Esters
What are Esters? Can be naturally occurring in plants and contribute to the _______________ of fruits and flowers. Uses: artificial/natural flavouring in foods, perfumes, cosmetics, oils, etc. Esters can be made in the lab (__________) pleasing odours synthetic
Has a carbonyl (C=O) group attached to an oxygen atom (bonded to an alkyl group) and as well another alkyl group. General Formula: -COO-
Esterification How an ester is formed Done by reacting a ____________ with an _______ in presence of a catalyst (an acid) over heat Small amounts of water is formed as well carboxylic acid alcohol
Naming Esters Form: (alcohol) (acid-anoate) Example: methylpropanoate Drop –anol, replace with “yl” Change from “-oic acid” to “-oate” methylpropanoate carboxylic acid alcohol
Naming Esters Form: (alcohol) (acid-anoate) Example: propylethanoate Drop –anol, replace with “yl” Take parent name, add “anoate” propylethanoate carboxylic acid alcohol
Naming Esters Draw the esterification reaction between methanol and ethanoic acid
Naming Esters Example: React methanol with butanoic acid. methylbutanoate
Drawing Esters propylbutanoate
Drawing Esters butylheptanoate
Example Draw the esterification reaction between propanol and hexanoic acid propylhexanoate
Properties of Esters Polar molecules (due to presence of O) Lower melting points and boiling points than carboxylic acids and alcohols (they both have OH groups = stronger) Smaller esters are gases (the ones you smell) and large esters are solids