Organic Compounds - Alcohols -

Common Alcohol Compounds Ethanol Adult beverages and Biofuel Menthol TigerBalm, Vicks Vaporub Listerine (menthol and ethanol) Ethylene glycol Car antifreeze Cholesterol

Alcohol Properties Members of the alcohol family contain a hydroxyl (-OH) group making them polar molecules The –OH is capable of hydrogen bonding (the strongest of intermolecular forces) Presence of –OH causes an increase in attractive forces between molecules in comparison to hydrocarbon chains of equal size e.g Ethanol b.p. 78 ºC Ethane b.p. -89 ºC

Short chained alcohols dissolve completely in water Longer chained alcohols dissolve well in non- polar solutions because of their long hydrocarbon tails (phospholipids) Three types of alcohols alcohols are sub-classified according to the type of carbon to which the –OH group is attached

Primary (1°) Alcohol An alcohol in which the hydroxyl functional group is attached to a carbon which is itself attached to only one other carbon atom

Secondary (2°) Alcohol An alcohol in which the hydroxyl functional group is attached to a carbon which is itself attached to only two other carbon atom

Tertiary (3°) Alcohol An alcohol in which the hydroxyl functional group is attached to a carbon which is itself attached to only three other carbon atom

IUPAC Naming of Alcohols Locate the longest chain that contains an – OH group attached to one of the carbon atoms. Name the parent alkane.   NOTE: Cyclic alcohols. An –OH (hydroxyl) group can be attached to a cyclic hydrocarbon and may be considered attached to the parent chain. Replace the –e at the end of the name of the parent alkane with –ol.

Add a position number before the root of the name to indicate the location of the –OH group. (Remember to number the main chain of the hydrocarbon so that the hydroxyl group has the lowest possible position number.) NOTE: If there is more than one –OH group, leave the –e in the name of the parent alkane, and put the appropriate preix (di-, tri-, or tetra-) before the suffix –ol)

Name the number of any other branches on the main chain Name the number of any other branches on the main chain. Add the name of these branches to the prefix. Put the name together: prefix + root + suffix

Naming Alcohols Practice 1,3-butadiol 2-methyl-2-propanol 1,2,3-propatriol 2-propanol

Naming Alcohols Practice phenol 2,3-dimethylphenol

Four Common Reactions Involving Alcohols Addition (hydration) Oxidation (combustion) Substitution Elimination (dehydration)

1) Addition (hydration) Preparing alcohols from alkenes Hydration: addition reaction with water An acid is needed as a catalyst (H2SO4(aq)) Must follow Markovnikov’s Rule General Equation: Specific Example:

2) Oxidation (combustion) Alcohols undergo complete combustion to produce carbon dioxide and water Specific Example:

CH3 – CH2 – OH + HCl  CH3 – CH2 – Cl + H2O 3) Substitution Preparing alkyl halides from alcohols Substitute a halogen for a hydroxyl group Aqueous acids (HCl, HBr, HF and HI) are needed Specific Example: CH3 – CH2 – OH + HCl  CH3 – CH2 – Cl + H2O

4) Elimination (dehydration) Preparing alkenes from alcohols Results in the removal of water Requires a catalyst (concentrated H2SO4) NOTE: The opposite reaction would be a hydration General Equation: Specific Example:

Learning Checkpoint Assigned Questions: p.41 #1,2,3 (naming) p.42 #4,5 (properties) p.44 #7,8,9 Worksheet - Reactions and Functional Groups (Alkenes and Alcohols) Read “Driving your car on ethanol article” and answer questions from the article