1. Chapter Thirteen Unsaturated Hydrocarbons

2. Chapter 13 | Slide 2 of 70 Unsaturated Hydrocarbons AlkANES –Hydrocarbons in which all of the carbon-carbon bonds are _____________ bonds AlkENES –Hydrocarbons in which at least one of the carbon- carbon bonds is a ____________ bond AlkYNES –Hydrocarbons in which at least one of the carbon- carbon bonds is a ______________ bond

3. Chapter 13 | Slide 3 of 70 Properties of Alkenes and Alkynes Similar to those of alkanes –..

4. Chapter 13 | Slide 4 of 70 Alkenes Draw the structures of the monounsaturated alkenes with 4, 5, and 6 carbons What is the relationship between the number of carbons and the number of hydrogens in these alkenes? –.

5. Chapter 13 | Slide 5 of 70 Alkynes Draw the structures of the monounsaturated alkynes with 4, 5, and 6 carbons What is the relationship between the number of carbons and the number of hydrogens in these alkenes? –.

6. Chapter 13 | Slide 6 of 70 Bond Angles in Alkenes and Alkynes According to VSEPR theory: –The four groups bonded to carbon atoms in single bonds are at angles of ____________________ –The three groups bonded to carbon atoms in a double bond are at angles of ______________________ –The two groups bonded to carbon atoms in a triple bond are at angles of _____________________

7. Chapter 13 | Slide 7 of 70 →Fig. 13.1 In ethene, the atoms are in a flat rather than a tetrahedral arrangement. Note the shapes using space filling molecular models. Unsaturated Hydrocarbons cont’d

8. Chapter 13 | Slide 8 of 70 σ and π Bonds A single bond between 2 carbon atoms is called a sigma (σ) bond. The second bond that forms in a double bond is called the pi (π) bond. The third bond that forms a triple bond is also called the pi (π) bond. There is π bonding in all double and triple bonds between two carbon atoms. π bonds are more reactive than sigma bonds.

9. Chapter 13 | Slide 9 of 70  Carbon-carbon double bonds  Names end in -___________ H 2 C=CH 2 H 2 C=CH-CH 3 Alkenes

10. Chapter 13 | Slide 10 of 70  Carbon-carbon triple bonds  Names end in _____________ HC  CH HC  C-CH 3 Alkynes

11. Chapter 13 | Slide 11 of 70 Naming Step 1: –Name ___________________________. Find the longest continuous carbon chain that contains the multiple bond. Name that chain with the __________ suffix if it has a double bond. Name the chain with the _______ suffix if it has a triple bond. CH 3 CH 2 CH 2 CH 3 CH 2 CH 2 C

12. Chapter 13 | Slide 12 of 70 Naming Step 2: –Number the carbon atoms. Begin numbering _____________________________ CH 3 CH 2 CH 2 CH 3 CH 2 CH 2 C

13. Chapter 13 | Slide 13 of 70 Naming Step 2: –Number the carbon atoms. If the multiple bond is the same distance from each end of the molecule, begin _________________________ CH 3 CHCH CHCH 2 CH 3 CH 3 123456 654321 ???

14. Chapter 13 | Slide 14 of 70 Naming Step 3: –Use ___________________________________ _________________to designate multiple bond position. –List the substituents ________________(with numbers to designate position). CH 3 CH 2 CH 2 CH 3 CH 2 CH 2 C 1 2 345

15. Chapter 13 | Slide 15 of 70 Naming Step 3: –Use “di”, “tri”, “tetra”, etc. to designate _________ _____________________________ CH 3 CH 2 CH 2 CH 3 CH 2 CH 2 C 1 2 345 pentene 2-ethyl 1-

16. Chapter 13 | Slide 16 of 70 Name these alkenes. CH 3 CHCH CHCH 2 CH 3 CH 3 CH 3 CH 2 CH 2 CH 3 CH CH C CH 2 CCH CH 2 CH 3

17. Chapter 13 | Slide 17 of 70 Name These Alkynes

18. Chapter 13 | Slide 18 of 70 Naming cycloalkenes Number the double bond ______________. The first substituent possesses __________ ______________________.

19. Chapter 13 | Slide 19 of 70 Name these cycloalkenes.

20. Chapter 13 | Slide 20 of 70 Write the IUPAC name for each of the following unsaturated compounds: A.CH 3 CH 2 C  CCH 3 CH 3 B. CH 3 C=CHCH 3 C. Learning Check

21. Chapter 13 | Slide 21 of 70 Learning Check Draw the structures that correspond to the following names –4-methyl-1-hexene –1,3-cyclohexadiene –4,4,5-trimethyl-2-heptene –4-chloro-1-pentyne –5-fluoro-4-ethyl-2-hexyne

22. Chapter 13 | Slide 22 of 70 Isomerism in Alkenes Alkenes have many possible structural isomers –Isomers depend not only on the position of the carbons, but on where the double bond is

23. Chapter 13 | Slide 23 of 70 A comparison of structural isomerism possibilities for four- and five-carbon alkane and alkene systems.

24. Chapter 13 | Slide 24 of 70 Cis-Trans Isomerism Another kind of isomerism exists in alkenes: _____ _________________________________________ –. C CH 3 HH C CH 3 H H C CH 3 HH C CH 3 H H CisTransHHHH

25. Chapter 13 | Slide 25 of 70 Cis-Trans Isomerism Two isomers are possible when groups are attached to the double bond –In a cis isomer, groups are attached ______________ of the double bond –In a trans isomer, groups are attached _____________ ______________________ of the double bond. –Cis-trans isomerism is not possible when ___________ _______________________ _______________________ cis trans

26. Chapter 13 | Slide 26 of 70 Draw the cis and trans isomers of 1- chloro-2-pentene. trans-1-chloro-2-pentene cis-1-chloro-2-pentene Review: How many hydrogens on each carbon?

27. Chapter 13 | Slide 27 of 70 Learning Check Determine whether each of the following substituted alkenes can exist in cis-trans isomeric forms. If they can, draw and name them. –1-chloropropene –2-chloropropene

28. Chapter 13 | Slide 28 of 70 Learning Check Name each, using cis-trans prefixes when needed

29. Chapter 13 | Slide 29 of 70 Cis-Trans Isomers in Nature Insects emit tiny quantities of pheromones, which are chemicals that send messages The silkworm moth attracts other moths by emitting bombykol, which has one cis and one trans double bond.

30. Chapter 13 | Slide 30 of 70 Terpenes---the basis for cholesterol, steroids and many other biologically active compounds

31. Chapter 13 | Slide 31 of 70 Chemical Reactions of Alkenes and Alkynes The pi (  ) bond is easily ______, which makes double and triple bonds very ________ Types of alkene reactions: –_________ reactions Symmetrical addition reactions (_____ atom is added to each side of the _________ bond) –Hydrogenation reaction –Halogenation reaction Unsymmetrical addition reactions (_________ atoms are added to the carbons in the ___________ bond) –Hydrohalogenation reaction –Hydration reaction

32. Chapter 13 | Slide 32 of 70 Addition Reactions _________ are _________ to the carbon atoms in the _________ or ________ bond –In the process, the __________ bond becomes a _________ bond C H HH H + HCl C H HH H ClH

33. Chapter 13 | Slide 33 of 70 In an addition reaction, the atoms provided by an incoming molecule are attached to the carbon atoms originally joined by a double bond. In the process, the double bond becomes a single bond.

34. Chapter 13 | Slide 34 of 70 Adds __________________ to each carbon atom of a double bond (catalyst: Pt or Ni) H H Ni H–C=C–H + H 2 ethene Hydrogenation

35. Chapter 13 | Slide 35 of 70 Adding H 2 to vegetable oils produces compounds with higher melting points (ie. can convert a liquid to a solid) Margarines Soft margarines Shortenings (solid) Products of Hydrogenation

36. Chapter 13 | Slide 36 of 70 Fatty acids in vegetable oils are omega-6 acids (the first double bond occurs at carbon 6 counting from the methyl group) A common omega-6 acid is linoleic acid CH 3 CH 2 CH 2 CH 2 CH 2 CH=CHCH 2 CH=CH(CH 2 ) 7 COOH 6 linoleic acid, a fatty acid Unsaturated Fatty Acids

37. Chapter 13 | Slide 37 of 70  In vegetable oils, the unsaturated fats usually contain cis double bonds.  During hydrogenation, some cis double bonds are converted to trans double bonds (more stable) causing a change in the fatty acid structure  If a label states “partially” or “fully hydrogenated”, the fats contain trans fatty acids. Trans Fats

38. Chapter 13 | Slide 38 of 70  In the US, it is estimated that 2-4% of our total Calories is in the form of trans fatty acid.  trans fatty acids behave like saturated fatty acids in the body.  Several studies reported that trans fatty acids raise LDL- cholesterol. Some studies also report that trans fatty acid lower HDL-cholesterol  The trans fatty acids controversy will continue to be debated. Trans Fats

39. Chapter 13 | Slide 39 of 70 Inuit people of Alaska have a high fat diet and high blood cholesterol levels, but a very low occurrence of atherosclerosis and heart attacks. Fat in the Intuit diet was primarily from fish such as salmon, tuna and herring rather than from land animals (as in the American diet). Fats and Atherosclerosis

40. Chapter 13 | Slide 40 of 70 Fatty acids in the fish oils are mostly the omega-3 type (first double bond occurs at the third carbon counting from the methyl group). linolenic acid 18 carbon atoms CH 3 CH 2 CH=CHCH 2 CH=CHCH 2 CH=CH(CH 2 ) 7 COOH  eicosapentaenoic acid (EPA) 20 carbon atoms CH 3 CH 2 (CH=CHCH 2 ) 5 (CH 2 ) 2 COOH Omega-3 Fatty acids

41. Chapter 13 | Slide 41 of 70 Plaques of cholesterol adhere to the walls of the blood vessels Blood pressure rises as blood squeezes through smaller blood vessels Blood clots may form Omega-3 fatty acids decrease the “sticking” of blood platelets (fewer blood clots) Omega-3 fatty acids can increase bleeding time Atherosclerosis

42. Chapter 13 | Slide 42 of 70 What is the product of adding H 2 (Ni catalyst) to 1-butene? Learning Check

43. Chapter 13 | Slide 43 of 70 ____________ also add to the carbons in a double or triple bond H 2 C  CH 2 + Cl 2 CH 3 C=CCH 2 CH 3 + 2Br 2 Halogenation

44. Chapter 13 | Slide 44 of 70 Using Bromination to Test for Double Bonds Bromine in water has a reddish brown color If another compound with a double bond reacts with the bromine, ______________________ –The reddish color persists ______________________________ ___________________________________________________

45. Chapter 13 | Slide 45 of 70 Write the product of the following addition reactions: CH 3 CH=CHCH 3 + H 2 Learning Check

46. Chapter 13 | Slide 46 of 70 Hydrohalogenation A _________________ is incorporated into the carbons involved in a multiple bond –The _____________ adds to one carbon –The ______________ adds to the other carbon Markovnikov’s rule: –. H 3 C CH CH 2 + H X

47. Chapter 13 | Slide 47 of 70 Where does the halide add to these double bonds (alkenes)?

48. Chapter 13 | Slide 48 of 70 Hydration A ______________ is incorporated into the carbons involved in a multiple bond –The ___________ adds to one carbon –The ___________ adds to the other carbon. H 3 C CH CH 2 + H OH

49. Chapter 13 | Slide 49 of 70 Learning Check Write the products of each reaction CH 3 -CH=CH 2 + Cl 2  CH 3 -CH=CH-CH 3 + H 2 O  Cyclopentene + H 2 

50. Chapter 13 | Slide 50 of 70 Addition Reactions: Polymers Polymers are large molecules built up by repetitive bonding of many smaller molecules called ____________________. May have thousands of monomer units in one polymer molecule. The monomers are __________ C H HH H Radical Catalyst C C C C C C C C C C HH HHHHHHHHHH HHHHHHHH

51. Chapter 13 | Slide 51 of 70 Synthetic Polymers

52. Chapter 13 | Slide 52 of 70 What is the monomer?

53. Chapter 13 | Slide 53 of 70 What is the monomer?

54. Chapter 13 | Slide 54 of 70 Aromatic Compounds Aromatic compounds contain _____________. Benzene has:. Have many properties similar to alkanes

55. Chapter 13 | Slide 55 of 70 Structure of Benzene: Resonance Two resonance structures. Neither resonance form is correct by itself. The true structure is a combination. –.

56. Chapter 13 | Slide 56 of 70 Benzene Structure The structure for benzene is also written as one formula with a circle within the ring to represented the alternating double bonds. The circle shows: Benzene structure

57. Chapter 13 | Slide 57 of 70 Aromatic Compounds in Nature and Health Many aromatic compounds are common in nature and in medicine. Aspirin Vanillin Ibuprofen

58. Chapter 13 | Slide 58 of 70 Naming Aromatic Compounds Aromatic compounds are named, With ________________ as the parent chain. Side chains are named:

59. Chapter 13 | Slide 59 of 70 Naming Aromatic Compounds When two groups are attached to benzene, the ring is numbered to give _________________ _____________________________________. ( para- chloromethylbenzene) ( meta- dichlorobenzene) ( ortho- dimethylbenzene) 1,2-dimethylbenzene 1,3-dichlorobenzene 1-chloro-4-methylbenzene Cl CH 3 Cl Cl CH 3 CH 3

60. Chapter 13 | Slide 60 of 70 Naming Aromatic Compounds Disubstituted benzenes are named using prefixes: –.

61. Chapter 13 | Slide 61 of 70 Naming Aromatic Compounds ortho- (o) meta- (m) para- (p)

62. Chapter 13 | Slide 62 of 70 Naming Aromatic Compounds Some aromatic compounds have common names.

63. Chapter 13 | Slide 63 of 70 Some Common Names Some substituted benzenes use common names. toluene 3-chlorotoluene phenol

64. Chapter 13 | Slide 64 of 70 Learning Check Select the correct name for each structure: 1) chlorocyclohexane 2) chlorobenzene 3) 1-chlorobenzene 1) 1,2-dimethylbenzene 2) 1,4-dimethylbenzene 3) 1,3-dimethylbenzene

65. Chapter 13 | Slide 65 of 70 Learning Check Write the structural formulas for each of the following: A. 1,3-dichlorobenzene B. 2-chlorotoluene

66. Chapter 13 | Slide 66 of 70 Naming Aromatic Compounds Tri- or higher-substituted benzenes. Number ________________________________ Use ____________________________________. Name substituents listed __________________. If any “common named” monosubstituted parent is used the principle substituent is on ____________

67. Chapter 13 | Slide 67 of 70 Naming Aromatic Compounds

68. Chapter 13 | Slide 68 of 70 Chemical Reactions of Aromatic Hydrocarbons Aromatic compounds can undergo substitution reactions –Alkylation. –Halogenation. –Nitration. –Sulfonation.

69. Chapter 13 | Slide 69 of 70 Learning Check Write the reaction for the bromination of benzene, including the catalyst.

70. Chapter 13 | Slide 70 of 70