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本文研究了乙丙共聚物在含臭氧的氧气流中的过氧化氢基化反应,考察了温度、时间、浓度以及添加剂等对过氧化氢基化物(EPHP)中过氧化氢基含量的影响;研究了EPHP与苯乙烯类单体进行接枝共聚反应以及接枝产物的共混增韧作用。 相似文献
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本文研究了以氯化血红素替代辣根过氧化物酶催化过氧化氢与4-氨基安替比林和苯酚的催化显色反应条件,拟订了测定过氧化氢的高灵敏催化分光光度法,做了多种离子对测定过氧化氢的干扰实验。并通过与葡萄糖氧化酶联用,拟订了水介质和血清中葡萄糖的分光光度测定方法,试用于测定血清样品中的葡萄糖含量得到了较满意的结果。 相似文献
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以有机过氧化氢物叔丁基过氧化氢(TBH)或异丙苯过氧化氢(CHP)与芳叔胺N,N-二甲基苯胺(DMA)或其衍生物组成的体系引发甲基丙烯酸甲酯(MMA)聚合。研究有机过氧化氢物与芳叔胺结构对聚合的影响,测定了TBH-胺与CHP-胺体系引发MMA聚合的总活化能分别为50-57KJ/mol与39-62KJ/mol,并对CHP-DMT(N,N-二甲基对甲苯胺)引发MMA聚合动力学以及有关引发聚合机理进行了研究。 相似文献
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The polymerization of acrylonitrile (AN) initiated by 1,4-dimethyl-1,4-bis(p-nitrophenyl)-2-tetrazene (Ie) was studied in dimethylformamide (DMF) at high temperature. The polymerization proceeds by a radical mechanism. The rate of polymerization is proportional to [Ie]0.64 and [AN]1.36. The overall activation energy for the polymerization is 21.5 kcal/mole within the temperature range of 115-130°C. The chain transfer of Ie was also undertaken over the temperature range of 120-135°C. The activation parameters for the decomposition of Ie at 120°C are kd = 2.78 × 10?6 sec?1, ΔH? = 40.8 kcal/mole, and ΔS? = 19.5 cal/mole-deg, respectively. 相似文献
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Abstract The isothermal free-radical copolymerization of styrene and acrylonitrile was examined in the temperature range of 333-373 °K. Initial rate studies of styrene homopolymerization were conducted and agreed favorably with values in the literature. Initial rate studies for acrylonitrile solution polymerization in DMF were also performed. Initiator decomposition rate constants measured in the presence of AN and styrene monomer are reported for AIBN, BP, and DTBP. Rate functions for the full spectrum of comonomer compositions initiated by AIBN and benzoyl peroxide are reported. Several copolymerization kinetic models were tested and found to be inadequate. Conversion histories were found to be consistent with observed initial rates and follow a simple pseudohomopolymerization kinetic model. Autoacceleration was observed and found to increase in severity with increased AN feed compositions and decreased reaction temperatures. 相似文献
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K. Sugiyama 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(1):13-30
The polymerization of acrylonitrile (AN) initiated by tetramethyl-2-tetrazene (TMT) and p-toluenesulfonic acid (TSA) in dimethylformamide (DMF) was studied. The polymerization was confirmed to proceed through a radical mechanism. The initial rate of polymerization R was expressed by the equation: Rp = k[TMT]0.6 [TSA]0.46 [AN]1.35. The overall activation energy for the polymerization was estimated as 20.7 kcal/mole. In the absence of monomer, the reaction of TMT with TSA was also studied kinetically by measuring the evolution of nitrogen. From these results and ESR measurement of the TMT/TSA system, a possible initiation mechanism is proposed. 相似文献
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The radiation-initiated copolymerization of styrene and acrylonitrile was investigated at 20° in dimethylformamide (DMF) and in benzylalcohol solutions. The compositions of the copolymers were only slightly affected by these polar solvents. The influence of temperature on the copolymerization in DMF solutions was studied in greater detail. It was found that the acrylonitrile content in the copolymer obtained at -78° drastically increased as a result of an anionic polymerization of acrylonitrile. Fractional precipitation of the products obtained at -78° showed that they were not mixtures of polymers but were block copolymers containing long sequences of acrylonitrile units. This copolymer is assumed to arise as a result of the simultaneous growing of the two ends of a primary radical-ion, acrylonitrile adding to one end by an anionic mechanism while the free radical end initiates a random copolymerization of styrene and acrylonitrile. The anionic contribution to the over-all process was established. The anionic homopolymerization of acrylonitrile was studied in DMF, toluene and their mixtures. The rate was found to exhibit a maximum for 20% acrylonitrile in DMF. It was further noticed that significant amounts of DMF could be replaced by toluene or styrene without affecting the rate. The reduction in rate in more concentrated monomer solutions was attributed to an autoinhibition of acrylonitrile in its anionic polymerization. 相似文献
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Kazuo Sugiyama Tadao Nakaya Minoru Imoto 《Journal of polymer science. Part A, Polymer chemistry》1971,9(9):2689-2702
The polymerization of acrylonitrile (AN) initiated by the system of tetramethyl tetrazene (TMT) and bromoacetic acid (BA) in dimethylformamide (DMF) was studied. The TMT–BA system could initiate the polymerization of AN more easily than TMT alone. The polymerization was confirmed to proceed through a radical mechanism. The initial rate of polymerization Rp was expressed by the equation: Rp = [TMT]0.62-[BA]0.5[AN]1.5. The overall activation energy for the polymerization was estimated as 9.4 kcal/mole. In the absence of monomer, the reaction of TMT with BA in DMF was also studied kinetically by measuring the evolution of nitrogen gas. The reaction was first-order in TMT and first-order in BA; the rate data at 49°C were k2 = 9.1 × 10?2l./mole-sec., ΔH? = 17.0 kcal/mole, and ΔS? = ? 6.6 eu. In addition, the treatment of TMT with BA in benzene led to the formation of tetramethylhydrazine radical cation, which was identified by its ESR spectrum. On the other hand, the relatively strong interaction between TMT and DMF was observed by absorption spectrophotometry. 相似文献
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Abstract Irradiation of benzophenone in the presence of a suitable hydrogen donor like alcohol leads to benzpinacol and the ketone as sole products. This reaction proceeds through ketyl radical intermediates. This photoredox system may be used for photopolymerization. Photopolymerization of acrylonitrile using isopropanol and benzophenone combination as initiator has been studied. The formation of the polymer is directly proportional to irradiation time, [acrylonitrile] and [isopropanol]. The rate of polymerization increases with an increase in concentration of benzophenone to an optimum and a further increase in benzophenone concentration decreases the polymerization rate. A suitable mechanism is suggested. 相似文献
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Methyl methacrylate (MMA) was polymerized at 40 in the presence of dimethyl formamide (DMF), using cetyl trimethyl ammonium bromide with benzoyl peroxide (CTABBZ2O2) as the initiating system. At high dilutions the rate of polymerization was proportional to (initiator)1–2. In near-bulk conditions using low [DMF], the rate was practically independent of [BZ2O2], while the kinetic order with respect to CTAB was about 0.16. The polymerization was inhibited by hydroquinone. A radical mechanism is suggested for the polymerization with primary radical termination significant in near-bulk systems and bimolecular termination significant for high dilution with DMF. Effects of various other solvents or additives on the polymerization were examined. DMF, acetonitrile and pyridine act as rate accelerating diluents; benzene, methanol, chloroform and acetone as inert diluents; formamide and acetamide cause pronounced retardation. 相似文献
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Sustmann R Korth HG Kobus D Baute J Seiffert KH Verheggen E Bill E Kirsch M de Groot H 《Inorganic chemistry》2007,46(26):11416-11430
The development of enzyme mimics of catalase which decompose hydrogen peroxide to water and molecular oxygen according to the 2:1 stoichiometry of native catalase and in aqueous solution at pH 7 and at micromolar concentrations of the enzyme model and hydrogen peroxide is reported. For this purpose, iron(III) complexes of 1,4,8,11-tetraaza[14]annulenes are prepared by various procedures. Efficacious preparations utilize reaction of the [N4] macrocyles with FeII salts in the presence of triphenylamine, followed by gentle oxidation of the FeII complexes by molecular oxygen or by tris(4-bromophenyl)aminium hexachloroantimonate. The complexes are characterized by SQUID magnetometry and by M?ssbauer, EPR, and UV/vis spectrometry. In the solid state, the iron(III) center of the catalytically active complexes exists in the intermediate (quartet, S = 3/2) spin state. Several of these complexes decompose hydrogen peroxide in aqueous buffer solution at pH 7.2 at room temperature with turnover numbers between 40 and 80. The apparent second-order rate constant for hydrogen peroxide decomposition is in the range of 1400-2400 M(-1) s(-1), about 3 orders of magnitude lower than the value for native catalase. Besides oxygen production, a non-oxygen releasing pathway of hydrogen peroxide decomposition is unveiled. 相似文献
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以旋光联萘二酚(BINOL)和甲苯-2,4-二异氰酸酯(TDI)为原料, 采用氢转移加成聚合法制备了含联萘基团的新型旋光聚氨酯(S-BPU和R-BPU), 并用FTIR, 1H NMR, UV-Vis, CD和DSC/TGA等手段对该聚氨酯进行了结构和性能表征. 结果表明, 当BINOL的光学纯度逐渐增加时, BPU的旋光度和特性粘度逐渐增大, S-BPU和R-BPU的旋光度最高可分别达到-78°和+54.6°, 具有较高的旋光能力; S-BPU和R-BPU的玻璃化转变温度(Tg)分别达到258.4和286.6 ℃, 热分解温度(Td)分别为305.6和323.6 ℃, 热分解温度比通常的PU材料提高了100 ℃ 左右, 显示了较好的热稳定性; R-BPU和S-BPU的红外发射率分别为0.682和0.618, 显示了较低的红外发射率. 相似文献