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本文用高分辨裂解色谱-质谱法研究了磺化聚芳醚醚酮的热分解过程,分离和鉴定了主要热分解产物;考察了磺化度和温度对热解产物分布的影响。发现磺化聚芳醚醚酮有两个热分解阶段。用分步裂解并结合动力学分析,讨论了其热分解机理。 相似文献
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半结晶的聚芳醚酮类聚合物 ( PAEKs)因其性能优异而在机械、航天等高技术领域中得到广泛应用 .有关其晶体结构的研究亦有许多文献报道[1~ 11] ,而醚基与酮基在晶体结构方面是否等效一直存在争议 .虽然醚酮等效性的观点已被广泛接受 [4~ 8] ,但对于聚合物主链中含联苯基团的 PAEKs的醚酮等效性的研究则复杂得多 .文献 [1 ]报道醚酮等效性在主链含有联苯基团时不再成立 .本文首次发现醚酮等效性在主链含有联苯基团时在适当条件下仍可成立 ,并对聚芳醚酮类聚合物晶体结构的醚酮等效性问题进行了系统阐述 .1 实验部分 样品联苯聚醚酮 … 相似文献
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聚芳醚醚酮的热老化寿命研究 总被引:1,自引:0,他引:1
本工作用热重法(TG)研究了聚芳醚醚酮(PEEK)在空气和氮气中的热分解反应过程;确定了PEEK在这两种气氛中的热分解反应模型均符合无规引发断裂模型;在空气中PEEK的热分解显示两个过程,由此计算其在空气中第一阶段的热分解和氮气中的热分解反应活化能分别为214.7kJ/mol和232.2kJ/mol;由热分解反应动力学参数推算出热老化寿命曲线,并讨论了实验条件对结果的影响,进而以失重5%作为材料寿终指标估算出PEEK在氮气和空气中使用10年的最高温度分别为307℃和274℃。 相似文献
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This letter describes methods for the synthesis of isopropylthiomethyl and cyanomethyl ethers from the corresponding MEM ethers and also a process for the cleavage of MEM or MOM ethers of 1,2- and 1,3-diols which avoids cyclization to formals. 相似文献
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《Tetrahedron letters》1989,30(2):239-242
Silyl enol ethers (2) react with tributyl [(phenylthio) chloromethyl] stannane (1) in the presence of Zinc bromide to give β-phenylthiomethylstannyl ketones (3) in good yields. Silyl dienol ethers (4) mainly give products (5) due to γ-attack, under these conditions. 相似文献
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Gromov S. P. Dmitrieva S. N. Vedernikov A. I. Churakova M. V. 《Russian Chemical Bulletin》2004,53(7):1417-1427
The review summarizes the results of studies aimed at constructing new promising macrocyclic ligands that bind metal and ammonium ions. A new approach to the synthesis of formyl and nitro derivatives of 1-aza-2,3-benzocrown ethers possessing considerable synthetic potential is described. The review presents a radically new methodology for the synthesis of such benzoazacrown ethers based on stepwise transformations of the macrocycle of readily accessible benzocrown ethers. The main structural factors and necessary conditions enabling stepwise transformations of the macrocycle of crown ethers into azacrown ethers were revealed. For the first time, the ability of N-methylbenzoazacrown ethers to form complexes was found, which is much superior to that of widely used N-phenylazacrown ethers and benzocrown ethers with the same size of the macrocycle. 相似文献
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Simin Maleknia Chien-Chung Liou Jennifer Brodbelt 《Journal of mass spectrometry : JMS》1991,26(11):997-1002
The collision-activated dissociation (CAD) mass spectra for a series of crown ethers, perfluoro crown ethers, cryptands and several dicyclohexano substituted crown ethers are reported. The CAD spectra were acquired with a triple quadrupole mass spectrometer, and in some cases spectra were recorded as a function of collision energy. In general, the protonated crown ethers dissociate via a series of losses of C2H4O units. The perfluoro crown ethers dissociate predominantly via losses of C2F4O units. The dicyclohexano ethers fragment in analogous ways in conjunction with cleavage of the cyclohexano rings. CAD spectra are also reported for acyclic ether systems. 相似文献
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Dimethylaluminiun chloride has been found to cleave THP ethers selectively without any removal of t-butyldimethylsilyl ethers 相似文献
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Magnetic nanoparticle-supported crown ethers 总被引:1,自引:0,他引:1
Magnetic nanoparticle (MNP)-supported crown ethers were successfully prepared and evaluated as catalysts for solid-liquid phase-transfer reactions; the catalytic activities of the MNP-supported crown ethers were not inferior to those of non-supported crown ethers; after the reactions, the catalysts could be readily separated using an external magnet and reused without significant loss of catalytic efficiency. 相似文献
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The influence of the trinitromethane salt cations and the substituents in the alkyl moiety of chloromethyl ethers of alcohols on the yields of trinitroethyl ethers of the substituted alcohols formed from them was established. On this basis a representative series of previously unavailable trinitroethanol ethers was synthesized. 相似文献
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Synthesis of anthracene ethers from anthracene methyl ethers via an acid-catalyzed exchange reaction
Selective synthesis of anthracene ethers was achieved under mild conditions via an acid-catalyzed ether-ether exchange reaction and its scope and limitations, as well as its potential in synthesizing anthracene-based crown ethers, tested. 相似文献
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Kenji Hirai Hiroharu Suzuki Yoshihiko Moro-Oka Tsuneo Ikawa 《Tetrahedron letters》1980,21(35):3413-3416
Acetylenic silyl ethers are converted catalytically to the corresponding conjugated dienol silyl ethers by ruthenium hydride complexes. 相似文献