水－乙二醇体系中氯化氢的电池热力学

测定了２９３．２～３２３．２Ｋ间的７个温度下电池ＧＥ｜Ｈ２Ｏ（１－ｗ）＋Ｅｎ（ＯＨ）２（ｗ）＋ＨＣｌ（ｍ）｜ＡｇＣｌ－Ａｇ的电动势，由此求得了上述７个温度下，ｍ＝０．００２０，０．００５０，０．０１００，０．０５００，０．１０００ｍｏｌ／ｋｇ的ＨＣｌ在０～９０％乙二醇—水二元混合溶剂中的平均活度系数γ±与Ｐｉｔｚｅｒ参数；ＨＣｌ自水向各组成Ｅｎ（ＯＨ）２—Ｈ２Ｏ混合溶剂中的标准迁移自由能，标准迁移熵和标准迁移焓．最后从分子间相互作用的角度对ＨＣｌ在该混合溶剂中的热力学行为给予了理论解释．     

An improved OPLS-AA force field for carbohydrates

This work describes an improved version of the original OPLS-all atom (OPLS-AA) force field for carbohydrates (Damm et al., J Comp Chem 1997, 18, 1955). The improvement is achieved by applying additional scaling factors for the electrostatic interactions between 1,5- and 1,6-interactions. This new model is tested first for improving the conformational energetics of 1,2-ethanediol, the smallest polyol. With a 1,5-scaling factor of 1.25 the force field calculated relative energies are in excellent agreement with the ab initio-derived data. Applying the new 1,5-scaling makes it also necessary to use a 1,6-scaling factor for the interactions between the C4 and C6 atoms in hexopyranoses. After torsional parameter fitting, this improves the conformational energetics in comparison to the OPLS-AA force field. The set of hexopyranoses included in the torsional parameter derivation consists of the two anomers of D-glucose, D-mannose, and D-galactose, as well as of the methyl-pyranosides of D-glucose, D-mannose. Rotational profiles for the rotation of the exocyclic group and of different hydroxyl groups are also compared for the two force fields and at the ab initio level of theory. The new force field reduces the overly high barriers calculated using the OPLS-AA force field. This leads to better sampling, which was shown to produce more realistic conformational behavior for hexopyranoses in liquid simulation. From 10-ns molecular dynamics (MD) simulations of alpha-D-glucose and alpha-D-galactose the ratios for the three different conformations of the hydroxymethylene group and the average (3)J(H,H) coupling constants are derived and compared to experimental values. The results obtained for OPLS-AA-SEI force field are in good agreement with experiment whereas the properties derived for the OPLS-AA force field suffer from sampling problems. The undertaken investigations show that the newly derived OPLS-AA-SEI force field will allow simulating larger carbohydrates or polysaccharides with improved sampling of the hydroxyl groups.     

立方晶体三氧化二锑的制备

研究比较了SbCl3在不同醇中氨解制备立方晶体Sb2O3，并用XRD，SEM等手段进行了鉴定。结果表明，反应温度和醇中的水质量分数均影响晶形。乙二醇最佳，温度90℃，水质量分数低于25％均能得到单一晶形Sb2O3，粒度为1μm。     

Dielectric relaxation studies of monoalcohol solutions with 1,2-diols

Dielectric relaxation processes in solutions of monoalcohols with ethanediol, 1,2-propanediol, and 1,2-butanediol have been studied using the dielectric time domain spectroscopy technique. The dielectric spectrum has been analyzed in terms of two dispersions. The influence of varying content of diol, and of chainlength of the alcohol, on the static dielectric constant _s and on the main dispersion is reported. For the long-chain alcohols _s is lowered and the main relaxation time successively shortened with the addition of diol to the solution. The results are compared to these found for aqueous alcohol solutions and discussed in terms of a structural model with rupturing of predominantly linear complexes on addition of water, diols, or on increasing the temperature.     

激光促进磷酸盐表面甲醇氧化偶联反应

激光促进表面反应;乙二醇;激光促进磷酸盐表面甲醇氧化偶联反应     

硫酸氢钠催化乙二醇合成二氧六环

硫酸氢钠能够代替硫酸作为成醚催化剂。以乙二醇为原料 ,一水硫酸氢钠为脱水催化剂 ,合成了 1,4-二氧六环。研究结果表明 ,硫酸氢钠的催化活性良好 ;当 0 .4mol乙二醇 ,0 .0 2mol硫酸氢钠 ,反应 2h ,产品收率达 6 7%。此法具有操作方便 ,反应温和的优点