Dithio and thiono. Esters. 61. Synthesis of α-Amino Dithioesters and Endothiodipeptides

The α-amino ester hydrochlorides ( 1 ) are converted into N-protected α-amino amides ( 3 ), α-amino thioamides ( 4 ) and α-amino dithiomethylesters ( 5 ). Condensation of 5 with the alkali salts of α-amino acids gives rise to the endothiodipeptide alkali salts ( 7 ).     

The effect of alkali metal salts promoted MgO catalysts for the oxidative coupling of methane

Catalytic activities of the alkali metal salts are discussed based on experimental observations in a fixed bed flow reactor at atmospheric condition and instrumental analysis. LiCl (30 wt%) and NaCl (30 wt%) promoted MgO catalyst showed superior activity to mono alkali metal salts promoted MgO catalysts based on the C₂ yield. This suggests that the bialkali metal salts neutralize the nonselective acid sites due to synergistic effect. Moreover, it is estimated that the active sites is O^- ions.     

Dissociation equilibria of 1-1 electrolytes in acetylacetone

The dissociation equilibria of tetraalkylammonium and alkali metal salts have been studied by conductometry in acetylacetone as a new electrochemical solvent. The limiting molar conductivities and ion association constants of these 1-1 electrolytes have been calculated by the Shedlovsky method, and the dependence of ion association constants on cation and anion sizes has been discussed in connection with the properties of acetylacetone. In acetylacetone, as well as in acetone, alkali metal ions are not strongly solvated, and alkali metal salts form contact ion-pairs predominantly. On the other hand, the small anions such as chloride and bromide are solvated in this solvent to a considerable extent based on the enol form of the solvent, and the ion-pairs of tetraalkylammonium halides are solvent-separated as in alcohols.     

Effects of alkali halides on the thermal decompositions of poly(methyl methacrylate) and poly(2-hydroxy ethyl methacrylate)

The effects of alkali halides on the nonoxidative thermal degradations of poly(methyl methacrylate) and poly(2-hydroxy ethyl methacrylate) are described. The magnitudes of the effects of various alkali halides on polymer thermal degradation were found to depend on the salt and the polymer. Mass spectrometric analysis of volatiles evolved during polymer degradation detected alkyl halides formed by reactions between the salts and polymers. Compared to poly(methyl methacrylate), more alkyl halide was evolved from samples containing alkali halides and poly(2-hydroxy ethyl methacrylate). To varying degrees, salts also catalyzed ester decomposition reactions for this polymer. Infrared spectroscopic analysis results showed that carboxylate salts, carbonate, and carbon monoxide were formed by heating polymer/salt mixtures. © 1996 John Wiley & Sons, Inc.     

Anion effects in alkali-catalysed steam gasification

Many alkali metal salts are good catalysts for gasification of carbon. Generally, the activity of alkali metal salts increase with the size of the cation, from litium to caesium, but the associated anion can influence activity more than the cation. It is proposed that some anions can compete with the char for the alkali cations and thus inhibit the formation of an alkali-carbon complex which is believed to be the active gasification site. Techniques are described which alter this balance and activate salts which are normally poor catalysts. The activation, by hydrolysis, of relatively inactive chlorides was used to estimate the tendency of the alkalis and alkaline earths to form carbon complexes. Free energies of formation were determined and used to explain the inhibiting effects of CO₂ in catalysed steam gasification of coal char.     

碱／碱土金属盐对提质褐煤自燃倾向的影响

利用煤着火点测定仪和热重仪对添加碱／碱土金属盐制的提质褐煤着火点、燃烧特性进行分析,研究碱／碱土金属盐对其着火点、燃烧特性的影响。研究表明,碱／碱土金属盐对提质褐煤着火点有影响,按对抑制作用大小排序：MgCl2〉CaCl2〉Na2CO3〉K2CO3;碱／碱土金属盐对提质褐煤燃尽段有促进作用,可以有效降低碳在灰分中的残余。     

聚丙烯与聚酯类高聚物共混纤维碱处理前后结构与性能

研究了聚丙烯（ＰＰ）加入一定量的无机盐或与含无机盐的聚酯（ＰＥＴ）,阳离子可染聚酯（ＣＤＰ）,水溶性聚酯（ＷＳＰＥＴ）共混纺丝的可纺性,讨论了不同碱处理时间及加入相容剂与否对纤维碱减率、形态结构及力学性能的影响。其结果表明：在ＰＰ中加入一定量的无机盐或与含无机盐的ＰＥＴ类高聚物共混纺丝,可纺性较好,经碱处理后,纤维中可形成微孔,随碱处理时间延长,碱减率增加,断裂强度下降;加入相容剂后,碱减率下降,微孔细密,力学性能提高。     

Preparation and study of some alkali metal salts of gluconic acid including lithium gluconate

A general method for preparation of the alkali metal salts of gluconic acid by electrolysing glucose in a 1% alkali bromide electrolytic solution containing alkali carbonate/bicarbonate is described.     

双（氟代磺酰）亚胺及其盐的制备、性能与应用进展

双（氟代磺酰）亚胺及其盐具有独特的结构和性能,在锂二次电池、离子液体、催化剂等领域引起了广泛的关注。本文综述了该类化合物的制备方法,比较了各类方法的优缺点;从分子结构上分析了该类化合物某些碱金属盐含有结合水的原因,并归纳了目前合成无水型碱金属盐的方法;综述了它们作为锂二次电池的电解质使用时的各项性能;最后介绍了它们的应用进展,并指出了今后的研究重点及方向。     

Ionic conductivity of a novel solid polymer electrolyte

A novel kind of solid polymer electrolyte, the solvation unit of which is O?CNHR, has been studied. The effects of host polymer structure, ion species, salt concentration, and plasticizers on ionic conductivity are discussed in detail. The solvability of host polymers is a very important factor that affects the ionic conductivity of electrolytes and is fully decided by the structure of solvation units and their density in polymer chain. The latter two rest with monomers structure and copolymerization ratio. Effects of alkali metal salts and divalent metal salts on ionic conductivity are different because of their different leading factor of cation radius. Salt concentration dependence of ionic conductivity appears as a double‐peak shape when alkali metal salts are added because of the total contribution of two kinds of ionic conductance modes, and appears as similar shapes when divalent metal salts are added. Different influences of plasticizers on ionic conductivity result from their different action ways. Ethylene glycol acts well because of its effective action from three different modes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2176–2184, 2001     

A novel method for the Amination of 4,6-Dinitrobenzofuroxan via meisenheimer complexes

The reaction of 4,6-dinitrobenzofuroxan 1 with alkali metal salts of succinimide, phthalimide, and formamides affords σ-N–C bonded Meisenheimer complexes 3 . The adducts 3a–c may be directly oxidized to the in 7-position aminated dinitrobenzofuroxan derivatives 6a–c by treatment with aqueous nitric acid. In the case of 6a the oxidation of 3a proceeds with loss of carbon monoxide. For the preparation of 6d–g the alkali metal salts 3d–g must be transformed to the corresponding silver salts 4d–g before oxidation.     

用斜发沸石岩分离提取卤水中钾、铷、铯

本文研究了我国浙江省缙云地区斜发沸石岩对碱金属离子的交换性能;考察了静态交换容量与离子半径的关系.在动态条件下测定K~+/Rb~+、K~+/CS~+、Rb~+/Cs~+体系的选择性系数.针对某厂的碱金属浓盐溶液研究了分离钾、铷、铯的条件,在该条件下,制定了提取铷、铯盐的工艺流程.     

Measurement of Residence Time in Hot Compressed Water: 2. Salts in Continuously Stirred Tank Reactors

The behavior of alkali salts in a continuously stirred tank reactor is of particular interest with respect to the development of the hydrothermal biomass gasification process. On the one hand, alkali salts increase gas formation. On the other hand, they may plug reactors due to precipitation. To obtain information on the potential enrichment of salts in continuously stirred tank reactors, cumulative residence time distribution functions were measured using K₂CO₃ and NaHCO₃ tracers and phenol as a reference.     

Deformation properties of modified polyacrylonitrile fibres

Conclusions Deformation properties of polyacrylonitrile fibres modified with alkali metal salts have been studied.The introduction of alkali metals by treatment of freshly spun gel-fibre with solutions of the appropriate salts aids in loosening fibre structure.Both the form of cation and also of the anion in the salt introduced affect the deformability of the modified fibres.Translated from Khimicheskie Volokna, No. 4, pp. 40–41, July–August, 1989.     

三氟碘甲烷气相合成催化剂分析

三氟碘甲烷是新型环保灭火剂和制冷剂的重要组分。通过对气相催化合成三氟碘甲烷催化剂的研究,发现碱金属盐的催化活性较高,对三氟碘甲烷转化率达到27%以上,在碱金属盐中,硝酸铷和硝酸铯催化的转化率可达39%,高于相应的氟化物催化活性。通过对反应前后催化剂的EDS和XPS分析发现,硝酸铷在活化过程中受热分解为亚硝酸铷,反应过程中主要生成氟氧化铷,表面约85%的Rb以氟氧化铷的形式存在;反应后催化剂的热解实验表明,表面的氟元素来自中间体二氟卡宾与活性炭的化学结合。     

窄分布吐温—80的合成研究

通过对几种碱金属、碱土金属盐催化剂的考察,研究了斯本－８０的乙氧基化反应,筛选出ＤＦ－１型新型催化剂。以该催化剂为重点,对其催化活性、反应影响因素等作了深入的考察。ＤＦ－１型乙氧基化催化剂不但具有催化活性较好,产物分子量分布较窄,色泽较浅等特点,而且在合成工艺上与传统生产工艺相比,具有操作简单的优点,可望在工业生产上获得广泛的应用。     

Synthesis and characterization of mercury oxide unusual nanostructures by ultrasonic method

A facile direct synthesis has been done to prepare HgO nanocrystallites of different shapes. The effect of different parameters such as the presence of alkali salts or stabilizers, power of the ultrasound, time of sonicating, and the starting materials on the size, morphology and crystallinity degree of the products were studied. Scanning electron microscopy observations revealed that using of polyvinyl alcohol (PVA) or alkali salts led to different shapes of product.     

Change in structure of polyacrylonitrile fibres on treatment with alkali metal salts

Conclusions Treatment of polyacrylonitrile fibre with alkali metal salts helps to change its supermolecular structure.As a result of treatment of the freshly spun gel-fibre with alkali metal salts and subsequent drying in the free condition, the degree of orientation of the structural elements is not reduced.Translated from Khimicheskie Volokna, No. 5, pp. 35–36, September–October, 1989.     

Composition and microstructure of a periclase–composite spinel brick used in the burning zone of a cement rotary kiln

The composition and microstructure of a periclase–composite spinel brick used in the burning zone of a cement rotary kiln were investigated and compared to the original brick. The results indicate that cement clinker and alkali salts are two important agents that cause corrosion especially of the bonding phase of refractories in cement rotary kilns. When the molar ratio of alkalis to anions ((Na+K)/(Cl+2S)) is more than one, alkali salts accumulated in the pores, cracks and grain boundaries of the refractory but the severe corrosion of the bonding phase of the refractory did not occur in zones with lower temperatures. The interaction between the cement clinker and the refractory formed a liquid, which, together with alkali salts, improved sintering. The reaction between the cement clinker and the refractory formed a dense reaction layer. Cracks formed in the dense layer and extended through the boundary between the reaction and non-reaction (penetrated) layers by mechanical and thermal stress, which caused the spalling of the reaction and coating layer from the refractory. The recurrence of this process during service leads to degradation of the refractory.     

Alkali-activated binders by use of industrial by-products

Cement kiln dust (CKD) materials are used as alkaline accelerators for latent hydraulic substances and as alkali activators for different alumosilicate materials, including ground-granulated blast furnace slag, low-calcium fly ash and metakaolin. The dusts differ in their phase composition, especially in the amount of reactive phases and the kind and amount of alkali salts. The quantitative phase composition, pore solution composition and strength behavior of the activated blends is reported.