W hen we discussed elimination reactions in Chapter 5, we learned that Lewis base can react with an alkyl halide to form an alkene. In the present chapter, you will find that the same kinds of reactants can also undergo a different reaction, one in which the Lewis base acts as a nucleophile to substitute for the halide substituent on carbon

Ikenes are hydrocarbons that contain a carbon-carbon double bond. A car- bon-carbon double bond is both an important structural unit and an important functional group in organic chemistry. The shape of an organic molecule is influ- enced by the presence of this bond, and the double bond is the site of most of the chem- ical reactions that alkenes undergo. Some representative alkenes include isobutylene(an industrial chemical), a-pinene (a fragrant liquid obtained from pine trees), and farnesene (a naturally occurring alkene with three double bonds

1.色谱法:起源与发展: 特点:分离分析技术;分析有色 物质、无色物质。 本质:色谱柱高选择性的高效分 离作用与高灵敏度检测技术的结合。 分类(流动相状态):气相色谱、 液相色谱、超临界色谱

tructure* is the key to everything in chemistry. The properties of a substance depend on the atoms it contains and the way the atoms are connected. What is less 0 obvious, but very powerful, is the idea that someone who is trained in chemistry can look at a structural formula of a substance and tell you a lot about its properties

ow that we've reviewed the various bonding models, we are ready to examine organic compounds in respect to their structure, reactions, properties, and appli cations. Were we to list the physical and chemical properties of each of the more than million organic compounds separately, it would tax the capacity of even a pow- erful computer. Yet someone who is trained in organic chemistry can simply look at the structure

一. 电环化反应(Electrocyclic Reactions) 在光或电的作用下，共轭烯烃转变为环烯烃或它的逆反应——环烯烃开环变为共轭烯烃的反应都称为电环化反应

first three chapters established some fundamental principles concerning the structure of organic molecules. In this chapter we begin our discussion of organic chemical reactions by directing attention to alcohols and alkyl halides. These two rank among the most useful classes of organic compounds because they often serve as starting materials for the preparation of numerous other families

drogen peroxide is formed in the cells of plants and animals but is toxic to them. neemen Consequently, living systems hav developed mechanisms to rid themselves of hydrogen peroxide, usually by enzyme-catalyzed reduction to water. An under- standing of how reactions take place, be they reactions in living systems or reactions in

醚，可以看成是水分子中的两个氢原子被烃基取代而生成的化合物。分为简单醚(两个烃基相同，R-O-R)、混合醚(两个烃基不同，R-O-R’)

1. 核磁共振的基本原理 （1）原子核的自旋 原子核的自旋量子数：I 或ms 表示原子核的自旋运动情况。ms 与原子的质量数和原子序数之间的关系：