Alcohols, Phenols, and Thiols General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Alcohols and Ethers An alcohol contains the hydroxyl (–OH) functional group. In an ether, an oxygen atom is bonded to two carbon atoms (–C–O–C–). ethanol chemspider dimethyl ether Chemspider General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

General, Organic, and Biological Chemistry Thiols In a thiol, the functional group –SH is bonded to a carbon atom. ethanthiol General, Organic, and Biological Chemistry

Learning Check 1) CH3–CH2–CH2–OH 2) CH3–O–CH2–CH3 3) CH3–CH2–NH2 O || Classify each of the following as alcohol, ether, aldehyde, ketone, carboxylic acid, ester, or amine. 1) CH3–CH2–CH2–OH 2) CH3–O–CH2–CH3 3) CH3–CH2–NH2 O || 4) CH3–C–OH 5) CH3–C–O–CH3 General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

General, Organic, and Biological Chemistry Alcohols and Phenols An alcohol contains a hydroxyl group (—OH) attached to a carbon chain A phenol contains a hydroxyl group (—OH) attached to a benzene ring General, Organic, and Biological Chemistry

Classification of Alcohols Alcohols are classified by the number of alkyl groups attached to the carbon bonded to the hydroxyl as primary (1°), secondary (2°), or tertiary(3) Primary (1º) Secondary (2º) Tertiary (3º) 1 group 2 groups 3 groups__ H CH3 CH3 | | | CH3—C—OH CH3—C—OH CH3—C—OH | | | H H CH3 methanol tert-butanol 2-propanol butanol 2-butanol 2-ethyl-2-propanol General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Learning Check OH | A. CH3—CH—CH2—CH3 B. CH3—CH2—CH2—OH Classify each alcohol as P) primary, S) secondary, or T) tertiary. OH | A. CH3—CH—CH2—CH3 B. CH3—CH2—CH2—OH C. CH3—CH2—C—CH2—CH3 CH3 General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Guide to Naming Alcohols General, Organic, and Biological Chemistry

Naming Alcohols The names of alcohols in IUPAC system replace -e of alkane name with -ol that are 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 General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

More Names of Alcohols In IUPAC names for longer carbon chains, the chain is numbered from the end nearer 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 General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

General, Organic, and Biological Chemistry Some Typical Alcohols OH | “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 General, Organic, and Biological Chemistry

Learning Check Give the IUPAC name for each of the following: A. CH3—CH2—CH2—CH2—OH OH CH3 | | B. CH3—CH—CH—CH2—CH3 C. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Learning Check Draw the condensed structural formula of the following: A. 3-Pentanol B. Propyl alcohol C. 3-Methylcyclohexanol General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Phenols in Medicine Phenol is the IUPAC name for benzene with a hydroxyl group is used in antiseptics and disinfectants Phenol Resorcinol 4-Hexylresoricinol General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Thiols organic compounds that contain a –SH group are named in the IUPAC system by adding thiol to the alkane name of the longest carbon chain are found in onions, oysters, and garlic - STINKY General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Naming Thiols In thiols with long carbon chains, the chain is numbered to locate the SH group. CH3—CH2—CH2—SH 1-Propanethiol SH | CH3—CH—CH3 2-Propanethiol General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

General, Organic, and Biological Chemistry Sources of Thiols Thiols often have strong odors are used to detect gas leaks are found in onions, oysters, and garlic General, Organic, and Biological Chemistry

Learning Check Draw the condensed structural formula of each of the following compounds: A. 2-Butanethiol B. 2-Methyl-1-butanol General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Learning Check Name each of the following compounds: OH | A. CH3—CH2 —CH—CH3 CH3 B. CH3—CH2—CH—CH2—CH2—OH C. CH3—CH2—CH2—SH General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Ethers Ethers contain an ─O─ between two carbon groups that are simple are named by listing the alkyl names in alphabetical order followed by ether CH3─O─CH3 CH3─CH2─O─CH3 Dimethyl ether Ethyl methyl ether General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

General, Organic, and Biological Chemistry Ethers as Anesthetics Anesthetics inhibit pain signals to the brain such as ethyl ether, CH3─CH2─O─CH2─CH3, were used for over a century but caused nausea and were flammable developed by the1960s were nonflammable General, Organic, and Biological Chemistry

Cyclic Ethers A cyclic ether contains an O atom in a carbon ring is called a heterocyclic compound typically has 5 (furan) or 6 atoms (pyran) in the ring Furan Tetrahydrofuran Pyran 1,4-Dioxane General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

IUPAC Names for Ethers In the IUPAC system, the shorter alkyl group and the oxygen are named as an alkoxy group attached to the longer alkane. Methoxy propane CH3—O—CH2—CH2—CH3 1 2 3 Numbering the longer alkane gives 1-Methoxypropane General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Boiling Points of Alcohols contain a strongly electronegative O in the OH groups form hydrogen bonds between alcohol molecules have higher boiling points than alkanes and ethers of similar mass General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Boiling Points of Ethers have an O atom, but no H is attached cannot form hydrogen bonds between ether molecules have boiling points similar to alkanes of similar mass General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Solubility of Alcohols and Ethers in Water Alcohols and ethers are more soluble in water than are alkanes because the oxygen atom hydrogen bonds with water. Alcohols with 1–4 C atoms are soluble, but alcohols with 5 or more C atoms are not. General, Organic, and Biological Chemistry

Comparing Solubility and Boiling Points General, Organic, and Biological Chemistry

Solubility of Phenol Phenol is soluble in water has a hydroxyl group that ionizes slightly (so is a weak acid) is corrosive and irritating to the skin + H2O + H3O+ General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Learning Check Which compound would have the higher boiling point, ethyl methyl ether or 1-propanol? Explain. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Learning Check Which compound would be more soluble in water, ethanol or 2-pentanol? Explain. General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Chapter 13 Alcohols, Phenols, and Thiols 13.4 Reactions of Alcohols and Thiols Combustion dehydration to an alkene 2 ROH  ether Oxidation of 1o to aldehyde (CHO) then carboxylic (COOH) Oxidation [O] of 2o to ketone R2-C=O Oxidation [O] of 3o??? Thiol [O] to disulfide General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Combustion of Alcohols Combustion is the reaction of an alcohol with O2 to produce CO2 and H2O. CH3─CH2─OH(g) + 3O2(g) 2CO2(g) + 3H2O(g) + heat General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Dehydration of Alcohols Dehydration of an alcohol occurs when heated with an acid catalyst with 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 General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

What would be the major dehydration products (S’s Rules)?

Learning Check Write the equations for the reactions when 2-propanol undergoes: A. combustion B. dehydration General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Oxidation and Reduction In the oxidation of an organic compound, there is an increase in the number of C—O bonds there is a loss of H (as H+ and e-) In the reduction of an organic compound, there is an decrease in the number of C—O bonds there is a gain of H (as H+ and e-) General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Oxidation and Reduction (continued) H’s are lost This H is lost General, Organic, and Biological Chemistry

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 –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) General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

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] ║ CH3—C—CH3 CH3—C—CH3 + H2O │ H 2-Propanone(dimethyl ketone, 2-Propanol (isopropyl alcohol) “acetone”) General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Oxidation of Tertiary (3) Alcohols Tertiary alcohols do not readily oxidize. [O] Tertiary alcohol no reaction OH │ [O] CH3─C─CH3 no product │ CH3 There is no H on the C—OH to oxidize. 2-Methyl-2-propanol General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Learning Check Select the compound that would result for each reaction of CH3—CH2—CH2—OH. O || 1) CH3—CH ═ CH2 2) CO2 + H2O 3) CH3—CH2—C—H A. H+, heat B. [O] C. O2, heat General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Learning Check OH │ [O] CH3—CH—CH2—CH3 ? O ║ Select the product from the oxidation of OH │ [O] CH3—CH—CH2—CH3 ? O ║ 1) CH3—CH ═ CH—CH3 2) CH3—C—CH2—CH3 │ 3) CO2 + H2O 4) CH3—CH—CH2—CH3 General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.

Oxidation of Thiols When thiols undergo oxidation, an H atom is lost from two –SH groups the product is a disulfide [O] CH3—SH + HS—CH3 CH3—S—S—CH3 + H2O disulfide General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.