Preparations of Alcohols & Phenols

1. Hydration of Alkenes - addition of water - uses H2SO4 and heat Ex.; Hydrate propene.

2. Hydrogenation of Aldehydes & Ketones – All carbon-carbon double bonds in the molecule will be hydrogenated at the same time Uses hydrogen, Pt, heat and pressure Ex. A. aldehydes – form primary alcohols Hydrogenate ethanal (acetaldehyde).

Ex. B. ketones – form secondary alcohols Hydrogenate 2-butanone. Hydrogenate 4-penten-2-one.

3. Reduction of Aldehydes & Ketones – Reagent is either lithium aluminum hydride (LiAlH4) or sodium borohydride (NaBH4) Will form unsaturated alcohols because metal hydrides do not react with carbon-carbon double bonds Ex. A aldehydes - form primary alcohols Reduce ethanal (acetaldehyde).

Ex. B. ketones - form secondary alcohols Reduce propanone. Reduce 4-penten-2-one

4. Reduction of Aldehydes & Ketones with Grignard Reagents Ex. A. aldehydes - form secondary alcohols Ex. B. ketones – form tertiary alcohols

5. Hydroboration of Alkenes Water seems to add “anti-Markovnikoff” because in the catalyst borane (BH3), the hydrogen is negative, not positive This is used as a complement to hydration in order to add the –OH to the carbon with the most hydrogens Ex. Hydroborate propene.

6. Hydrolysis of Alkyl Halides This is the reverse of the reaction that converts alcohols to alkyl halides Reacts with water or hydroxide ions Ex. Hydrolize bromoethane.

Catechol - an antioxidant in paint Resorcinol – used in adhesives, dyes, antiseptics Hydroquinone – a photographic developer

Thiols: Sulfur Analogs of Alcohols & Phenols Sulfur - has similar properties to oxygen and forms similar compounds Sulfur analogs of alcohols are called thiols -SH group – called the sulfhydral group Usually have very disagreeable odors Ex. 1-butanthiol (responsible for the odor of skunks

Polyhydric Alcohols & Phenols Polyhydric - compounds with several hydroxy groups attached to different carbon atoms Ex. Ethylene glycol IUPAC name: Ex. Glycerine