Synthesis and structure of 2,3,6,8,10,13,14-heptaaza-6,8,10-trinitro-4,12-dioxapentadeca-2,13-diene 2,14-bisoxide

Alkylation of potassium salt of methylnitrosohydroxylamine with 1,7-dichloro-2,4,6-triaza-2,4,6-trinitroheptane afforded 2,3,6,8,10,13,14-heptaaza-6,8,10-trinitro-4,12-dioxapentadeca-2,13-diene 2,14-dioxide. The structure of the reaction product was established by X-ray diffraction analysis.     

Application of the pKa rule to synthesize salts of bezafibrate

ABSTRACT

Co-crystallization frequently employs forces such as hydrogen bonds, halogen bonds, and π-π stacking to assemble molecules in a multi-component crystal. In an effort to increase the strength of the intermolecular interaction between the anti-cholesterol drug bezafibrate (BEZA), a wastewater contaminant, and hydrogen-bond-acceptor molecules, we modified the pK_a values of the acceptors. Here, we describe the first series of salts incorporating BEZA and achieve a variety of supramolecular architectures including discrete assemblies, 1D chains, tapes, and 2D sheets. We discuss exceptions to the pK_a rule, and demonstrate that the presence of hydrogen-bond-donor atoms on the acceptor molecule supports salt formation.     

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.     

新型阳离子光引发剂[4-(2-羟基-3-丁氧基-1-丙氧基)苯基]苯碘鎓-六氟锑酸盐的合成及光敏性能的研究

以丁基缩水甘油醚和苯酚为起始原料,进行开环缩合反应制得1-丁氧基-3-苯氧基丙-2-醇.再与羟基对甲苯磺酰氧基苯反应得到[4-(2-羟基-3-丁氧基 -1-丙氧基)]二苯碘鎓-六氟锑酸盐(简称BPI·SbF₆),产率达79%.用¹HNMR、UV、IR和元素分析对其结构进行了分析.初步研究了以BPI·SbF₆为阳离子光引发剂的脂肪族环氧(CY179)感光体系的感光特性,结果表明CY179/BPI·SbF₆感光体系有一定的后固化活性.     

Modification of polybenzimidazole: Synthesis and thermal stability of poly(N1-methylbenzimidazole) and poly(N1,N3-dimethylbenzimidazolium) salt

Poly(N₁,N₃-dimethylbenzimidazolium) (PDMBI) salt and poly(N₁-methylbenzimidazole) (PMMBI) were synthesized by methylation of commercial polybenzimidazole [poly-2,2′-(m-phenylene)-5,5′-bibenzimidazole (PBI)]. First, the N-lithium salt of polybenzimidazole was formed by treating polybenzimidazole solution of 1-methyl-2-pyrolidinone (NMP) with lithium hydride at 80°C for 18 h. Ninety percent substitution of PMMBI was obtained by treating the N-lithium salt of PBI with equimolar ratio of iodomethane at room temperature. Upon addition of excess iodomethane to the lithium salt of PBI at 80°C, a polymer was formed that showed 100% substitution on the N₁ nitrogen and about 30% substitution of the methyl group on the N₃ nitrogen in the form of N₁,N₃-dimethylbenzimidazolium iodide salt [PDMBI (30%)]. The content of the benzimidazolium iodide salt was increased to about 90% by dissolving PDMBI (30%) in dimethyl sulfoxide (DMSO) and re-treating with excess iodomethane at 80°C overnight. The modified PBI polymers were characterized by NMR and FTIR. The modified PBI differed in solubility from PBI. PMMBI could be easily dissolved in NMP and PDMBI in DMSO at room temperature. The solution of PDMBI could be mixed with water in all proportions without precipitation. PDMBI could be also dissolved directly in a mixture of DMSO and water (1 : 1). Typical polyelectrolyte behavior of viscosity was found in solution of PDMBI (30%) and PDMBI (90%) when DMSO and a mixture of DMSO and water were used as solvents. A salt effect on viscosity was also found in the mixed solvent solution. Thermogravimetric analysis (TGA) showed that the methyl group on the imidazole ring was unstable above 180°C under nitrogen. When PDMBI was heated under nitrogen, one of the methyl groups was lost with the counterion to result in a neutral PMMBI. © 1993 John Wiley & Sons, Inc.     

警惕锌剂治疗的毒性和副作用

临床实践证明某些疾病补锌治疗有效，但也发现1％左右的人出现副作用，人类对锌过量虽具有耐受性，但据报道不管是急性中毒量，治疗量，还是常用的自选补充量，均可出现中毒症状。原因是锌与其它元素间有相互作用，特别是与铜的拮抗作用，所以用锌剂一定要严格掌握适应症、剂量、疗程，以免引起不良反应，影响儿童健康。     

模式识别—人工神经网络在化学中的若干新应用

本文通过我们应用模式识别－人工神经网络方法预报新化合物、熔盐相图以及复杂化学反应体系的研究，展示应用模式识别－人工神经网络方法与物理化学理论相结合，研究化学现象的可能性和应用价值。     

l-Hexanesulphonic acid sodium salt promoted the one-pot synthesis of amidoalkyl naphthols under microwave-irradiation

Amidoalkyl naphthols have been synthesized in high yields in the presence of 1-hexanesulphonic acid sodium salt as an inexpensive solid catalyst under solvent-free conditions and microwave-irradiation.This catalyst provides clean conversion;greater selectivity and easy workup make this protocol practical and economically attractive.