选择性

In this dissertation, metal oxide supported nano gold catalysts were applied to catalyze selective oxidation of cyclohexane to cyclohexanone and cyclohexanol using oxygen.

本文尝试采用普通氧化物负载的纳米金催化剂用于以氧气为氧化剂的环己烷选择性氧化反应。

The commercial process of cyclohexane oxidation to cyclohexanone and cyclohexanol shows low conversion, poor selectivity, high-energy consumption and environmental pollution. It is of great academic and practical importance to study and develop highly efficient and environmentally friendly catalytic cyclohexane oxidation processes.

现有的环己烷氧化制环己酮生产工艺，存在转化率低、选择性差、能耗高以及污染环境的缺点，研究和开发高效、环境友好的环己烷催化氧化工艺具有重要的理论意义和实用价值。

Cyclohexane conversion of 33.7%,selectivity to cyclohexanone and cyclohexanol of 97.2%,cyclohexan...

在70℃和n(C6H12)∶n(H2O2)=1∶2条件下，采用两次加入过氧化氢的方式，环己烷转化率为33.7%，酮醇总选择性97.2%，n∶n=1.99，过氧化氢利用率37.1%。

It was found that manganese porphyrin had the highest activity, and a maximum 15.4% of cyclohexane conversion and 93.9% selectivity of cyclohexanone and cyclohexanol could be obtained under the suitable conditions.

结果发现，锰卟啉催化活性最好，在适宜反应条件下，环己烷转化率高达15.4%，环己酮和环己醇的总选择性约为93.9%。

The commercial processes of cyclohexane oxidation to cyclohexanone and cyclohexanol generally show many problems, such as low conversion, poor selectivity, complicated technology, high-energy consumption and environmental pollution. So it seems to be of great academic and practical interesting to study and develop highly efficient and environmentally friendly catalytic cyclohexane oxidation processes.

现有的环己烷氧化制环己酮和环己醇生产工艺普遍存在转化率低、选择性差、工艺复杂、耗能大和对环境污染严重等问题，这就使得研究和开发高效、环境友好的环己烷催化氧化工艺具有重要的理论意义和实用价值。

Under the conditions of n∶n = 1∶100,95 ℃ and 6 h,the conversion of nitrocyclohexane reached to 100% and the selectivity for cyclohexanone oxime was 84.2%.

在催化剂与硝基环己烷摩尔比为1∶100、反应温度95 ℃的条件下，反应6 h后的硝基环己烷转化率可达100%，环己酮肟选择性可达84.2%。

Cyclohexanone yield of 85% and selectivity to cyclohexanone of nearly 100% were attained over the catalyst prepared under optimum condition.

在优化条件下制得的催化剂用於环己醇脱氢时，环己酮产品收率达85%，选择性近100%。

Whereas the tin hydride is used, for preparing functional fivemembered rings ,to induced alkenyl radical translocation/ cyclization process ——oxidaton process by selective activation of a C H bond——developed by Curran et al., thiophenol, non-tin chemical, is used in this new synthetic method for preparing cyclopentane derivatives through a 1,5-hydrogen transfer/cyclization sequenceEq.

在这些目标中，发展无毒、环保试剂实施有效的自由基反应是一具有挑战性的目标。Curran等发明了用氢化锡介导的自由基易位/环化过程是一种通过C H键的选择性氧化制备功能五元环的高效的方法。

In this dissertation, eight novel bisoxazoline ligands L1-L8 containing 2,2-dimethyl cyclopropane units have been synthesized and evaluated in the asymmetric cyclopropanation and Diels-Alder reaction, moreover the influence of many factors on the enantioselectivity of the new ligands was studied in detail.

在本论文中，我们设计并合成了8个新型双噁唑啉手性配体L1～L8，并研究它们在环丙烷化反应与Diels-Alder反应中的对映选择性，以及影响配体不对称诱导性能的各种因素。

The easy recovery of chiral auxiliary, good selectivity and high yield of this reaction make it a potential method in the synthesis of multifunctional optically active cyclopropane derivatives.

手性硫叶立德控制的高对映选择性合成多取代烯基环丙烷衍生物。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷