烯基

Uncured natural rubber is sticky, easily deforms when warm, and is brittle when cold. In this state it cannot be used to make articles with a good level of elasticity .

一般需经过硫化的橡胶品种有丁二烯、氯丁二烯、异戊二烯的1，4-聚合物--顺丁、异戊、氯丁橡胶，以及共聚物丁苯、丁基和丁腈橡胶等。

In comparison with the organic solvents as reaction medium, higher conversion was achieved the tert-ethyl valerate could be formed in the ionic liquid medium.

当反应体系中存在水时，有特戊酸生成。表明反应中2，2，4-三甲基戊烷首先发生β-断裂反应，生成叔丁基正碳离子和异丁烯。

Via comprehensive computations, the possibilities of vinylidene and allene intermediates were excluded, and the reaction mechanism was found to contain the following three steps:(1) gold-catalyzed cyclization to give the cyclic intermediate,(2) the cyclic intermediate undergoing a 1,3-H migration to give a more stable intermediate, with the assistance of water-cluster,(3) finially, the 1,2-H or 1,2-silyl migration occuring for generation of the observed product.

通过对各种可能的反应路径的进行计算和比较，排除了亚甲基卡宾和连二烯中间体的可能性，并确定该异构化反应机理包含以下三个步骤：（1）炔丙基吡啶反应在金催化条件下发生分子内的成环得到环状中间体；（2）环状中间体在水分子簇的协助下优先发生1，3-氢迁移反应，异构化得到更为稳定的中间体；（3）最后再进行1，2-氢迁移或是1，2-硅烷基团迁移即得到实验中所观察到的环异构化产物。

Rotary viscosimeter is employed to reflect the effect of the composition, shear, temperature and salt concentration on viscosity of the modified polyacrylamide was studied in different synthesis approaches.

为了增强聚丙烯酰胺的增粘性能，提高其抗剪切、抗温和抗盐性，使用实验室自制的疏水单体、丙烯酰胺和离子型单体，通过3种不同的聚合方法进行自由基共聚合。

It was found that ARA was composed of esterification products of (2-HEA)-ester with pimaric acid, dehydroabietic acid, abietic acid and two isomers of acrylpimaric acid. ARA is a good crosslinking agent which can copolymerize with most vinyl monomers. The properties of solvent-resistance and heat resistance of the copolymer were improved considerably by the use of ARA.

实验结果表明：ARA主要由海松酸、脱氢枞酸、枞酸和丙烯海松酸的二种异构体的丙烯酸－2-羟基乙基酯的酯化产物组成，ARA是一种良好的交联剂，可与大多数乙烯基单体共聚合，其与MMA的共聚物的耐溶剂性和耐热性均得到了较大幅度的提高。

By virtue of the coordination of Cr2L (L = CO; PPh3; C3H5 BF4-) with N-vinylcarbazole, acenaphthylene and their derivatives as organic ligands, a series of organometallic complexes have been synthesized. Their spectra characterization and X-ray diffraction analysis have been performed. It is found that this kind of complexes possesses an electronic structure with highly extensive π- delocalization.

以N－乙烯基咔唑、苊烯及其衍生物作为配体与金属基团Cr2L(L = CO； PPh3； C3H5 BF4-)配位，合成了一系金属有机配合物，并对其进行了光谱表征和单晶X射线衍射分析，发现该类配合物具有高度离域的电子结构。

A run flat tire wheel assembly having a run flat support member formed by a ring-shaped metal shell and rubbery elastic members in an inside cavity of a tire/rim, wherein the rubbery elastic member comprises a rubber composition including 100 parts by weight of a diene-based rubber and 0.1 to 5 parts by weight of cobalt acetyl acetonate and/or, as a reinforcing filler, 40 to 90 parts by weight of carbon black/silica in a ratio of 10/1 to 1/2 and 1 to 20% by weight based upon the weight of the silica, of a silane coupling agent, whereby the bondability between the ring-shaped metal shell and rubbery elastic members is improved.

一种轮胎车轮组装体，它是在轮胎/轮辋的内空洞部具有由环状金属壳和橡胶状弹性体形成的漏气保用支撑体的漏气保用轮胎车轮组装体，其中通过由下述的橡胶组合物来构成上述橡胶状弹性体，改良环状金属壳与橡胶状弹性体的粘结性，所述橡胶组合物含有：100重量份的二烯烃类橡胶；以及0.1～5重量份的乙酰基丙酮酸钴、及/或作为增强性填充剂，40～90重量份的以10/1～1/2的比例配合的炭黑/硅石，和相对于上述的硅石重量，1～20重量％的硅烷偶联剂。

The invention discloses a process for preparing N-Boc derivative or N-Cbz derivative of chiral alpha, alpha'-double substituent pyrrolidine which contains ethylenic link and acetylenic link substituent.

本发明公开了一种制备含烯键和炔键取代基的手性α，α'-二取代吡咯烷的N-Boc衍生物或N-Cbz衍生物的方法。

A method to synthsis a - methylene - r - butyrolactones was reported by the substituted (a - carbethoxyvinyl) cuprate intermediates, generated by the addition of higer order cuprate to acetylenic ester,traping with epoxides stereoselectively.

本文报道了通过以高序铜代替低序铜对炔酸酯加成得到的取代铜与端基或环状环氧化合物的立体选择性反应，较高产率的合成α，β-取代烯酯，进而可合成α-亚烷基-γ-丁内酯类衍生物。

The catalytic system composed of NHPI and transition metal ion can catalyze effectively ethane into acetic acid,cyclane into dicarboxylic acid,toluene into benzoic acid,alkene into epoxide,alkyne into acetylenic ketone,and amide into imide;NHPI used alone can catalyze adamantane to be carbonylated,hydrogen peroxide prepared by oxidization alcohol;NHPI combined with as...

NHPI与过渡金属离子组成的催化体系能高效地催化乙烷氧化为乙酸、环烷烃氧化为二元羧酸、甲苯氧化为苯甲酸、烯烃氧化为环氧化物、炔烃氧化为炔酮、酰胺氧化为酰亚胺；NHPI单独使用能催化金刚烷发生氧化羰基化反应、催化氧化醇制取过氧化氢；NHPI与有机助催化剂如偶氮二异丁腈、溴化季铵盐、蒽醌和醇等也能催化分子氧氧化反应。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。