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钼-水杨基荧光酮-溴化十六烷基三甲基铵显色反应的研究 总被引:11,自引:0,他引:11
在0.2-0.8/Ⅳ的盐酸介质中,钼(Ⅵ)与水杨基荧光酮以及溴化十六烷基三甲基铵,可以形成一红色三元络合物。络合物的最大吸收峰位于530纳米,表观摩尔吸光系数ε530=1.40×105。钼的浓度为0-8微克/25毫升时,络合物溶液的吸光度遵守比尔定律。三元络合物的组成经测定Mo:SAF:CTMAB=1:2:2。常见金属离子中,除钛与钨(Ⅵ)以外,均不干扰钼的测定。利用本显色反应,曾对多种合金钢中的钼含量进行了测定,取得了较好的效果。 相似文献
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TBP萃淋树脂微孔色谱柱分离富集钼的研究与应用 总被引:1,自引:0,他引:1
王玉学 《理化检验(化学分册)》1998,34(9):403-405
提出了用减压高效微孔色谱柱分离富集矿石中痕量钼,并对TBP苹淋树脂微孔层析柱的性能进行了较为详细的研究.试验发现,在零空床体积下,以3.0mol·L~(-1)盐酸溶液(在抗坏血酸存在下)为介质上柱,0.5mol·L~(-1)盐酸1.2ml洗脱,可以实现钢与大量铁、钨、钒、钛、锡、锆、铀等共存元素的分离.与常规柱相比较,减压微孔层析柱具有柱效高,洗脱体积小,分离速度快等优点,并能节省大量试剂.方法经标准样品验证,结果满意. 相似文献
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Nigel J. Brookes David C. Graham Gemma Christian Robert Stranger Brian F. Yates 《Journal of computational chemistry》2009,30(13):2146-2156
Electronic structure methods have been combined with the ONIOM approach to carry out a comprehensive study of the effect of ligand bulk on the activation of dinitrogen with three‐coordinate molybdenum complexes. Calculations were performed with both density functional and CCSD(T) methods. Our results show that not only is there expected destabilization of the intermediate on the pathway due to direct steric interactions of the bulky groups, but also there is significant electronic destabilization as the size of the ligand increases. This latter destabilization is due to the inability of the molecule to accommodate a rotated amide group bound to the molybdenum once the amide reaches a certain size. This destabilization also leads to a clear preference for the triplet intermediate (rather than the singlet intermediate) for bulky substituents which is in agreement with experiment. Overall, the calculated reaction profile for the bulky substituents shows a good correlation with the available experimental data. © 2009 Wiley Periodicals, Inc. J Comput Chem 2009 相似文献
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以N2与H2的混合气为反应气,和三氧化钼进行多段程序升温反应,制得一种β晶型的氮化钼。以噻吩为模型化合物的常压加氢脱硫反应表明,β-Mo2N0.78具有较强的加氢脱硫活性和强的抗硫化性能。同时考察了预还原、反应温度以及氮化末温、升温速率、反应气中N2-H2比及氮化时间等制备参数对β-Mo2N0.78加氢脱硫活性的影响。研究发现,β-Mo2N0.78的加氢脱硫活性在320 ℃~400 ℃随反应温度的升高增强,而还原预处理会降低催化剂的活性。氮化末温、氮化时间、反应气组成和升温速率等制备参数对催化剂的活性有明显的影响:随着氮化末温的升高,所制备的催化剂催化加氢脱硫活性降低;在氮化末温恒温较长时间,可以引起制备催化剂的加氢脱硫活性下降;存在最佳的反应气组成和各段升温速率。小晶粒的β-Mo2N0.78具有强的加氢脱硫活性。 相似文献
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本文用MINDO/3方法研究了硝基胍热解反应的机理。研究结果表明, 硝基胍热解反应可经历两条途径得到主产物(N_2O、H_2O和NH_3)。这两条途径相互竞争, 但生成N_2O及H_2O的途径Ⅰ要容易进行, 是整个反应的启动步。 相似文献
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本文报导用半经验方法研究N_1-氢-4-氨基-2-羰基胞嘧啶与4-氨基-2-羟基胞嘧啶异构化反应。MINDO/3能量梯度法优化孤立体系的全部自由度, 计算得ΔE=36.79 kJ mol~(-1),内酰胺型比醇式内酰胺型稳定。限定分子体系在同一平面内, 用MINDO/3中的Powell法优化过渡态的几何构型, 计算得正反应活化势垒为204.08 kJ mol~(-1), 逆反应活化势垒为167.30 kJ mol~(-1)。从IRC途径分析了该异构化反应的物理实质。 相似文献
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The chain structure of 1,2-polybutadienes prepared with molybdenum catalyst systems has been studied by IR, ~(13)C-NMR and T_g method, and the method to regulate the chain structure investigated. It was found that some polar additives, e. g., allyl halides, are able to regulate not only the content of 1,2-units in the polymer, but also its configuration and sequence distribution. Attempt has been made to estimate the sequence length of stereo-isomers of 1,2-units by statistical theory. 相似文献