Naming Alcohols

• In an alcohol, a hydroxyl group (-OH) replaces a hydrogen atom in an alkane.
• The ending (-e) in the alkane name is changed to (-ol) to indicate an alcohol.
• Example alcohol: CH2=CH-CH2-CH2-OH, named 3-Buten-1-ol

Naming Alcohols

• For the IUPAC name, the -e in the alkane name is replaced with -ol.
• Common names for simple alcohols involve naming the alkyl group followed by "alcohol."
• CH4 is methane; CH3-OH is methanol (methyl alcohol).
• CH3-CH3 is ethane; CH3-CH2-OH is ethanol (ethyl alcohol).
• CH3-CH2-CH2-OH is 1-propanol
• CH3-CH(OH)-CH3 is 2-propanol (isopropanol).
• CH3-CH(CH3)-CH2-CH2-CH(OH)-CH3 is 5-methyl-2-hexanol.
• CH3-C(CH3)(OH)-CH3 is 2-methyl-2-propanol (Tert-butanol).

Physical Properties of Alcohols

• Alcohols are polar molecules because of O-H and C-O bonds: C-O polarity is 1.0 (3.5 - 2.5), and O-H polarity is 1.4 (3.5 - 2.1).
• There is hydrogen bonding between alcohol molecules.
• Alcohols have higher boiling points than alkanes, alkenes, and alkynes.
• Alcohols are more soluble in water, but solubility decreases as molecular weight increases.
• The carbon side of alcohols is nonpolar, while the -OH side is polar.

Methanol (CH3OH)

• It is the simplest alcohol, found in many solvents and paint removers.
• It is sometimes called wood alcohol because it is produced when wood is heated to high temperatures in the absence of air.
• Methanol is prepared commercially by reacting carbon monoxide with hydrogen gas at 200-300C and 200Atm, using a ZnO/Cr2O3 catalyst: CO + 2H2 → CH3-OH.
• Methanol is a poisonous liquid.
• If ingested, methanol is oxidized to formaldehyde, causing headaches, blindness, and death by rapidly reacting with and denaturing cell proteins.

Ethanol (CH3CH2OH)

• In hospitals, "alcohol" often refers to ethanol.
• Ethanol can denature proteins by forming hydrogen bonds.
• 70% ethanol is widely used as an antiseptic.
• Ethanol is in many household products like pharmaceuticals, tinctures of iodine, colognes, perfumes, mouth washes, and hair sprays.
• 'Gasohol' is a fuel mixture of ethanol and gasoline.
• Ethanol is used as a beverage, made by fermentation of starch or sugars.
• Complex sugars undergo hydrolysis to form C6H12O6, which then undergoes a reaction with Zymase to produce 2CH3CH2OH + 2CO2.
• Extensive ethanol ingestion can lead to liver deterioration (cirrhosis), memory loss, and strong physiological addiction.

2-Propanol (isopropanol) CH3-CHOH-CH3

• Used as an astringent antiseptic because it evaporates rapidly, cools the skin, and reduces blood vessel size near the surface.
• Used to clean skin before injections or blood samples.
• Used to sterilize equipment because it destroys bacteria by coagulating protein.

Ethelene glycol (ethanediol)

• Is a dihydroxy alcohol with the formula HO-CH2-CH2-OH.
• Used as antifreeze in heating and cooling systems, a solvent for paints, inks, and plastics, and in the preparation of fibers like Dacron.
• Ethylene glycol is extremely toxic if ingested.
• In the body, it is oxidized to oxalic acid, which forms insoluble salts in the kidneys, causing renal damage, convulsions, and death.
• Ethylene glycol solutions must be stored carefully due to their sweet taste, which is attractive to pets and children.
• HO-CH2-CH2-OH oxidizes in the body to form HOOC-COOH.

Fomepizole

• Also known as 4-methylpyrazole.
• It is used to treat methanol and ethylene glycol poisoning, alone or with hemodialysis, administered by injection into a vein.
• Common side effects include headache, nausea, sleepiness, and unsteadiness.
• Fomepizole blocks the enzyme that converts methanol and formaldehyde to their toxic breakdown products.

Glycerol

• Also known as Glycerin or 1,2,3 propanetriol
• Tri hydroxyl alcohol
• A constituent of fats, produced from hydrolysis of all fats.
• TG + 3H2O undergoes a reaction via Lipase to produce Glycerol + fatty acids
• It is used in the production of nitroglycerin (Glyceryl tri nitrate).
• Glycerol + 3HNO3 undergoes a reaction via H2SO4 to produce Nitroglycerin + 3H2O

Nitroglycerin

• Used to relieve angina pectoris (chest pain).
• It relaxes cardiac muscle and smooth the muscle in smaller vessels.
• Provided in small tablets of 0.3-0.6 mg under the tongue or applied to the skin as a cream.

Reactions of Alcohols

• Dehydration: CH3-CH2-OH undergoes a reversible reaction via H2SO4/180 to produce CH2=CH2 + H2O
• Ester formation: R-OH + R-COOH undergoes a reversible reaction via ACID to produce RCOOR + H2O
• Oxidation: Primary alcohols are oxidized to aldehydes. RCH2-OH oxidizes to form RCHO, which then oxidizes to form RCOOH.
• Secondary alcohols are oxidized to ketones: RCH(OH)R oxidizes to form RCOR.
• Oxidation of alcohols in living systems is an important reaction catalyzed by enzymes called dehydrogenases.
• The oxidation of malate to oxaloacetate is an example. Malate + NAD via Malate dehydrogenase becomes Oxaloacetate + NADH + H