查询词典 olefins

The chlorination in allylic position of olefins is an important transformation in organic synthesis.

二。烯烃的烯丙位氯化是制备化学中间体的一个重要反应。

The epoxidation of of various olefins was carried out using LDH-F with Mg/Al=5 as the catalyst and H2O2 and benzonitrile as the oxidants. This catalytic system has excellent catalytic activity. The conversion and selectivity are both above 95% when using styrene, indene, allyl alcohol, and allyl chloride as the substrates.

以Mg/Al=5的LDH-F为催化剂，H2O2和苯甲腈为氧化剂对不同官能团化烯烃进行环氧化反应，结果表明，此催化体系具有良好的催化性能，在苯乙烯、茚、丙烯醇和烯丙基氯环氧化反应中转化率和选择性均在95%以上。

The product of propane gas chromatography, second is the highest percentage of butane and isobutane is, The content of olefins are relatively low.

气相产物中丙烷的百分含量最高，其次是正丁烷和异丁烷；烯烃的含量均较低。

"Rare in nature, olefins are obtained by the cracking of petroleum fractions at high temperatures. The simplest ones (ethylene, propylene, butylene, butadiene, and isoprene) are the basis of the petrochemical s industry."

烯烃在自然界很稀少，但在石油裂解成汽油过程中可大量生成，低级的单烯烃已成为庞大的石油化学工业的基础。

"Rare in nature, olefins are obtained by the cracking of petroleum fraction s at high temperatures. The simplest ones (ethylene, propylene, butylene, butadiene, and isoprene) are the basis of the petrochemicals industry."

烯烃在自然界很稀少，但在石油裂解成汽油过程中可大量生成，低级的单烯烃已成为庞大的石油化学工业的基础。

"Rare in nature, olefins are obtained by the cracking of petroleum fractions at high temperatures. The simplest ones (ethylene, propylene, butylene, butadiene, and isoprene) are the basis of the petrochemicals industry."

烯烃在自然界很稀少，但在石油裂解成汽油过程中可大量生成，低级的单烯烃已成为庞大的石油化学工业的基础。

AIM: To synthesize 2 novel chiral ligands derived from cinchona alkaloids and study their catalytic performance in asymmetric dihydroxylation of 5 olefins.

目的：合成两种新的金鸡纳生物碱类衍生物配体并将其用于催化五种烯烃的不对称二羟化反应，考察催化效果。

METHODS: Inexpensive quinine and cinchonine were transformed to 9NH2quinine and 9NH2cinchonine, which reacted with 4chlorobenzoyl chloride to afford 2 novel chiral ligands. The AD reactions of olefins were performed in H2OtBuOH (1∶1) using the 2 ligandsK2OSO24 as catalysts.

以价廉易得的奎宁和辛可宁为原料，经过结构转换得到9氨基奎宁和9氨基辛克宁，进而与对氯苯甲酰氯反应制得两种新型手性配体，并将其用于锇催化的烯烃的不对称双羟化反应。

The investigation of the catalytic activity and stereoselectivity of ligand 10 was also carried out under another standard set of K〓Fe 〓 conditions (〓/ligand/substrate=0.002: 0.01: 1). The AD reaction of seven olefins gave corresponding diols in 72～99% yield (except for ethyl cinnamate, 48%) and 91～99% ees, which was comparable to those obtained from the reactions using the commercial ligand 〓PHAL.

将单季铵盐手性配体10用于AD反应的另一个催化体系〓BuOH-H〓O/K〓Fe〓中考察其催化活性和立体选择性，在七种烯烃的AD反应中，〓、配体与底物的摩尔比为0.002：0.01：1时，化学产率为72～99％（肉桂酸乙酯除外，为48％），ee值为91～99.9％，与商品配体〓PHAL的催化结果相当。

The yield of the poly-alpha-olefins synthetic lubricant is 81.42%. The results show that the viscosity at 100℃ is 4.87mm^2/s, the viscosity at 40 is 21.15mm^2/s, the viscosity index is 126, the condensation point is -62℃.

结果表明，产品收率为81.42%，100℃的粘度为4.87mm^2/s，40℃的粘度为21.5mm^2/s，粘度指数为126，凝点为－62℃。

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。