Biological Chemistry FIRST YEAR ORGANIC CHEMISTRY Lecture Eight Carboxylic acids + Esters Convenor : Dr. Fawaz Aldabbagh

Carboxylic Acids We can distinguish a water-insoluble carboxylic acid and phenol from an alcohol

Highly Polar Low molecular weight acids show Appreciable Solubility in Water High Bpt – Extensive H-bonds to themselves and water Carboxylic Acids NAMES Methanoic acid Ethanoic acid Propanoic acid 4-Bromo-2-ethylpentanoic acid Ethanedioic acid (oxalic acid) rhubarb Red ants Terephthalic acid Phthalic acid

Esterification Alcohol part appears first in the name

Ester molecules cannot H-bond to each other, because they do not have an –OH Consequently, B.pt is much lower than that of alcohols and acids of comparable mass H-bonding to water is possible -low mw esters are soluble in water Solubility rapidly decreases with carbon chain length. Equilibrium reaction -Reversible with acid And water

Salicyclic acid is the active ingredient of aspirin. - It has analgesic, antipyretic and anti-inflammatory properties Buffered aspirin contains bases. Esters are also largely responsible for the flavour and smell of fruits and flowers Esters are hydrolysed in acid and base catalysed reactions

Ester Saponification - is the base-catalysed hydrolysis of an ester

Write a mechanism for the acid and base hydrolysis of a lactone

Redox Reactions Addition of Oxygen or Removal of Hydrogen is OXIDATION Removal of Oxygen or Addition of Hydrogen is REDUCTION

Examples of Reduction Reactions Examples of Oxidation Reactions