Alcohols

• Alcohols have an OH functional group, and the general formula CnH2n+1OH. They can be produced via fermentation or hydration.
• Alcohols can be primary, secondary or tertiary depending on the position of the hydroxyl group.
• Alkenes undergo a hydration reaction (adding H2O) to form alcohols. This occurs in the presence of a phosphoric (V) acid catalyst, and the system is at 300 degrees C and high pressure. This reactions occurs in aqueous conditions.
• Hydration of alkenes is an ideal method for making alcohols, since it has a high percentage yield (ethanol is the only product).
• The formation of alcohols from alkenes vis hydration reactions is known as an elimination reaction.
• When burned in air, alcohols react with oxygen to form carbon dioxide and water. Therefore, alcohols are useful as fuels because lots of energy is released.
• Alcohols react with halogenating agents via nucleophilic substitution. These produce halogenoalkanes, including chloroalkanes, bromoalkanes and iodoalkanes.
• Potassium chloride (PCl5) reacts with alcohols to produce chloroalkanes. This can be used to test for alcohols, since steamy white fumes are produced that turn damp blue litmus paper pink.
• 50% concentrated sulfuric acid and potassium bromide react together to form hydrogen bromide. Alcohols can then react with hydrogen bromide to form bromoalkanes.
• Red phosphorous and iodine can be used to produce iodoalkanes. Firstly, the red phosphorous and iodine react together to form phosphorous (III) iodide. This then reacts with alcohol to form iodoalkane.