火焰原子吸收光谱法测定齿科烤瓷修复用金基和钯基合金中银的不确定度评定

探讨了火焰原子吸收光谱法测定齿科烤瓷修复用金基和钯基合金中银的不确定度的评价方法。分析了不确定度的重要来源,包括称样质量、标准溶液的配制、工作曲线拟合、试液定容体积及测量重复性等引入的不确定度分量组成。对各不确定度分量进行分析计算,求得标准不确定度为0.023%,扩展不确定度为0.046%。     

石蜡相光度法测定痕量钯

本文系统研究了钯（Ⅱ）与１－亚硝基－２－萘酚显色体系酚显本系在石蜡相中的显色反应。在ＰＨ＝０．０６～１１．０范围内,石蜡能定量吸附此显色络合物。采用等吸收点双波长光度法测定固相吸不镀差值,钯的含量在０～１．４ｍｇ／Ｌ范围内符合比一律,从而建立了钯的石蜡相光度分析法。方法应用于钯分子中痕量钯的测定,结果满意。     

国外钯分析研发动态

1钯的最新标准分析方法 根据2003年版ASTM标准方法,钯的分析方法有3个。     

三正辛基氧化膦萃取钯的研究

本文研究了用三正辛基氧化膦(TOPO)煤油溶液从盐酸介质中萃取钯及用硫脲反萃钯的条件。用等摩尔系列法、饱和法、化学分析法和斜率法确定了萃合物的组成。用紫外-可见光谱法探讨了TOPO萃取钯的机理。     

N, N''－双［(1－苯基－3－甲基－5－氧－4－吡唑啉基)亚苄基］乙二亚胺萃取钯的机理及钯－铂体系中钯的选择性萃取

本文首次报道了标题试剂Ｈ２Ａ对钯的萃取行为，确定了萃取物的组成，讨论了萃取机理，算出了萃取平衡常数，通过化学分析、红外及拉曼光谱，紫外光谱，研究得出了萃合物的结构，并且实现了Ｈ２Ａ从钯－铂混合溶液中选择性萃钯。     

含氮配体的分子内邻位钯化反应

总结了近年来含氮配体的分子内邻位钯化反应,分析了钯化试剂、金属环大小、溶剂以及底物结构等因素对钯反应的影响以及它们在有机合成中的应用,讨论了邻位钯反应的机制。     

钯盐中负离子对聚合物载钯催化剂加氢性能的影响

将三种钯盐（Ｐｄ（ＯＡｃ）２，ＰｄＣｌ２，ＰｄＩ２）分别与聚乙烯苄二甲胺反应，然后将其还原制成三种不同的高分子负载钯金属催化剂，考察了起始钯盐中负离子的不同对所合成的高分子催化剂表面上钯粒子大小，钯粒子分布状况的影响及催化剂的催化性能。研究结果表明，由Ｐｄ（ＯＡｃ）２制备的高分子载钯催化剂具有最好的催化活性和使用寿命。     

钯复合膜的研究进展

钯复合膜具有很高的透氢选择性以及良好的化学和热稳定性,一直是膜技术领域的研究热点。本文综述了近年来在钯复合膜透氢机理、钯膜制备方法以及钯膜反应器等方面的研究进展;着重讨论了近3年来钯复合膜制备方法的新进展,包括超临界条件下制备钯复合膜的新技术等内容;总结了钯复合膜在脱氢、部分氧化以及耦合反应过程中应用的一些代表性工作,并对钯复合膜制备与应用的发展趋势进行了展望。     

电感耦合等离子体原子发射光谱测定铂钯渣中铂、钯含量

铂钯属于贵金属,对于冶炼企业而言,有效回收铂钯,可以提高生产经营单位的经济效益。本文针对某铜冶炼企业工艺中产生的铂钯渣中铂、钯含量较高、难以溶解、不宜直接测定等问题,研究了一种测定铂、钯含量的新方法。首先对铂钯渣样品进行火试金熔融、富集,溶解,再用电感耦合等离子体原子发射光谱仪 (ICP-AES) 测定,方法精密度和准确度好。     

TBA浸渍树脂对钯的吸附性能及应用

研究了三苄胺浸渍树脂吸附钯的机理、溶液酸效应、吸附等温线、吸附容量1吸附速率及操作条件等，用于测定钯催化剂中微量钯，取得了较好的效果。     

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.     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

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.

     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。     

Investigation of Kinetics of Solid-Phase Synthesis of Lithium Orthosilicate

The kinetics of the interaction between lithium carbonate and silica with various degrees of dispersion was investigated by TG and DTA methods. It was found that the utilization of pyrogenic silica with a specific surface area of about 300 m²g^-1 instead of aerosil with one of 175 m²g^-1 leads to an increase of the reaction rate between lithium carbonate and silica, which depends on the formation and growth of lithium orthosilicate crystals in the first stage, and is conditioned by the diffusion of lithium and oxygen ions through the lithium orthosilicate layer formed at temperatures above 800 K. This supposition is supported by the kinetic analysis results obtained with the use of the different models. The optimal regime of heating is recommended. This revised version was published online in July 2006 with corrections to the Cover Date.     

小环化合物中饱和碳质子化学位移的计算

小环化合物由于其张力、构型、构象和各向异性效应等原因,环碳上质子化学位移缺乏规律性,难以预测,对此作者曾提出一种近似算法。本文根据303种小环化合物中饱和碳质子的化学位移实验数据,将适于计算这类质子化学位移的公式表述为:     

解决能源问题的新途径--光解水制氢的研究

面对日益枯竭的能源危机,氢能是一种洁净、最有前景的替代能源。目前在各种制氢的方法中光催化分解水制氢的研究最多,光解水过程中催化剂最关键,本文对利用太阳能光解水的途径、提高光催化反应效率以及光催化剂的开发研究进行了综述。