1. 1 Announcements & Agenda (03/07/07) Exam next Wednesday! Covers Ch 7, 8, 10-12 (not 12.6, on Exam 3) Covers Ch 7, 8, 10-12 (not 12.6, on Exam 3) Practice Exam Posted! Practice Exam Posted! Come visit Bob!!! Come visit Bob!!!Today Aromatic Compounds (11.5) Aromatic Compounds (11.5) Polymers (11.4) Polymers (11.4) Properties & Reactions of Alcohols (12.1-12.3) Properties & Reactions of Alcohols (12.1-12.3)

2. 2 Last Time: Bond Angles in Alkenes & Alkynes According to VSEPR theory: the 3 groups bonded to C atoms in a double bond are at 120° angles.the 3 groups bonded to C atoms in a double bond are at 120° angles. alkenes are flat because the atoms in a double bond all lie in the same plane.alkenes are flat because the atoms in a double bond all lie in the same plane. the 2 groups bonded to each carbon in a triple bond are at 180° angles.the 2 groups bonded to each carbon in a triple bond are at 180° angles.

3. 3 Last Time: Cis-Trans Isomers In an alkene, the double bond is rigid, i.e. NO ROTATION around the double bond!is rigid, i.e. NO ROTATION around the double bond! holds attached groups in fixed positions.holds attached groups in fixed positions. makes cis/trans isomers possible.makes cis/trans isomers possible. Important in nature – such as in pheromonesImportant in nature – such as in pheromones CH 3 CH 3 CH 3 CH 3 CH 3 CH 3 CH = CH CH = CH CH = CH CH = CH cis trans CH 3 cis trans CH 3 (similar groups on same side) (similar groups on opp. sides)

4. 4 By the way, cyclohexane & other cyclic compounds are not flat. Example: a monosaccharide

5. 5 Geometric Isomerism in cycloalkanes: Cyclobutane chlorocyclobutane 1,2-dichlorocyclobutane Trans = “across” Cis = same side

6. 6 Last Time: Addition Reactions The double/triple bond can be brokenThe double/triple bond can be broken alkenes & alkynes are very reactive. alkenes & alkynes are very reactive. In addition reactions, reactants are added to the carbon atoms in the double or triple bond.In addition reactions, reactants are added to the carbon atoms in the double or triple bond.

7. 7 One Last Thing about Hydration… Hydration is also reversible – the equilibrium amounts of alkene compared to alcohol depend on how much water is around. Lots of water – the reaction tends to use up as much water as it can, and most of the alkene forms alcohol. If water is removed, water can be pulled off from alcohol to form the alkene. (concentrated acid).

8. 8 Conjugated bonds If you have alternating double & single bonds, you get “extended, conjugated” pi bonds. you get “extended, conjugated” pi bonds. what looks like a single bond in between two double bonds, is actually sort of a double bond itself. what looks like a single bond in between two double bonds, is actually sort of a double bond itself. multiple pairs of electrons can spread out all the way through the aligned parallel orbitals -> molecules like this! multiple pairs of electrons can spread out all the way through the aligned parallel orbitals -> molecules like this!

9. 9 One Important Example: Benzene (Know This One!) a ring of 6 C & 6 H atoms.a ring of 6 C & 6 H atoms. a flat ring structure drawn with three double bonds.a flat ring structure drawn with three double bonds. represented by 2 structures because electrons are shared among all the C atoms.represented by 2 structures because electrons are shared among all the C atoms. Aromatic Compounds “Special Conjugation” By the way, aromatics are called as such b/c many of them have noticeable odors!

10. 10 Benzene and Aromaticity Aromatics are compounds that have conjugated pi bonds around a ring. Electrons love this, and aromatics are very stable.

11. 11 Occurrences in Nature & Health Vanillin Aspirin Ibuprofen Acetaminophen Aromatics can be bad too  Many are carcinogens! Can interact with DNA.

12. 12 Aromatic rings can include N atoms, too. They can be 5 or 6 membered rings (and >), fused rings, etc. Adenine Thymine Phenylalanine Pyridine

13. 13 By the way, why is blood red? Highly conjugated pi bonds! It’s the HEME in hemoglobin!!! Note: Highly conjugated molecules are typically colored!

14. 14 11.4 Polymers of Alkenes

15. 15 Polymers: What are they? large, long-chain molecules.large, long-chain molecules. found in naturefound in nature Examples: cellulose in plants, starches in food, proteins, DNA, etc.Examples: cellulose in plants, starches in food, proteins, DNA, etc. also synthetic such as polyethylene and polystyrene, Teflon, and nylon.also synthetic such as polyethylene and polystyrene, Teflon, and nylon. have small repeating units called monomers.have small repeating units called monomers. can be made from reaction of small alkenescan be made from reaction of small alkenes

16. 16 Common Synthetic Polymers

17. 17 Common Synthetic Polymers Important: Properties of polymers depend on what monomers they are made from and how they are put together!

18. 18 Polymerization In polymerization, small repeating units called monomers join to form a long chain polymer. monomer unit repeats n

19. 19 Recycling Plastics Recycling is simplified by using codes on plastic items. 1 PETE Polyethyleneterephtalate 2 HDPE High-density polyethylene 3 PV Polyvinyl chloride 4 LDPE Low-density polyethylene 5 PP Polypropylene 6 PS Polystyrene

20. 20 CHAPTER 12!

21. 21 28 Good Practice Problems (Ch 12) 12.01, 12.03, 12.07, 12.09, 12.11, 12.13, 12.15, 12.17, 12.19, 12.23, 12.25, 12.31, 12.33, 12.35, 12.37, 12.39, 12.41, 12.43, 12.45, 12.49, 12.51, 12.53, 12.55, 12.63, 12.65, 12.67, 12.71, 12.75

22. 22 An alcohol contains a hydroxyl group (—OH) attached to a carbon chain. occur in many important molecules like sugars and -ol compounds (cholesterol, menthol, etc.) occur in many important molecules like sugars and -ol compounds (cholesterol, menthol, etc.) A phenol contains a hydroxyl group (—OH) attached to a benzene ring. water alcohol phenol water alcohol phenol Alcohols

23. 23 Properties of Alcohols contain polar OH groups.contain polar OH groups. form hydrogen bonds with other alcohol molecules.form hydrogen bonds with other alcohol molecules. Short alcohols (1-4 C atoms) are soluble in waterShort alcohols (1-4 C atoms) are soluble in water > 4 C atoms less soluble > 4 C atoms less soluble have much higher BPs than alkanes of similar mass.have much higher BPs than alkanes of similar mass.

24. 24 Some Typical Alcohols (Know These) OH OH | | “rubbing alcohol”CH 3 —CH—CH 3 2-propanol (isopropyl alcohol) antifreeze HO—CH 2 —CH 2 —OH antifreeze HO—CH 2 —CH 2 —OH 1,2-ethanediol (ethylene glycol) OH OH | | glycerolHO—CH 2 —CH—CH 2 —OH glycerolHO—CH 2 —CH—CH 2 —OH1,2,3-propanetriol Could make you sick Will kill you Part of cooking oil

25. 25 http://www.annals.org/cgi/content/full/122/6/456 The Elixir Sulfanilamide disaster of 1937 105 people died 1938 Federal Food, Drug and Cosmetic Act, which required proof of safety before the release of a new drug In the 1980s similar incident happened in Haiti killing dozens of Haitian infants

26. 26 Properties of Phenol is soluble in water.is soluble in water. has a hydroxyl group that ionizes slightly (weak acid).has a hydroxyl group that ionizes slightly (weak acid). is corrosive and irritating to skin.is corrosive and irritating to skin. + H 2 O + H 3 O +

27. 27 Derivatives of Phenol Compounds of phenol are the active ingredients in the essential oils of cloves, vanilla, nutmeg, and mint.

28. 28 Drawing structures revisited

29. 29 Naming Alcohols IUPAC: Alcohols will be called somethingolIUPAC: Alcohols will be called somethingol If other functional groups present, the -OH group will sometimes be named as a “hydroxyl” groupIf other functional groups present, the -OH group will sometimes be named as a “hydroxyl” group Formula IUPACCommon Name Formula IUPACCommon Name CH 4 methane CH 3 ─OH methanol methyl alcohol CH 3 ─CH 3 ethane CH 3 ─CH 2 ─OH ethanol ethyl alcohol Also know common names for propyl alcohol and those mentioned earlierAlso know common names for propyl alcohol and those mentioned earlier

30. 30 determined by the number of alkyl groups attached to the carbon bonded to the hydroxyl.determined by the number of alkyl groups attached to the carbon bonded to the hydroxyl. primary (1°), secondary (2°), or tertiary(3).primary (1°), secondary (2°), or tertiary(3). Primary (1º) Secondary (2º) Tertiary (3º) 1 group 2 groups 3 groups H CH 3 CH 3 | | | Primary (1º) Secondary (2º) Tertiary (3º) 1 group 2 groups 3 groups H CH 3 CH 3 | | | CH 3 —C—OH CH 3 —C—OH CH 3 —C—OH | | | H H CH 3 CH 3 —C—OH CH 3 —C—OH CH 3 —C—OH | | | H H CH 3 Classification of Alcohols

31. 31 Reactions of Alcohols

32. 32 Combustion of Alcohols Alcohols undergo combustion with O 2 to produce CO 2 and H 2 O. 2CH 3 OH + 3O 2 2CO 2 + 4H 2 O + Heat 2CH 3 OH + 3O 2 2CO 2 + 4H 2 O + Heat

33. 33 Alcohols dehydrate when heated with an acid catalystAlcohols dehydrate when heated with an acid catalyst Lose —H and —OH from adjacent carbon atomsLose —H and —OH from adjacent carbon atoms H OH H OH | | H—C—C—H H +, heat H—C=C—H + H 2 O | | | | H H H H H H H H alcohol alkene alcohol alkene Dehydration of Alcohols

34. 34 Learning Check Write the equations for the reaction of 2- propanol when it undergoes 1. combustion. 2. dehydration.

35. 35 Solution OH OH │ CH 3 ─CH─CH 3 = 2-propanol = C 3 H 8 O 1. combustion 2C 3 H 8 O + 9O 2 6CO 2 + 8H 2 O 2C 3 H 8 O + 9O 2 6CO 2 + 8H 2 O 2. dehydration OH OH │ H + │ H + CH 3 ─CH─CH 3 CH 3 ─CH=CH 2 + H 2 O Major Product: Alkene w/ more alkyl substiuents

36. 36 When a primary alcohol is oxidized, [O], one H is removed from the –OH.one H is removed from the –OH. another H is removed from the C bonded to -OH.another H is removed from the C bonded to -OH. an aldehyde is produced.an aldehyde is produced. [O] [O] Primary alcohol Aldehyde Primary alcohol Aldehyde OH O OH O | [O] || | [O] || CH 3 —C—H CH 3 —C—H + H 2 O CH 3 —C—H CH 3 —C—H + H 2 O | | H Ethanol Ethanal Ethanol Ethanal (ethyl alcohol) (acetaldehyde) (ethyl alcohol) (acetaldehyde) Oxidation of Primary (1  ) Alcohols This is a carbonyl group…

37. 37 Oxidation of Secondary (2  ) Alcohols When a secondary alcohol is oxidized, [O], one H is removed from the –OH.one H is removed from the –OH. another H is removed from the C bonded to -OH.another H is removed from the C bonded to -OH. a ketone is produced.a ketone is produced. [O] [O] secondary alcohol ketone secondary alcohol ketone OH O OH O │ [O] ║ │ [O] ║ CH 3 ─C─CH 3 CH 3 ─C─CH 3 + H 2 O CH 3 ─C─CH 3 CH 3 ─C─CH 3 + H 2 O │ H 2-propanol (isopropyl alcohol) 2-propanol (dimethyl ketone) 2-propanol (isopropyl alcohol) 2-propanol (dimethyl ketone) ASK ME ABOUT “R”!!!

38. 38 Oxidation of Tertiary ( 3)  Alcohols Tertiary 3  alcohols do not readily oxidize. [O] Tertiary alcoholno reaction OH OH │ [O] │ [O] CH 3 ─C─CH 3 no product CH 3 ─C─CH 3 no product │ CH 3 no H on the C-OH to oxidize CH 3 no H on the C-OH to oxidize 2-methyl-2-propanol

39. 39 Oxidation of Ethanol in the Body In the body, enzymes in the liver oxidize ethanol.enzymes in the liver oxidize ethanol. aldehyde product impairs coordination.aldehyde product impairs coordination. blood alcohol over 0.4% can be fatal. O Oblood alcohol over 0.4% can be fatal. O O ║ ║ ║ ║ CH 3 CH 2 OH CH 3 CH CH 3 COH 2CO 2 + H 2 O ethanol acetaldehyde acetic acid

40. 40 acts as a depressant.acts as a depressant. kills or disables more people than any other drug.kills or disables more people than any other drug. is metabolized at a rate of 12-15 mg/dL per hour by a social drinker.is metabolized at a rate of 12-15 mg/dL per hour by a social drinker. is metabolized at a rate of 30 mg/dL per hour by an alcoholic.is metabolized at a rate of 30 mg/dL per hour by an alcoholic. Ethanol CH 3 CH 2 OH

41. 41 Effect of Alcohol on the Body

42. 42 % EthanolProduct 50%Whiskey, rum, brandy 40%Flavoring extracts 15-25%Listerine, Nyquil, Scope 12%Wine, Dristan, Cepacol 3-9%Beer, Lavoris Alcohol Contents in Common Products