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What are alcohols? An alcohol contains a hydroxyl group (—OH) attached to a carbon chain. water A phenol contains a hydroxyl group (—OH) attached to a benzene ring. alcohol phenol 1 How do we name alcohols? Formula IUPAC Name CH4 methane CH3─OH methanol CH3─CH3 ethane CH3─CH2─OH ethanol The names of alcohols • in IUPAC replace the -e with -ol. More names of alcohols CH3─CH2─CH2─OH 1-propanol OH │ CH3─CH─CH2─CH3 2-butanol • IUPAC names for longer chains number chain from – end nearest -OH group. CH3 OH │ │ CH3─CH─CH2─CH2─CH─CH3 5-methyl-2-hexanol 6 5 4 3 2 1 3 What are phenols? Phenol • IUPAC name for benzene with a hydroxyl group. • is used in antiseptics and disinfectants. OH OH OH OH OH CH2CH2CH2CH2CH2CH3 phenol resorcinol 4-hexylresorcinol 4 Derivatives of Phenol Compounds of phenol are the active ingredients in the essential oils of cloves, vanilla, nutmeg, and mint. 5 How to name a phenol! To name a phenol •with two substituents, assign C-1 to carbon attached to –OH. •Number ring to give lowest numbers. OH OH 1 1 3 Cl 4 Br 3-chlorophenol 4-bromophenol 6 Classification of alcohols • determined by number of alkyl groups attached to carbon bonded to hydroxyl. • primary (1°), secondary (2°), or tertiary(3). Primary (1º) 1 group H | CH3—C—OH | H Secondary (2º) Tertiary (3º) 2 groups 3 groups CH3 | CH3—C—OH | H CH3 | CH3—C—OH | CH3 7 What are ethers? An ether • contains an ─O─ between two carbon groups. • has a common name that gives alkyl names of attached groups followed by ether. CH3─O─CH3 CH3─CH2─O─CH3 dimethyl ether ethyl methyl ether 8 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 1960’s 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 Ethane(enflurane) Penthrane 9 Now let’s look at the Properties of Alcohols and Ethers, Alcohols •contain polar OH groups. •form hydrogen bonds with other alcohol molecules. •have higher boiling points than alkanes and ethers of similar mass. 10 However 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. 11 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. 12 Reactions of alcohols are… Alcohols undergo combustion with O2 to produce CO2 and H2O. 2CH3OH + 3O2 2CO2 + 4H2O + Heat 13 Dehydration of Alcohols 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 + H2O | | | | H H H H alcohol alkene 14 Oxidation vs 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. 15 Oxidation of primary (1) alcohols 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] || CH3—C—H CH3—C—H + H2O | H Ethanol (ethyl alcohol) Ethanal (acetaldehyde) 16 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. secondary alcohol OH │ CH3─C─CH3 │ [O] [O] ketone O ║ CH3─C─CH3 + H2O H 2-propanol 2-propanone 17 Oxidation of tertiary ( 3)alcohols Tertiary 3alcohols do not readily oxidize. [O] Tertiary alcohol no reaction OH │ [O] CH3─C─CH3 no product │ CH3 no H on the C-OH to oxidize 2-methyl-2-propanol 18 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 ║ ║ CH3CH2OH CH3CH CH3COH 2CO2 + H2O ethyl alcohol acetaldehyde acetic acid 19 Ethanol CH3CH2OH Ethanol • acts as a depressant. • 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. % Ethanol 50% 40% 15-25% 12% 3-9% Product Whiskey, rum, brandy Flavoring extracts Listerine, Nyquil, Scope Wine, Dristan, Cepacol Beer, Lavoris 20 What do Aldehydes and Ketones have in common? A carbonyl group • in an aldehyde is attached to at least one H atom. • in a ketone is attached to two carbon groups. 21 More examples! O C H Benzaldehyde (almonds) O CH=CH C H Benzaldehyde (almonds) 22 How to name ketones In naming ketones • as IUPAC, -e in alkane name replaced with –one. • With a common name, alkyl groups attached to carbonyl group are named alphabetically followed by ketone. O O ║ ║ CH3 ─C─CH3 CH3─C─CH2─CH3 propanone 2-butanone 23 Are they soluble? aldehydes and ketones • electronegative O atom of carbonyl group •aldehydes and ketones •hydrogen bonds with water •not between each other, thus •higher boiling points •alkanes and ethers of similar mass. •lower boiling points •alcohols of similar mass. 24 Reactions of aldehydes Aldehydes oxidize readily to carboxylic acids. Ketones do not oxidize further O || CH3—C—H oxidation O || CH3—C— CH3------- oxidation O || CH3—C—OH NO REACTION 25