CH 3: Alcohols, Phenols, and Ethers

Structure Alcohol Functional Group Alcohol functional group: -OH – Also called hydroxyl group – Some consider as alkyl derivative of water

Naming Alcohols 1.Name the longest C chain that contains the –OH group Replace the “ane” ending with “ol” 2.Number the C in the chain from the end closest to the –OH group When numbering the –OH has priority over the numbering of multiple bonds, alkyl substituents, and halogen substituents 3.Name and number any other substituents.

Common Names to Know IUPAC Name……..Common Name a)Methanol b)Ethanol c)1-propanol d)2-propanol e)1-butanol d)sec-butyl alcohol e)tert-butyl alcohol

Isomerism Constitutional Isomers – Positional isomers 1-hexanol and 3-hexanol – Skeletal isomers 2-butanol and tert-butyl alcohol

Classification of Alcohols

Physical Properties Alcohols 1.Polarity of alcohols – Both polar and nonpolar character – Physical properties depend upon which portion of the molecule dominates – Consider length of C chain (nonpolar) and number of –OH groups (polar)

Physical Properties Alcohols 2.Boiling Point – page 88 – Higher than that of alkane of similar C # – Increases as length of C chain increases – Increases as # -OH groups increases 3.State of matter – Even small alcohols are liquids at RT

Physical Properties Alcohols 4.Water Solubility – 1-3 C alcohols are miscible in water – Solubility drops off for straight chain alcohols with 4-5 C – Water insoluble for 6c and up with single -OH Diols of up to 7 C are water soluble – Diols are more soluble than single –OH alcohols of similar size/structure

Methyl alcohol - Methanol Wood alcohol – used to made by the heating of wood to a high temperature in the absence of air Used as fuel for race cars Produces TOXIC metabolites in the body – Methanol  formaldehyde  formic acid results in blindness, death from acidosis with ingestion of small amounts 1 ounce, ~30 ml can result in blindness ~100 ml is generally fatal – Reaction is catalyzed by the liver enzyme alcohol dehydrogenase – enzyme has a much higher affinity for ethanol therefore initial treatment can be giving individual ethanol

Ethyl alcohol – Ethanol Alcohol of alcoholic beverages – Also called grain alcohol – Often made by the fermentation of grains Also potentially toxic – ~200 ml (pure) ethanol can be fatal – Comment on denatured alcohol at some point Metabolized by the liver enzyme alcohol dehydrogenase – Ethanol  acetaldehyde  acetic acid – Metabolites are less toxic than those of methanol – Acetaldehyde is responsible for most of the hangover symptoms dehydration also contributes to symptoms

Ethanol, continued – chronic alcohol use can cause liver damage (cirrhosis) and more…. memory loss increased risk of breast cancer in women? (with ~2+ drinks/day) addiction FAS in infants born to moms who drank during their pregnancies – Table on page 86 shows alcohol content of common alcoholic beverages….. VERY INTERESTING!

FAS Brains of 6 week old infants FASNo FAS

FAS Physical Characteristics – Broad, short, flat nose – No dimple above lip – Narrow eyes – Flat face

Ethylene Glycol Toxicity following ingestion generally progress in three stages: 1.effects on the central nervous system - intoxication, lethargy, seizures, and coma 2.Metabolic disturbances - acidosis, hyperkalaemia, hypocalcaemia 3.Effects on the heart and lungs - tachycardia, hypertension, degenerative changes - and ending with renal toxicity - deposition of calcium oxalate, haematuria, necrosis, renal failure.

Ethylene Glycol & Propylene Glycol Both: – Used in anti-freeze – Colorless and odorless It’s the additives in antifreeze that give it odor and color ETHYLENE GLYCOL – VERY TOXIC ETHYLENE GLYCOL – Sweet taste – Metabolized to form oxalic acid – Calcium oxalate crystals in kidney

Propylene Glycol Nontoxic Metabolized to pyruvic acid

Reactivity Alcohols 1.Combustion 2.Halogenation – Substitution reaction – Reagent: PX 3 – heat required – Single halogenated product + phosphoric acid

3. Oxidation of Alcohols Common oxidizing agents and evidence of a reaction: – KMnO 4 – K 2 Cr 2 O 7 Primary alcohol   Secondary alcohol  Tertiary alcohol 

4. Dehydration Reaction Elimination reaction – Alcohol  alkene + water – Reagent: concentrated sulfuric acid – Conditions: high temperature, C – Zaitsev’s rule used to predict major product formed At lower temps, C, primary alcohols react with each other to form an ether + water Sulfuric acid catalyst still needed

Still to come…. Phenol Phenols Ethers