N－乙酸基取代四氮杂大环及其镧系配合物的热力学研究

用ｐＨ电位滴定法分别在２５±０．１℃，４０±０．１℃和８０±０．１℃，０．５ｍｏｌ／ＬＫＮＯ３水溶液中测定了Ｈ_４Ｌ（５，７，１２，１４－四甲基－１，４，８，１１－四氮杂环十四烷－Ｎ＇，ｎ＂，Ｎ＂＇，Ｎ＂＂－四乙酸）的逐级质子化常数和焓值。又在４０±０．１℃和８０±０．１℃条件下测定了Ｈ４Ｌ与镧系金属离子（Ｌａ~（３＋），Ｎｄ~（３＋），ｐｒ~（３＋），Ｓｍ~（３＋），Ｅｕ~（３＋），Ｇｄ~（３＋），Ｄｙ~（３＋），Ｙｂ~（３＋））配合物的稳定常数。结果表明：配合物稳定性高。     

Synthesis of inorganic-organic hybrids by incorporation of inorganic components into organic polymer using metal alkoxides

Inorganic-organic hybrids have been synthesized by incorporation of the inorganic component of Ti(OC₂H₅)₄ into the organic polymer of ethyl cellulose. The inorganic-organic hybrids did not dissolve in toluene used as a solvent for the starting materials. The ethanol was formed as a by-product of the alcoholysis condensation reaction between Ti(OC₂H₅)₄ and ethyl cellulose. These results suggest that ethoxy groups of Ti(OC₂H₅)₄ react with hydroxy groups of ethyl cellulose to form cross-linking bonds of –O–Ti–O–. The reaction of Ti(OC₂H₅)₄ with ethyl cellulose was further investigated by Fourier transform infrared (FT-IR) spectroscopy. The FT-IR spectroscopic experiments revealed that the Ti–O bond state of Ti(OC₂H₅)₄ was changed by refluxing a toluene solution of Ti(OC₂H₅)₄ with ethyl cellulose. The inorganic-organic hybrids have an interesting dielectric property; their dielectric constant is higher than that of ethyl cellulose and that of a simple mixture of TiO₂ and ethyl cellulose.     

固定pH滴定法测定弱酸弱碱性药物

报道一种水溶液吕测定弱酸弱碱性药物的新型滴定分析方法－固定ｐＨ滴定法，其理论基础是弱酸弱碱在水溶液中各种存在形式的分布系数在ｐＨ值固定时为常数，对甲硝唑，盐酸美西律等离散常数在１０＾－８至１０＾－１１范围内的７种弱酸弱碱性药物进行测定。结果与药典法吻合，回收率在９９．４％～１００．６％，方法简便，快速，准确，制剂中的赋形剂及色物不影响测定。     

Volumetric study on the inclusion complex formation of α- and β-cyclodextrin with 1-alkanols at different temperatures

The partial molar volumes (V_a) of 1-alkanols (carbon number, m=5, 6, 7) in - and -cyclodextrin (CD) solutions at 5.00 mmol kg^–1 have been determined as a function of alkanol concentration (C_a) between 293.2 and 308.2 K by using a dilatometer. It has been observed that with an increase in C_a, V_a increased in -CD solution but decreased in -CD solution, asymptotically to a value of V_a in CD-free water. The dependence of V_a on C_a provided the binding constant (K) of 1:1 complex, the volume change in complex formation, and the partial molar volume of complex itself. The complex formation mechanism has been discussed on the basis of these values and their carbon number dependences in the respect of geometric behavior, hydrophobic interaction, and van der Waals interaction. It is concluded that the CD cavity in water is not rigid but flexible for fitting in nicely with guest molecule.     

Novelties of solid-liquid phase transfer catalysed synthesis of p-toluenesulfonyl fluoride from p-toluenesulfonyl chloride

Organic sulfonyl fluorides are of interest owing to their insecticidal, germicidal and enzyme inhibitory properties. In the current work, synthesis of p-toluenesufonyl fluoride was accomplished by reacting p-toluenesulfonyl chloride with solid potassium fluoride using PEG-400 as a catalyst under solid-liquid phase transfer catalysis (S-L PTC) at 30 °C. p-Toluenesulfonyl fluoride is used as peroxygen bleach activator. It also finds use in the treatment of Alzheimer's disease. The mechanism is based on homogeneous solubilization of solid. PEG forms a complex with metal cation which associates with the nucleophile and it participates in SN₂ type reactions. The reaction is intrinsically kinetically controlled. A complete theoretical analysis is done to determine both the rate constant and equilibrium constant from the same set of data. The activation energy and Gibbs free energy are also calculated.     

Clathrate formation and phase transitions in β-hydroquinone

Clathrate thermodynamic stability conditions and the phase transitions associated with either the orientational ordering of the guest molecules or with the condensation of the guest molecules in the host lattice are investigated by means of the common microscopic model. The theory proposed describes the thermodynamic properties of -hydroquinone (Q ) clathrates. The dielectric constant (T) was measured experimentally inQ ·CH₃OH andQ ·SO₂ in the temperature range from 4.2 to 300 K and the phase transitions were found. It is shown that the theory qualitatively explains the experimental data obtained.Dedicated to Professor H. M. Powell.     

硅酸及其盐的研究 ⅩⅩⅠ.三甲基硅烷化-气相色谱法测定单硅酸的离解常数

单硅酸的离解常数是表征其基本性质的重要数据,前人已有不少工作,但由于测定的方法和实验条件不同,所得数据很不一致。     

A new approach to the determination of the statistical segment length of wormlike polymers

The Stockmayer-Fixman-Burchard (SFB) and the Dondos-Benoit (DB) equations have been applied to determine the unperturbed dimensions parameterK of wormlike polymers. An empirical relation between the Flory's constant and the Mark-Houwink-Sakurada (MHS) exponenta has been proposed. The values found by this equation are lower than the value 2.5×10²³ used in the case of flexible polymers and this deviation is attributed to the influence of the draining effect. From theK value and the so calculated value of , we calculate the Kuhn statistical segment length of wormlike polymers. The obtained — for a great number of wormlike polymers — statistical segment lengths are almost the same as these calculated by the Yamakawa-Fujii and the Bohdanecky methods. The molecular mass regions in which the SFB, the DB, and the MHS equations are valid are explored. A criterion for the distinction between flexible and wormlike polymers is proposed based on the way of approach to the power law.     

Influence of CTAB/alkanol/cyclohexane w/o microemulsions on the basic hydrolysis of crystal violet

The basic hydrolysis of crystal violet has been studied in w/o microemulsions of the CTAB/alkanols/cyclohexane system (alkanols: 1-butanol and 1-hexanol). The reaction can be considered to occur in the water phase of the droplets and from the rate constant the apparent dielectric constant of the water phase was determined. The cyclohexane incorporation in the system produces a decrease in the effective dielectric constant of the water phase and in the specific conductivity.