共查询到20条相似文献,搜索用时 125 毫秒
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众所周知,受阻胺光稳定剂对聚烯烃有良好的光稳定效率,已引起世界的注意。然而,小分子量的受阻胺易于挥发,从而影响它的效率发挥[1,2],为了克服这个缺点,使小分子受阻胺的高分子化是近年来受阻胺光稳定剂发展的方向,本文主要是研究三种商品化高分子受阻胺光稳定剂对聚丙烯的稳定化作用及其效率和机理。 相似文献
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以对硝基苯甲酰氯为酰基化试剂,通过与含胺基的高分子受阻胺光稳定剂944在四氢呋喃中发生酰胺化反应形成沉淀,改变反应配比确定对硝基苯甲酰氯与高分子受阻胺光稳定剂944反应比例为5∶1。利用傅立叶红外光谱分析反应沉淀来实现高分子受阻胺光稳定剂944的定性分析,利用高效液相色谱分析反应上层清液,实现定量分析,紫外可见检测器检测波长为360 nm,反应测试结果回收率可达到90%以上。 相似文献
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以二胺类化合物、丙烯酸甲酯、1,2,2,6,6-五甲基哌啶醇为主要原料, 经Michael加成、酯交换反应合成了一系列分子中含四个哌啶胺结构的新型树枝状化合物. 目标产物结构经1H NMR, 13C NMR分析进行了确认. 选取其中一种结构进行抗氧化及抗老化性能测试, 结果表明其抗氧化性能优于主流抗氧剂Irganox B215及受阻胺光稳定剂Tinuvin770, Chimassorb944, Tinuvin622, 其抗老化性能优于受阻胺光稳定剂Tinuvin770. 相似文献
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本文报道了用红外光谱方法鉴定的高分子和小分子受阻胺光稳定剂。此法包括溶解聚丙烯,接着用H_2SO_4沉淀并萃取,所得水溶液用NaOH中和并用二氯甲烷萃取,除去溶剂后残渣用IR鉴定。 相似文献
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Soumitra Maity 《Tetrahedron》2009,65(45):9202-7242
A direct route for the synthesis of highly functionalized angularly substituted hydrindanes has been developed. The key step involves RO-RCM of an appropriately functionalized norbornene derivative. The hydrindane derivative obtained in this way has been used to accomplish a formal synthesis of bakkenolide-A. This protocol has also been extended for the synthesis of an advanced intermediate to the synthesis of the diterpene umbellactal. 相似文献
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The condensation of aniline and cyclohexanol (cyclohexanone) yielding intermediates and the subsequent dehydrogenation of these intermediates into diphenylamine have been studied. The mechanism of diphenylamine synthesis is substantiated. The kinetics of diphenylamine synthesis from aniline and cyclohexanol over a NiSnMg catalyst has been studied. A kinetic model in terms of the conversion of strongly chemisorbed species has been developed. The rate constants of diphenylamine synthesis at 260–300°C have been determined, which are consistent with the observed regularities. The kinetic model can be used in the determination of optimal synthetic conditions and in the design of a reactor for diphenylamine synthesis from aniline and cyclohexanol. Conditions have been found under which diphenylamine synthesis occurs at a high rate of up to 1 kg/(1h), with high selectivity, and with a high yield of up to 95%. 相似文献
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Rapid synthesis of gold nanorods of controlled dimensions is one of the desired aspects of nanotechnology as a result of the potential of these nanomaterials for biomedical applications. The synthesis of gold nanorods has been achieved using a photoinitiator as an instant source of ketyl radicals, which allows the synthesis of gold nanorods in minutes. This is the first report providing a one-step synthesis of nanorods of controlled dimensions in 20-30 min using photoinitiator I-2959 as a source of ketyl radicals. Furthermore, the role of UV intensity, the concentration of silver ions, and the presence of cosolvents and a cosurfactant have been studied in detail in an effort to produce nanorods with controlled dimensions in higher yields. The role of acetone in nanorod synthesis has been explored in detail, and it has been demonstrated that, for the photochemical synthesis of nanorods using a photoinitiator, acetone is not a critical component and can be replaced by other water-miscible solvents, thus the successful synthesis of nanorods in tetrahydrofuran (THF) has been demonstrated. It has also been found that a cosurfactant and an organic solvent are not required for the synthesis of nanorods; however, their presence is found to improve the monodispersity of nanorod samples, in addition to providing a higher yield. 相似文献
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己二酸是工业上具有重要应用的二元羧酸,其合成方法的研究受到了广泛的关注.其传统的合成方法对环境造成了极大的破坏.利用含钨化合物作为催化剂催化合成己二酸是一种绿色环保的新方法,引起了人们的重视.作者介绍了近年来含钨化合物催化合成己二酸的研究进展,分析比较了不同催化剂体系的研究情况,展望了今后己二酸合成的发展前景. 相似文献
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Ramachandran PV Chandra JS Prabhudas B Pratihar D Reddy MV 《Organic & biomolecular chemistry》2005,3(20):3812-3824
Studies towards the synthesis of epothilone A via organoboranes have been described. A modified procedure for the large-scale preparation of B-gamma,gamma-dimethylallyldiisopinocampheylborane from prenyl alcohol has been developed. This reagent, upon reaction with various aldehydes, provides the corresponding alpha,alpha-dimethylhomoallylic alcohols in high enantioselectivities. The application of this reagent for the synthesis of the C1-C6 subunit of epothilone has been demonstrated. Alternatively, inter- and intramolecular asymmetric reduction protocols have also been utilized for the synthesis of the C1-C6 subunit of epothilone A. The synthesis of the C7-C21 fragment of epothilone A involving asymmetric alkoxyallyl- and crotylboration using alpha-pinene-derived reagents has also been described. 相似文献
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The new developments in the field of gas phase synthesis, synthesis from the condensed phases and solid‐state synthesis allowing for the fabrication of new ceramic materials for diverse technical applications have been reviewed. The Flame Spray Pyrolysis, aqueous and non‐aqueous sol‐gel techniques, hydro‐ and solvothermal methods, polymer pyrolysis route and high pressure techniques have been considered as synthesis methods with great technical potential. 相似文献
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Ashok K PrasadSucharita Roy Rajesh Kumar Neerja KalraJesper Wengel Carl E OlsenAshok L Cholli Lynne A SamuelsonJayant Kumar Arthur C WattersonRichard A Gross Virinder S Parmar 《Tetrahedron》2003,59(8):1333-1338
The selectivity of Candida antarctica lipase has been demonstrated and employed in the manipulation of a diastereotopic furanose diol as the key step in the synthesis of a novel bicyclo 3-amino-3-deoxy furanose derivative, which is an important intermediate for the synthesis of bicyclic analogs of AZT. The asymmetrization of the diol has been achieved with preferred formation of a monoacylated product with 100% diastereoselectivity. An efficient synthesis of an intermediate in the synthesis of amino derivatized bicyclonucleosides is also described, two such novel compounds containing cycloamino residues have been prepared. 相似文献
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微波辅助组合合成的研究进展 总被引:2,自引:0,他引:2
微波辅助组合合成技术是近年来发展起来的一种新的制备化合物库的组合化学技术, 它不仅可以克服传统固相组合合成技术以及液相组合合成技术无法提高产物收率的不足, 而且利用该技术所制得的化合物库中对应的是高纯度的单一化合物, 采用高通量筛选技术可以快速直接地确定高活性结构, 极大地提高了新药开发的效率. 主要就近年来微波辅助组合合成技术的研究进展情况进行介绍, 内容包括固相组合合成、基于聚合物支载的催化剂的组合合成、液相组合合成、氟相组合合成以及组合平行合成等. 相似文献