- Electrochemical degradation of bisphenol A in chloride electrolyte—Factor analysis and mechanisms study
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Electrochemical oxidation technology is a powerful method in the degradation of recalcitrant organics, due to the high oxidizing ability of active chlorine and reactive oxygen species generated in the cell. However, influencing factor analysis and intermediates detection during the electrochemical removal of organics has not been extensively studied in the chloride electrolyte. In this study, an orthogonal test array design of L16(4)3 was carried on with Pt anode in NaCl electrolyte, using the typical endocrine disruptor bisphenol A (BPA) as the model pollutant. The influencing order of the three main factors for BPA degradation rate was current density?>?initial organic concentration?>?chloride concentration, based on the analysis of variance in this experiment. This emphasized the very significance of the active chlorine and hydroxyl radicals which were closely related with the potential of the system and the applied current density. Then both organic and inorganic Cl-byproducts were determined. The concentration of chloride decreased to 9.88?mM with an initial of 10?mM in the 480-min electrolysis and extremely low concentration of active chlorine was produced in this system (maximized at 0.037?mM) for the first set. Neither chlorate nor perchlorate was detected with the Pt anode. The factor of current density influenced greatest on the formation of chloroform due to the amount of active chlorine affected by the current density. Finally, intermediates generated in the electrolysis cell were concretely investigated. Compared with traditional chlorination, the amount of chlorinated-BPA (2, 2′-D2CBPA and T4CBPA) generated was relatively less (2.46 and 10.00?μM equiv BPA), which might be due to their fast simultaneously transformation in the electrochemical system. With the isopropylidene bridge cleavage of chlorinated-BPA, one-ring aromatic compounds (2,6-dichlorophenol, 2,6-dichloro-2,5-cyclohexadiene, 2,4,6-trichlorophenol) occurred at the same time. Finally, chlorinated-BPA was totally transformed and low molecular chlorinated compounds were detected to the end of the experiment. This is one of the very few studies dealing with chlorinated organic intermediates formed in chloride electrolyte, and thus these findings may have significant technical implications for electrochemical treatment of wastewater containing BPA.
- Li, Hongna,Long, Yujiao,Wang, Yu,Zhu, Changxiong,Ni, Jinren
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p. 1144 - 1152
(2017/01/06)
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- MEDICAL DEVICE USING SULFONATED NEUTRALIZED POLYMERS WITH REDUCED ADHESION OF BIOLOGICAL FLUIDS
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A medical article having neutralized sulfonic acid groups on its surface, is disclosed. The article has reduced interaction with biological fluids such as insulin, human growth hormone and human serum albumin.
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- Flame retardant thermoplastic resin composition
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The present invention relates to a flame retardant thermoplastic resin composition that comprises a polycarbonate resin, a rubber modified graft copolymer, a styrene-containing copolymer, an oligomeric phosphoric acid ester morpholide compound as a flame retardant and a fluorinated polyolefin resin. The present invention relates to a polycarbonate thermoplastic resin composition which is superior to the resin composition using oligomeric phosphorus ester in flame retardancy, heat resistance and flexural modulus and superior to the resin composition using monophosphorus ester in the resistance for juicing, heat stability, heat resistance, flexural modulus and appearance.
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- Identification and quantification of chlorinated bisphenol A in wastewater from wastepaper recycling plants
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Chlorinated derivatives of bisphenol A were detected in the final effluents of eight paper manufacturing plants in Shizuoka, Japan, where thermal paper and/or other printed paper is used as the raw material. Their amounts were determined by gas chromatography/mass spectrometry (GC/MS) after treatment with N, O-bis(trimethylsilyl) trifluoroacetamide, and ranged from traces to 2.0 μg/1. They are likely produced by chlorination of bisphenol A, which was released into the effluents from the pulping process of wastepaper, during or after bleaching with chlorine.
- Fukazawa, Hitoshi,Hoshino, Kentaro,Shiozawa, Tatsushi,Matsushita, Hidetsuru,Terao, Yoshiyasu
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p. 973 - 979
(2007/10/03)
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- Processes for producing aromatic polycarbonate oligomer and aromatic polycarbonate
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A process for producing continuously an aromatic polycarbonate oligomer by reacting an aromatic dihydroxy compound and an alkali metal base or an alkaline earth metal base with a carbonyl halide compound comprises: (1) feeding continuously to a tank reactor an aromatic dihydroxy compound, water, a molecular weight controlling agent, a polymerization catalyst, a carbonyl halide compound, and an organic solvent, and an alkali metal base or an alkaline earth metal base in an amount of 1.15-1.6 equivalents based on the aromatic dihydroxy compound, (2) carrying out the reaction with a residence time as defined by the following formula, where X is an amount of the polymerization catalyst in terms of mole % based on the amount of mole of the aromatic dihydroxy compound fed per unit time, and Y is a residence time (min.), and (3) continuously withdrawing the reaction mixture from the tank reactor to obtain an aromatic polycarbonate oligomer having a number average molecular weight of 1,000-10,000. An aromatic polycarbonate is produced by polycondensation of the aromatic polycarbonate oligomer.
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- Method for preparing aromatic bischloroformate compositions
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Bischloroformate oligomer compositions are prepared by passing phosgene into a heterogeneous aqueous-organic mixture containing at least one dihydroxyaromatic compound, with simultaneous introduction of a base at a rate to maintain a specific pH range and to produce a specific volume ratio of aqueous to organic phase. By this method, it is possible to employ a minimum amount of phosgene. The reaction may be conducted batchwise or continuously. The bischloroformate composition may be employed for the preparation of cyclic polycarbonate oligomers or linear polycarbonate, and linear polycarbonate formation may be integrated with bischloroformate composition formation in a batch or continuous process.
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- Bischoloroformate preparation method with phosgene removal and monochloroformate conversion
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Aqueous bischloroformates are prepared by the reaction of a dihydroxyaromatic compound (e.g., bisphenol A) with phosgene in a substantially inert organic liquid (e.g., methylene chloride) and in the presence of an aqueous alkali metal or alkaline earth metal base, at a pH below about 8. After all solid dihydroxyaromatic compound has been consumed, the pH is raised to a higher value in the range of about 7-12, preferably 9-11, and maintained in said range until a major proportion of the unreacted phosgene has been hydrolyzed. At the same time, any monochloroformate in the product may be converted to bischloroformate.
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- Cyclic monocarbonate bishaloformates
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Cyclic monocarbonate bischloroformates are prepared by the reaction of a carbonyl halide such as phosgene with a bridged substituted resorcinol or hydroquinone such as bis(2,4-dihydroxy-3-methylphenyl)methane or bis(2,5-dihydroxy-3,4,6-trimethylphenyl)methane in the presence of aqueous alkali metal hydroxide. The cyclic monocarbonate bischloroformates may be used for the preparation of linear or cyclic polycarbonates containing cyclic carbonate structural units, which may in turn be converted to crosslinked polycarbonates.
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- Polyetherimide bisphenol compositions
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Polyetherimide bisphenols and bischloroformates are prepared by the reaction of dianhydrides or certain bisimides with aminophenols or mixtures thereof with diamines. They are useful as intermediates for the preparation of cyclic heterocarbonates, which may in turn be converted to linear copolycarbonates. The bisphenols can also be converted to salts which react with cyclic polycarbonate oligomers to form block copolyetherimidecarbonates.
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- Branched polycarbonates containing 2,4,6-tris(4'-Hydroxyaryl)-amino-s-triazines
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Branched, soluble, high-molecular-weight, thermoplas-tic polycarbonates having improved properties, and, in particular, suitable to the fabrication by blow-moulding, characterized by the presence in their structure of units deriving from the use in the synthesis of tris(4'-hydrox-yaryl)-amino-S-triazines having the formula:, wherein R1 and R2, equal to, or different from each other, indicate hydrogen, linear or branched C1-5alkyl, or halogen (in particular, chlorine and bromine).
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