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正常沸点的蒸发热是重要的基础数据。它可用来计算物质的临界性质、蒸汽压和要求温度的蒸发热。因之前人做了不少基础工作,测定各种物质的实验值并造表备查用。但测定的实验值总是为数有限,故有 相似文献
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The (cis-1,4 and 1,2) polybutadiene polymerized with iron catalyst was investigated by ~(13)C-NMR. Assignments have been made on the spectra for all peaks of the aliphatic and olefinic carbons using chemical shift corrective terms together with Furukawa parameters. The relative intensities of peaks were calculated from the Bernoulli distribution of cis-1,4 and 1,2 units.Quantification of cis-1,4 and 1,2 contents, sequence distribution, alternation pattern of cis-1,4 and 1,2 units, and the chain propagation mechanism were discussed as a result of the detailed study of the spectra. 相似文献
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近二十年来,在络合催化研究中,由镍、钴、钛及希土等过渡元素组成的共轭双烯烃聚合和齐聚的催化体系效果明显,受到了国内外的普遍重视.但由最常见的过渡元素铁所组成的催化体系,却从未取得满意的结果,一直是大家关心的问题.我们在广泛探讨共轭双烯烃聚合和齐聚的络合催化体系时,发现了一种由乙酰丙酮铁-烷基铝-氮杂环类配位体组成的体系,不仅有极高的聚合活性,而且聚合产物是含有相当数量1,2-结构聚合物的弹性体,具有较好的应用性能.可见,这一发现无论对发展络合催化理论,还是对提供新型高分子材料都有一定的意义. 相似文献
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用 Fe(acac) 3- Al(i- Bu) 3- α,α′-联吡啶 (acac=乙酰丙酮 )催化邻苯二甲酸酐 (PA)与环氧丙烷 (PO)、邻苯二甲酸酐与环氧氯丙烷 (ECH)开环交替共聚 .研究了 Fe/Al、Fe/α,α′-联吡啶摩尔比对聚合的影响 ;用核磁共振技术研究了共聚物的交替度 ,测得共聚物中邻苯二甲酸酐含量达 46 %以上 .共聚反应动力学研究表明 ,共聚反应速度与单体浓度及催化剂浓度均呈一级关系 ;PA- PO、PA- ECH的表观活化能分别为 10 9.3和 99.7k J/mol 相似文献
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前文报道了聚丁二烯微观结构的分析方法,在目标因素分析中测摩尔消光系数对标定聚丁二烯含量要作校正,少量杂质还会影响准确定量,如在1000~650 cm~(-1)谱区的结果不是很满意的。本文按文献的谱线趋向,去掉谱区内的杂质吸收部分,以此修正摩尔消光系数作为目标向量,从而进行目标因素分析定量计算,所得结果较满意。 相似文献
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Catalysts consistiug of different iron compounds, triisobutylaluminium and warious ligands containing nitrogen used for butadiene polymerization were investigated by UV-visible, infrared spectroscopy. Spectra obtained illustrate an exchange taking place between the acetylacetonyl group in Fe(acac)_3 and the isobutyl group in Al(i-Bu)_3. During the exchange iron was reduced to lower valence state and coordinated with dipyridine or phenanthroline forming an active intermediate complex. A correlation between the absorption strength of the active intermediate complex in the visible range and the activity of catalyst was established. 相似文献
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