选择性

Propyleneoxide is produced with chlorohydrin method or Halcon method which gives rise toenvironmental pollution or a large amount of co-product.

是最洁净、廉价的氧源，但工业上除乙烯外，其它环氧化合物还不能通过〓直接高选择性环氧化相应的烯烃制得。

In my opinion, Cu complexes with unsaturated alcohol to form a complex compound; the nitrogenous compound introduced serves as the complex compound's stabilizing agent and reduces activation energy of reaction; TMPO serves as oxygen carrier and displays it's selective oxidation function. This new method and mechanism also demonstrates significance to other similar organic reactions.3 In the chlorohydrin reaction, NaCIO is replaced by Ca2see Chapter4.4.3.4(2 .A, this method hasn't been reported in previous literature,which exerts more buffer action to the react system, the yield increased from 52% to 88.6%; at the same time it solve the problem of poor stability and low percentage composition of NaCIO.

认为：CuD与烯醇形成络合物：含氮有机物的引入起到稳定络合物，降低活化能的作用：而TMPO则充当携氧子起传递氧的作用，并具有选择氧化功能：这种新的方法和理论对类似的反应(不饱和醇类在络合体系下选择性催化氧化为对应的醛也具有重要的指导作用。3在异戊二烯的氯醇化反应中，用次氯酸钙代替次氯酸钠见第4章4.3.4(2.A，本方法未见文献报道，使反应系统更加温和，收率由52%提高到88.6%：并解决了次氯酸钠稳定性差、有效氯含量低的实际问题，具有重要的实用意义。

A sensitive spectrophotometric method for the determination of trace amounts of chlorine dioxide based on the fading reaction of chlorophenol red by chlorine dioxide has been developed in the alkaline solution.

在弱碱性条件下，二氧化氯(ClO2 )氧化氯酚红使其褪色，于 5 75nm波长处测定剩余氯酚红的吸光度，当用试剂空白参比时，吸光度的降低值与ClO2 的浓度呈直线关系，其它氧化剂在测定条件下无干扰，方法有较高的灵敏度和很好的选择性。

If the laser is in ultraviolet-visible wave, photons activate choicely electron energy level or destroy weak bond of compound molecule, and result in chemistry reaction, which is photo leading decomposition mechanism, if the laser is in infrared wave, the chemistry reaction mainly is heat decomposition mechanism.

如果激光是可见紫外波段，光量子能量有利于选择性地激发分子的电子能级，或破坏化合物中弱键而诱导化学反应发生，化合物属于光致分解机理、引发弱键断裂机理；如果激光是红外波段，化合物表现的则是热分解机理。

Experiments showed that catalytic activity of magnetic solid superacids could attain above 97%, and selectivity of reaction 100%, which illustrated the choiceness of these catalysts in esterifications.

实验表明，磁性固体超强酸催化剂的催化活性可达97％以上，反应的选择性为 100％，说明此催化剂是良好的酯化催化剂。

All cases were verified by the DNA of chorion amnionic fluid and neonatal cord blood.

PCR扩增技术，检测游离在孕妇血浆内的无细胞胎儿DNA，能在孕期鉴别胎儿性别，尤其是对早期某些选择性遗传性疾病的非创伤性产前诊断意义重大。

Here we applied many types of cinchona alkaloid derivatives and otherβ-aminoalchohol compounds in IFB reactions and investigated the effects of solvent, temperature and catalyst amount on the enantioselectivities in order to find the proper catalyst and optimize reaction condition.

本文考察了多种金鸡纳生物碱衍生物及其它一些β-氨基醇类化合物在IFB反应中的应用，并研究了催化剂的结构、溶剂效应、温度、催化剂用量及反应底物类型对立体选择性的影响，以筛选适合的催化剂和优化反应条件。

This paper is focused on the preparation, characterization of metal clusters and theircatalytic performance in the enantioselective as well as stereoselective hydrogenations. It iscomposed of the five parts as follows: Chapter 1 A review was given on the two most studied enantioselective systems—Ni/TA and Pt/cinchona system, including some recent progress.

本论文研究了铂、铱纳米金属簇在α-酮酯、α-二酮不对称氢化中的催化性能及金属离子在α-二酮立体选择性氢化中的修饰作用，主要分为以下几部分：第一章对多相不对称催化体系一Ni／TA和Pt／cinchona及其一些最新进展作了较系统的评述；同时简要介绍了纳米金属簇的特性及其在催化中的一些应用。

The proper in-situ polymerization systems of acidic and basic compounds using amino acid derivatives and cinchona alkaloids as template molecules respectively were adopted for preparation of molecularly imprinted monolithic columns by systematically investigating the effect of polymerization conditions on pore structure and selectivity of resulting polymers. The enantiomers of amino acid derivatives and the diastereomers of cinchona alkaloids were successfully resolved on these columns.

本文分别以氨基酸衍生物和辛可纳生物碱为模板分子，系统研究了制备条件对聚合物孔结构和选择性的影响，建立了合适的酸性化合物和碱性化合物的原位印迹体系。

In the asymmetric hydrogenation of ethyl pyruvate catalyzed by 0 5% Rh/PVP TiO 2, the chiral modifier cinchonidine not only induces the enantioselectivity, but also accelerates the reaction rate greatly.

研究了辛可尼定作手性修饰剂修饰的负载型纳米铑簇合物催化剂(0 5 %Rh/PVP TiO2 )催化丙酮酸乙酯不对称氢化反应，在该反应中手性修饰剂辛可尼定不仅具有对产物生成的手性诱导作用，而且对反应具有明显加速作用；在优化反应条件后，反应的TOF和对映选择性分别可以达到 5 8 0min-1和

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。