2. 7.1 Introduction

3. Reactions of Radicals General reaction

4. 7.2 Homolytic bond dissociation energies 7.2A Homolytic bond dissociation energies and heats of reaction 7.2B Homolytic bond dissociation energies and the relative stabilities of radicals

5. 7.2B Homolytic bond dissociation energies and the relative stabilities of radicals Homolytic bond dissociation energies also provide us with a convenient way to estimate the relative stabilities of radicals.

6. Relative stabilities of radicals

7. Relative stabilities

8. 7.3 The reactions of alkanes with halogens Methane, ethane, and other alkanes react with the first three members of the halogen family: fluorine, chlorine, and bromine. Alkanes do not react appreciably with iodine. With methane the reaction produces a mixture of halomethanes and a hydrogen halide.

9. Halogenation reactions ( 卤化反应） The reaction of an alkane with a halogen is called halogenation. In these reactions a halogen atom replaces one or more of the hydrogen atoms of the alkane. Reactions of this type, in which one atom or group replaces another, are called substituion reactions

10. 7.3A Halogenation reactions (multiple substitution reactions)

13. 7.4 Chlorination of methane: Mechanism of reaction

15. 7.5 Chlorination of methane: Energy Changes

16. 7.5A The overall free-energy change 7.5B Activation energies ( 活化能）

17. 7.6 Reaction of methane with other halogens

18. Chain Initiation ( 链的引发）

19. Chain Propagation ( 链的增长）

20. 7.7 Halogenation of higher alkanes （长链烷烃的卤化）

21. Chlorination of higher alkanes

22. 7.7A Selectivity of bromine

24. 7.8 The geometry of alkyl radicals

25. 7.9 Reactions that generate tetrahedral stereocenters When achiral molecules react to produce a compound with a single tetrahedral stereocenter, the product will be obtained as a racemic form. Let us examine a reaction that illustrates this principle, the radical chlorination of pentane

26. The radical chlorination of pentane

27. How to get (±)-2- Chloropentane ?

29. 7.10 Other important radical chain reactions 7.10A Combustion of alkanes 7.10B Autoxidation 7.10C Freons and ozone depletion( 氟里 昂和臭氧 O 3 的损耗 )

30. 7.10C Freons and ozone depletion( 氟里昂和臭氧 O 3 的损 耗 ) In the stratosphere ( 同温层, 最上层, 最高 阶段 )at altitudes of about 25 km, very high-energy (very short wavelength) UV light converts diatomic oxygen ( O 2 ) into ozone ( O 3 ). The reactions that take place may be represented as follows:

31. 氟里昂损耗了大气层中臭氧 O 3