异构体

The nitration of toluene was carried out in the presence of acetic anhydride with CCl4 as solvent, 95% nitric acid as nitrating reagent, and niobic acid calcinated at 300℃ for 3 h as catalyst for 60 min at 40℃.

实验结果表明，当反应温度为40℃，反应时间为60min时，以CCl4为溶剂，以质量分数为95%的硝酸为硝化剂，在醋酐存在条件下，以经300℃焙烧3h后的铌酸作为催化剂，甲苯硝化产物中异构体的邻对比达1.26，较硝硫混酸的1.67显著降低，产物得率达99.3%。

The nitrophenol and hydroxybenzoic acid isomers imprinted monolithic columns were prepared by in-situ polymerization.

采用原位聚合法制备了硝基苯酚和羟基苯甲酸位置异构体的分子印迹整体柱。

The nitrophenol and hydroxybenzoic acid isomers imprinted monolithic columns were prepared by in-sim polymerization.

采用原位聚合法制备了硝基苯酚和羟基苯甲酸位置异构体的分子印迹整体柱。

It was found that manganese porphyrins linked with stable nitroxyl radials could oxidize sulfides using NaOCl as the oxidant to give the corresponding sulfoxides in good to excellent yields (80-97%) with high chemoselectivity and diasteroselectivity (dr≥7:1 for glycosyl sulfoxides).

发现连有稳定氮氧自由基的卟啉锰络合物对NaOCl选择性氧化各种硫醚底物有较好的催化效果，获得了高的产率(80％～97％)、化学选择性和非对映选择性(糖基亚砜非对映异构体的比例大于7：1)。

The electron impact mass spectra of noncyclic crown ether s with heterocyclic methmazole as terminal groups 1a￣4a and fo were given and discussed in the present article.

本文给出以杂环甲巯咪唑为端基的非环冠醚1a～4a及1a的异构体1b的电子轰击质谱并讨论之。

In this part, the densities of sodium benzoate, sodium nitrobenzoate, sodium chlorobenzoate and sodium methylbenzoate in DMFwater mixed solvents have been measured at 298.15K with an Anton Paar Model 55 densimeter. From these densities, apparent molar volumes and partial molar volumes have been calculated, transfer volumes from water to DMF-water mixtures and substituent contributions to the transfer volumes have also been obtained. Solvent and substituent effects are discussed in detail. The Scaled Partical Theory has been applied to the ternary solutions to evaluate the partial molar volumes of cavity formation and the volumes change associated with solute-solvent interaction.

选择了含有取代基团的芳香类有机电解质，主要是苯甲酸钠、硝基苯甲酸钠、氯苯甲酸钠和甲基苯甲酸钠的邻、间、对同分异构体作为研究对象，用DMA 55型振荡管密度计测定了它们在不同质量百分数组成的DMF-水混合溶剂中的密度，利用这些密度数据，计算了表观摩尔体积和偏摩尔体积，得到了这些单取代苯甲酸钠从水到DMF-水混合溶剂中的迁移偏摩尔体积及苯环上不同位置的取代基对迁移偏摩尔体积的贡献值，讨论了溶剂效应和取代基效应，并将定标粒子理论应用于此三元电解质溶液中。

Polyethylene glycol ethers of alkyl alcohols having the general formula CH3(CH2)xCH2(OCH2CH2)nOH wherein x is 8 to 20 (of which ceteareth-20, steareth-20 and steareth-100 are preferred), poloxamer 185, poloxamer 407, N,N-dimethyl dodecylamine N-oxide, and mixtures thereof, are employed to increase follicular delivery and/or follicular residence time of certain water soluble ornithine decarboxylase inhibitors of which 2-2,5-diamino pentanoic acid and its pharmaceutically acceptable salts, hydrates, optical enantiomers and racemic mixture are preferred.

使用通式为CH3(CH2)xCH2(OCH2CH2)nOH的烷基醇的聚乙二醇醚，其中x为8-20(其中鲸蜡硬脂醇醚-20、硬脂醇醚-20和硬脂醇醚-100是优选的)、poloxamer 185、poloxamer 407、N，N-二甲基十二烷胺N-氧化物及其混合物来提高某些水溶性的鸟氨酸脱羧酶抑制剂的毛囊传输和/或毛囊停留时间，优选的抑制剂是2--2，5-二氨基戊酸及其药学上可接受的盐、水合物、光学对映异构体及外消旋混合物。

The composition ratio of cis/tran isomers tends to be constant in with irradiation time. The photostationary state composition is only related to irradiation were length.

它们的反、顺异构体组分比随光照时间趋于某稳定值，该稳定的组分比与照射光波长有关。

Nevertheless, the yield of pinacol was also strongly affected by the steric environment surrounding the carbonyl group. The pinacol coupling of aromatic aldehydes has been achieved with high yields under such a condition. However, the diastereose-lectivities of pinacols were not satisfying. Unfortunately, the ketones and most aliphatic aldehydes appeared inert under the same reaction conditions.

然而， 呐偶合反应的产率受到羰基周围环境的立体位阻影响较大，在此条件下，锌粉能有效地促进芳香族醛类化合物进行水相呐偶合反应，得到的呐醇产率高，但非对映异构体选择性差，而脂肪族醛类化合物得到的呐醇产率较低，在同样的条件下，酮类化合物不能顺利进行呐偶合反应。

Besides off-column preconcentration, on-column preconcentration method has been attracting a lot of researchers because of its simplicity.

采用同样的装置，本论文首次建立了毛细管电泳分析血浆中的维甲酸异构体的方法，灵敏度提高100倍以上。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。