Chapter 3 Hydrocarbons: Nomenclature and Reactions

1. Chapter 3Hydrocarbons: Nomenclature and Reactions

2. Chapter 3 Problems • Review Section 3.9 • Read Essays on petroleum (p 204-207) and gasoline (p 221-223) for interest. • I recommend that you do all problems except Prob. 8, 14, 33, 34 and 41 • Skip ethenyl, 2-propenyl etc on p. 200 • Read Section 3.15 and 3-16, but don’t take them too seriously.

3. Sect. 3.1: IUPAC nomenclature systematic nomenclature I nternational U nion of P ure and A pplied C hemistry colloquially: “eye-you-pac”

4. Sect. 3.2: the alkanes • Hydrocarbons • “Paraffins” • Alkanes: formula CnH2n+2

5. The alkanes: table 3-2

6. Sect. 3.4: IUPAC nomenclature of alkanes Single substituent group 1. Find the longest continuous chain of carbon atoms and name it (use linear names). 2. Number the chain starting from the end nearest a branch. 3. Give the substituent a name based on the number of carbon atoms it has. replace the -ane ending with -yl 4. Give the substituent a number determined on its location on the chain. 5. Assemble the name.

7. Finding the longest continuous chain of carbon atoms is not always simple all possibilites must be examined C-C C-C-C-C-C-C-C-C-C it won’t always be the horizontal one as shown here C 9 try these also …….. C-C C-C C-C-C-C-C-C C-C-C- C-C-C C- -C-C-C-C-C C 6 8 C

8. Sect. 3.3: Common alkyl groups (C1 through C4): table 3-3

9. Name this alkane 4 3 2 1 2-methylbutane

10. Find the longest continuouscarbon chain 1 2 3 4 5 3-methylpentane

11. You must choose the longestcontinuous carbon chain 4 3 2 1 5 6 7 4-ethylheptane

12. Two different substituents • number chain from end closest to a group, regardless of alphabetical order • locate where groups are on chain with numbers • place groups in alphabetical order, with the appropriate number • assemble the complete name, using hyphens to separate numbers from “text”

13. Number from the end nearestthe first substituent 7 6 5 4 3 2 1 4-ethyl-3-methylheptane

14. Number from the end nearestthe first substituent 8 7 6 5 4 3 2 1 3-ethyl-5-methyloctane

15. Two or more identical substituent groups • for two identical groups, use prefix di with the name of the group: dimethyl, diethyl, etc. • dimethyl alphabetized as methyl, not dimethyl • use numbers to locate groups on chain • use commas to separate numbers • prefixes: di = 2 tri = 3 tetra = 4 penta = 5

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

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

18. You need numbers, even though it appears on the same carbon! 5 4 3 2 1 2,2,4-trimethylpentane

19. Number from the end nearestfirst substituent 10 9 8 7 6 5 4 3 2 1 2,7,8-trimethyldecane

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

21. Number from the end nearestthe “first difference”Dimethyl alphabetized as methyl, not dimethyl 1 2 3 4 5 6 7 8 6-ethyl-3,4-dimethyloctane

22. If you can name this,you can name almost anything! 1 2 3 4 5 6 7 8 9 4-isopropyl-2,6,6-trimethylnonane

23. The isopropyl group can be named as a “complex” substituent 1-methylethyl

24. Now, rename the isopropyl group. Notice the alphabetical order! 1 2 3 4 5 6 7 8 9 2,6,6-trimethyl-4-(1-methylethyl)nonane

25. Deciding on alphabetical order for complex groups • Complex groups are alphabetized under the first letter of the name • (1,3-dimethylbutyl) = d • (1,1,2-trimethylpropyl) = t • (1-ethyl-1,2-dimethylbutyl) = e

26. Naming complex substituents -- this one is aphabetized under d 1,3-dimethylbutyl

27. Naming complex substituents 2-ethyl-1,1-dimethylbutyl

28. Name this compound! 1 2 3 1 2 3 4 5 6 7 8 9 5-(1-ethyl-1-methylpropyl)-5-propylnonane

29. Name this two ways -- (the complex group) 7-(1,1-dimethylethyl)-3-ethyl-7-methyldecane 7-tert-butyl-3-ethyl-7-methyldecane

30. Sect. 3.5: Common names of alkanes • butane • isobutane • pentane • isopentane • neopentane

31. Sect. 3.6: the cycloalkanes • The names of the cycloalkanes always contain the prefix cyclo • Cycloalkanes have the general formula CnH2n

32. Cyclic molecules

33. Nomenclature of the substituted cycloalkanes • If there is only one substituent, do not use the “1”. • If there is more than one substituent, you must use all numbers, including “1”! • Number around the ring in a direction to get from the first substituent to the second substituent by the shorter path. • For equivalent degrees of substitution, number in a direction that follows the alphabetical sequence. • A carbon with greater substitution has precedence in numbering.

34. 1,1-dimethylcyclohexane

35. 4-ethyl-1,1-dimethylcyclohexane

36. C H 3 C H 3 C H 3 C H C H 3 3 C H 3 C H 3 C H C H 3 2 C H C H 2 3 Some cycloalkanes 1,3-dimethylcyclopentane Drawn differently but same name. 1 2 1 = 2 3 3 4 3 1 2 2 1 3 3-ethyl-1,1-dimethylcyclobutane 1-ethyl-4-methylcyclohexane The more substituted carbon takes precedence even though E comes before M. E before M

37. Two ways of naming this 1-isopropyl-2-methylcyclohexane 1-methyl-2-(1-methylethyl)cyclohexane

38. Numbering starts at the most highly-substituted carbon 2 1 3 7 4 6 5 2-chloro-1,1,6-trimethylcycloheptane

39. Sect. 3.7: cycloalkyl groups

40. 3-cyclobutyl-3-methylpentane

41. Rings with one substitutent (1-methylpropyl)cyclohexane or 2-cyclohexylbutane No locant is needed. With one substituent on a ring , it is automatically on carbon 1. 1-(1-methylpropyl)cyclohexane is overkill, but OK!

42. Another name of a group

43. 3-methyl-2-phenylpentane

44. methylene methyl methine Sect. 3.8:Degree of Substitution

45. Example A hydrocarbon containing carbon atoms with differing degrees of substitution PRIMARY QUATERNARY TERTIARY SECONDARY All of the methyl groups (CH3) are primary.

46. Sect. 3.9 -- review We already did this in Chapter 1

47. Sect. 3.10 and 3.11: nomenclature of halides and nitro compounds

48. bromoethane (IUPAC) ethyl bromide (common)

49. bromocyclopropane

50. 2-chloro-2-methylpropane (IUPAC) tert-butyl chloride (common)