聚合温度对聚甲基丙烯酸三丁基锡酯等规度的影响(Ⅰ)

本文测定了0—130℃温度范围内,由~(60)Co-γ射线和两种活性不同的引发剂引发聚合的聚甲基丙烯酸三丁基锡酯的等规度。利用~(13)C-NMR测定聚合物分子链的等规度,如预料的那样,以间同立构为主,并随着聚合温度的升高间同立构等规度降低。作者认为影响聚合物等规度的因素主要是取代基的极性效应。计算出的控制等规度的活化能参数与聚甲基丙烯酸甲酯和聚甲基丙烯酸三甲基锡酯的属同一数量级,可相互比较。     

磷酸锡晶体去除海水中Pb(Ⅱ)研究

利用合成的磷酸锡晶体作为吸附剂,考察了pH值、吸附时间、初始浓度、温度等因素对吸附水溶液中Pb2+的影响,同时考察了在模拟海水中的吸附效果。结果表明,磷酸锡对Pb2+的吸附量随着pH(3~6)以及吸附时间的增大而增加。吸附动力学过程符合准二级动力学模型。等温吸附数据用Langmuir方程拟合效果最好,20℃时饱和吸附量达到110.50mg/g。Dubinin-Radushkevich(D-R)模型研究表明吸附机理属于化学离子交换。反应机理为磷酸锡中的H+与溶液中的Pb2+发生了离子交换反应。热力学研究表明磷酸锡对Pb2+的吸附是一个自发的、吸热的过程,升温有利于吸附。模拟海水中Pb2+的吸附实验结果表明,高盐度对磷酸锡吸附Pb2+有一定的不利影响,但幅度不大,可以用于去除养殖海水中的Pb2+。所吸附的Pb2+可以用HCl解吸,说明磷酸锡具有重复利用的潜能。     

DECARBONYLATION OF ACYLCHLOROBIS-(TRIPHENYLPHOSPHINE) PLATINUM(II) COMPLEXES PROMOTED BY TIN(II) CHLORIDE

Abstract

While it might be expected that the availability of vacant coordination sites in the four coordinate acyl complexes trans[Pt(PPh₃)₂ (RCO)Cl] provides low energy pathways for alkyl and aryl migration and subsequent decarbonylation, the decarbonylation has been previously achieved only at elevated temperatures. The addition of SnCl₂ greatly facilitates decarbonylation of [Pt(PPh₃)₂ (RCO)Cl] where R is CH₃, C₂ H₅, Y[sbnd]C₆ H₄. Compounds of the type [Pt(PPh₃)₂ (RCO)SnCl₃] and [Pt(PPh₃)₂ R(SnCl₃)] have been isolated. The removal of SnCl₂ from these compounds has been achieved with ethanol. A kinetic study of the decarbonylation of [Pt(PPh₃)₂ (RCO)SnCl₃] (where R is CH₃, C₂ H₅, Y[sbnd]C₆ H₄ for Y=H, CH₃, CH₃ O, NO₂, Cl) is reported. The role of 3 and 5 coordinate intermediates in alkyl-aryl migrations in Pt(II) systems is discussed.     

Electron Transfer Studies of TIN(IV)/TIN(II) in Acid Media

Abstract

Cyclic voltammaetry of mixed tin(II)/tin(IV) solutions was investigated in 6M HCl on gold and mercury electrodes. It was found that the reduction of tin(II) to tin(iv) proceeded irreversibly while tin(II) to tin(IV) was reversible. Two forms of tin(IV) are postulated. The peak potential for the reduction of tin(IV) was a function of both tin(II) and tin(IV) while that for the oxidation of tin(II) was a function only of tin(II) concentration Potentials for all oxidations and reductions were a function of potential scan rate.     

Tetrachloro (NN-dimethylformamide) (dimethylsulphoxide) TIN (IV) revisited

The previously reported mixed ligand compound SnCl₄ (DMF) (DMSO) (DMF=NN-Dimethylformamide, DMSO=Dimethylsulphoxide) has been studied by IR, Raman and Mössbauer spectroscopy. Our results confirm its homogeneity with the DMF and DMSO ligands coordinating in cis position through the oxygen atoms. The compound does not isomerize when heated to 135 C, but decomposes giving rise to cis-SnCl₄(DMSO)₂ and trans-SnCl₄ (DMF)₂.     

REACTIVITY OF HALIDE COMPLEXES OF TIN(II) I. The Reduction of Methyl Orange

Abstract

Halide ion is required for the reduction of methyl orange by Sn(II). Equilibrium data on the formation of SnCl^2-n _n and SnI^2-n _n combined with kinetic data indicate that SnCl₃ ^? and SnI₃ ^? form activated complexes with protonated methyl orange. The data also suggest pathways involving SnCl₄ ^? SnCl₅ ³, SnI₅ ³ and SnI₇ ^5-.     

薄层树脂吸光光度法测定痕量锡（Ⅳ）研究

提出了薄层树脂相光度法测定锡的操作条件，采用在0．1mol.L^-1的HCl介质中，以水杨基荧光酮（SAF）为显色剂，用阴离子交换树脂吸附测定锡，灵敏度比溶液光度法提高80倍，除As（Ⅲ），Sb(Ⅲ),Fe(Ⅲ)外，其余共存离子基本无干扰，测定了天然水中锡，加标回收率为93％－99％。Ⅲ     

桑色素与二氯化双（丁氧羰乙基）锡的显色反应及其应用

在pH 3.0的HOAc NaOAc缓冲介质中 ,有TritonX 10 0存在下 ,二氯化双 (丁氧羰乙基 )锡 (R2 SnCl2 )与桑色素形成 1∶1的有色络合物。该络合物最大吸收波长在 4 2 0nm ,表观摩尔吸光系数为 3.33× 10 4 L·mol- 1·cm- 1。R2 SnCl2 中的锡浓度在 0～ 4 .0mg·L- 1范围内符合比耳定律。方法用于测定PVC中间产品及排放污水中R2 SnCl2 的测定 ,结果满意     

络合滴定法测锡进展

介绍和讨论了络合滴定测锡的方法,锡离子水解的防止,测锡常用的掩蔽或解蔽剂、返滴定剂和指示剂,以及同时测定锡和其它金属离子等。     

QUANTUM CHEMICAL STUDY OF TIN–SUBSTITUENT BONDS IN TRICOORDINATED TIN COMPOUNDS

Journal of Structural Chemistry - A quantum chemical study of tin–substituent bonds in tricoordinated tin compounds is conducted using the PC GAMESS-Firefly package. The structures of the...     

THE ROLE OF LIPOPROTEINS IN THE DISTRIBUTION OF TIN ETIOPURPURIN (SnET2) IN THE TUMOR-BEARING RAT

The role of plasma lipoproteins in the distribution of the photosensitizing agent tin etiopurpurin (SnET2) was examined in male rats bearing the N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide-induced tumor. Treatement with 17α-ethinyl estradiol resulted in the depletion of total plasma cholesterol by > 70% and a corresponding decrease in plasma lipoproteins. To both control and estradiol-treated animals, a therapeutic dose (1.5mg/kg) of SnET2 was administered and biodistribution measured 24 h later. Estradiol treatment was not associated with difference in the distribution of SnET2 to liver, skin or tumor, or in the pattern of affinity of SnET2 to plasma albumin and lipoprotein. These results indicate that a substantial decrease in circulating lipoprotein levels does not alter patterns of SnET2 biodistribution.     

锡(Ⅳ)-柠檬酸-溴邻苯三酚红-溴化十六烷基三甲基铵显色体系及其应用

在 pH 1.8的氯乙酸缓冲溶液中和有溴化十六烷基三甲基铵存在下 ,锡 (Ⅳ )和柠檬酸及溴邻苯三酚红形成 1∶1∶2的橙红色胶束混配络合物。该络合物最大吸收波长为 5 34nm ,表观摩尔吸光系数为 1.72× 10 5L·mol- 1·cm- 1。锡 (Ⅳ )浓度在 0～ 0 .2 4mg·L- 1范围内符合比耳定律。方法的灵敏度、选择性和稳定性均比无柠檬酸存在时好 ,可用于食品包装盒中微量锡的测定。     

锡锭的直读光谱分析

应用直读原子发射光谱法分析了锡锭中9种杂质元素,对各元素的分析线及测定的分析参数,包括试样制备的要求,校正曲线的拟合等进行了试验及优化。此方法的特点是试样制备较简单,且避免了污染。各元素的检出限在0.000 9~6 mg.kg-1之间。RSD值在1.76%~9.09%之间,应用此方法分析了两件标准样品中各8种杂质元素,所得结果与证书值相符。     

蒸镀薄膜的分形生长行为

自Mandelbrot的分形几何学问世以来,分形理论的应用日趋广泛。在薄膜生长方面亦是如此。真空蒸镀薄膜的生长遵循着一定的规律。基本上是:(1)成核在此期间形成小的晶核,它们按统计规律分布(有一些例外)在基片表面上;(2)晶核生长并形成较大的岛这些岛通常具有小晶体(微晶)的形状;(3)岛(微晶)和岛(微晶)之间聚集并形成含有空沟道的许多连接着的网络;(4)沟道被填充,形成连续的薄膜。     

Cation Exchange and Sorption Properties of TIN(IV) Phosphate

The ion exchange and sorption properties of crystalline Tin bis(monohydrogen orthophosphate) monohydrate of composition Sn(HPO(4))(2).H(2)O were studied in an aqueous solution of KCl over the temperature range 300-320 K, varying the pH and metal ion concentration in the solution. The data were explained on the basis of the law of chemical equilibrium. The metal ion sorption data were fitted to the Langmuir adsorption equation to evaluate the Langmuir parameters. The extent of adsorption was found to increase with an increase in temperature and metal ion concentration in the selectivity order Cu(2+)>Co(2+)>Ni(2+). The Langmuir parameters were used to calculate the thermodynamic functions like standard entropy, enthalpy, and free energy changes during the process of sorption. Copyright 2000 Academic Press.     

锑精矿中锡的快速测定

报道了大量锑中微量锡的分离方法。在一定的碱量条件下，使锑大部分沉淀，分离后的溶液用水杨基荧酮进行锡的光度法测定。     

导数示波极谱法测定锡铅

在Ｈ２ＳＯ４－Ｈ２Ｃ２Ｏ４介质中,用示波极谱法,Ｐｂ（Ⅱ）和Ｓｎ（Ⅳ）－ＤＰＧ体系可产生灵敏的络合吸附波。铅和锡的浓度分别在０．０８～１．６ｍｇ·Ｌ＾－１和０．０１～０．４ｍｇ·Ｌ＾－１范围内与各自的导数波高呈线性关系关系,检出限分别为０．０１ｍｇ·Ｌ＾－１和０．００２ｍｇ·Ｌ＾－１,并用于硬聚氯乙烯饮用水管材和管件酸浸泡液及饮用水中微量铅和锡的测定,结果满意。同时,测得Ｓｎ（Ⅳ）－Ｃ２Ｏ４＾２－