage with neurotransmitters was also examined using agarose gel electrophoresis of an aqueous solution containing pBR322 DNA, NADH, and catecholamine neurotransmitters under photoirradiation. DNA cleavage was significantly inhibited by the presence of catecholamine neurotransmitters that can scavenge hydroperoxyl radicals produced under photoirradiation of an aerated aqueous solution of NADH. The inhibition effect of dopamine on DNA cleavage was enhanced by the presence of Mg2+ because of the enhancement of the radical scavenging reactivity.
Does Metal Ion Complexation Make Radical Clocks Run Fast? An Experimental Perspective
Abdel Latif, Marwa K.,Spencer, Jared N.,Paradzinsky, Mark,Tanko, James M.
, p. 9682 - 9686 (2017)
The rate constant for the β-scission of the cumyloxyl radical (kβ) was measured in the presence of various added electrolytes in acetonitrile and DMSO solvent. The results show that in CH3CN, kβ increases in the presence of added electrolyte, roughly paralleling the size of the cation: Li+ > Mg2+ ≈ Na+ > nBu4N+ > no added electrolyte. As suggested by Bietti et al. earlier, this effect is attributable to stabilizing ion-dipole interactions in the transition state of the developing carbonyl group, a conclusion further amplified by MO calculations (gas phase) reported herein. Compared to the gas phase predictions, however, this effect is seriously attenuated in solution because complexation of the cation to the electrophilic alkoxyl radical (relative to the solvent, CH3CN) is very weak. Because the interaction of Li+ and Na+ is much stronger with DMSO than with CH3CN, addition of these ions has no effect on the rate of β-scission.
Reactivity and Product Analysis of a Pair of Cumyloxyl and tert-Butoxyl Radicals Generated in Photolysis of tert-Butyl Cumyl Peroxide
Oyama, Ryoko,Abe, Manabu
, p. 8627 - 8638 (2020/07/21)
Alkoxyl radicals play important roles in various fields of chemistry. Understanding their reactivity is essential to applying their chemistry for industrial and biological purposes. Hydrogen-atom transfer and C-C β-scission reactions have been reported from alkoxyl radicals. The ratios of these two processes were investigated using cumyloxyl (CumO?) and tert-butoxyl radicals (t-BuO?), respectively. However, the products generated from the pair of radicals have not been investigated in detail. In this study, CumO? and t-BuO? were simultaneously generated from the photolysis of tert-butyl cumyl peroxide to understand the chemical behavior of the pair of radicals by analyzing the products and their distribution. Electron paramagnetic resonance and/or transient absorption spectroscopy analyses of radicals, including CumO? and t-BuO?, provide more information about the radicals generated during the photolysis of tert-butyl cumyl peroxide. Furthermore, the photoproducts of (3-(tert-butylperoxy)pentane-3-yl)benzene demonstrated that the ether products were formed in in-cage reactions. The triplet-sensitized reaction induced by acetophenone, which is produced from CumO?, clarified that the spin state did not affect the product distribution.
