Chapter 12 Organic Compounds with Oxygen and Sulfur 12.1 Alcohols, Phenols, Thiols, and Ethers

Alcohols An alcohol contains a hydroxyl group (–OH) that replaces a hydrogen atom in a hydrocarbon. A phenol contains a hydroxyl group (–OH) attached to a benzene ring.

Naming Alcohols The names of alcohols in the IUPAC system replace the -e with -ol with common names use the name of the alkyl group followed by alcohol Formula IUPAC Common Name CH4 methane CH3─OH methanol methyl alcohol CH3─CH3 ethane CH3─CH2─OH ethanol ethyl alcohol

Naming Alcohols

Naming of Alcohols Step 1 Name the longest carbon chain with the –OH group. Name an aromatic alcohol as a phenol. CH3CH2CH2OH propanol OH CH3CHCH2CH3 butanol CH3 OH CH3CHCH2CH2CHCH3 hexanol 6 5 4 3 2 1

Naming of Alcohols Step 2 Number the chain starting at the end closer to the –OH. CH3CH2CH2OH 1-propanol OH CH3CHCH2CH3 2-butanol CH3 OH CH3CHCH2CH2CHCH3 2-hexanol 6 5 4 3 2 1

Naming of Alcohols Step 3 Give the location and name of each substituent relative to the –OH group. CH3CH2CH2OH 1-propanol OH CH3CHCH2CH3 2-butanol CH3 OH CH3CHCH2CH2CHCH3 5-methyl-2-hexanol 6 5 4 3 2 1

Some Typical Alcohols | “Rubbing alcohol” CH3—CH—CH3 2-propanol (isopropyl alcohol) Antifreeze HO—CH2—CH2—OH 1,2-ethanediol (ethylene glycol) Glycerol HO—CH2—CH—CH2—OH 1,2,3-propanetriol

Learning Check Name the following compounds: 1. CH3—CH2—CH2—CH2—OH OH CH3 | | 2. CH3—CH—CH—CH2—CH3 3.

Solution Step 1 Name the longest carbon chain with the –OH group. Name an aromatic alcohol as a phenol. 1. CH3—CH2—CH2—CH2—OH butanol OH CH3 | | 2. CH3—CH—CH—CH2—CH3 pentanol 3. cyclopentanol

Solution Step 2 Number the chain starting at the end closer to the –OH. 1. CH3—CH2—CH2—CH2—OH 1-butanol OH CH3 | | 2. CH3—CH—CH—CH2—CH3 2-pentanol 3. cyclopentanol

Solution Step 3 Give the location and name of each substituent relative to the –OH group. 1. CH3—CH2—CH2—CH2—OH 1-butanol OH CH3 | | 2. CH3—CH—CH—CH2—CH3 3-methyl-2-pentanol 3. cyclopentanol

Phenols in Medicine Phenol is the IUPAC name for benzene with a hydroxyl group used in antiseptics and disinfectants Phenol Resorcinol 4-Hexylresorcinol

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

Naming Phenols Step 1 Name the longest carbon chain with the –OH group. Name an aromatic alcohol as a phenol. phenol phenol

Naming Phenols Step 2 Number the chain starting at the end closer to the –OH. phenol phenol

Naming Phenols Step 3 Give the location and name of each substituent relative to the –OH group. 3-chlorophenol 4-bromophenol

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

Solution Write the structure of each of the following: A. 3-pentanol OH | CH3—CH2—CH—CH2—CH3 B. ethyl alcohol CH3—CH2—OH C. 4-methylphenol O H C 3

Thiols Thiols contain sulfur are similar to alcohols contain a thiol (–SH) group often have strong odors are found in cheese, onions, garlic, and oysters are used to detect gas leaks

Thiols Thiols are named in the IUPAC system by adding thiol to the alkane name of the longest carbon chain.

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 CH3OCH3 CH3CH2OCH3

Learning Check Write the structure of the following: A. 3-pentanol B. ethanethiol C. diethyl ether

Solution OH | A. 3-pentanol CH3CH2CHCH2CH3 B. ethanethiol CH3CH2SH C. diethyl ether CH3CH2OCH2CH3

Ethers as Anesthetics Anesthetics inhibit pain signals to the brain like diethyl ether, CH3CH2OCH2CH3, were used for over a century, but caused nausea and were flammable developed by the 1960s were nonflammable Cl F F Cl F H HCCOCH HCCOCH F F F H F H Ethrane (enflurane) Penthrane

Chapter 12 Organic Compounds with Oxygen and Sulfur 12.2 Properties of Alcohols and Ethers

Classification of Alcohols 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 (1) Secondary (2) Tertiary (3) 1 group 2 groups 3 groups H CH3 CH3 | | | CH3—C—OH CH3—C—OH CH3—C—OH | | | H H CH3

Learning Check OH | A. CH3—CH—CH2—CH3 B. CH3—CH2—CH2—OH Classify each alcohol as primary, secondary, or tertiary. OH | A. CH3—CH—CH2—CH3 B. CH3—CH2—CH2—OH C. CH3—CH2—C—CH2—CH3 CH3

Solution | A. CH3—CH—CH2—CH3 secondary B. CH3—CH2—CH2—OH primary C. CH3—CH2—C—CH2—CH3 tertiary CH3

Solubility of Alcohols in Water contain polar OH groups and form hydrogen bonds with other alcohol molecules that have one to three carbons are soluble in water solubility in water decreases with increasing number of carbons

Solubility of Ethers in Water do not have a polar OH group, but have a COC group do not form hydrogen bonds with less than four carbons are slightly soluble in water with more than four carbons are not soluble in water

Solubility of Alcohols and Ethers in Water

Solubility of Phenols Phenols are slightly soluble in water have an OH group that can form hydrogen bonds with water can react with water to produce phenoxide ions were once used as antiseptics + H2O + H3O+

Learning Check Indicate whether each of the following is soluble in water and explain why. A. CH3CH2CH2CH2CH2CH2OH B. CH3OCH2CH3 C. CH3CH2OH

Solution Indicate whether each of the following is soluble in water and explain why. A. CH3CH2CH2CH2CH2CH2OH Not soluble Alcohols with long carbon chains (nonpolar) are not soluble. B. CH3OCH2CH3 Slightly soluble Ethers with less than four carbons are only slightly soluble in water. C. CH3CH2OH Soluble Short-chain alcohols form hydrogen bonds with water.

Chapter 12 Organic Compounds with Oxygen and Sulfur 12.3 Reactions of Alcohols and Thiols

Dehydration of Alcohols Alcohols undergo dehydration when heated with an acid catalyst the loss of –H and –OH from adjacent carbon atoms, producing an alkene H OH | | H+, heat H—C—C—H H—C=C—H + H2O | | | | H H H H alcohol alkene

Oxidation of 1 Alcohols Alcohols undergo oxidation, increasing the number of carbon and oxygen bonds. Primary alcohols are oxidized to produce an aldehyde. 1 bond to O 2 bonds to O H OH H O | | oxidation | || H—C—C—H H—C—C—H | | | H H H 1 alcohol aldehyde

Oxidation of 1 Alcohols Alcohols undergo oxidation, increasing the number of carbon and oxygen bonds. Aldehydes can further oxidize to produce a carboxylic acid. 1 bond to O 2 bonds to O H O H O | || oxidation | || H—C—C—H H—C—C—OH | | H H aldehyde carboxylic acid

Oxidation of 2 Alcohols Secondary alcohols are oxidized to produce a ketone. To indicate the process of oxidation, [O] is placed over the reaction arrow. 1 bond to O 2 bonds to O H OH H H O H | | | [O] | || | H—C—C—C—H H—C—C—C—H | | | | | H H H H H 2 alcohol ketone

Oxidation of Tertiary 3 Alcohols Tertiary (3) alcohols do not readily oxidize. OH CH3CCH3 [O] no product CH3 no H to oxidize 3 alcohol no reaction

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 a decrease in the number of C–O bonds there is a gain of H

Oxidation and Reduction

Methanol Poisoning Methanol is also known as methyl alcohol is highly toxic and found in windshield washer fluid, Sterno, and paint strippers is rapidly absorbed and oxidized to formaldehyde and then formic acid O O [O] [O] CH3OH HCH HCOH methyl alcohol formaldehyde formic acid

Ethanol, CH3CH2OH Ethanol acts as a depressant and 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 30 mg/dL per hour by an alcoholic

Effect of Alcohol on the Body

Oxidation of Thiols When thiols undergo oxidation, an H atom is lost from each of two –SH groups the product is a disulfide protein in hair is cross-linked by disulfide bonds found in the amino acid cysteine

Learning Check OH [O] CH3CHCH2CH3 O Select the product for the oxidation of OH [O] CH3CHCH2CH3 O A. CH3CH=CHCH3 B. CH3CCH2CH3 C. CO2 + H2O D. CH3CHCH2CH3

Solution OH [O] CH3CHCH2CH3 O The answer is B. CH3CCH2CH3 Select the product for the oxidation of OH [O] CH3CHCH2CH3 O The answer is B. CH3CCH2CH3

Learning Check Select the product when CH3–CH2–CH2–OH undergoes each of the following reactions: [O] [O] CH3—CH2 —CH2OH B. C. 1) CH3—CH=CH2 2) CO2 + H2O O || 3) CH3—CH2—C—H O 4) CH3—CH2—C—OH

Solution Select the product when CH3–CH2–CH2–OH undergoes each of the following reactions: O [O] B. 3) || CH3—CH2—CH2OH CH3—CH2—C—H [O] C. 4) || CH3—CH2—C—OH

Learning Check Give the primary product for the reaction of 2-propanol when it undergoes A. oxidation B. dehydration

Solution OH CH3CHCH3 = 2-propanol = C3H8O A. oxidation OH O [O] 2CH3CHCH3 + 9O2 CH3CCH3 + 6CO2 + 8H2O B. dehydration H+, heat CH3CHCH3 CH3CH=CH2 + H2O

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

Carbonyl Group in Aldehydes and Ketones A carbonyl group consists of a carbon-oxygen polar double bond has a very electronegative oxygen atom has two lone pair electrons on the O atom has partial positive charge on C and partial negative charge on O

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

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 following prefixes: 1 carbon, form 2 carbons, acet 3 carbons, propion 4 carbons butyr followed by aldehyde

Naming Aldehydes

Naming Aldehydes

Naming Aldehydes Give the IUPAC name for the following aldehydes: O || CH3CH2CH2CHCH | CH3

Naming Aldehydes Step 1 Name the longest carbon chain containing the carbonyl group by replacing the e in the alkane name with al. O || CH3CH2CH2CHCH | CH3 pentanal benzaldehyde

Naming Aldehydes Step 2 Name and number substituents by counting the carbonyl group as carbon 1. O || CH3CH2CH2CHCH | CH3 2-methylpentanal 3,4-dichlorobenzaldehyde

Aldehydes in Flavorings Several naturally occurring aldehydes are used as flavorings for foods and fragrances.

Naming Ketones When naming the following ketones in the IUPAC system, 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 CH3 CCH3 CH3CCH2CH3 propanone 2-butanone (dimethyl ketone) (ethyl methyl ketone)

Naming Ketones

Naming Ketones Name the following ketones using the IUPAC system. O || CH3CH2CHCH2CCH3 | CH3

Naming Ketones Step 1 Name the longest carbon chain that contains the carbonyl group by replacing the e in the alkane name with one. O || CH3CH2CHCH2CCH3 | CH3 hexanone pentanone

Naming Ketones Step 2 Number the carbon chain starting from the end nearer the carbonyl group and indicate its location. O || CH3CH2CHCH2CCH3 | CH3 2-hexanone pentanone

Naming Ketones Step 3 Name and number any substituents on the carbon chain. O || CH3CH2CHCH2CCH3 | CH3 4-methyl-2-hexanone 2,3-dimethylcylcopentanone

Ketones in Common Use Acetone (propanone) is a solvent used in nail polish remover. Butanedione is the butter flavoring used in margarine.

Learning Check Classify each as an aldehyde or ketone. O O || || A. CH3—CH2—C—CH3 B. CH3—C—H CH3 O | || C. CH3—C—CH2—C—H D. | CH3

Solution Classify each as an aldehyde or ketone. O O || || A. CH3—CH2—C—CH3 B. CH3—C—H CH3 O | || C. CH3—C—CH2—C—H D. | CH3 ketone aldehyde aldehyde ketone

Learning Check Classify each as an aldehyde, ketone, alcohol, or ether. O A. CH3CH2CCH3 B. CH3OCH3 CH3 O OH C. CH3CCH2CH D. CH3CHCH3 CH3

Solution Classify each as an aldehyde, ketone, alcohol, or ether. O A. CH3CH2CCH3 B. CH3OCH3 CH3 O OH C. CH3CCH2CH D. CH3CHCH3 CH3 ketone ether aldehyde alcohol

Learning Check Give the IUPAC name for each of the following ketones. O A. CH3CH2CH2CH2CCH3 B. ClCH2CH2CCH3

Solution Give the IUPAC name for each of the following ketones. Step 1 Name the longest carbon chain that contains the carbonyl group by replacing the e in the alkane name with one. O A. CH3CH2CH2CH2CCH3 pentanone B. ClCH2CH2CCH3 butanone

Solution Give the IUPAC name for each of the following ketones. Step 2 Name the carbon chain starting from the end nearer the carbonyl group and indicate its location. O A. CH3CH2CH2CH2CCH3 2-pentanone B. ClCH2CH2CCH3 2-butanone

Solution Give the IUPAC name for each of the following ketones. Step 3 Name and number any substituents on the carbon chain. O A. CH3CH2CH2CH2CCH3 2-pentanone B. ClCH2CH2CCH3 4-chloro-2-butanone

Learning Check Give the IUPAC name for the following aldehyde compounds. O || A. CH3—CH2—CH2—C—H CH3 O | || B. CH3—C—CH2—C—H | CH3

Solution Give the IUPAC name for the following aldehyde compounds. Step 1 Name the longest carbon chain containing the carbonyl group by replacing the e in the alkane name with al. O || A. CH3—CH2—CH2—C—H butanal CH3 O | || B. CH3—C—CH2—C—H butanal | CH3

Solution Give the IUPAC name for the following aldehyde compounds. Step 2 Name and number substituents by counting the carbonyl group as carbon 1. O || A. CH3—CH2—CH2—C—H butanal CH3 O | || B. CH3—C—CH2—C—H 3,3-dimethylbutanal | CH3

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

Solution Draw the structural formulas for each: CH3 O A. 4-methylpentanal CH3CHCH2CH2CH Cl O B. 2,3-dichloropropanal ClCH2CHCH CH3 O C. 3-methyl-2-butanone CH3CHCCH3

Chapter 12 Organic Compounds with Oxygen and Sulfur 12.5 Properties of Aldehydes and Ketones In Tollens’ test, a silver mirror forms when the oxidation of an aldehyde reduces silver ion to metallic silver. The silvery surface of a mirror is formed in a similar way.

Physical Properties The polar carbonyl group provides dipole-dipole interactions. + - + - C=O C=O Because the electronegative oxygen atom forms hydrogen bonds with water molecules, aldehydes and ketones with one to four carbons are very soluble.

Solubility of Aldehydes and Ketones in Water

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

Learning Check Indicate whether each is soluble or insoluble in water. A. CH3—CH2—CH3 B. CH3—CH2—OH O || C. CH3—CH2—CH2—C—H D. CH3—C—CH3

Solution Indicate whether each is soluble or insoluble in water. A. CH3—CH2—CH3 insoluble B. CH3—CH2—OH soluble O || C. CH3—CH2—CH2—C—H soluble D. CH3—C—CH3 soluble

Oxidation of Aldehydes Primary alcohols can be oxidized to aldehydes, which can be easily oxidized to carboxylic acids. Secondary alcohols can be oxidized to ketones, which cannot be further oxidized.

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.

Tollens’ Test

Benedict’s Test In Benedict’s test, Benedict’s reagent, which contains Cu2+, reacts with aldehydes that have an adjacent OH group.

Benedict’s Test In Benedict’s test, an aldehyde is oxidized to a carboxylic acid, while Cu2+ is reduced to give red Cu2O(s). The blue Cu2+ in Benedict’s solution forms a brick-red solid of Cu2O in a positive test for many sugars and aldehydes with adjacent hydroxyl groups.

Reduction of Aldehydes and Ketones Aldehydes and ketones can be reduced by sodium borohydride, NaBH4, or H2. The reduction of aldehydes and ketones decreases the number of carbon–oxygen bonds by addition of hydrogen or loss of oxygen.

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

Solution A. O O || Tollens’ || CH3—CH2—CH2—C—OH CH3—CH2—CH2—C—OH butanal butanoic acid B. O O || Tollens’ || CH3—C—H CH3—C—OH acetaldehyde acetic acid C. Ethyl methyl ketone + Tollens’ No reaction Ketones are not oxidized by Tollens’ reagent.

Chapter 12 Organic Compounds with Oxygen and Sulfur 12.6 Chiral Molecules

Isomers Molecules are structural isomers when they have the same molecular formula, but different bonding arrangements.

Stereoisomers Stereoisomers have identical molecular formulas, but they are not structural isomers. In stereoisomers, the atoms are bonded in the same sequence but differ in the way they are arranged in space. When stereoisomers have mirror images that are different, they are said to have “handedness.”

Chiral Molecules Have Handedness 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.

Some Everyday Chiral and Achiral Objects

Chiral Carbon Atoms Are 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.

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.

Learning Check A. C H l B. C. B r Identify each as a chiral or an achiral compound. A. C H 2 3 l B. C. B r

Solution chiral achiral chiral A. C H l B. C. B r Identify each as a chiral or an achiral compound. chiral achiral chiral A. C H 2 3 l B. C. B r

Fischer Projections A Fischer projection is a two-dimensional representation of a three-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

Drawing Fischer Projections

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.

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

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

Concept Map – Organic Molecules with O and S