2. Aliphatic Hydrocarbons 2. Branched & Isomeric Alkanes 1

3. n-Pentane CH 3 CH 2 CH 2 CH 2 CH 3 Isopentane (CH 3 ) 2 CHCH 2 CH 3 Neopentane (CH 3 ) 4 C C 5 H 12 2

4. Common alkyl groups (C 1 through C 4 ) 3

5. Number the Carbons Start at the end closest to the first attached group. If two substituents are equidistant, look for the next closest group. 4 1 2 345 67

6. 4 3 2 1 2-methylbutane 5

7. Find the longest continuous carbon chain 1 2 3 4 5 3-methylpentane 6

8. You must choose the longest continuous carbon chain 4 3 2 1 5 6 7 4-ethylheptane 7

9. Number from the end nearest the first substituent 7 6 5 4 3 2 1 4-ethyl-3-methylheptane 8

10. Number from the end nearest the first substituent 8 7 6 5 4 3 2 1 3-ethyl-5-methyloctane 9

11. Use “di-” with two substituents 1 2 3 4 2,3-dimethylbutane 10

12. Every substituent must get a number 1 2 3 4 5 6 3,3-dimethylhexane 11

13. Number from the end nearest first substituent 10 9 8 7 6 5 4 3 2 1 2,7,8-trimethyldecane 12

14. Number from the end which has the “first difference” 1 2 3 4 5 6 7 8 9 10 3,4,8-trimethyldecane 13

15. A More-Highly-Substituted Carbon Takes Precedence 5 4 3 2 1 2,2,4-Trimethylpentane 14

16. Which end do we number from? 8 7 6 5 4 3 2 1 3-ethyl-6-methyloctane 15

17. Halogens and other side groups Flouro –F Chloro –Cl Bromo –Br Iodo –I Nitro –NO 2 16

18. Bromoethane “Ethyl bromide” 17

19. 2-Chloro-2-methylpropane “tert-Butyl chloride” 18

20. 2-Bromo-3-methylpentane 19

22. In normal conditions alkanes do not react with acids and alkalis because  -bonds in their molecules are very strong. But alkanes take part in such reactions as: - -Substitution Reactions -Oxidation Reactions -Destruction Reactions 21

23. Halogenation of alkanes. Alkanes react with halogens (except I 2 ). 22

24. Alkanes can burn if oxygen is present. As the result H 2 O and CO 2 appear. CH 4 + 2O 2 → CO 2 + 2H 2 O Cracking is the destroying of ­­some −C−C− and −C−H bonds in the molecule of alkanes at high temperature. CH 3 −CH 3 → CH 2 =CH 2 + H 2 23

25. Practice Exercise: Circle each molecule that can be classified as an alkane 24

26. 25