A view and a review of the melting of alkali metal halide crystals

Summary A representational model, proposed to account for the physical changes that accompany the melting of alkali halides, was described in Part 1 [1]. The liquid is portrayed as undergoing continual dynamic structural reorganization of its constituent ions between individual small domains, zones of various regular, crystal-type arrays. These alternative arrangements are stabilized by the enthalpy of melting, which, in liquids, relaxes the restriction for solids that only the single, most stable, crystal structure can be present. The dynamic character of the melt accounts for its fluid character and the loss of long-range order [1, 2]. This model is extended here to consider the phase diagrams of binary, common ion, alkali halide mixtures comprehensively reviewed in [3]. Factors determining whether each of these yields a eutectic, or a solid solution, on cooling are discussed and several trends in the 70-phase diagrams are identified. Eutectic formation, involving maintenance of the liquid state below the melting points of the pure components, is ascribed to the participation, in an extended dynamic equilibrium, of additional domains having the regular structures characteristic of double salts. The known crystalline double binary halides [3], Li/Cs or Rb/F, Cl, Br or I, melt at temperatures well below those of the simpler pure component salts. It is concluded that the set/liq model for melting, proposed in [1, 2], accounts for some important properties of the phase diagrams presented in [3].     

Solvent extraction and bulk liquid membrane transport of Co(II) and Ni(II) ammine cations by proton-ionizable crown ethers

Separation efficiencies and selectivities in solvent extraction of Co(II) and Ni(H) ammine cations from aqueous solutions into chloroform and toluene and in transport through bulk toluene membranes by proton-ionizable crown ethers have been determined. Six proton-ionizable crown ethers with differing lipophilicities, polyether cavity sizes and ionizable groups (carboxylic and sulfonic acid functions) were examined. Higher selectivity and efficiency for Co(II) ammine cation extraction was observed for the more lipophilic, proton-ionizable crown ethers. Highly lipophilic crown carboxylic acids provided effective and selective transport of Co(II) ammine cations through bulk toluene membranes.Presented in part at the 6th International Symposium on High Purity Materials in Science and Technology: Preparation, Characterization and Application of Well-Defined Materials, Dresden, GDR, May 1985, Poster D91, Poster Abstracts, pp. 144, 145.All extraction and transport experiments were conducted at this location.     

电位法测定异价阳离子通过阳离子交换膜时的选择透过性

从理论上导出了不等价的两种阳离子在通过阳离子交换膜时的选择透过性与膜电位的关系，并用电位法对一些不等价阳离子组合在两种商品膜中的选择透过性进行了测定。本方法测定结果与电渗析实际分离效果相符。     

药用缓释辅料——羟丙基甲基纤维素的合成及其缓释性能的研究

本文研究了药物缓释材料HPMC的合成方法,探讨了碱纤维素制备,醚化剂浓度,混合醚化剂配经以及产品后处理对高粘度HPMC的影响。本文还初步对KCl,氨茶碱,硝酸异山梨醇酯等药物采用合成的HPMC作辅料,进行了缓释制剂的研究,结果表明合成的HPMC具有满意的缓释性能。     

Initiation of cationic polymerization of n-butyl vinyl ether by stable cation radicals of substituted phenothiazines

3,7-Diethyl- 10-phenylphenothiazine (DEPPT), a phenothiazine derivative whose 3,7- and 10-positions are blocked, was synthesized. Potentiostatic electrolysis of DEPPT in acetonitrile (ACN) in the presence of 0.1M of LiClO₄ at 0.7 V (vs. Ag/Ag/Cl) yielded the stable cation radical of DEPPT (DEPPT^+·) which was characterized by cyclic voltammetry, UV-visible spectroscopy, and ESR spectrometry. Stable cation radicals of 10-phenylphenothiazine and 3,7-diethyl-10-methylphenothiazine were also prepared. The cationic polymerization of n-butyl vinyl ether was initiated by these cation radicals, including DEPPT^·+. The electron transfer mechanism for the initiation step, which we proposed previously, was supported by the fact that DEPPT^·+ was capable of initiating the polymerization; dimerization of DEPPT^·+ by releasing protons is precluded because 3,7- and 10-positions are all blocked. © 1994 John Wiley & Sons, Inc.     

Design of Supramolecular Cyclodextrin Complex Sensors for Ion and Molecule Recognition in Water

The design and function of novel supramolecular fluoroionophore/cyclodextrin (CyD) complex sensors for ion and molecule recognition in water are reviewed. For the crown ether fluoroionophore/-CyD complex, the dimerization of the fluoroionophore inside the -CyD is found to be selectively promoted by alkali metal ion binding, thereby resulting in metal-ion-selective pyrene dimer emission in water. This supramolecular function is successfully utilized in the design of a podand fluoroionophore/-CyD complex for sensing toxic lead ion in water. The boronic acid fluoroionophore/-CyD complex binds sugars and produces increased fluorescence emission in water. The response mechanism appears to be due to the suppression of the photoinduced electron transfer (PET) from pyrene donor to trigonal phenylboronic acid acceptor. This is a novel emission function provided by the boronic acid fluoroionophore/-CyD complex sensors in water.     

Photocrosslinking of copolymers of vinyloxyethyl methacrylate–styrene initiated by sulfonium salts. I. Transient species formed on photolysis of sulfonium salt

Benzyl cation was detected by transient absorption spectroscopy with a spectroscopic multichannel analyzer on pulse excitation (fourth harmonic of Nd:YAG laser, 266 nm; 10 ns fwhm) of benzyl(4-hydroxyphenyl) methylsulfonium hexafluoroantimonate(BSS) in 1,2-dichloroethane (EDC). The benzyl cation was long-lived (lifetime, 59 ms) at room temperature and quenched by a vinyl ether compound. The formation of the benzyl cation as active species on photolysis of BSS is in contrast to the formation of Brønsted acids in other sulfonium salts so far reported. © 1992 John Wiley & Sons, Inc.     

芳香酸淋洗液的单柱阳离子色谱法测定碱金属,铵离子和烷基胺

研究了邻苯二甲酸、苯甲酸和对羟基苯甲酸３种芳香酸分别做淋洗液的单柱阳离子色谱法分离测定Ｌｉ＋、Ｎａ＋、ＮＨ４＋、Ｋ＋、甲胺、乙胺和正丙胺７种物质。３种芳香酸做淋洗液均可将７种物质分离开，且分离结果差异不大。在淋洗液浓度相同的条件下，邻苯二甲酸做淋洗液测定的检出限较低。选择３．０ ｍｍｏｌ／Ｌ邻苯二甲酸做淋洗液测得了上述７种物质的检出限和线性范围，并进行了叶面肥试样分析，７种物质的加标回收率在９６．４％～９８．６％之间。     

Synthesis and metal ion complexing properties of novel chromogenic cryptands

Four novel chromogenic benzocryptands and one side-armed chromogenic cryptand have been synthesized and their complexing abilities for alkali metal cations are described.     

Production of submicron-sized multihollow polymer particles by alkali/cooling method

Submicron-sized styrene-methacrylic acid copolymer particles, which were produced by emulsion copolymerization, were changed to those having multihollow structure by treating stepwise the emulsion as follows. First alkali treatment was carried out at higher temperature than the glass transition temperature and subsequently the emulsion was cooled by keeping it at room temperature. This was named alkali/cooling method. The effects of methacrylic acid content, pH, time and temperature in the alkali treatment on the formation of multihollow structure were clarified.Part CLV of the series Studies on suspension and emulsion