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Showing 1 to 20 of 71 for “"Hydroquinone"”.
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Hydroquinone as an oxidation catalyst
Thesis (M.S.)--Michigan State College of Agriculture and Applied Science, 1926
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Studies of blends containing liquid crystalline polymers with PET and related investigations of hydroquinone/biphenol polysulfone systems
The investigation of structure-property behavior of extruded cast films prepared from blends of thermotropic liquid crystalline copolyesters with polyethylene terephthalate (PET). Data were obtained which showed not only the temperature dependence of the moduli and stress-strain behavior but also …
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Gas-Phase Formation of Environmentally Persistent Free Radicals from Thermal Degradation of Catechol, Hydroquinone, Phenols and Tobacco
Catechol, hydroquinone and Phenol are major constituents of the mainstream tobacco smoke. The toxicity of tobacco has been attributed to the ability of catechol and hydroquinone to undergo endogenous or exogenous redox cycling to form semiquinone type radicals responsible of Reactive Oxygen Species …
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Synthesis, Characterization and Structure - Property Relationships of Post - sulfonated Poly(arylene ether sulfone) Membranes for Water Desalination
… the polysulfone backbone on isolated rings of hydroquinone moiety, and on adjacent rings of biphenol moiety- and its effect on the transport and hydrated mechanical properties of the membranes. Selective post sulfonation of poly(arylene ether sulfone) in mild conditions was also found to be an …
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Synthesis and Characterization of Sulfonated Poly(arylene ether sulfone)s for Membrane Separations
… investigate poly(arylene ether sulfone)s with a hydroquinone unit that could be controllably post-sulfonated without degradation, providing a polymer with controlled sulfonation through controlling hydroquinone content. It also avoided the disadvantages noted previously in polymers with …
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Determination of illegal and toxic ingredients in face creams
… determine thirteen compounds of interest such as hydroquinone, kojic acid (KA), and steroids. Secondly, Inductively Coupled plasma mass spectrometry (ICP-MS) assisted with MARS 6 digester was employed to determine metals (mercury, lead, chromium, nickel, cadmium, arsenic, etc.). Lastly, the study …
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Synthesis and characteristics of polyarylene ether sulfones
… would vastly improve its solvent resistance. Hydroquinone polysulfone, homopolymer was reported to be semi-crystalline "as made". We thus synthesized and studied "random" copolymers obtained by reacting various mole ratio combinations of bisphenol-A and hydroquinone with dichlorodiphenyl …
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Synthesis and Properties of Novel Triptycene-containing Segmented Polyurethanes and Semicrystalline Polysulfone-polyester Multiblock Copolymers
… was carried out by using triptycene-1,4-hydroquinone bis(2-hydroxyethyl)ether (TD) as the chain extender. Segmented polyurethanes based on poly(tetramethylene glycol) (PTMG) of 1000 g/mol were synthesized using a two-step polymerization procedure. Hydroquinone bis(2-hydroxyethyl)ether …
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Synthesis and Characterization of Hydrophobic-Hydrophilic Multiblock Copolymers for Proton Exchange Membrane and Segmented Copolymer Precursors for Reverse Osmosis Applications
… synthesis and characterization of a novel hydroquinone-based random copolymer system precursor, which after post-sulfonation, shall form mono-sulfonated polysulfone materials with potential applications in reverse osmosis. The ratio of the amount of hydroquinone incorporated in the …
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The aqueous photochemistry of 4-chlorophenol
… together with smaller amounts of para-hydroquinone and 2-hydroxy-1,4-benzoquinone. The latter is found to be the dominant photoproduct at pH values above the pKa of 4-chlorophenol (9.4). A quantum yield for reaction of the 4-chlorophenol in neutral solution of 0.44 ± 0.1 has been …
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Segmented Aromatic Polymers Containing Thermally Reversible Linkages
… 2) entails the synthesis of 2-substituted hydroquinones, which are needed as monomers in the later stages. The novelty of our hydroquinone synthesis stems from the use of allylic and other alkenyl ethers as the source of the ring substituent, and from the utilization of catalytic …
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Synthesis and Characterization of Linear and Crosslinked Sulfonated Poly(arylene ether sulfone)s: Hydrocarbon-based Copolymers as Ion Conductive Membranes for Electrochemical Systems
… of water. One series contained solely hydroquinone as the phenolic monomer, while the second series contained a mixture of resorcinol and hydroquinone as phenolic comonomers. The polymers that contained only the hydroquinone monomer showed exceptionally good mechanical properties due to …
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Ultrafast Dynamics of Flavin Cofactor in Photolyase/Cryptochrome Family
… energy transfer from MTHF to the fully reduced hydroquinone FADH¯ occurs in 170 ps, but it takes 20 and 18 ps to the oxidized FAD and neutral semiquinone FADH<sup>•</sup>, respectively. The orientation factors were estimated from the acquired energy transfer rates and compared with values from …
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Mechanistic Study of Pollutant Degradation
… rate constant increased by about 2.3 times. Hydroquinone was the major observed reaction intermediate both in the presence and absence of hydrogen atom scavengers. Hydroquinone yields were substantially higher in the presence of hydrogen atom scavengers, suggesting that hydroxyl radical …
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Polymer- and Bioadditives-Assisted Synthesis and Surface Modification of Anisotropic Gold Nanocrystals
… biocompatibility. Chapter 2 discusses new hydroquinone-assisted seedless and seed-mediated protocols of gold nanorods (AuNRs) by incorporation of nanomolar concentration of distinct molecular weights of poly(vinylpyrrolidone) PVP after growth initiation. Surface chemistry characterization …
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Effects of phosphoroamides on transformations of urea nitrogen in soil
… for retarding urea hydrolysis in soils (PPD and hydroquinone);All six of the phosphoroamides evaluated compared favorably with hydroquinone as soil urease inhibitors and two of them, NBPT and DPCA, were superior to PPD for retarding urea hydrolysis, nitrite accumulation, and ammonia …
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Total Syntheses of (+)-Geldanamycin, (-)-Ragaglitazar, and (+)-Kurasoin A and Phase-Transfer-Catalyzed Asymmetric Alkylation
… solve this critical oxidation issue. A protected hydroquinone model compound was determined to be the optimum choice. Using Pd in the presence of air with a 1,4-hydroquinone provided the desired <em>para</em>-quinone quickly and nearly quantitatively in 98% yield. This study formulated the recipe …
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Reactive Oxygen Species-Induced Necrotic Cell Death
… cell death. 2,3,5-Tris(Glutathion-S-yl)-hydroquinone (TGHQ), a reactive oxygen species (ROS) generating nephrotoxic and nephrocarcinogenic metabolite of hydroquinone, causes necrotic renal cell death, the basis for which is unclear. We therefore investigated TGHQ-mediated cell death in …
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