Inorganic Molten Salts as Solvents for Cellulose

Inorganic molten salts can be used as efficient solvents for cellulose in a wide range of degrees of polymerization. Furthermore, molten salts can be applied as reaction medium for the derivatization of cellulose. For both dissolution and derivatization of cellulose, knowledge of the solution state as well as information about chemical interactions with the solvent system is essential. Using the melts of LiClO₄·3H₂O, NaSCN/KSCN/LiSCN·2H₂O and LiCl/ZnCl₂/H₂O as cellulose solvents, factors which determine the dissolving ability will be discussed. Besides the specific structure of the molten salt hydrate, the cation and the water content of the melt are the most important factors for the dissolving capability of a molten salt hydrate system. FT-Raman spectroscopy, ⁷Li and ¹³C NMR spectroscopy were applied to describe solvent–cellulose interactions and the state of cellulose dissolved in the molten salts. Using Raman and solid state NMR spectroscopy it was proved that cellulose is amorphous in the frozen solvent system. The application of inorganic molten salts as a medium for cellulose functionalization is demonstrated for cellulose carboxymethylation and acetylation.     

NaCl-KCl-CeCl3熔盐体系电解精炼铈的研究

用Ce作为模拟金属,开展了NaCl-KCl-CeCl3熔盐体系电解精炼提纯金属Ce的研究,为乏燃料干法后处理提纯U, Pu等金属提供了研究基础。研究了CeCl3浓度、电解温度和阴极电流密度对电解精炼Ce的收率和电流效率的影响,得到优化的工艺条件为:CeCl3浓度为20%~25%,电解精炼温度为900~950℃,阴极电流密度为0.35~0.45 A·cm^-2,得到了成型致密的金属铈锭,产品的收率大于70%。杂质元素Al, Fe, Cu, Cr,Mn的含量均有大幅度的下降,尤其是Fe的去除效果明显从1300×10^-6降低为200×10^-6。     

Effective Charges and Ionicity in Molten Salts

Abstract

We have used experimental values of the entropies, near melting, of molten salts to calculate their effective charges by using a charge a spheres model in the Mean Spherical Approximation (MSA).

We compare the values of the effective charges with the electronegativity differences for a number of 1:1 molten salts. We find a reasonable good correlation for the alkali halides, but no for the copper, silver and thallium halides, and we offer an explanation for these results.     

溶液稳定、高导电性波纹状石墨烯片

特殊的单原子层二维sp²碳结构给石墨烯带来众多独特的性能和潜在的应用. 然而, 单层石墨烯容易聚集并会逐渐重新石墨化, 这成为其应用的一个重要障碍. 本文报道了一种新策略来解决这个问题, 即通过在石墨烯表面引入sp²碳纳米结构作为永久的波纹来阻止石墨烯的聚集和石墨化, 并使之在溶液中易于分散和稳定. 和其他功能化方法不同, 该方法没有引入杂原子, 不破坏石墨烯的结构和功能. 制得的石墨烯具有优异的导电性能(~65000 S·m^-1), 并具有较好的溶液稳定性.     

熔盐热腐蚀的电化学交流阻抗谱研究

采用电化学阻抗谱技术研究了Ｎｉ３Ａｌ、ＩＮ１００和ＩＮ７３８合金在７００℃熔融（Ｎａ,Ｋ,Ｌｉ）２ＳＯ４中的腐蚀行为．结果表明,Ｎｉ３Ａｌ和ＩＮ１００合金的腐蚀呈典型的扩散控制特征,在合金表面形成疏松的腐蚀层;而ＩＮ７３８合金因在表面形成保护性的Ｃｒ２Ｏ３膜,腐蚀不受扩散控制．提出了等效电路并计算了相应的电化学参数．     

熔盐体系及有关应用的新进展

介绍近年来熔盐体系的概况,着重室温熔盐的发展.熔盐在电化学制备合金和功能材料、能源、分析和分离、用作反应介质和催化剂、环境保护等方面应用前景良好.     

The Coordination Chemistry of f-Block Elements in Molten Salts

The coordination chemistry of f-block elements (lanthanide and actinide) in molten salts has become a resounding topic in view of its great importance to the research and development (R&D) of molten salt reactors and pyroprocessing. In this Review article, a general overview of the coordination chemistry of f-block elements in molten salts is provided including past achievements and recent advances. Particular emphases are placed on the oxidation state, speciation, and solution structure of f-block metal ions in molten salts, as well as their relationships with the salt composition. Furthermore, this review briefly discusses the spectroscopic and theoretical methods that complement each other in revealing the coordination properties.     

在LiCl-KCl-NaCl熔盐体系中碳的阴极还原的研究

用循环伏安法和电位阶跃法研究了LiCl-KCl-NaCl熔盐体系中碳的阴极还原机理。在钨、铂、不锈钢等微电极上得到的伏安图表明碳的还原是由CO_3~(2-)离子经一步电化学反应实现的,电极反应速度控制步骤为CO_3~(2-)离子向阴极的扩散过程,还原过程具有反应物吸附特征。碳在W、Pt、不锈钢电极上析出电位分别为-2.05V、-1.745V和-1.90V(均相对于Ag/AgCl参比电极)。     

Theories of the Thermodynamic Properties of Pure Molten Salts

Abstract

The analytical theories may be classified into (a) the older, semi-empirical theories, in which the approximations are physically motivated and rather unsystematic; typical of these are the so-called Significant Structures and Hole theories; (b) the newer theories, which we will, rather arbitrarily, refer to as the fundamental theories; here the approximations are of a more mathematical character and more systematically introduced; the perturbation and variational theories exemplify this approach. In addition, there are the Corresponding States methods, which occupy an intermediate position, in that, while having some fundamental justification, they are generally applied in an empirical manner.     

一种高透明、可拉伸导电水凝胶的制备及其在电容传感器中的应用

导电水凝胶由于具备良好的电学特性、可调节的机械性能、易于加工性和生物相容性等,是制备柔性电子设备的理想基材。本文使用马来酸与丙烯酰胺作为共聚单体,氯化锂作为导电离子,N,N'-二甲基双丙烯酰胺作为交联剂,使用光引发剂,采用原位光聚合的方式制备了一种导电水凝胶。制得的水凝胶可见光透过率高达93%,最大拉伸形变~380%,导电率最大为12 S/m。鉴于其优异的综合性能,实验中使用导电水凝胶制备了电容传感器并应用于人体活动监测。结果表明,制备的导电水凝胶电容传感器对不同程度的手指弯曲形变和不同力度的手指触碰均表现出灵敏的响应行为,为未来可穿戴柔性电子产品的发展起到了一定的推动作用。     

Ultralight,Ultraflexible, Anisotropic,Highly Thermally Conductive Graphene Aerogel Films

Graphene aerogels have attracted much attention as a promising material for various applications. The unusually high intrinsic thermal conductivity of individual graphene sheets makes an obvious contrast with the thermal insulating performance of assembled 3D graphene materials. We report the preparation of anisotropy 3D graphene aerogel films (GAFs) made from tightly packed graphene films using a thermal expansion method. GAFs with different thicknesses and an ultimate low density of 4.19 mg cm⁻³ were obtained. GAFs show high anisotropy on average cross-plane thermal conductivity (K_⊥) and average in-plane thermal conductivity (K_||). Additionally, uniaxially compressed GAFs performed a large elongation of 11.76% due to the Z-shape folding of graphene layers. Our results reveal the ultralight, ultraflexible, highly thermally conductive, anisotropy GAFs, as well as the fundamental evolution of macroscopic assembled graphene materials at elevated temperature.     

Ba-K-Bi-O超导体熔盐阳极电结晶研究

用ＸＰＳ和ＸＲＤ表征了Ｂａ－Ｋ－Ｂｉ－Ｏ超导体熔盐电结晶的阳极和阴 极产物，用ＳＥＭ分析了Ｂａ－Ｋ－Ｂｉ－Ｏ单生长形态。结果表明，阳极产物是Ｂａ－Ｋ－Ｂｉ－Ｏ超导体单晶，以台阶式方式生长。－Ｋ－Ｂ－     

Entropy Calculations for Charged Spheres and the Entropy of Molten Salts

Abstract

We derive an expression for the entropy S of a system of charged hard spheres within the Mean Spherical Approximation (MSA). We study the behaviour of the coulombic contribution as a function of both the charging process and the ionic radii ratio. We find that the latter gives an important ordering contribution to S, which is greatly exaggerated in the MSA. We have also calculated S using the data appropriate for the molten alkali halides. The results compare poorly with the experimental entropies and therefore cast doubts on the MSA as a suitable reference system for molten salts.     

熔盐电解法制备纳米碳管及纳米线

以LiCl、LiCl+SnCl2等为熔盐电解质,采用电解石墨的方法制备了纳米碳管和纳米线,并运用TEM、XRD、EDS等分析手段对产物的形貌和结构进行了表征.结果表明,熔盐成分对电解产物的形态和性质有显著影响.在LiCl熔盐中可得到直径为75～100nm的纳米碳管;在LiCl+1.0%SnCl2熔盐中可生成β-Sn填充的纳米碳管.XRD测试表明,电解制备的β-Sn纳米线经氧化处理后在碳管内可转变为SnO2,其晶体结构为四方晶系,直径为20～50 nm.电解过程中Li+在石墨阴极上反应生成的LiC6化合物对纳米碳结构的形成具有重要作用.     

RP-HPLC Separation of Highly Charged Quaternary Ammonium Salts

Abstract

The reverse phase HPLC separation of polycationic viologenes 1 – 4 and macrotricyclic quaternary ammonium salts 5 – 8 using ion pair conditions is described. Whereas the compounds 1 – 4 could be analysed on any of 4 stationary RP-18 phases tested, the cage compounds 5 – 8 were much more sensitive to the source of the matrix material. Optimal separation conditions for the latter up to eightfold positively charged macrocycles employ sodium perchlorate in acidic aqueous methanol using Nucleosil RP-18 or Lichrospher CH-18 columns.     

三氯化铝烷基氯化咪唑盐结构和红外光谱的模拟计算

采用量子化学密度泛函的方法计算了三氯化铝烷基氯化咪唑盐的红外光谱, 预测了三氯化铝烷基氯化咪唑盐的分子结构和光谱. 合成了三氯化铝1-丁基-3-甲基-咪唑盐[(BMIM)AlCl4], 并测试了其红外光谱, 对预测的分子结构和红外光谱进行了验证.     

Highly Conductive MXene Film Actuator Based on Moisture Gradients

MXene (Ti₃C₂T_x) is a new 2D material with both hydrophilicity and high electrical conductivity, and it has shown promise in smart electronic devices. Reported herein is a homogeneous MXene film actuator with high electrical conductivity triggered by moisture gradients. The actuator is highly sensitive to moisture and undergoes deformation, with the maximum bending angle as high as 155° at a relative humidity difference of 65 %. Several analysis methods show that the humidity drive and large deformation of the MXene film occur in situ by asymmetric expansion of the bilayer structure. The combination of deformation and electrical conductivity makes this film applicable to flexible excavators, electrical switches, and other fields, applications that are difficult to achieve directly by using other 2D materials. More importantly, this work further expands the new application range of MXene materials and provides new opportunities for building the next generation of high‐conductivity smart actuators.     

Hydrophobic Materials Based on Salts of Di(2-ethylhexyl)phosphoric Acid

Russian Journal of Physical Chemistry A - Interfacial formations of material based on metals di(2-ethylhexyl)phosphates of various metals exhibit hydrophobic properties. The contact angle of the...