Esterification of Acid Chlorides

Esters are chemical compounds that are commonly derived from a carboxylic acid and an alcohol. Many are used as fragrances as they give off sweet-smelling aromas such as fruits, caramel, and rum. Esters were synthesized through refluxing a carboxylic acid derivative and an alcohol in an imidazole-buffered environment. The presence of imidazole will maintain the pH by absorbing any acid produced. The carboxylic acid derivative was initially an acid anhydride but later switched to an acid chloride to yield purer esters. The products were purified through acid-base extraction and vapor distillation. The esters produced were analyzed by infrared (IR) spectroscopy, gas chromatography (GC), and nuclear magnetic resonance (NMR). An esterification procedure was developed to be completed in two hours for use in an organic chemistry lab. Students will choose an unknown combination of an acid chloride and an alcohol to produce an ester. After obtaining spectroscopic data to determine the structure of the ester, students will determine their unknowns