Chapter Fourteen Alcohols, Phenols, And Ethers

Ch 14 | 2 of 52 Functional Groups Groups of atoms within a larger molecule that have characteristic chemical behavior. A functional group behaves almost the _____ way in every molecule it is in (electronic structure, reactivity, geometry all generally stay the ______). The chemistry of every organic molecule is determined by the functional groups it contains. It is very important for this course that you learn to recognize functional groups.

Ch 14 | 3 of 52 Functional Groups NameStructureExample Alkane (Not a functional Group) Alkene Alkyne Arene (aromatic ring)

Ch 14 | 4 of 52 Functional Groups NameStructureExample Halide Alcohol Ether

Ch 14 | 5 of 52 Fig Space-filling models for the three simplest unbranched chain alcohols: methyl alcohol, ethyl alcohol, and propyl alcohol. Alcohols, Phenols, and Ethers cont’d

Ch 14 | 6 of 52 The Bonding of Oxygen To understand the bonding patterns of oxygen, we must review what we know about oxygen –How many valence electrons does oxygen have? –How many electrons does oxygen need to have an octet of electrons in its valence shell? –Oxygen’s octet is filled when it forms ___ bonds to other atoms:

Ch 14 | 7 of 52 →Fig The similar shapes of water and methanol. Methyl alcohol may be viewed structurally as an alkyl derivative of water. Alcohols, Phenols, and Ethers cont’d

Ch 14 | 8 of 52 Classifying Alcohols Alcohols are classified by the number of carbon substituents bonded to the carbon. –primary (1 o ) –secondary (2 o ) –tertiary (3 o ) PrimaryTertiarySecondary

Ch 14 | 9 of 52 Alcohols, Phenols, and Ethers cont’d Which are primary? Which are secondary? Which are tertiary?

Ch 14 | 10 of 52 ←Fig Racing cars are fueled with methyl alcohol. Alcohols Used As Fuels and Fuel Additives Jonathan Ferrey/Getty Images

Ch 14 | 11 of 52 Ethyl Alcohol In Beverages and Other Consumer Products

Ch 14 | 12 of 52 ←Fig Ethylene glycol is the major ingredient in de- icers for planes. Commercial Uses of Alcohols © Hank Morgan/Rainbow

Ch 14 | 13 of 52 →Fig For survival in northern winters, many fish and insects produce large amount of glycerol that dissolve in their blood, thereby lowering the freezing point. Metabolic Alcohols James Cotier/Getty Images

Ch 14 | 14 of 52 A carbon compound that contain -OH (hydroxyl) group In IUPAC name, the -e in alkane name is replaced with -ol. CH 4 methane CH 3 OH methanol (methyl alcohol) CH 3 CH 3 ethane CH 3 CH 2 OH ethanol (ethyl alcohol ) Naming Alcohols

Ch 14 | 15 of 52 IUPAC names for longer chains number the chain from the end nearest the -OH group. CH 3 CH 2 CH 2 OH1-propanol OH CH 3 CHCH 3 2-propanol CH 3 OH CH 3 CHCH 2 CH 2 CHCH 3 5-methyl-2-hexanol Naming Alcohols, Part II

Ch 14 | 16 of 52 OH “rubbing alcohol”CH 3 CHCH 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 Anti-freeze Some Typical Alcohols

Ch 14 | 17 of 52 Name these alcohols.

Ch 14 | 18 of 52 Fig (a) The polar hydroxyl functional group dominates the physical properties of methanol. (b) Conversely, the nonpolar portion of 1- octanol dominates its physical properties. Alcohols, Phenols, and Ethers cont’d

Ch 14 | 19 of 52 ←Fig (a) Boiling points and (b) solubilities in water of selected 1- alcohols. Alcohols, Phenols, and Ethers cont’d

Ch 14 | 20 of 52 Table 14.3 Alcohols, Phenols, and Ethers cont’d

Ch 14 | 21 of 52 ←Fig Alcohol boiling points are higher than those of the corresponding alkanes because of the alcohol-alcohol hydrogen bonding. Alcohols, Phenols, and Ethers cont’d

Ch 14 | 22 of 52 →Fig Because of hydrogen bonding between alcohol molecules and water molecules, small molecular mass alcohols have unlimited solubility in water. Alcohols, Phenols, and Ethers cont’d

Ch 14 | 23 of 52 Synthesis of Alcohols Alcohols can be prepared from many other kinds of compounds. –Alkenes Hydration! –Alkyl halides –Ketones –Aldehydes –Esters They can also be transformed into a wide assortment of compounds. alcohol R-OH R=R R-X R-C-R R-O-R R-C-H =O

Ch 14 | 24 of 52 Preparation by hydration of alkenes.

Ch 14 | 25 of 52 Aldehyde and ketone reduction (adding hydrogen across the double bond) reactions:

Ch 14 | 26 of 52 Combustion 2CH 3 OH + 3O 2 2CO 2 + 4H 2 O + Heat Dehydration H OH H +, heat H-C-C-H H-C=C-H + H 2 O H H H H alcohol alkene Reactions of Alcohols

Ch 14 | 27 of 52 ←Fig In an intramolecular alcohol dehydration the components of water are removed from neighboring carbon atoms. This is an elimination reaction. Alcohols, Phenols, and Ethers cont’d

Ch 14 | 28 of 52 Reactions of Alcohols: Dehydration Dehydration of an alcohol produces an _________ Phenols __________ undergo dehydration Zaitsev’s rule –The major product in an intramolecular alcohol dehydration reaction is the ________ that has the greatest number of alkyl groups attached to the carbon atoms of the double bond

Ch 14 | 29 of 52 Reactions of Alcohols: Intermolecular Alcohol Dehydration Ethers form when two alcohols dehydrate at a ____ temperature (140 o C) –H 3 C-OH + HO-CH 3  H 3 C-O-CH 3 + H 2 O –Two methanol  dimethyl ether + water –Note: Dehydration to an alkene at _____ o C

Ch 14 | 30 of 52 Reactions of Alcohols: Oxidation and Reduction In organic chemistry, an easy way to recognize oxidation: –An increase in the number of C-O bonds OR –A loss of hydrogen atoms In organic chemistry, an easy way to recognize reduction: –A decrease in the number of C-O bonds OR –A gain of hydrogen atoms

Ch 14 | 31 of 52 Oxidation of alcohols. Valuable reaction to yield carbonyl (C=O) compounds. –Product depends on starting alcohol and amount of oxidizer.

Ch 14 | 32 of 52 Oxidation of alcohols. –Primary alcohols yield aldehydes and carboxylic acids. –Secondary alcohols yield ketones. –Tertiary alcohols do not react. From primary alcohols From secondary alcohols

Ch 14 | 33 of 52 Oxidation reactions: R-OH  R(CO)R or RCHO  RCOOH * PCC = Pyridinium chlorochromate *

Ch 14 | 34 of 52 Levels of oxidation of secondary alcohols: –Ketone (Most oxidized) –Alcohol (Least oxidized) Levels of oxidation of primary alcohols: –Carboxylic Acid (Most oxidized) –Aldehyde –Alcohol (Least oxidized) Most OxidizedLeast Oxidized

Ch 14 | 35 of 52 Reactions of Alcohols: Halogenation Substitution reactions –Halogen replaces the hydroxyl group –Reactants: Phosphorus trihalides (with heat) –3R-OH + PX 3  3R-X + H 3 PO 3

Ch 14 | 36 of 52

Ch 14 | 37 of 52 Chemistry at a Glance: Summary of Reactions Involving Alcohols

Ch 14 | 38 of 52 →Fig Phenol molecule Phenols

Ch 14 | 39 of 52 Phenols. –Phenols are named as seen in Chapter 13. –Use “phenol” as the parent name instead of benzene.

Ch 14 | 40 of 52 Phenols in Medicine Phenols are weak acids and are used as antiseptics

Ch 14 | 41 of 52 →Fig The similar shapes of water and dimethyl ether molecules. Ethers

Ch 14 | 42 of 52 ←Fig Alcohols and ethers with the same number of carbon atoms and the same degree of saturation are structural isomers. Ethers

Ch 14 | 43 of 52 CC 14.3 Marijuana

Ch 14 | 44 of 52 →Fig Thiols are responsible for the strong odor of "essence of skunk.“ What is the chemical composition of a thiol, and how does it relate to alcohols? Thiols contain sulfur, in particular a R–S-H group. PHEW ! Jeff Lepore/Photo Researchers

Ch 14 | 45 of 52

Ch 14 | 46 of 52 Alcohols, Phenols, and Ethers cont’d

Ch 14 | 47 of 52 Thiols Many thiols have disagreeable odors Used to detect gas leak Found in onions, oysters, garlic and oysters Onions CH 3 CH 2 CH 2 -SH 1-propanethiol Garlic CH 2 = CHCH 2 -SH 2-propene-1-thiol Skunk spray CH 3 trans-2-butene-1-thiol CH = CH CH 2 SH

Ch 14 | 48 of 52 ←Fig A comparison involving dimethyl ether and demethyl sulfide. Alcohols, Phenols, and Ethers cont’d

Ch 14 | 49 of 52 Properties of Ethers Non-polar Low boiling points Anesthetic (diethylether) Flammable React slowly with oxygen to form unstable hydroperoxides and perioxides However, generally unreactive

Ch 14 | 50 of 52 Ethers Contain an oxygen atom between ______ carbon atoms Simple ethers are named by listing the alkyl names in alphabetical order followed by “ether” –CH 3 -O-CH 3 –CH 3 -O-CH 2 CH 3 –CH 3 -CH 2 -O-CH 2 CH 3

Ch 14 | 51 of 52 Ethers (naming). –Simple ethers that contain no other functional groups: name the two organic groups and add the word “ether.” –Otherwise, use “alkoxy” as the substituent name.

Ch 14 | 52 of 52 Ethers as Anesthetics Anesthetics inhibit pain signals to the brain CH 3 CH 2 -O-CH 2 CH 3 used for over a century (Morton, 1846) Causes nausea and is highly flammable 1960s developed nonflammable anesthetics Cl F F Cl F HH-C-C-O-C-H F F F H F H Ethane(enflurane) Penthrane