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1.
邓爱华  陈小明  杨拥平 《分析化学》2002,30(11):1325-1329
以环氧氯丙烷为中间体,合成了七{2,6-二-O-[3-(1,3-二羟基丙氨酸)]}-β- 环糊精(谷氨酸-β-环糊精)。为了使其能更好的适用于气相色谱分析提高其涂渍性能,用醋酸酐将其乙酰化,得到了一种淡黄色粘稠液体,作为一种新型的气相色谱固定相。在该固定相上对一系列化合物的分离和保留行为进行了研究,结果表明该固定相对各类化合物,特别是对位置异构体和对映异构体具有良好的分离效果,显示了很强的立体选择性。  相似文献   

2.
将甲氧甲基引入β-环糊精的2,3,6-位合成了新的气相色谱手性固定相七(2,3,6-三-O-甲氧甲基)-β-环糊精,并采用静态法将其涂渍在毛细管内壁制备毛细管气相色谱柱。考察了毛细管柱的柱性能和分离性能。结果表明该固定相对Grob试剂、苯的二取代位置异构体(硝基甲苯、溴甲苯、二氯苯和二甲苯)及手性化合物(2-羟基丙酸甲酯、2-羟基丙酸乙酯和2-甲磺酰基丙酸甲酯)都具有良好的分离效果。与固定相2,3,6-三-O-甲基-β-环糊精的手性分离效果对比,结果显示两种手性固定相的分离能力各异,对一些手性脂类化合物对映体的分离存在互补性。  相似文献   

3.
将全甲基-β-环糊精、全戊基-β-环糊精及二者的混合液分别静态涂渍在氯化钠粗糙化的弹性石英毛细管内壁.为提高固定相的色谱性能,将环糊精衍生物与OV-1701按1∶4的质量比相混合,制备手性柱.对毛细管的特性、固定相的极性进行了测试,并对手性化合物(±)茚满醇、DL-丙氨酸、DL-缬氨酸、(±)乙酸二氢香芹酮等难分离物质对进行了拆分.结果表明,三种手性固定相均属于中等极性,具有较好的分离性能和成膜能力.分离效果表明,混合固定相对手性化合物及难分离物质对的分离存在协同效应.  相似文献   

4.
将全甲基-β-环糊精分别与全乙基-β-环糊精、全丁基-β-环糊精和全戊基-β-环糊精混合作为气相色谱固定相,并以全甲基-β-环糊精单一固定相作为对照,测试了这4根毛细管柱的柱效、极性和手性分离性能,探讨了固定相和溶质的结构和性质对手性分离结果的影响.结果表明:4根毛细管柱在100 ℃时的麦氏常数平均值分别为180.5、163.3、149.9和146.6,表明随着与全甲基-β-环糊精混涂的环糊精的烷基链长加长,固定相的极性逐渐降低;16种含苯环的手性化合物在这4根柱上均得到了较好地分离,但随着固定相的极性减弱,其手性分离能力减小;溶质分子中取代基的位置、碳链长度和结构对分离结果具有一定的影响.  相似文献   

5.
合成了一种新的环糊精接枝聚硅氧烷固定相(DPP-β-CD),并将其成功涂渍到气相色谱毛细管柱上.发现其涂渍性能良好:对二甲苯、氯苯胺等难分离的芳香族位置异构体和一些对映异构体具有好的分离能力,是一种有应用前景的气相色谱固定相。  相似文献   

6.
合成了一种新的手性固定相: 七(2, 6-二-O-正丁基-3-O-三氟乙酰基)-β-环糊精(DB-TFA-β-CD), 使用该固定相涂渍的石英毛细管柱, 对卤代烃、环氧化合物、酮、胺、醇、二醇、羧酸和氨基酸等化合物的对映体进行了色谱分离。结果表明:该固定相具有较好的对映体分离选择性。  相似文献   

7.
合成了一种新的手性固定相: 七(2, 6-二-O-正丁基-3-O-三氟乙酰基)-β-环糊精(DB-TFA-β-CD), 使用该固定相涂渍的石英毛细管柱, 对卤代烃、环氧化合物、酮、胺、醇、二醇、羧酸和氨基酸等化合物的对映体进行了色谱分离。结果表明:该固定相具有较好的对映体分离选择性。  相似文献   

8.
合成了一种新的手性固定相:七(2,6-二-O-正丁基-3-O-三氟乙酰基)-β-环糊精(DB-TFA-β-CD).使用该固定相涂渍的石英毛细管柱,对卤代烃、环氧化合物、酮、胺、醇、二醇、羧酸和氨基酸等化合物的对映体进行了色谱分离.结果表明:该固定相具有较好的对映体分离选择性.  相似文献   

9.
合成了一种新的手性固定相2,6-O-二丁基-3-O-三甲基硅烷基-β-环糊精,以甲基苯基硅油为稀释剂,采用快速超动态法,成功地将其涂渍到弹性石英毛细管柱上;柱性能稳定,柱寿命较长;用该柱分离了酯、酮、烯烃等一些对映体。  相似文献   

10.
合成了七(2,3-二-O-乙酰基-6-O-叔丁基二甲基硅烷基)-β-环糊精,并采用静态法成功地将其涂渍到弹性石英毛细管柱上。研究了其气相色谱分离性能,发现此固定相涂渍性好,柱效较高,热稳定性好,对卤代芳烃异构体以及难分离的二取代苯的位置异构体具有良好的分离能力。  相似文献   

11.
利用手持技术改进测定乙醇分子结构实验   总被引:1,自引:0,他引:1  
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。  相似文献   

12.
13.
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。  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.

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.

  相似文献   

17.
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。  相似文献   

18.
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.  相似文献   

19.
Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.  相似文献   

20.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

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