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以硅胶球为基质键合γ-GOPS并各接枝上具有络合功能的三种配体,邻位氨基吡啶、间酰氨基吡啶及对酰氨基吡啶,再和TiCl_4络合成固载化的Lewis酸催化剂,将这些催化剂进行缩醛、缩酮及酯化反应,有很好的催化活性,重复使用多次不失效.本文在合成此类催化剂的过程中利用热失重(TG)法及等离子光谱法(ICP)等检测方法对合成此类催化剂的每一步进行跟踪检测,得到键合反应,开环反应及络合反应过程中的键合量,开环相量和TiCl_4络合量的定量数据.对固载化催化剂表面的接枝量有所了解,从而可进一步检测此类催化剂的催化效应并得到一些启示. 相似文献
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A novel pseudo simulated moving bed was suggested to separate a ternary mixture. A solvent gradient was created to make the solvent strength decreasing from zone II to zone III. Under suitable conditions, the least retained solute A moved forward and the most retained solute C moved backward in zones II and III whereas the medium retained solute B moved forward in zone II but backward in zone III to be trapped in the two zones consequently. Once the columns in zones II and III were saturated with solute B, the solvent dissolving the feed was introduced at the feed port to remove solute A from the raffinate-port and solute C from the extract-port. Finally, solute B was recovered from the extract port by stopping the liquid flow in zone II. This scheme was validated by the successful separation of dihydrocapsaicin from capsaicinoids. 相似文献
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二苯胺重氮盐由于每个分子中有二个苯环,其中末键连重氮基的苯环可与甲醛在酸性介质中发生缩聚反应[1~3],形成的重氮树脂具有良好的感光性能,并可溶于有机溶剂或碱性显影液,极适合于制备感光胶印版,已发展成为阴图PS版最重要的感光剂[4~7]. 相似文献
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本文对直接法合成并经不同条件水蒸汽处理的HZSM-5分子筛进行了粉末X-射线衍射分析和红外光谱(IR)、程序升温脱附(TPD)的考察.结果表明:水蒸汽处理的温度、时间及环境中的水含量是影响HZSM-5结构和表面酸性的三个重要因素.对水蒸汽影响酸性变化的规律也进行了研究和讨论. 相似文献
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设P是有限偏序集,f是P上的秩函数。P_m表示P中秩为m的元素集合。若max|P_m|=max{|A|}:A是P中的反链},则称P有Spernet性质。设a_1,…,a_kν;∈P,记F=;υ{b:a_i≤b,b∈P},称F是由a_1,…,a_k生成的序滤子。本文我们考虑的偏序集是布尔代数B~N,秩函数f(x)=|x|.K.W.LIH提出了下面猜想 相似文献
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Abstract— We measured 6β-cholesterol hydroperoxide (6β-CHP), a specific singlet-oxygen (O2 (δg)) product, during irradiation of unilamellar dimyristoyl 1-α-phosphatidylcholine liposomes containing cholesterol and zinc phthalocyanine (ZnPC). The effects of liposome size, the hydrophobic (O2 (1 δg )) quencher, β-carotene, and hydrophilic O2 (1 δg ) quenchers upon the amount of 6β-CHP formed were determined and interpreted in terms of a one dimensional model of 2 (1 δg ) quenching and diffusion. The model correctly predicted (1) that the amount of 6β-CHP was increased with increasing liposome size, (2) that P-carotene was more effective at reducing 6β-CHP formation in 400 nm diameter liposomes than 100 nm diameter liposomes and (3) that the hydrophilic quencher, water, was also more effective in large liposomes than in small liposomes.
The hydrophobic quencher, β-carotene, was more effective at reducing the formation of 6β-CHP than at reducing the 1270 nm O2 (1 δg ) emission. This difference was found to be due to the size distribution present in the liposome preparations because the difference between the 6β-CHP data and the 1270 nm emission data was much smaller in liposome preparations with a narrow size distribution. When a significant size distribution was present, the 6β-CHP data were weighted more heavily with large-diameter liposomes, while the 1270 nm emission data were weighted more heavily with small-diameter liposomes. 相似文献
The hydrophobic quencher, β-carotene, was more effective at reducing the formation of 6β-CHP than at reducing the 1270 nm O
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Wei ZL Xiao Y George C Kellar KJ Kozikowski AP 《Organic & biomolecular chemistry》2003,1(22):3878-3881
A novel method for the epimerization of endo-2-(6-chloro-3-pyridyl)-7-azabicyclo[2.2.1]heptan-3-one (12) on silica gel was developed and used as the key step to synthesize functionalized analogues of epibatidine which were evaluated for their nicotine receptor subtype selectivity in binding studies. 相似文献