Esterification and Fermentation

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How Carboxylic Acids and Alcohols React to Produce Esters:
Esters and Ester Production:

Esters are abundant and ever present, and are the chemical basis of almost all fatty acids and oils. Small esters are responsible for the aroma of fruits, perfumes and, by extension, wines and other alcohols. Esters are formed when a carboxylic acid and an alcohol chemically combine, losing a molecule of water in the process. Carboxylic acids are organic molecular compounds that form a homologous series and have the generic formula CnH2nO2. The functional group; or group of atoms that provide a carbon compound with its distinguishing molecular properties, of carboxylic acids is the –COOH carboxyl group. In the process of forming an ester, the hydrogen in the carboxyl group is replaced by a hydrocarbon group. This hydrocarbon group is provided by an alcohol, most commonly ethanol, or grain alcohol. An alcohol is a chemical compound whose molecular structure is comprised of a hydroxyl group –OH chemically bonded to a carbon. One of the simplest and most common esters is ethyl ethanoate, or ethyl acetate, a combination of ethanoic acid and ethanol. The ethyl ethanoate chemical reaction is C2H4O2 + CH3CH2OH C4H8O2 + H2O. As seen in this reaction, an acid and an alcohol are combining to form an ester, with a water molecule as a bi-product. The water molecule is lost from the reactants as the carboxylic acid in the reaction loses a –OH hydroxyl group and the alcohol loses a single hydrogen to allow bonding to occur between the carbon and oxygen atoms. Esters are polar molecules, or molecules that are separated in polarity by differences in electronegativity and each individual atom’s pull on electrons. Basically, one part of the molecule is slightly positive and the other slightly negative. Whilst esters have dipole-dipole interactions and dispersion forces at work, they are not hydrogen-bond donors, as they do not self-associate, and hence cannot hydrogen-bond with each...
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