查询词典 olefins

The results of AD reactions are as follows:(1) When the AD reaction of eight olefins was performed at 0.5mo1% OsO〓 and 2mol% ligand 8 in PEG/NMO system, the diols were obtained in 78～90% yields and 78～96% ees (except for trans-5-decene and ally naphthyl ether).

催化结果如下：(1)在PEG/NMO体系中，将配体8用于八种烯烃的AD反应，配体、OsO〓和底物的摩尔比为0.02/0.005/1时，化学产率为78～90％，除反式-5-癸烯和萘基烯丙基醚较低外，其它六种烯烃的相应二醇产物的ee值为78～96％。

The osmium-catalyzed asymmetric dihydroxylation of olefins provides one of the most effective methods for the preparation of vicinal diols. Almost all kinds of olefinic substrates can be transformed to the corresponding diols by means of AD reaction. The chiral osmium catalyst is generated in situ by the chiral ligand complexing with OsO〓 in the reaction.

手性锇催化剂催化的烯烃不对称二羟基化反应是合成手性邻二醇最有效的途径之一，可以将几乎所有类型的烯烃转变成相应的手性邻二醇，因此广泛地应用于药物、天然产物以及精细化工产品的合成。

Selected novel olefinic orthoesters, may be copolymerized with other olefins using certain late metal transition catalysts, to form novel polyolefins containing orthoester pendant groups.

利用某些后过渡金属催化剂，可以使选择的新颖烯烃原酸酯与其它的烯烃共聚合，以形成含原酸酯侧基的新颖聚烯烃。

The process comprises polymerizing olefins in the presence of a supported indenoindolyl catalyst system and an organoboron or organoaluminum-treated solid.

该方法包括在茚并吲哚基载体催化剂体系和无机硼或无机铝处理的固体存在下聚合烯烃。

Results indicated that the existence of olefins in the reformate raffinate was the major factor engendering the deactivation of 5A molecular sieve.

结果表明，重整抽余油中的烯烃是引起分子筛结焦失活的主要因素。

The structures of various SAPO and their suitable catalytic reaction systems were described in this paper.The application possibilities of SAPO as catalysts in the conversion of methanol to light olefins or supports of catalysts for the automotive exhaust control were also prospected.

在此论述了SAPO的结构类型及适用的催化反应体系，并对它作为甲醇转化制低碳烯烃过程催化剂和汽车尾气净化催化剂载体的应用前景作了展望。

A desulfurization method is proposed for the removal of sulfur compounds from FCC gasoline by alkylation reaction of thiophenic sulfur with olefins over acid catalysts, and the higher boiling sulfur-containing products are removed by fractional distillation.

选择以噻吩的甲基取代衍生物(包括 2-甲基噻吩、3-甲基噻吩及 2，5-二甲基噻吩)与异丁烯的烷基化反应为模型反应，考察了经三氯化铝气相固载法改性的 CT175 树脂催化剂催化噻吩的甲基取代衍生物与烯烃的烷基化反应性能。

The catalytic activity is much higher than that of the unpromoted sample Fe/Zr, while light olefins selectivity decreases and methane formation increases.

催化剂的催化活性比Fe/Zr及Fe/La催化剂都大大提高，甲烷选择性也有所增加，烯烃选择性降低。

In addition, we found that 4-phenyl-l,2,4-triazolinium N-ylides reacted withvarious electron-deficient olefins to afford pyrrole derivatives in good yields via 1,3-dipolar cycloaddition oxidative ring fission, In some cases, tetrahydropyrrolo[1,2-b]triazole and pyrrolo[1,2-b]triazole, which are stable and are not aromatized orcleaved in the reaction conditions, could be isolated, This is a facile and novel route forthe synthesis of pyrrole derivatives.

此外，本文研究了五员三氮杂环化合物4-苯基1，2，4-三氮唑的N-叶立德，发现在氧化剂存在下与缺电子烯烃发生1，3-偶极环加成反应生成的吡咯并[1，2-b]三氮唑，在大多数情况下开环生成吡咯衍生物，反应条件温和，收率良好，是合成吡咯衍生物的一个新的途径。

A one-step method for the synthesis of aromatic indolizine derivatives byintramolecular 1,5-dipolar cyclization reaction of 2-(2-arylethenyl)pyridinium N-ylidesin the presence of an oxidant has been studied for the first time. In the presence ofelectron-deficient olefins, however, 2-(2-phenylethenyl)pyridinium N-ylides underwent1,3-dipolar cycloadditions and then aromatized in situ by TPCD to produce indolizinederivatives, indicating 1,3-dipolar cycloaddition proceed more readily than 1 ,5-dipolarcyclization in these conditions. Pyridinium disubstituted N-ylides, readily obtainedfrom corresponding pridinium and β-chlorovinyl ketone, underwent thermalintramolecular 1,5-dipolar cyclization to give indolizine derivatives easily.Indolizinecarbaldehyde derivatives were synthesized starting from 2-pyridinecarbaldehyde in four-steps involving 1,3-dipolar cycloaddition reaction.

本文首次研究了2-(2-芳基乙烯基)吡啶N-叶立德在氧化剂存在下的分子内1，5-偶极环化反应，采用一锅法合成了中氮茚衍生物；研究了这些N-叶立德的1，5-偶极环化和1，3-偶极环加成反应的选择性，发现当有缺电子烯烃存在时，优先进行1，3-偶极环加成反应，而不再发生分子内1，5-偶极环化反应；由β-氯乙烯酮方便地得到了烯丙基N-叶立德，他们在加热时进行分子内1，5-偶极环化反应而得到中氮茚衍生物；由2-吡啶甲醛为起始原料，通过1，3-偶极环加成反应等四步反应，得到了重要的中氮茚甲醛衍生物，这些反应都具有条件温和和操作简便的特点，是合成中氮茚衍生物的新方法。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。