查询词典 aromatic compound

A novel trifunctional fluorinated epoxy compound was synthesized, which was cured with one alicyclic anhydride and two aromatic diamines, respectively.

固化后的含氟三官能团环氧树脂表现出高玻璃化转变温度、低介电常数、低热膨胀系数、低吸水率等特点。

1H NMR spectroscopic analysis of aromatic protons combined with theoretical analysis of molecular structures proved the existence of two rotational isomers at 300 K, as well as a rapid interconversion equilibrium at 330 K for both compounds Ⅰ and Ⅱ. However, only one conformer exists for compound Ⅲ and puerarin containing 7-phenolic hydroxyl instead of propyl in A-ring as the case of compounds Ⅰ and Ⅱ. Based on UV-Visible absorption data of neutral and basic solutions, and on the density function calculations, the 7-phenolic hydroxyl group in A-ring was found to be more acidic than the 4'-phenolic hydroxyl group in B-ring. The mechanism of derivation reaction and the structure-reactivity relationship of puerarin as an antioxidant were further discussed.

其中7-丙基葛根素Ⅱ属于新型取代衍生物；变温1H NMR和理论计算结果表明，在300 K时，葛根素和4'-丙基葛根素以单一构型存在；而7，4'-二丙基葛根素和7-丙基葛根素则存在两种核磁可分辨的旋转异构体，当温度升至330 K时，两种异构体可以相互转化；通过对比分析葛根素及其衍生物脱质子产物的紫外可见吸收光谱并结合理论计算，确定了A环上7位酚羟基比B环上4'位酚羟基先脱去质子，并由此进一步阐明了葛根素衍生化反应机理以及在抗氧化作用中可能的活性位点和结构活性关系。

The influence of each condition on the reaction speed and yield was studied, and the optimal conditions were: the ratio of the amount of substance of aromatic amine and heptafluoro-isopropyl iodine was 1:1.1~1.5, the amount of substance of sodium dithionite, sodium bicarbonate, aniline compounds were respectively 1.1~1.3, the amount of substance of phase transfer catalyst TBAB and aniline compounds was 0.05~0.1, the concentration of aniline compound was 0.5~1.0 mol/L, reaction temperature was 10~20 ℃, and the solvent was aether.

最佳结果为：芳胺与七氟异丙基碘的物质的量比1：1.1~1.5，连二亚硫酸钠、碳酸氢钠与苯胺的物质的量分别为1.1~1.3，相转移催化剂四丁基溴化铵与苯胺的物质的量比在0.05~0.1，溶剂总用量使苯胺浓度在0.5~1.0 mol/L；反应温度10~20℃；溶剂采用乙醚。取代基供电子性越强，反应时间越短，产率越高；氨基的对位优先反应，氨基的邻位较难发生反应；且七氟异丙基总是优先取代在芳环电子云密度较高的位置上。

The copolymerization compound comprises based on a proportioning ratio by weight: 25-99 percent ethylene aromatic series monomer; 0-30 percent olefinic undersaturation nitrile monomer; 1-50 percent olefinic dibasic acid ramification monomer.

这种共聚组合物按重量百分比包含：25至99％的乙烯基芳香族单体；0至30％的烯属不饱和腈类单体；1至50％的烯属二元酸衍生物单体。

It is a high-tech enterprise specialized in manufacturing carbon fiber fabric,aromatic fiber fabric,perform of space thermo structure material,perform of carbon brake for plane,new reinforcing materials such as high performance carbon/carbon compound materials.

是专业生产碳纤维织物、芳纶纤维织物、航天热结构预制件、飞机碳刹车预制件以及高性能碳/碳复合材料的新型增强材料的高科技企业。

A serial of novel thiophene-based main chain conjugated compound with varieties of aromatic rings and heterocycle, such as acenaphtenequinoxaline phenanthrenequinoxaline ,have been synthesized on the base of looking for lots of references and summarized others research work.

在查阅大量文献和综合前人所作工作的基础上，我们选择卤代芳烃与Sn金属有机试剂在Pd催化下合成了以萘基喹喔啉和菲基喹喔啉为主的一系列噻吩与杂环构成的交叉共轭化合物。

A catalyst composition for the polymerization of propylene comprising one or more Ziegler-Natta procatalyst compositions comprising one or more transition metal compounds and one or more esters of aromatic dicarboxylic acid internal electron donors; one or more aluminum containing cocatalysts; a selectivity control agent comprising at least one silicon containing compound containing at least one C1-10 alkoxy group bonded to a silicon atom, and one or more activity limiting agent compounds comprising one or more aliphatic or cycloaliphatic carboxylic acids; alkyl-, cycloalkyl- or alkyl-ester derivatives thereof; or inertly substituted derivatives of the foregoing.

一种用于丙烯聚合的催化剂组合物，所述催化剂组合物包括：一种或多种齐格勒-纳塔主催化剂组合物，该主催化剂组合物包括一种或多种过渡金属化合物和一种或多种芳族二羧酸酯内部电子给体；一种或多种包含铝的助催化剂；选择性控制剂，该选择性控制剂包括至少一种包含硅的化合物，该化合物包括至少一种与硅原子连接的C 1-10 烷氧基；和一种或多种活性限制剂化合物，该活性限制剂包括一种或多种脂族或脂环族的单或聚羧酸类、其烷基-、环烷基-或烷基-衍生物、或上述惰性取代的衍生物。

It was found that the geometries of the studied materials were significantly affected by the ring size and intramolecular charge transfer. The HOMO level, LUMO level, and band gap of the studied model compounds were well controlled by the acceptor strength. However, the electronic properties of the studied polymer showed a significant different trend with the acceptor strength due to the geometrical transformation. The model compound of EDOT-TP and T-TP has the aromatic geometry but is transformed to the quinoid geometry for large intramolecular charge transfer. The small bond length alternation and large acceptor strength in the EDOT-BDP polymer also results in the smallest Eg of 0.7 eV among the studied polymers.

我们发现环的大小以及分子内电荷转移对结构有很大的影响，而小分子的HOMO、LUMO和能隙受到电子受体强度所控制，然而，高分子的电子特性与其构成分子却有明显不同的趋势，这主要是由於分子结构的转变，如小分子EDOT-TP以及T-TP因分子内电荷转移，使其高分子结构由aromatic转变成quinoid；而EDOT-BPP因其键长改变量小和良好的电子受体强度，使其能隙仅0.7个电子伏特。

Since aromatic ring is a very stable compound, it would needs very high activation energy to begin the ring opening reaction. It is therefore interesting to investigate how the micro-organism can catalyze this reaction in room temperature at natural buffer condition.

由於芳香环是一种非常稳定的化学结构，如果想要进行开环反应必要要经过极大的活化能，而了解生物体中是如何在常温的环境下进行这样的反应将会是非常有趣的题材。

Phenol: Any of a class of organic compounds with a hydroxyl group (-OH; see functional group) attached to a carbon atom in a ring of an aromatic compound.

酚：以羟基(-OH；参阅functional group)与芳香族化合物环上的碳原子相连为特征的一类有机化合物。

Cable dampener cannot be rolled up but must be hung over the cable.

缆帆不能被卷起，必须保证处于展开状态

"This skylark is a present from my master," he says.

"这只云雀是我主人献上的礼物。"他说。