水解聚合铝溶液中Al_(30)形态的研究

水解聚合铝形态一直是分析、催化、土壤、地球化学、新材料、环境科学和生物毒理学等众多领域研究的前沿和热点。Keggin结构的Al30形态是迄今为止发现的电荷最高的水解铝聚合阳离子,具有独特的分子结构和纳米分子尺寸,它对催化化学、新型功能材料、高效絮凝剂的开发以及铝的水解聚合转化规律研究具有重要意义。本文主要论述了Al30形态的形成、形态分析方法、结构模型以及形成机理等方面的最新研究进展,并对水解聚合铝溶液的研究发展趋势进行了展望。     

水解聚合铝溶液中Al30形态的研究*

水解聚合铝形态一直是分析、催化、土壤、地球化学、新材料、环境科学和生物毒理学等众多领域研究的前沿和热点。Keggin 结构的Al₃₀ 形态是迄今为止发现的电荷最高的水解铝聚合阳离子,具有独特的分子结构和纳米分子尺寸,它对催化化学、新型功能材料、高效絮凝剂的开发以及铝的水解聚合转化规律研究具有重要意义。本文主要论述了Al₃₀形态的形成、形态分析方法、结构模型以及形成机理等方面的最新研究进展,并对水解聚合铝溶液的研究发展趋势进行了展望。     

水解聚合铝溶液中Al30形态的研究

水解聚合铝形态一直是分析、催化、土壤、地球化学、新材料、环境科学和生物毒理学等众多领域研究的前沿和热点。Keggin 结构的Al₃₀ 形态是迄今为止发现的电荷最高的水解铝聚合阳离子,具有独特的分子结构和纳米分子尺寸,它对催化化学、新型功能材料、高效絮凝剂的开发以及铝的水解聚合转化规律研究具有重要意义。本文主要论述了Al₃₀形态的形成、形态分析方法、结构模型以及形成机理等方面的最新研究进展,并对水解聚合铝溶液的研究发展趋势进行了展望。     

羟基聚合铝晶体研究进展

羟基聚合铝的研究在环境化学中具有重要作用。自然条件下存在的无机单核铝本身具有毒性,而多核铝是比单核铝更毒的铝形态,它们很容易进入人体和植物产生毒害作用。因此,水解聚合铝形态研究一直是环境化学、地球化学和材料催化等众多研究领域的前沿热点课题。本文综述了在新环境材料开发中羟基聚合铝晶体研究的进展,对已获得表征的典型羟基聚合铝的结构特点进行了对比与评述,讨论了不同羟基聚合铝晶体的科学意义和应用价值。     

水解聚合铝阳离子Al13和Al30的27Al核磁共振定量研究

采用不同磁场强度的NMR谱仪和不同测试温度,对水解聚合铝溶液中Keggin结构的聚合铝阳离子形态的定量分析方法进行了研究。检测结果表明,高场27A l NMR分析技术不仅能精确定量地检测出水解聚合铝溶液中具有Keggin结构的[A lO4A l12(OH)24(H2O)12]7 (简称A l13)聚合阳离子,而且还能定量地检测出[(A lO4)2A l28(OH)56(H2O)26]18 (简称A l30)聚合阳离子。提高测试温度,有利于降低A l30共振峰的线宽,增强其分辨率。在70℃测试温度下,采用高场27A lNMR分别对8种中、高浓度(0.1~2.0 mol/L)水解聚合铝溶液中的A l13和A l30形态分布进行了定量研究,证实了A l30形态是高浓度水解聚合铝溶液中的一种优势聚合形态。     

通过Boltzmann拟合方程定量计算Al(Ⅲ)盐强制水解聚合溶液中的羟基多核铝型体

在表征聚合铝的3种传统测试方法中,只有酸碱电位滴定法至今还没有用于定量计算羟基多核铝。本文依据Al(Ⅲ)盐强制水解聚合过程的电位滴定实验结果,利用铝盐水解聚合电位滴定曲线的三个临界特征点,同时利用Origin软件自备的Boltzmann方程对滴定曲线拟合,可以很方便地计算出铝盐强制水解聚合溶液中聚合铝的含量。模式计算结果与Al-Ferron逐时络合比色法的测试结果线性符合较好,为研究Al(Ⅲ)盐水解聚合过程及其聚合铝形态的定量测定尝试了一种新的方法。     

聚合硫酸铝的盐基度及其混凝性能

采用硫酸铝为主要原料制备了高稳定性的聚合硫酸铝,并对其盐基度、铝的水解聚合形态分布、混凝性能及其影响因素进行了研究。结果表明,在室温条件下,聚合硫酸铝在对不同水样进行混凝处理后,水中余浊随盐基度的增加先降低后升高,其中盐基度为53.8%的聚合硫酸铝混凝效果最好,对流溪河水及高岭土水的除浊率均在90%以上。与硫酸铝及聚合氯化铝相比,聚合硫酸铝具有更宽广的温度和pH的适用范围及更快的水解絮凝速度。通过对聚合硫酸铝中铝的水解聚合形态分布和混凝性能的综合分析表明,Alb为混凝优势形态。     

铝盐水解聚合及其形态转化过程的电位滴定曲线研究

通过对中等滴碱速度下强制铝盐水解聚合过程中的电位滴定曲线分析,提出了临界点的概念。临界点是铝盐水解聚合电位滴定曲线的特征点,它与实验条件有关,临界点的变化反映了实验条件对铝盐水解聚合过程和羟基铝形态转化的影响．按照OH与Al摩尔比的大小,利用铝盐水解聚合电位滴定曲线的3个临界特征点,可以将铝的形态变化定量地划分为4个区：即水解单核铝区（包括Al^3 和单核铝Ala);低／中聚合铝区(主要包括Al2～Al12形态);高聚合铝区(主要包括AL13～AL54形态)和溶胶／凝胶区(Ale即Al(OH)3形态);溶胶／凝胶溶解区主要形态为Al(OH)4^-),从而为研究铝的水解聚合过程提供了定量基础。同时考察了铝浓度、温度、卤素离子、硅酸根、有机酸根等多种凶素对铝溶液碱滴定pH～n曲线及其划分铝形态临界点的影响,探讨了这些凶素对铝盐水解聚合过程及其形态转化的影响规律,为研究各种凶素对铝的水解聚合过程的影响提供了一种新思路。     

多碱化学的研究—纪念恩师戴安邦教授逝世一周年

本文为戴安邦教授及其学生们关于多碱化学的研究的回顾和总结 ,叙述了他的早期工作 ,Cr3 的水解聚合 ,富马酸和马来酸存在下Cr3 的水解聚合 ,及稀土离子的水解聚合。这项研究对实用领域是有益的 ,诸如核化学 ,鞣革及塑料与金属的粘接     

温度和电极互换频率对电解过程中聚合Al13形成的影响

聚合铝作为一种无机高分子絮凝剂,具有比传统絮凝剂如硫酸铝、氯化铁等效能优异,比有机高分子絮凝剂价格低廉等优点[1￣3]。研究表明,聚合铝絮凝剂实际上是在一定条件下控制铝的水解-聚合-沉淀过程的中间产物,其溶液除存在铝的单体及二聚体外,     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Effect of the Method of Modification of Zeolite X on Selectivity of Catalytic Methylation of Toluene

Theoretical and Experimental Chemistry - The effect of the method of modification of catalysts based on zeolite X by cesium and magnesium cations (ion exchange and impregnation) on the selectivity...