用L-脯氨酸衍生物作为手性流动相添加剂拆分对映异构体

用自制的N-十二酰基-L-脯氨酸和N-十二酰基-L-脯氨酸-3，5-二甲基苯胺两种L-脯氨酸衍生物作手性流动相添加剂，在氨丙基硅烷化硅胶柱上，用正己烷／异丙醇作流动相，对多种手性化合物进行了高效液相色谱拆分。实验结果表明：用N-十二酰基-L-脯氨酸作添加剂拆分的12种手性化合物，有8种手性化合物能得到拆分，具有较好的手性选择性。虽然用N-十二酰基-L-脯氨酸-3，5-二甲基苯胺作添加剂，手性选择性也较好，但由于含有苯环，紫外吸收增强，基线波动严重。     

几种手性化合物在直链淀粉-三(环己基氨基甲酸酯)手性固定相上高压液相中的拆分

正相条件下, 在自制的涂敷型直链淀粉-三(环己基氨基甲酸酯)手性固定相上, 直接拆分了九种不同类型的手性化合物, 考察了流动相中极性添加剂对手性拆分的影响, 并与直链淀粉-三(3,5-二甲基苯基氨基甲酸酯)进行了比较. 研究发现, 此种手性固定相不仅具有较高的手性识别能力, 而且对某些类型手性化合物的选择性与后者明显不同; 探讨了此种固定相可能的拆分机理.     

正十二烷基-L-羟基脯氨酸手性配位萃取拆分外消旋苯丙氨酸

本文合成新手性配体正十二烷基-L-羟基脯氨酸,研究手性配体正十二烷基-L-羟基脯氨酸与Cu髤配位萃取拆分苯丙氨酸的性能和机理,考察起始氨基酸浓度、配位铜离子浓度、萃取剂浓度、溶液pH值及温度等因素分别对D-和L-苯丙氨酸萃取性能的影响,萃取剂对D-苯丙氨酸的识别能力强。利用多种手段对萃合物的组成进行表征,推测萃合物的结构为1∶1∶1型三元配合物。对比发现:该萃取剂配位萃取拆分苯丙氨酸性能优于正辛基-L-羟基脯氨酸,空间位阻效应反而对拆分有利。     

一种新型DNB-L-脯氨酸手性键合相的合成及联萘酚衍生物的拆分

以3,5-二硝基苯甲酰-L-脯氨酸为手性选择子,通过11-氨基十一酸臂和3-氨丙基硅烷偶联剂,制备了一种新型的硅胶手性键合固定相。采用V(正己烷)∶V(乙醇)∶V(乙酸)=98.0∶2.0∶0.5作为流动相,在柱温30℃,流速1.0mL·min-1和紫外254nm检测条件下,拆分了4种联萘酚及其衍生物对映体。     

原子转移自由基聚合技术制备新型手性配体交换色谱固定相及对手性化合物的拆分

采用原子转移自由基聚合(ATRP)技术, 以溴代硅胶为引发剂, CuCl/2,2'-联吡啶(Bpy)为催化体系, 水为溶剂, N-丙烯酰基-L-脯氨酸为单体, 室温下在硅胶表面进行聚合反应, 制得硅胶接枝聚N-丙烯酰基-L-脯氨酸分子刷. 通过改变ATRP反应体系中单体的量, 制备了3种不同键合量且键合量可控的手性配体交换色谱固定相, 利用元素分析和热重分析对其进行表征. 考察了配体接枝率、 流动相Cu²⁺浓度、 pH值和柱温等对DL-氨基酸和α-羟基酸拆分的影响, 优化了色谱分离条件, 探讨了拆分过程的热力学. 结果表明, 所合成的手性配体交换色谱固定相能够分离9种DL-氨基酸和α-羟基酸, 其中DL-酪氨酸、 DL-色氨酸和DL-苏氨酸3种氨基酸可同时进行拆分, 且拆分过程由熵控制.     

以邻苯二甲醛与N-乙酰-L-半胱氨酸作为柱前手性衍生化试剂拆分 DL-氨基酸的反相高效液相色谱法研究

本文用邻苯二甲醛和N-乙酰-L-半胱氨酸作柱前手性衍生化试剂,经反相高效液相色谱法拆分DL-氨基酸。研究了衍生化反应条件以及固定相、流动相对出峰顺序和分离效果的影响。实现了11对DL-氨基酸的同时拆分。本方法用于(±)-2,4,6三甲基苯丙氨酸的分离取得满意结果。     

基于N-十二酰基-l-脯氨酸为载体的对映异构PVC膜选择性电极的研制

合成了手性物质N-十二酰基-l-脯氨酸(N-DDO-l-Pro)(脯氨酸, Pro), 作为PVC膜电极的载体, 在PVC膜表面与被测试液中Cu(II)与脯氨酸形成的配合物[Cu(II)(l-Pro)₂]或[Cu(II)(d-Pro)₂]进行配体交换, 形成[(l-Pro)Cu(II) (N-DDO-l-Pro)]或[(d-Pro)Cu(II)(N-DDO-l-Pro)]配合物. 由于生成的配合物热力学稳定性不同, 电极能优先响应l-Pro, 线性范围10^－4～10^―1 mol•L^－1, 斜率57 mV•dec^－1, 检测限3.89×10^－5 mol•L^－1. 电极能够对脯氨酸进行手性检测, 其对映选择性系数lg为－3.19.     

几种新的外消旋过渡金属簇合物在纤维素衍生的高效液相色谱手性固定相上的直接拆分

正相条件下,在自制的涂敷型纤维素-三(3,5-二甲基苯基氨基甲酸酯)手性固定相上,首次直接拆分了几种新的外消旋过渡金属簇合物,考察了流动相中极性添加剂对手性拆分的影响.结果发现不仅不同立体结构的醇对手性簇合物的选择性不同,而且手性簇合物四面体骨架的四个顶点上的原子及与之配位的基团,对它们的色谱行为都有重要的影响.     

多糖衍生物手性固定相上采用酸性或碱性添加剂的流动相拆分β受体阻滞剂对映体

考察了多糖类手性固定相在含有酸性或碱性添加剂的流动相下高效液相色谱法拆分β受体阻滞剂对映体的效果。色谱条件: 流动相为10%～30%(体积分数,下同)乙醇-正己烷(含0.1%三氟乙酸)和10%～30%乙醇-正己烷(含0.1%三乙胺),流速1.0 mL/min,紫外检测波长254 nm。结果表明,在直链淀粉-三(3,5-二甲基苯基氨基甲酸酯)衍生物手性固定相(Chiralpak AD和Chiralpak IA)上拆分β受体阻滞剂对映体,酸性添加剂的流动相体系与碱性添加剂的流动相体系相比,碱性添加剂的流动相的拆分效果比酸性添加剂的流动相要好。而在纤维素-三(3,5-二甲基苯基氨基甲酸酯)衍生物的手性固定相(Chiralcel OD和Chiralpak IB)上分离β受体阻滞剂,比较酸性添加剂的流动相与碱性添加剂的流动相的拆分效果,发现酸性添加剂的流动相条件下对映体的保留减弱,但对映体的选择性增大,特别是在Chiralcel OD上,酸性添加剂的流动相体系对对映体的选择性非常理想,而且随着流动相中酸性添加剂含量的增加,β受体阻滞剂对映体的分离效果更佳。     

手性有机磷农药对映体在衍生化环糊精类手性固定相上的分离

正相色谱条件下,首次在两种新型衍生化β-环糊精键合硅胶手性固定相上,对系列2-(噻唑基)-α-氨基膦酸酯化合物进行了有效的手性拆分研究,对映异构体选择性α达1.812,Rs高达4.072,为该类化合物的制备型拆分提供了一条行之有效的方法.探讨了化合物结构、流动相组成及流速对拆分的影响及其相应的手性识别机理.     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Effect of the Method of Modification of Zeolite X on Selectivity of Catalytic Methylation of Toluene

Theoretical and Experimental Chemistry - The effect of the method of modification of catalysts based on zeolite X by cesium and magnesium cations (ion exchange and impregnation) on the selectivity...