环乙烯

There exists π-π electronic transition of benzene ring and unsaturated C=C bond in vinylidene of PDBOPV at 310 and 520 nm through ultraviolet-visible absorption spectrum.

研究表明，PDBOPV在310nm和520nm处分别出现苯环和亚乙烯基中的不饱和―C═C―双键的π-π*电子跃迁。

The reaction takes place as soon as 3a is dissolved in solution. With the presence of a tethering terminal vinyl group bound to the vinylidene ligand, the [2+2] cycloaddition of two C=C double bonds readily occurred.

当有一乙烯基键结在丙二烯基上，分子内的两个碳碳双键会马上发生[2+2]的环化加成反应。

The sodium sulphonate of ethoxylated acrylic modified rosin can be obtained from acrylic modified rosin after the reaction with ethylene oxide and then be sulphonated with chlorosulphonic acid.

以松香为原料，用丙烯酸进行改性后再与环氧乙烷聚合，然后用氯磺酸进行磺化处理制得丙烯酸改性松香聚氧乙烯醚磺酸钠阴离子表面活性剂。

R-1,c-2, t-3, t-4-1,3-bis(4-biphenyl)-2,4-di(4-pyridyl)cyclobutane was obtained in diluted sulfuric acid by photodimerization reaction.

通过反-1-(4-联苯基)-2-(4-吡啶基)乙烯在稀硫酸中的光二聚反应合成了r-1，c-2，t-3，t-4-1，3-双(4-联苯基)-2，4-二(4-吡啶基)环丁烷。

A Product main business categories: chemical solvents white oil, toluene, xylene, durene, valitin water, acetate, D resin, acetone, butanone, cyclohexanone , anti-white water, dichloromethane, trichloroethane, trichlorethylene, loose water-saving washing network water, open water, wash water, and days that water, rust agent, to water-logging, washing machine water, decontamination water, n-butyl alcohol, isopropyl alcohol, ethanol, industrial alcohol, car-washing water, washing machine water, clean lines of water, cleaning machine water, fire water, paint remover, fungicides, antifreeze water, chloroform, grinding fluid , diluent, release agent, dehydration agent substantial industrial solvents.

主要经营产品 A类：化工溶剂白电油、甲苯、二甲苯、四甲苯、凡立水、乙脂、丁脂、丙酮、丁酮、环己酮、防白水、二氯甲烷、三氯乙烷、三氯乙烯、松节水、洗网水、开油水、洗面水、天那水、除锈剂、去渍水、洗枪水、去污水、正丁醇、异丙醇、乙醇、工业酒精、洗车水、洗机水、抹线水、抹机水、火水、脱漆剂、杀菌剂、防冻水、哥罗仿、研磨液、稀释剂、脱模剂、脱水剂等大量工业溶剂。

Regular vinyl addition polymers may be obtained from particularly strained endocyclic double bonds.

由带特殊张力的桥环双键可以得到规整的乙烯类加成聚合物。

This article reports a new kind of copolymer, non polar polar terpolymer : poly(styrene-butadiene-methyl methacrylate ) P(S-b-B-b-MMA prepared by anionic polymerization with n BuLi as initiator, 1,1 diphenylethylene as capping agent and lithium 2-(-methoxyethoxy) ethoxide as complex agent.

以正丁基锂为引发剂， 1 ，1-二苯基乙烯为戴帽剂， 2-(2-甲氧基乙氧基)乙氧基锂为络合剂，在环己烷、四氢呋喃混合溶剂中，采用阴离子聚合法，于－70℃～－40℃合成了非极性-极性的三嵌段共聚物聚苯乙烯-聚丁二烯-聚甲基丙烯酸甲酯，并借用GPC、1H-NMR、DSC、TEM、IR等仪器对共聚物进行了表征。

The formation mechanism for the C-PPV aggregation we proposed is: complex between K+ and the crown ether derivatives in the C-PPV brings two polymer chains closer together, and the K+ ions create interpolymer bridges, forming aggregations in the solution.

本文合成了可溶的带冠醚取代基的聚苯撑乙烯，其中冠醚基团的氧原子直接连在PPV主链上苯环的2、3位，并研究了聚合物在K~+存在下的自组装形成聚集体的行为。

Based on the different reaction results with-menthyl,-8-(2-naphthyl)menthyl or-8-phenylmenthyl as the chiral auxiliary, it is was proposed that the possible p -stacking effect between the aryl of chiral auxiliary and dienyl group of α,β-unsaturated esters is involved in the diastereoselectivity of these reactions.

该反应手性辅基易于回收、选择性好，产率高，这一工作为合成多取代的光学活性乙烯基环丙烷衍生物的提供了一种较为简便的方法。

Bis-imidazoline was prepared from triethylene tetraamine and N,N-dimethylformamide dimethyl acetal at 85℃ for 2 h with toluene as solvent, with a yield of 90.4%. The reaction of bis-imidazoline with 1,2-dibromoethane and potassium carbonate in acetonitrile provided with a monobromide salt yield of 78.7%. Hydrolysis of monobromide salt under aqueous causic solution formed 1,4,7,10-tetraazzcyclododecane in a 74.2% yield.

用甲苯作溶剂，使三乙烯四胺和N，N-二甲基甲酰胺二甲基缩醛在85℃反应2 h，得到中间体双咪唑啉，产率90.4%，在乙腈溶剂中，碳酸钾存在下，双咪唑啉和1，2-二溴乙烷进行扩环反应，得到环状中间体一溴盐，产率78.7%，一溴盐经碱性水解2 h，得到1，4，7，10-四氮杂十二烷，产率74.2%。

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。