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1 C hapter 12 Organic Compounds with Oxygen and Sulfur 12.1 Alcohols, Ethers, and Thiols Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin.

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Presentation on theme: "1 C hapter 12 Organic Compounds with Oxygen and Sulfur 12.1 Alcohols, Ethers, and Thiols Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin."— Presentation transcript:

1 1 C hapter 12 Organic Compounds with Oxygen and Sulfur 12.1 Alcohols, Ethers, and Thiols Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

2 2 Alcohols An alcohol contains a hydroxyl group (—OH) attached to a carbon chain. A phenol contains a hydroxyl group (—OH) attached to a benzene ring. wateralcohol phenol Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

3 3 Naming Alcohols The names of alcohols in IUPAC replace the -e with -ol. with common names use the name of the alkyl group followed by alcohol. FormulaIUPACCommon Name CH 4 methane CH 3 ─OH methanol methyl alcohol CH 3 ─CH 3 ethane CH 3 ─CH 2 ─OH ethanol ethyl alcohol

4 4 More Names of Alcohols IUPAC names for longer chains number the chain from the end nearest the -OH group. CH 3 ─CH 2 ─CH 2 ─OH 1-propanol OH │ CH 3 ─CH─CH 2 ─CH 3 2-butanol CH 3 OH │ │ CH 3 ─CH─CH 2 ─CH 2 ─CH─CH 3 5-methyl-2-hexanol

5 5 Some Typical Alcohols OH | “rubbing alcohol”CH 3 —CH—CH 3 2-propanol (isopropyl alcohol) antifreeze HO—CH 2 —CH 2 —OH 1,2-ethanediol (ethylene glycol) OH | glycerolHO—CH 2 —CH—CH 2 —OH 1,2,3-propanetriol

6 6 Learning Check Name the following compounds. 1. CH 3 —CH 2 —CH 2 —CH 2 —OH OH CH 3 | | 2. CH 3 —CH—CH—CH 2 —CH 3 3.

7 7 Solution 1. CH 3 —CH 2 —CH 2 —CH 2 —OH 1-butanol OH CH 3 | | 2. CH 3 —CH—CH—CH 2 —CH 3 3-methyl-2-pentanol 3. cyclopentanol

8 8 Phenols in Medicine Phenol is the IUPAC name for benzene with a hydroxyl group. is used in antiseptics and disinfectants. phenol resorcinol 4-hexylresorcinol

9 9 Derivatives of Phenol Compounds of phenol are the active ingredients in the essential oils of cloves, vanilla, nutmeg, and mint.

10 10 Naming Phenols To name a phenol with two substituents, assign C-1 to the carbon attached to the –OH. number the ring to give the lowest numbers. 3-chlorophenol 4-bromophenol

11 11 Write the structure of each of the following. A. 3-pentanol B. ethyl alcohol C. 4-methylphenol Learning Check

12 12 Solution Write the structure of the following. A. 3-pentanol OH | CH 3 —CH 2 —CH—CH 2 —CH 3 B. ethyl alcohol CH 3 —CH 2 —OH C. 4-methylphenol OH CH 3

13 13 Classification of alcohols is determined by the number of alkyl groups attached to the carbon bonded to the hydroxyl. primary (1°), secondary (2°), or tertiary(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 Classification of Alcohols

14 14 Classify each alcohol as 1) primary, 2) secondary, or 3) tertiary. OH | A. CH 3 —CH—CH 2 —CH 3 B. CH 3 —CH 2 —CH 2 —OH OH | C. CH 3 —CH 2 —C—CH 2 —CH 3 | CH 3 Learning Check

15 15 OH | A. CH 3 —CH—CH 2 —CH 3 secondary B. CH 3 —CH 2 —CH 2 —OH primary OH | C. CH 3 —CH 2 —C—CH 2 —CH 3 tertiary | CH 3 Solution

16 16 Thiols are carbon compounds that contain a –SH group. are named in the IUPAC system by adding thiol to the alkane name of the longest carbon chain. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

17 17 Thiols often have strong odors. are used to detect gas leaks. are found in onions, oysters, and garlic.

18 18 Ethers An ether contains an ─O─ between two carbon groups. has a common name that gives the alkyl names of the attached groups followed by ether. CH 3 ─O─CH 3 CH 3 ─CH 2 ─O─CH 3 dimethyl ether ethyl methyl ether

19 19 Learning Check Write the structure of the following. A. 3-pentanol B. diethyl ether

20 20 Solution OH | A. 3-pentanolCH 3 ─CH 2 ─CH─CH 2 ─CH 3 B. diethyl ether CH 3 ─CH 2 ─O─CH 2 ─CH 3

21 21 Ethers as Anesthetics Anesthetics inhibit pain signals to the brain. like diethyl ether CH 3 ─CH 2 ─O─CH 2 ─CH 3 were used for over a century, but caused nausea and were flammable. developed by the 1960’s were nonflammable. Cl F F Cl F H │ │ │ │ │ │ H─C─C─O─C─HH─C─C─O─C─H │ │ │ │ │ │ F F F H F H Ethane(enflurane) Penthrane

22 22 MTBE Methyl tert-butyl ether CH 3 │ CH 3 ─O─C─CH 3 │ CH 3 is second in production of organic chemicals. is an additive used to improve gasoline performance. use is questioned since the discovery that MTBE has contaminated water supplies.

23 Properties of Alcohols, Ethers, and Thiols Chapter 12 Organic Compounds with Oxygen and Sulfur Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

24 24 Boiling Points of Alcohols Alcohols contain polar OH groups. form hydrogen bonds with other alcohol molecules. have higher boiling points than alkanes and ethers of similar mass. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

25 25 Boiling Points of Ethers Ethers do not have a polar group. have an O atom, but there is no H attached. cannot form hydrogen bonds between ether molecules. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

26 26 Solubility of Alcohols and Ethers in Water Alcohols and ethers are more soluble in water than alkanes because the oxygen atom can hydrogen bond with water. with 1-4 C atoms are soluble, but not with 5 or more C atoms.

27 27 Comparing Solubility and Boiling Points Molar Boiling Soluble Compound Mass Point (°C) in Water? Alkane CH 3 ─CH 2 ─CH No Ether CH 3 ─O─CH Yes Alcohol CH 3 ─CH 2 ─OH 4678 Yes

28 28 Solubility of Phenol Phenol is soluble in water. has a hydroxyl group that ionizes slightly (weak acid). is corrosive and irritating to skin. + H 2 O + H 3 O +

29 29 Chapter 12 Organic Compounds with Oxygen and Sulfur 12.3 Reactions of Alcohols and Thiols Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

30 30 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 Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

31 31 Alcohols undergo dehydration when heated with an acid catalyst. the loss of —H and —OH from adjacent carbon atoms. H OH | | H +, heat H—C—C—H H—C=C—H + H 2 O | | H H H H alcohol alkene Dehydration of Alcohols

32 32 Learning Check Write the equations for the reaction of 2-propanol when it undergoes 1. combustion. 2. dehydration.

33 33 Solution 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 2. dehydration OH │ H + CH 3 ─CH─CH 3 CH 3 ─CH=CH 2 + H 2 O

34 34 Oxidation and Reduction In an oxidation, there is an increase in the number of C-O bonds. there is a loss of H. In a reduction, there is an decrease in the number of C-O bonds. there is a gain of H.

35 35 Oxidation and Reduction

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

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

38 38 Oxidation of Tertiary ( 3)  Alcohols Tertiary 3  alcohols do not readily oxidize. [O] Tertiary alcoholno reaction OH │ [O] CH 3 ─C─CH 3 no product │ 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. aldehyde product impairs coordination. blood 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 ethyl alcohol acetaldehyde acetic acid

40 40 Ethanol acts as a depressant. kills or disables more people than any other drug. is metabolized at a rate of mg/dL per hour by a social drinker. 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

43 43 Oxidation of Thiols When thiols undergo oxidation, an H atom is lost from each of two –SH groups. the product is a disulfide. [O] CH 3 ─SH + HS─CH 3 CH 3 ─S─S─CH 3 + H 2 O

44 44 Learning Check Select the product for the oxidation of OH │ [O] CH 3 ─CH─CH 2 ─CH 3 O ║ 1) CH 3 ─CH=CH─CH 3 2) CH 3 ─C─CH 2 ─CH 3 OH │ 3) CO 2 + H 2 O 4) CH 3 ─CH─CH 2 ─CH 3

45 45 Solution Select the product for the oxidation of OH │ [O] CH 3 ─CH─CH 2 ─CH 3 O ║ 2) CH 3 ─C─CH 2 ─CH 3

46 46 Select the product when CH 3 —CH 2 —CH 2 —OH undergoes each of the following reactions: A) H +, heatB) [O]C) + O 2 1) CH 3 —CH=CH 2 2) CO 2 + H 2 O O || 3) CH 3 —CH 2 —C—H Learning Check

47 47 A. H +, heat 1) CH 3 —CH=CH 2 O [O] || B. 3) CH 3 —CH 2 —C—H C. + O 2 2) CO 2 + H 2 O Solution

48 48 Chapter 12 Organic Compounds with Oxygen and Sulfur 12.4 Aldehydes and Ketones

49 49 Carbonyl Group in Aldehydes and Ketones A carbonyl group in an aldehyde is attached to at least one H atom. in a ketone is attached to two carbon groups.

50 50 Naming Aldehydes An aldehyde has an IUPAC name in which the -e in the alkane name is changed to –al. has a common name for the first four aldehydes that use the prefixes: form (1C), acet (2C), propion (3C), and butyr (4C), followed by aldehyde. O O O ║ ║ ║ H─C─H CH 3 ─C─HCH 3 ─CH 2 ─C─H methanal ethanalpropanal ( form aldehyde) ( acet aldehyde)( propion aldehyde)

51 51 Naming Aldehydes

52 52 Aldehydes in Flavorings Several naturally occurring aldehydes are used as flavorings for foods and fragrances. Benzaldehyde (almonds) Cinnamaldehyde (cinnamon)

53 53 Naming Ketones In naming ketones as IUPAC, the -e in the alkane name is replaced with –one. With a common name, the alkyl groups attached to the carbonyl group are named alphabetically followed by ketone. O O ║ ║ CH 3 ─C─CH 3 CH 3 ─C─CH 2 ─CH 3 propanone 2-butanone (dimethyl ketone) (ethyl methyl ketone)

54 54 Ketones in Common Use Nail polish remover, solvent Propanone, Dimethylketone, Acetone Butter flavoring

55 55 Classify each as 1) aldehyde or 2) ketone. O O || || A. CH 3 —CH 2 —C—CH 3 B. CH 3 —C—H CH 3 O | || C. CH 3 —C—CH 2 —C—H D. | CH 3 Learning Check

56 56 A. 2 ketone B. 1 aldehyde C. 1 aldehyde D. 2 ketone Solution

57 57 Learning Check Classify each as an 1) aldehyde2) ketone3) alcohol or 4) ether. O ║ A. CH 3 ─CH 2 ─C─CH 3 B. CH 3 ─O─CH 3 CH 3 O OH │ ║ │ C. CH 3 ─C─CH 2 ─C─HD. CH 3 ─CH ─CH 3 │ CH 3

58 58 Solution O ║ A. CH 3 ─CH 2 ─C─CH 3 B. CH 3 ─O─CH 3 2) ketone 4) ether CH 3 O OH │ ║ │ C. CH 3 ─C─CH 2 ─C─HD. CH 3 ─CH─CH 3 │ CH 3 1) aldehyde 3) alcohol

59 59 Learning Check Name each of the following. O ║ 1. CH 3 ─CH 2 ─CH 2 ─CH 2 ─C─H O ║ 2. Cl─CH 2 ─CH 2 ─C─H O ║ 3. CH 3 ─CH 2 ─C─CH 3

60 60 Solution Name each of the following: O ║ 1. CH 3 ─CH 2 ─CH 2 ─CH 2 ─C─H pentanal O ║ 2. Cl─CH 2 ─CH 2 ─C─H3-chloropropanal O ║ 3. CH 3 ─CH 2 ─C─CH 3 2-butanone; ethyl methyl ketone

61 61 Name the following compounds. O || A. CH 3 —CH 2 —CH 2 —C—CH 3 B. CH 3 O | || C. CH 3 —C—CH 2 —C—H | CH 3 Learning Check

62 62 A. 2-pentanone; methyl propyl ketone B. cyclohexanone C,3,3-dimethylbutanal Solution

63 63 Learning Check Draw the structural formulas for each: A. 4-methylpentanal B. 2,3-dichloropropanal C. 3-methyl-2-butanone

64 64 Solution Draw the structural formulas for each: CH 3 O │ ║ A. 4-methylpentanalCH 3 ─CH─CH 2 ─CH 2 ─C─H Cl O │ ║ B. 2,3-dichloropropanal Cl─CH 2 ─CH─C─H CH 3 O │ ║ C. 3-methyl-2-butanoneCH 3 ─CH─C─CH 3

65 Properties of Aldehydes and Ketones Chapter 12 Organic Compounds with oxygen and Sulfur

66 66 Physical Properties The polar carbonyl group provides dipole-dipole interactions.  +  -  +  - C=O Without an H on the oxygen, aldehydes and ketones cannot form hydrogen bonds.

67 67 Boiling Points Aldehydes and ketones have polar carbonyl groups (C=O).  +  - C=O attractions between polar groups.  +  -  +  - C=O higher boiling points than alkanes and ethers of similar mass. lower boiling points than alcohols of similar mass.

68 68 Comparison of Boiling Points 58

69 69 Solubility in Water The electronegative O atom of the carbonyl group of aldehydes and ketones forms hydrogen bonds with water.

70 70 Learning Check Indicate if each is soluble or insoluble in water. A. CH 3 —CH 2 —CH 3 B. CH 3 —CH 2 —OH O || C. CH 3 —CH 2 —CH 2 —C—H O || D. CH 3 —C—CH 3

71 71 Solution Indicate if each is soluble or insoluble in water. A. CH 3 —CH 2 —CH 3 insoluble B. CH 3 —CH 2 —OH soluble O || C. CH 3 —CH 2 —CH 2 —C—H soluble O || D. CH 3 —C—CH 3 soluble

72 72 Tollens’ Test In Tollens’ test, Tollens’ reagent, which contains Ag +, oxidizes aldehydes, but not ketones. Ag + is reduced to metallic Ag, which appears as a “mirror” in the test tube.

73 73 Benedict’s Test In the Benedict’s test, Benedict’s reagent, which contains Cu 2+, reacts with aldehydes that have an adjacent OH group. An aldehyde is oxidized to a carboxylic acid, while Cu 2+ is reduced to give red Cu 2 O(s).

74 74 Learning Check Write the structure and name of the oxidized product when each is mixed with Tollens’ reagent. A. butanal B. acetaldehyde C. ethyl methyl ketone

75 75 Solution A. butanal O || CH 3 —CH 2 —CH 2 —C—OH butanoic acid B. acetaldehyde O || CH 3 —C—OH acetic acid C. ethyl methyl ketoneNone. Ketones are not oxidized by Tollen’s reagent.

76 Chiral Molecules Chapter 12 Organic Compounds with Oxygen and Sulfur Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

77 77 Chiral Objects Chiral objects have the same number of atoms arranged differently in space. have one or more chiral carbon atoms each of which is bonded to four different groups. are like your hands. Try to superimpose your thumbs, palms, back of hands, and little fingers. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

78 78 Mirror Images The mirror images of chiral compounds cannot be superimposed. When the H and I atoms are aligned, the Cl and Br atoms are on opposite sides.

79 79 Achiral Structures are Superimposable When the mirror image of an achiral structure is rotated, the structure can be aligned with the initial structure. Thus this mirror image is superimposable.

80 80 Some Everyday Chiral and Achiral Objects

81 81 Learning Check Identify each as a chiral or achiral compound. A CH 2 CH 3 HCH 3 Cl C B H HCH 3 Cl C C Br HCH 3 Cl C

82 82 Solution Identify each as a chiral or achiral compound. chiral achiral chiral A CH 2 CH 3 HCH 3 Cl C B H HCH 3 Cl C C Br HCH 3 Cl C

83 83 Fischer Projections A Fischer projection is a 2-dimensional representation of a 3-dimensional molecule. places the most oxidized group at the top. uses vertical lines in place of dashes for bonds that go back. uses horizontal lines in place of wedges for bonds that come forward.

84 84 Drawing Fischer Projections

85 85 D and L Notations By convention, the letter L is assigned to the structure with the —OH on the left. The letter D is assigned to the structure with the —OH on the right. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

86 86 Learning Check Indicate whether each pair is a mirror image that cannot be superimposed (enantiomers).

87 87 Solution Indicate whether each pair is a mirror image that cannot be superimposed (enantiomers). Yes No


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