共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
铀酰萃取剂双亚砜的合成及其微胶囊萃取铀性能的研究 总被引:1,自引:0,他引:1
铀是一种非常重要的能源物质 ,现在国际上一般使用磷酸三丁酯 (TBP)作为铀的萃取剂提取及回收铀。TBP对铀有较强的萃取能力 ,但它耐辐照能力较差 ,有关双亚砜的报道仅局限于n =1 ,2 [1,2 ] 。本文以硝酸为氧化剂 ,采用硫醚氧化法 ,合成了四个新的双亚砜类化合物PhSO(CH2 ) nSOPh(n分别为 2、3、4、6) ,并经元素分析、核磁共振对其结构进行了表征。为避免萃取过程中乳化或三相的出现 ,采用界面缩聚法[3 ] 以高分子材料包覆TBP和自制的双亚砜类化合物 (n =2 ,4,6) ,制成微胶囊 ,对其在酸性水溶液 (pH =1~1 .5 )中萃… 相似文献
3.
4.
用双对数法测出酒石酸石油亚砜萃合物的在观结构,并用红外光谱证明酸与亚砜以氢键相连。利用场解吸质谱可直接观察到有机酸亚砜萃合物的分子离子和准分子离子,比较多种有机酸纸层析的R_f值发现,亚砜萃取有机酸的机理中空腔效应起着重要作用。 相似文献
5.
6.
7.
8.
9.
N—正辛基己内酰胺从硝酸介质中萃取铀(Ⅵ)的动力学研究 总被引:3,自引:0,他引:3
采用上升单液滴法研究了N-正辛基己内酰胺从硝酸介质中萃取铀(Ⅵ)的动力学,得出U(Ⅵ)的萃取速率与水相中铀浓度的1次方成正比,与温度(10-45℃)无关;萃合物向有机相的扩散为萃取过程的速控步骤。 相似文献
10.
11.
在水-乙腈混合溶剂中用(NH~4)~2Ce(NO~3)~6氧化烷基蒽. 甲基, 乙基和环丙基蒽经历氧化-水解-氧化-水解-消除-氧化-去质子历程, 得到蒽环氧化产物, 消除烷基(或氢原子)的可能顺序是:H>CH~3>C~2H~5. 当蒽环的1,9-位连着1,2-亚乙基桥时, 却经由氧化-去质子-氧化水解-氧化(或消除)历程, 得到侧链氧化产物. 烷基的本质对多核芳烃的氧化机理有显著的影响. 相似文献
12.
Rong-Min Wang Zong-Fan Duan Yu-Feng He Zi-Qiang Lei 《Journal of molecular catalysis. A, Chemical》2006,260(1-2):280-287
A new kind of Co–Na heterodinuclear polymer complex based on Salen Schiff base and crown ether has been successfully prepared by condensation polymerization. Its catalytic behavior for aerobic oxidation of cyclohexene, alkylbenzenes and linear aliphatic olefins was studied in the absence of any solvents or reducing agents under mild conditions. The oxidation of cyclohexene catalyzed by the above catalyst proved to be a simple and efficient method for obtaining 2-cyclohexen-1-one (CO) and 2-cyclohexen-ol (OH) in a high selectivity. Kinetics of the oxidation was also investigated. The results showed that the aerobic oxidation of cyclohexene catalyzed by Salen-crown ether heterodinuclear polymer complex follows a radical chain aerobic oxidation mechanism. This oxidation system is also efficient in the oxidation of alkylbenzenes and linear aliphatic olefins, which afforded corresponding benzylic oxidation products and epoxides, respectively. 相似文献
13.
14.
M. V. Tsarev V. V. Mokrushin A. V. Sten’gach A. I. Tarasova P. G. Berezhko I. K. Kremzukov E. V. Zabavin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2010,84(4):679-683
The oxidation of titanium hydride powder by air oxygen and the influence of oxidation conditions on the degree of oxidation of hydride particles, specific gas content in the powder, and kinetics of its thermal decomposition were studied. The resistometry method was used to determine the effective activation energy of oxidation of titanium hydride by air oxygen. The content of the surface nonconducting phase formed by titanium oxide and oxohydride films under various oxidation conditions was estimated. 相似文献
15.
为快速、无损判别乳制品脂氧化程度,提出了利用乳制品三维荧光光谱的氧化水平进行判别的方法。该方法用平行因子分析对荧光矩阵进行分解,用载荷向量组确定脂氧化过程中的光敏成分,用不同成分得分向量对样本进行聚类,并建立了不同氧化水平样本的偏最小二乘判别模型。实验采集不同存储环境下氧化程度各异的酸奶样本,找出了核黄素等荧光团在脂氧化过程中的变化规律,选取得分向量建立偏最小二乘判别模型对不同存储阶段氧化程度各异的样本判别分类,其特异度和灵敏度达88.9%以上,验证了该法对评判乳制品脂氧化水平的有效性。 相似文献
16.
A. V. Solomonov E. V. Rumyantsev B. A. Kochergin E. V. Antina 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(7):1048-1052
The results of a comparative study of the oxidation of bilirubin, ascorbic acid, and their mixture in aqueous solutions under the action of air oxygen and hydrogen peroxide are presented. The observed and true rate constants for the oxidation reactions were determined. It was shown that the oxidation of tetrapyrrole pigment occurred under these conditions bypassing the stage of biliverdin formation to monopyrrole products. Simultaneous oxidation of bilirubin and ascorbic acid was shown to be accompanied by the inhibition of ascorbic acid oxidation by bilirubin, whereas ascorbic acid itself activated the oxidation of bilirubin. 相似文献
17.
Pt及其修饰电极上甲醇吸附和氧化的CV和EQCM研究 总被引:1,自引:1,他引:0
运用电化学循环伏安和石英晶体微天平 (EQCM )研究了 0 .1mol·L- 1H2 SO4 溶液中甲醇在Pt电极和以Sb ,S不可逆吸附原子修饰的Pt(Pt/Sbad和Pt/Sad)电极上的吸附和氧化过程 .结果表明甲醇的氧化与电极表面氧物种有着极其密切的关系 .Pt电极表面Sb吸附原子能在较低的电位下吸附氧 ,可显著提高甲醇电催化氧化活性 .与Pt电极相比较 ,Sb吸附原子修饰的Pt电极使甲醇氧化的峰电位负移了 0 .13V .相反 ,Pt电极表面S吸附原子的氧化会消耗表面氧物种 ,抑制了甲醇的电氧化 .本文从表面质量变化提供了吸附原子电催化作用的新数据 相似文献
18.
提出了一条合成苯胺齐聚物的新路线:由高氧化态的苯胺四聚体与二苯胺或N-苯基-1,4-对苯二胺反应合成苯基封端的苯胺五聚体和六聚体,用红外、质谱、核磁共振、基底辅助激光解吸质谱(MALDI-MS)进行了表征.提出一条可能的机理,即高氧化态的苯胺四聚体与二苯胺或N-苯基-1,4-对苯二胺在酸性溶液中混合时,四聚体、二苯胺和N-苯基-1,4-对苯二胺的分子中均形成阳离子自由基,四聚体的阳离子自由基与后二者的阳离子自由基耦合形成苯胺五聚体和六聚体.还原态的苯胺齐聚物氧化成中间氧化态的苯胺齐聚物,使用硫酸铵和六水和三氯化铁等氧化剂能打断苯胺五聚体和六聚体的分子链.实验发现,氧化银是将还原态苯胺齐聚物氧化成中间氧化态的齐聚物的最好的氧化剂.用紫外可见光谱对中间氧化态的五聚体和六聚体进行了研究,对其分子中醌环的数目进行了讨论. 相似文献
19.
《Analytical letters》2012,45(13):2581-2589
Abstract The characteristics of the boron‐doped diamond (BDD) electrode in this work were studied by atomic force microscope (AFM), scanning electron microscopy, and Raman spectroscopy. The electro‐oxidation of formaldehyde at the BDD electrode in 0.5 M K2SO4 with different pH was studied by cyclic voltammetry and amperometry. There is no significant oxidation peak of formaldehyde in acidic solution because the oxidation of formaldehyde is at the potential range of water discharge. However, in neutral solution, there is a well‐defined oxidation peak at about +2.2 V vs. Ag/AgCl. The relation between the response current and formaldehyde concentration is linear behavior at the concentration range from 50 to 600 µM. Besides, in neutral solution, the oxidation of formaldehyde is dominated by indirect oxidation at lower formaldehyde concentration, and it is dominated by direct oxidation at higher concentration. Finally, in alkaline solution, the oxidation of formaldehyde is dominated by indirect oxidation caused by a powerful oxidant and is related to the ratio of the amounts of formaldehyde and OH molecules at the BDD electrode surface. 相似文献
20.
Richard Pazur Michel Troquet Jean-Luc Gardette 《Journal of polymer science. Part A, Polymer chemistry》1997,35(9):1689-1701
Polyisobutylene films (PIB) were submitted to a thermal oxidation at 100°C and to a photooxidation by exposure to long-wavelength radiations (λ ≥ 300 nm) at 60°C. The modifications of the chemical structure resulting from the oxidation were determined by FT-IR analysis of the polymer films, coupled to chemical treatments that converted specifically the oxidation products. Dissolution of oxidized samples permitted analysis of the polymer by 13C- and 1H-NMR. The structure of the volatile products was determined by mass spectroscopy analysis of the gas phase. Identification of the numerous products formed permitted the proposal of a scheme that accounts for the oxidation of PIB. When the irradiations are carried out at a temperature above 50°C, the depolymerization is favored and the mechanism involves two main routes of oxidation. A direct oxidation starts with the oxidation of radicals obtained by homolysis of the C C bonds on the main chain, and an induced oxidation involves hydrogen abstraction on the methylene and methyl groups by radicals formed by the direct oxidation of the polymer. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1689–1701, 1997 相似文献