Studies on conductance behaviour of magnesium soaps in lower aliphatic alcohols

Summary The colloid chemical behaviour of magnesium soaps in n-aliphatic alcohols has been investigated at various temperatures by conductivity method. The soaps form micellar aggregates and the c. m. c. determined is found to be independent of the nature of solvent. The conductivity behaviour of soaps is exhibited by an equation: log _M =A +B logc WhereA andB are constants andc is the concentration in g moles/litre. The values ofA increases with temperature whereas it decreases with increase in chain length of the solvent. The values of constantB are independent of temperature and chain length of the soap. The dissociation constant,K molecular conductance at infinite dilution and heat of dissociation,H° have been obtained graphically. The results confirm that c. m. c. remains unaffected by the change in temperature (35–50 °C).

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Zusammenfassung Es wurde das kolloidchemische Verhalten von Magnesiumseifen in geradkettigen aliphatischen Alkoholen bei verschiedenen Temperaturen untersucht. Die Seifen bilden mizellare Aggregate; die CMC erwies sich als unabhängig von der Natur des Lösungsmittels. Das Leitfähigkeitsverhalten läßt sich durch die Beziehung log _M = +B logc beschreiben. In dieser sindA undB Konstante,c die Konzentration in Mol pro Liter.A steigt mit der Temperatur und sinkt mit steigender Kettenlänge von Seife und Lösungsmittel.B ist temperatur- und kettenlängenunabhängig.Die erhaltenen Ergebnisse bestätigen, daß die CMC im Temperaturbereich 35–50 °C temperaturunabhängig ist.

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With 3 figures and 3 tables     

氨基膦酸树脂吸附镨的研究

氨基膦酸树脂 (简称ＡＰＡＲ)是一类性能优良的螯合树脂 ,功能基为 ＣＨ2 ＮＨＣＨ2 Ｐ(Ｏ) (ＯＨ) 2 ,由于功能基上同时含有Ｎ和Ｏ等配位原子 ,它能与多种金属离子形成比较稳定的配合物。近年来有关含磷的螯合树脂吸附金属离子的各种研究比较活跃[1～ 4] 。本文就氨基膦酸树脂在ＨＡｃ ＮａＡｃ体系中对镨 (Ⅲ )的吸附行为进行了研究。获得了诸多基本参数 ,为氨基膦酸树脂在湿法冶金中对镨离子的富集、提取等方面的应用提供了理论依据。1　实验部分1 1　试剂及仪器72 1型分光光度计 ,ＳＨＡ Ｃ水浴恒温振荡器(± 0 .1℃ ) ,ｐＨＳ 3ｃ型…     

Studies on molar volume and rheology of terbium soaps in a benzene-DMF mixture

Summary Molar volume (V), apparent molar volume (_v), and fluidity () of terbium soaps in benzene-DMF (7:3 v/v) were evaluated at constant temperature from density and viscosity measurements. The results were used to determine the critical micelle concentration (CMC), soap-solvent and soap-soap interactions, and the effect of the chain length of soap molecules on various parameters. The molar volume and viscosity results are discussed in terms of known relations.

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Untersuchungen zum Molvolumen und zur Rheologie von Terbiumseifen in Benzol-DMF

Zusammenfassung Molvolumen (V), scheinbares Molvolumen (_v) und Fluidität () von Terbiumseifen in einer Mischung aus Benzol undDMF (7:3 v/v) wurden bei konstanter Temperatur aus Dichte-und Viskositätsmessungen ermittelt. Aus den Ergebnissen wurden die kritische Micellenkonzentration (CMC), Seifen-Lösungsmittel- und Seifen-Seifen-Wechselwirkungen sowie der Effekt der Kettenlänge der Seifenmoleküle auf verschiedene Parameter bestimmt. Die Resultate bezüglich Molvolumen und Viskosität werden anhand bekannter Beziehungen diskutiert.

     

Studies on ultrasonic velocity and electrical conductivity of samarium soaps in non-aqueous medium

Summary The ultrasonic velocity of solutions of samarium soaps in non-aqueous medium has been measured at a constant temperature and the results have been used to evaluate the various acoustic parameters. The pre-micellar association and the formation of micelles in samarium soap solutions have been determined by conductometric measurements. The molar conductance at infinite dilution, degree of ionisation and ionisation constant have been evaluated. The results show that samarium soaps behave as weak electrolyte in dilute solutions.

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Untersuchungen zur Ultraschallgeschwindigkeit und elektrischen Leitfähigkeit von Samarium-Seifen in nichtwäßrigem Medium

Zusammenfassung Die Ultraschallgeschwindigkeit in Lösungen von Samarium-Seifen in nichtwäßrigem Medium wurde bei konstanter Temperatur gemessen, und die Ergebnisse wurden zur Auswertung verschiedener akustischer Parameter genutzt. Die vormicellare Assoziation und die Ausbildung von Micellen in Samarium-Seifen-Lösungen wurden mittels konduktometrische Messungen bestimmt. Die molare Leitfähigkeit bei unendlicher Verdünnung, der Ionisierungsgrad und die Ionisationskonstante wurden ermittelt. Die Ergebnisse zeigen, daß sich Samarium-Seifen in verdünnten Lösungen als schwache Elektrolyte verhalten.

     

Pseudophase behavior in the epsilon and iota regions of the praseodymium oxide-oxygen system

Besides line and nonstoichiometric phases complex oxide systems exhibit reproducible bivariant behavior, termed pseudophases, in the two-phase regions. This occurrence exaggerates chemical hysteresis. Two of these pseudophases in the praseodymium oxide-oxygen system are examined in some detail by tensimetric and high temperature X-ray studies.The tensimetric measurements show marked and progressive shifting of the curves away from stoichiometry with increasing pressure. In addition, unusual reversals are seen to occur both in oxidation and reduction. X-ray diffraction patterns at temperature are seen to show systematic changes in line positions and line widths. These are analyzed and their implications discussed in terms of suggested structural changes. Similarities and relevance to other systems are suggested.     

Potentiometric microanalysis of soaps and mixtures of soaps with anionic surfactants

Summary An attempt was made to find a method for potentiometric titration of soaps and mixtures of soaps and anionic surfactants. A liquid-membrane electrode based on bis(dimethylglyoxime)-l,10-phenanthrolinecobaltate(III) dodecyl sulphate was used. The effects of pH, ionic strength, and temperature on the titration were studied.

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Zusammenfassung Eine Methode zur potentiometrischen Titration von Seifen und Gemischen von Seifen und anionischen Schaummitteln wurde auszuarbeiten versucht. Eine Flüssigmembran-Elektrode aus Bis-(dimethylglyoxim)-l,10-phenanthrolincobaltat(III)-Dodecylsulfat wurde dazu verwendet. Die Wirkung von pH, lonenstärke und Temperatur auf die Titration wurden untersucht.

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Paper presented at the International Symposium on Microchemical Techniques, Davos, May 1977.     

Thermal decomposition of praseodymium acetate as a precursor of praseodymium oxide catalyst

Thermal events encountered throughout the heat treatment of praseodymium acetate, Pr(CH₃COO)₃·H₂O, were studied in nitrogen and air atmospheres. The samples calcined at the 300–700 °C temperature range were characterized using XRD, IR and N₂ adsorption. Moreover, in situ electrical conductivity was employed to follow up the formation of the different decomposition intermediates. The results indicated that the anhydrous salt decomposes to the final product, PrO_1.833, through the formation of the following intermediates: Pr(OH)(CH₃COO)₂, PrO(CH₃COO) and Pr₂O₂(CO₃). PrO_1.833 formed at 500, 600, and 700 °C possesses a surface area of 17, 16 and 10 m²/g and crystallites size of 14, 17 and 30 nm, respectively.     

Calculation of the crystal field parameters of praseodymium ethyl sulfate and praseodymium trichloride

A method of applying the extended Hückel molecular orbital method for the evaluation of crystal field parameters in the rare earth compounds is presented. The charge distribution in the crystal field and the effect of the outer coordinated sphere on the calculation of the crystal field parameters is discussed. From the calculated charge distribution, the crystal field parameters A₂₀r², A₄₀r⁴, A₆₀r⁶, and A₆₆r⁶ of praseodymium ethyl sulfate crystal and praseodymium trichloride crystal have been obtained. The calculated results are in agreement with the experimental data. Some possible sources of the error in the calculation are discussed.     

镨配合物的热化学及其对酵母菌作用的热动力学研究

用六水合氯化镨、硫代脯氨酸(C4H7NO2S)和水杨酸(C7H6O3)合成了三元固体配合物[Pr(C7H5O3)2(C4H6NO2S)]-2H2O.根据盖斯定律设计一个热化学循环,用溶解-反应量热法研究得到合成反应的标准摩尔焓变为(133.70±1.02)kJ/mol,配合物298.15K时的标准摩尔生成焓为-(2909.3±3.2)kJ/mol.用TAMair微量热仪测定其在28.00℃时对粟酒裂殖酵母作用的产热曲线,进而算出在配合物作用下,酵母菌生长代谢的最大发热功率Pmax、速率常数κ、传代时间tG、抑制率I和半抑制浓度cI,50等热动力学参数.结果表明:稀土水杨酸硫代脯氨酸配合物在低浓度下对酵母菌有刺激作用,高浓度下为抑制作用,即稀土配合物对微生物的生长具有双向生物效应,也称为Hormesis效应.     

Physico-chemical studies on manganese soaps in solid state

The physico-chemical characteristics of manganese soaps (caproate, caprylate and caprate) in solid state were investigated by infrared (IR), x-ray diffraction, magnetic and TGA measurements. The IR results revealed that the fatty acids exist in dimeric state through hydrogen bonding and manganese soaps possess ionic character. The x-ray analysis showed that manganese soaps have single-layer structure with molecular axes slightly inclined to the basal plane. The magnetic results suggested the presence of five unpaired electrons with octahedral geometry and possesssp ³ d ² hybridization. The thermal decomposition of these soaps is kinetically of zero order and the energy of activation for the decomposition process lies in the range 9.2–12.8 K Cal mol^–1.     

Physico-chemical studies on samarium soaps in solid state

Summary The physico-chemical characteristics of samarium soaps (caproate and caprate) in solid state were investigated by IR, X-ray diffraction and TGA measurements. The IR results revealed that the fatty acids exist in dimeric state through hydrogen bonding and samarium soaps possess partial ionic character. The X-ray diffraction measurements were used to calculate the long spacings and the results confirmed the double layer structure of samarium soaps. The decomposition reaction was found kinetically of zero order and the values of energy of activation for the decomposition process for caproate and caprate were found to be 8.0 and 7.8 kcal mol^–1, respectively.

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Physikochemische Untersuchungen an Samariumseifen in festem Zustand

Zusammenfassung Die physikochemischen Charakteristika von Samariumseifen (Caproat und Caprat) wurden im festen Zustand mittels IR, Röntgendiffraktion und TGA-Messungen untersucht. Die IR-Ergebnisse zeigten, daß die Fettsäuren durch Wasserstoffbrücken dimer vorliegen und daß die Samariumseifen partiell ionischen Charakter besitzen. Die Röntgenuntersuchungen bestätigen die Doppelschichtstruktur der Seifen. Die Zersetzungsreaktion verlief nach nullter Ordnung, und die Aktivierungsenergien für den Zersetzungsprozeß für Caproat und Caprat waren 8.0 und 7.8 kcal mol^–1.

     

Studies on the behavior of liquid hydrocarbon systems

A method for estimating the effect of intermolecular interaction and component structure on oil system properties is suggested. The results of calculations via the models of oil system properties taking into account their non-additivity are presented.     

Melting of saturated fatty acid zinc soaps

The melting of alkyl chains in the saturated fatty acid zinc soaps of different chain lengths, Zn(C(n)H(2n+1)COO)(2); n = 11, 13, 15, and 17, have been investigated by powder X-ray diffraction, differential scanning calorimetry, and vibrational spectroscopy. These compounds have a layer structure with the alkyl chains arranged as tilted bilayers and with all methylene chains adopting a planar, all-trans conformation at room temperature. The saturated fatty acid zinc soaps exhibit a single reversible melting transition with the associated enthalpy change varying linearly with alkyl chain length, but surprisingly, the melting temperature remaining constant. Melting is associated with changes in the conformation of the alkyl chains and in the nature of coordination of the fatty acid to zinc. By monitoring features in the infrared spectra that are characteristic of the global conformation of the alkyl chains, a quantitative relation between conformational disorder and melting is established. It is found that, irrespective of the alkyl chain length, melting occurs when 30% of the chains in the soap are disordered. These results highlight the universal nature of the melting of saturated fatty acid zinc soaps and provide a simple explanation for the observed phenomena.     

紫草素的电化学伏安行为研究

紫草素在0.2 mol/L HAc-NaAc缓冲溶液(pH4.3)中,产生灵敏的线性扫描极谱峰,峰电位EP=-0.186 V(vs.Ag/AgCl)。峰电流与紫草素浓度在5×10-7~1×10-5mol/L范围内呈良好的线性关系。可用于紫草中紫草素含量的测定。用线性扫描和循环伏安法测试表明,该体系属具有反应物吸附性的可逆过程体系。     

EDTA 介质中元素的 ICP-MS行为研究

研究了在EDTA介质中元素的ICP－MS质谱行为，探讨了在不同质谱条件下，EDTA的引入对不同元素分析信号的影响，结果表明：EDTA的引入对元素分析信号有不同程度的增强效应，氧化物产率明显降低，对轻质量元素^9Be,^59Co信号增强的100％，中质量元素^115In,^159Tb信号增强约20％，重质量元素^209Bi,^238U信号变化不明显：LaO^ /La^ ,CeO^ /Ce^ 产率降低约10％，与通常2％HNO3介质的溶液相比，在相同入射功率条件下，EDTA介质中信号达最佳时，需采用稍低的雾化气流速，实验了以有机酸形式引入钠盐对元素分析信号的影响。