Simple Estimates for Eutectic Behavior

A simple formula is derived for the eutectic point of an A–B system in terms of the monomer melting points and melting enthalpies. This estimate is tested on several non-ionic or ionic systems, with or without common ions, including choline chloride/urea mixtures. The results are compared with the Schröder-van Laar equation.     

碱性季铵盐“一锅法”催化合成四氢苯并[b]吡喃的水相反应研究

报道了以2-二甲氨乙基苄基二甲基氯化铵为催化剂,在水相介质中"一锅法"催化芳醛、丙二腈和5,5-二甲基-1,3-环己二酮合成2-氨基-3-氰基-4-芳基-7,7-二甲基-5-氧代-4H-5,6,7,8-四氢苯并[b]吡喃的方法.该法具有产率高、反应时间短、操作简便、对环境友好、催化剂可重复使用等优点.     

掺盐MEBA-co-KH570共聚物的湿敏性能

采用甲基丙烯酸二甲氨基乙酯的溴代丁烷季铵盐和硅烷偶联剂KH570的共聚物作为感湿聚合物,并向该聚合物中掺杂LiCl、CaCl2、FeCl33种不同的盐类,制备了高分子电阻型湿敏元件,系统研究了聚合物浓度、无机盐的种类和浓度对元件湿敏性能的影响。结果表明,在33%～95%RH湿度范围内,元件显示出较高的灵敏度(b为-0.043 8～-0.038 8)和较好的线性(R为-0.994 8～-0.981 6),且阻抗随聚合物浓度的增加而下降,但响应变慢;掺杂LiCl和CaCl2可使元件阻抗变小,掺杂FeCl3却使元件阻抗增大;在1×10-2mol/L的最佳LiCl掺杂浓度下,元件具有最好的灵敏度(b=-0.044 6)和最短的脱湿时间(20 s)。     

Li(NTO)(H2O)2的热分解行为及其结构与性质的关系研究

摘要在水中合成了3-硝基-1,2,4．三唑-5-酮(NTO)的锂盐Li(NTO)(H2O)2,利用DSC,TG／DTG和IR方法研究了其金属配合物的热分解机理,并用Kissinger法、Ozawa法、积分法和微分法对标题配合物进行了非等温动力学研究,得到了热分解反应的动力学参数,确定了热分解第一阶段的动力学方程及配合物的热爆炸临界温度(Tb)为289．33℃．采取RHF／6-31G,DFT-RB3LYP／6-31G方法对标题化合物进行了几何全优化,并对其成键情况、电荷分布和化合物的稳定性进行了分析．     

五元体系Li~ /Cl~-,CO_3~(2-),SO_4~(2-),B_4O_7~(2-)-H_2O298K相关系实验研究

青藏高原盐湖富含锂、钠、钾的氯化物、硫酸盐、碳酸盐和硼酸盐,尤以其高锂、硼而闻名于世[1]。这些盐湖卤水大多属于Li ,Na ,K ,Mg2 /Cl-,SO42-,CO32-,Borate-H2O体系。在卤水蒸发浓缩后期,由于绝大部分钠盐、钾盐均已结晶析出,所以卤水的化学组成实际变成Li ,Mg2 /Cl-,SO42-,     

Thermal behavior and network structure of poly(N‐vinyl‐2‐pyrrolidone‐crotonic acid) hydrogels prepared by radiation‐induced polymerization

Poly(N‐vinyl‐2‐pyrrolidone‐crotonic acid) [P(VP/CrA)] hydrogels were prepared by irradiating the ternary mixture of VP/CrA and crosslinking agent ethylene glycol dimethacrylate (EGDMA) in water by γ rays at ambient temperature. Differential scanning calorimetry and thermogravimetric analysis were performed to evaluate the thermal properties of ionized networks and to establish if they showed thermal differences that could be related to the CrA content in the gel system. The volume swelling ratio of P(VP/CrA) hydrogels were investigated as a function of the pH in the immersing solution. The volume swelling ratio of these hydrogels increased with an increase in pH and a decrease CrA content in the hydrogel. The volume swelling ratio of the hydrogels was also evaluated using an equation, based on the Flory—Huggins thermodynamic theory, the phantom network theory of James–Guth and Donnan theory of swelling of weakly charged ionic gels for determination of the molecular weight between crosslinks and the polymer–solvent interaction parameter (χ). Copyright © 2004 John Wiley & Sons, Ltd.     

Complete 1H and 13C NMR spectral assignment of cis- and trans- 3-(2-[2-(4-methylphenyl)ethenyl]phenyl])sydnones

1H and 13C NMR spectra of cis- and trans-3-(2-[2-(4-methylphenyl)ethenyl]phenyl])sydnones, the first stilbene-substituted mezoionic oxadiazolium rings, were fully assigned combining the information in various solvents, such as deuterated benzene, acetone and chloroform, using 2D NMR techniques.     

Dawson型杂多酸钕盐催化氧化甲苯制备苯甲醛

合成了Dawson型磷钼钒杂多酸稀土(钕)盐,并用红外光谱分析(IR)、X射线衍射(XRD)方法对催化剂进行了表征;以H2O2为氧化剂,进行了甲苯氧化制备苯甲醛的反应研究.由于钕和钒的协同作用,催化剂表现出高的活性.实验结果表明,甲苯的转化率90.1%,苯甲醛的选择性达51.0%,双氧水的转化率89.0%,双氧水的有效利用率43.1%.基于对杂多酸盐结构的研究,对反应机理进行了初步的探讨.     

Preparation and solution properties of a novel cationic hydrophobically modified polyacrylamide for enhanced oil recovery

Abstract

A novel cationic water-soluble monomer allyldimethylisooctylammonium bromide (ADIAB) containing a short-chain alkane was synthesized successfully. This monomer was copolymerized with acrylamide and sodium acrylate to produce hydrophobically modified polyacrylamide (HMPAM) using solution polymerization without surfactants. The structures of monomer ADIAB and HMPAM were characterized with infrared spectroscopy and nuclear magnetic resonance spectroscopy. Influence of preparation condition on viscosities of products was studied. The aqueous solution viscosity of the terpolymer was also investigated as functions of concentration, temperature and salinity. The results showed that when the temperature exceeds the 60?°C and NaCl concentration exceeds about 2000?mg/L, the temperature and salt tolerance characters of terpolymer were demonstrated. The enhanced oil recovery tests were initially carried out using homogeneous sandpack models.