2-羰基丙酸(4-吡啶甲酰基)腙与碱土金属配合物的晶体结构及热 稳定性

报道了2-羰基丙酸(4-吡啶甲酰基)腙(H~2L)与碱土金属(Ca,Mg,Sr,Ba)四种配合物的合成,结构及热稳定性。同时,用X射线单晶衍射仪测定了Mg和Ba两种配合物的晶体结构,结构分析表明两种配合物均属单斜晶系,空间群均为P2~1/c。此外,还比较讨论了各配合物不同成键方式所对应的IR特征及热稳定性变化规律。     

Steam chromatography of aliphatic and aromatic amines on packed columns with aqueous potassium hydroxide as the stationary liquid phase

Aqueous alkali was proposed as the stationary liquid phase (SLP) for separation of amines by steam chromatography. Characteristic features of retention of amines of various structures were studied. The retention of primary and secondary amines on aqueous potassium hydroxide as the SLP differs fundamentally from that observed with common organic SLP. Primary amines are eluted in the following order,n-pentylamine <n-butyl-amine <n-propylamine <n-hexylamine <n-octylamine for secondary amines, the following sequence was established; diethylamine < dibutylamine < dimethylamine. Higher-boiling tertiary amines containing ethyl andn-butyl radicals are eluted ahead of diamines containing the same radicals. Translated fromIzvestiya Akademii Nau. Seriya Khimicheskaya, No. 8 pp. 1507–1509, August, 1999.     

Detergent-Induced Removal of β-Lactoglobulin from Stainless Steel Surfaces as Influenced by Surface Pretreatment

The adsorption of β-lactoglobulin to stainless steel and its subsequent removal were followed using in situ null ellipsometry. The influence of the surface pretreatment on the protein removal by the surfactant SDS and by sodium hydroxide was studied. All surfaces were precleaned in strongly alkaline solution. Some surfaces received no further pretreatment, while others were either passivated in nitric acid or plasma-cleaned prior to experiments. Stainless steel surfaces subjected to different surface pretreatments showed considerable differences in cleaning behavior. Cleaning, using NaOH, of surfaces which had been precleaned with alkali only or with plasma resulted in practically complete β-lactoglobulin removal. In contrast, appreciable amounts of protein remained on passivated stainless steel. Protein removal by SDS was limited and comparable for all three surface pretreatments investigated. Only minor effects on the protein adsorption tendency were observed. The amounts of β-lactoglobulin adsorbed tended to be somewhat lower on the passivated surfaces.     

溶剂萃取分离碱性氰化液中的金

氰化亚金;碱性氰化液;溶剂萃取分离碱性氰化液中的金     

碱金属盐和碱土金属盐溶液的红外光谱研究进展

利用红外光谱技术可以直观地从分子水平上研究溶液中离子-离子和离子-分子之间的相互作用情况,本文引了44篇参考文献,对碱金属盐及碱金属盐溶液的红外光谱研究进展情况进行了综述。     

Theoretical study of the role of low-barrier hydrogen bonds in enzyme catalysis: a model of proton transfer in serine protease

 A model of low-barrier hydrogen bonds (LBHBs) in enzymes has been studied by ab initio quantum mechanical calculations including the self-consistent reaction field solvent model. The hydrogen-bond strengths and the deprotonation energies for the hydrogen-bonded and non-hydrogen-bonded cis-urocanic acid were calculated at the HF/6-31 + G(d,p) level at various dielectric constants. The same calculations were performed for the α,β-dihydrourocanic acid to model the catalytic dyad of serine protease. The deprotonation energy of N^ɛ2 in α,β-dihydrourocanic acid is increased by formation of LBHBs and depends very much on the dielectric constant. This study suggests that the formation of LBHBs increases the basicity of the dyad, and the polarity change near the reaction center in the active site could help the proton abstraction from Ser 195 and the donation to the leaving group. Both the LBHBs and the environment can play crucial roles in the enzyme catalysis. Received: 8 March 2000 / Accepted: 3 January 2001 / Published online: 3 May 2001     

碱性纳米复合聚合物电解质研究

为了提高聚氧化乙烯(PEO)/KOH 基碱性聚合物电解质的电导率, 制电解质膜时分别将纳米 TiO2、纳米β-Al2O3和纳米 SiO2添加到 PEO/KOH 体系中, 制备出了兼顾电学和力学性能的碱性纳米复合聚合物电解质. 交流阻抗测试显示, 其室温(28 ℃)电导率可达到 10-3 S?cm-1数量级. 循环伏安研究表明, 制得的电解质膜在不锈钢惰性电极上的电化学稳定窗口约为 1.6 V. 分别研究了聚合物电解质膜中 KOH, H2O, 无机纳米粉末的含量以及温度对体系电导率的影响.     

碱性介质中甲醇在铂电极表面吸附和氧化的电化学原位FTIR反射光谱和EQCM研究

运用电化学循环伏安、原位FTIR反射光谱和石英晶体微天平(EQCM)等方法研究了碱性介质中甲醇在Pt电极表面吸附和氧化行为. 结果表明: 甲醇电氧化与溶液酸碱性有密切的关系. 酸性介质中甲醇在Pt电极上的CV曲线有两个正向氧化峰, 而碱性介质中只有一个正向氧化峰, 第二个氧化峰的消失可能是由于碱性介质中Pt电极在高电位下形成高氧化态的氧物种毒化其表面引起的. 碱性介质中甲醇解离吸附产物的数量比酸性介质的明显减少, 对甲醇氧化的第一个氧化峰表现出更高的电催化活性. 目前实验条件下, 原位FTIR反射光谱检测到: 碱性介质中甲醇电氧化的最终产物是CO₂和CO₃^2－, 反应中间体主要为HCOO^－物种. 从电极表面质量定量变化的角度提供了甲醇反应机理的新数据.     

不同煅烧方式对粉煤灰水热合成沸石的影响

针对粉煤灰中含有活性较差的莫来石和石英晶体,在不同条件下对粉煤灰进行活化处理,水热晶化合成出不同种类的沸石样品.试验结果证明加碱煅烧活化效果较好,并对其活化机理、煅烧温度和结块现象等进行了研究.     

Eu~(2+),Mn~(2+)共激活碱土镁硅酸盐基红色荧光粉的发光性能

制备了以R3MgSi2O8(R=Ba,Sr,Ca)为基,Eu2+,Mn2+共激活的红色荧光粉并研究了其荧光性质。分别以Ba3MgSi2O8,Sr3MgSi2O8,Ca3MgSi2O8为基质时,由于晶体场环境不同,发光强度、发射峰产生相应变化。研究了以(Ba,Sr)3MgSi2O8为基的荧光粉中Ba,Sr相对量,及Eu2+,Mn2+浓度对发光性质的影响并探讨了Eu2+,Mn2+在基质中所处格位;结果表明,红光是由基质中处于九配位的Eu2+将能量传递给八面体六配位的Mn2+,而由Mn2+所发射的。