ALCOHOLS

=Alcohols= Alcohols are identified as having an -OH (hydroxyl) functional group attached to the parent chain. [image:http://upload.wikimedia.org/wikipedia/commons/thumb/e/e8/Ethanol-structure.svg/220px-Ethanol-structure.svg.png] ==Naming Alcohols== Alcohols all have the suffix "-ol" at the end of their name. The rules for naming alcohols is very similar to the rules for naming an alkene. You must have the functional group as part of the parent chain You must specify where the hydroxyl group is. E.g. Butan-1-ol is different to butan-2-ol. [image:http://upload.wikimedia.org/wikipedia/commons/thumb/4/4b/Butanol_flat_structure.png/640px-Butanol_flat_structure.png] [image:http://upload.wikimedia.org/wikipedia/commons/c/c4/2-butanol.png] Then you may have side-chains that are named first. E.g. 2-methylpropan-2-ol. ==Properties== Alcohols have similar properties to haloalkanes. However they are capable of hydrogen bonding between other alcohol molecules! This (relatively) strong intermolecular force increases alcohol melting and boiling points. Because of the -OH atoms, alcohols are polar. However as the carbon chain (non-polar) increases in length, the overall polarity will become less polar. Try mixing ethanol in water and pentanol in water. ==Reactions== Alcohols can be made from haloalkanes and from oxidation of alkenes. Alcohols can undergo substitution, elimination, and oxidation reactions. For substitution reactions PCl~3~ or SOCl~2~ are sources of Cl, which replaces the -OH group. Elimination of alcohols to form alkenes is also a 'dehydration' reaction (concentrated H~2~SO~4~ reagent). ONLY primary alcohols oxidise to form carboxylic acids. Oxidants such as potassium permanganate (KMnO~4~) and potassium dichromate (K~2~Cr~2~O~7~) are reagents for this reaction. Potassium permanganate is purple and turns colourless when it reacts. Potassium dichromate is orange and turns green.