乙烯酮

It is important theoretically and practically that the ketene photodissociationas a model system for unimolecular dissociation.

乙烯酮分子的光解反应作为研究单分子解离的模型系统具有重要的理论和实际意义。

Photodissociation dynamics of ketene at 218 nm has been investigated using the velocity map ion-imaging method.

用离子速度成像方法研究了乙烯酮分子在218 nm光解下的光解动力学，得到了光解产物CO的共振多光子电离谱，以及在不同振转态的角分布和平动能分布。

Reactions of ketene (CH2CO) with some small molecular free radicals play an important role in combustion and atmospheric chemistry. The experimental and theoretical studies to these reactions have attracted many interests of chemists these years.

乙烯酮(CH2CO)与某些小分子自由基的反应在燃烧和大气化学中起着重要作用，近年来已成为化学家们广泛关注的研究课题之一。

In chapter four molecular modeling method is employed to comparatively study five S-allyl γ-hydroxy ketene dithioacetals reactions of Thio-Claisen rearrangement with and without zeolite catalysts.

第四章用分子模拟途径研究了在有、无分子筛催化条件下五种丙烯基羟基乙烯酮二硫代乙缩醛Thio-Claisen重排反应。

Keywords ketene;isopropenyl acetate;esterification;strong acidic cation-exchange resin;fine chemical intermediates

乙烯酮；乙酸异丙烯酯；酯化反应；强酸性离子交换树脂；精细化工中间体

Which have high reactivity for its high unsaturation,so that it application in many ways,such as:pesticide, medicine ,dyestuff and food additive,etc.

介绍了双乙烯酮在国内外的生产情况，并对它或以它的衍生物作原料，在医药、农药、染料、有机合成等方面的应用作了较详细论述。

Starting with two reactive methylene compounds, ethyl cyanoacetate and malononitrile, two 5-amino-1H-pyrazoles were prepared through the intermediates ketene dithioacetal.

从两个活泼亚甲基化合物开始，经过乙烯酮二硫代缩醛中间体，合成了两个5-氨基-1H-吡唑，以这个两个化合物为中间体，与芳香族和脂肪族α-溴代酮反应，而后经酸催化亚胺化互变异构后得到含咪唑并[1，2-b]吡唑甲硫醚类化合物6a-6g。

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。

The products include antioxidants,blowing agents,organic solvents, intermediates for pesticides,drugs and dyestuffs,perfumes,water glass,silicates,molybdenum compounds,graphite series,activated carbon,plasticizers,flame retardant,heat stabilizers,food additives and chemical reagents,etc.

注册商标有&鹿牌&合成樟脑，&桃浦&牌合成樟脑副产物和其他化工产品，&金牛&牌抗氧剂，发泡剂，水合肼，二甲基乙酰胺，二甲基乙醇胺，&海球&牌硅胶系列，&飞铃&牌磷氯，双乙烯酮衍生物，磷酸酯，乙烯利等，&泉字&牌，&水晶&牌各类泡化碱系列，&上胶&牌钼类化合物，石墨类产品系列。

The intermediate 5-amino-1H-pyrazole-4-carboxylic acid ethyl ester prepared in the first part underwent successively hydrazinolysis, condensations with ketene dithioacetals and alkylations to give rise to the dipyrazolyhnethanes.

从第一部分中的中间体5-氨基-1H-吡唑-4-羧酸乙酯开始，经过肼解、与乙烯酮二硫代缩醛的缩合反应和烷基化反应，合成了二吡唑基甲酮类化合物。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。