查询词典 ionic bond

Taking advantage of better solubility and thermal stability of ionic liquid, the ionic liquid supported acetylacetone catalyst can be simply recycled by water washing or vacuumdistillation.The background of this research is renovation on the traditional oxidation reactions by green chemistry principle.

根据离子液体支载催化剂的两个特性：在水中良好的溶解性和具有很好的热稳定性，在反应结束后通过水洗涤或精馏的方法，很方便的对催化剂进行了回收再利用。

Basing on above researches, we designed a series of ionic liquid supported acetylacetone metal catalysts and non ionic liquid supported acetylacetone metal catalysts. The catalytic abilities of these catalysts were evaluated by using them to catalyze the methane oxidation reaction.

在以上研究的基础上，本论文设计了系列离子液体支载的乙酰丙酮金属催化剂及非离子液体支载的乙酰丙酮金属催化剂，并通过这些催化剂对甲烷氧化反应的催化效果来预测它们的活性。

For low molar ratios of Al/Zr, a hypsochromic shift of the initial catalyst absorption band, corresponding to the monomethylation of the catalyst, was observed. Further addition of AlEt2Cl was accompanied by a continuous bathochromic shift of the maximal wavelength corresponding to the formation of more dissociated ionic active species. Then, there would be a coordination of monomer to the ionic active species.

结果表明，无论是AlEt_2Cl还是MAO，少量的助催化剂首先使催化剂发生单烷基化反应，主催化剂金属中心的最大吸收峰波长发生蓝移，而当助催化剂量进一步增加时，金属中心的最大吸收峰波长红移，单烷基取代的催化剂被大量的助催化剂夺去电子成为缺电子的阳离子活性中心，以便烯烃单体的配位插入。

Enzymes of widely different types are catalytically active in ionic liquids or aqueous biphasic ionic liquid systems.

许多酶能在ILs或其形成的两相体系或单相体系中保持催化活性。

On the other hand, a method for the synthesis of-vinyl chalcogenides by the coupling of vinyl bromides with thiols or diphenyl diselenide using copper salts as catalysts in ionic liquids based on amino acids also has been described. The ionic liquids play multiple roles in the reaction: they act as solvent, base, and excellent promoter for the copper-catalyzed coupling reactions.

在新型的氨基酸负离子的离子液体中，开发了一个亚铜盐催化的Z-型溴代烯烃与硫族元素的交叉偶联反应，为立体选择性的制备Z-型烯基硫醚或烯基硒醚类化合物提供了一个新的方法；在此反应体系中，离子液体不仅起到了反应溶剂的作用，而且还起到了金属催化剂的配体和中和反应副产物的碱的作用。

A new method was proposed to prepare water-soluble ionic liquids by using four-compartment electrodialysis.1-Ethyl-3-methylimidazolium tetrafluoroborate (［EMIm］BF4), used as a model ionic liquid, was synthesized.

以1-乙基-3-甲基咪唑四氟硼酸盐（［EMIm］BF4）的制备为例，对四隔室电渗析法制备水溶性离子液体进行了研究。

Transesterification of geranol and vinyl acetate in ionic liquids were investigated to synthesize geranyl acetate using immobilized Candida antarctica lipase B as biocatalyst. The reuse of ionic liquids and lipase were also studied in this reaction.

以固定化的南极假丝酵母脂肪酶为催化用酶催化香叶醇和乙酸乙烯酯在离子液体中的酯交换反应，合成了香料乙酸香叶酯，同时通过该反应了解了酶和离子液体的重复利用性。

When doping the first periodic transition elements in TiO〓, the relationships between the photocatalytic activities and the ratio of electronic affinity energy to the ionic radius and the ionic magnetic moment of heteratomic ion were studied.

通过第一过渡系元素对纳米TiO〓光催化剂的掺杂，发现催化活性与掺杂元素的稳定氧化态的电子亲和势Ea与离子半径r的比值Ea/r有顺应关系，该比值越大，催化活性越低。

Both catalytic activity and selectivity of Ru(PPh_3)_3Cl_2 were improved in ionic liquid BMImPF_6/DME medium.The conversion of hexene and selectivity ofβ-adduct for the hydrosilylation reaction of 1-hexene with triethoxysilane catalyzed by Ru(PPh_3)_3Cl_2 in ionic liquid BMImPF_6DME (V/V=1/4) medium at 90℃were 100% and 89.0%,respectively.

实验结果表明，在乙二醇二甲醚/离子液体1-丁基-3-甲基咪唑六氟磷酸盐(BMImBF_6)(V/V =1/4)介质中，于90℃下，己烯与三乙氧基硅烷反应的转化率为100%，β加成物的选择性可达89.0%，而用Rh(PPh_3)_3Cl作为反应的催化剂，在纯离子液体BMImPF_6中，就可以高效催化烯烃与三乙氧基氢硅烷的加成反应，过渡金属Rh(PPh_3)_3Cl，Ru(PPh_3)_3Cl_2催化剂/离子液体BMImPF_6催化体系，不仅解决了产物与催化剂分离困难这一难题，同时，离子液体BMImPF_6的存在提高了过渡金属Rh(PPh_3)_3Cl，Ru(PPh_3)_3Cl_2催化硅氢加成反应的活性，特别是β加成物的选择性。

ABSTRACT The ionic strength of mobile phase can significantly affect the peak shape of ionogenic compounds such as antibiotics in reversedphase high performance liquid chromatography. The influence may be attributed to overloading of ionogenic analytes in lower ionic strength mobile phase.

在反相高效液相色谱过程中，流动相的离子强度可显著影响可解离的化合物如抗生素的色谱峰形，原因在于流动相的离子强度较低时，色谱填料的固定相易于过载，使离子化的化合物的色谱峰形呈典型的过载特征――峰形接近直角三角形。

Foods high in this vitamin include oily fish such as salmon, tuna and, and fish liver oils.

维生素D含量高的食物包括诸如大麻哈鱼、金枪鱼和鲭鱼之类的油鱼以及鱼肝油。

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我们需要您cosign我们的公共信，要求记者立即停止恐吓，并要求所有收费下降。