Esters occur naturally but they can be made in the laboratory by reacting an alcohol with an organic acid. A little sulfuric acid is needed as a catalyst.The general word equation for the reaction is:alcohol (OH) + organic acid (COOH) → ester + waterFor example:methanol + butanoic acid → methyl butanoate + watermethyl= 1Cbutane= 4CThe alcohol (methanol) loose an H, and the carboxylic acid loose an OH which form the by product of this reaction = water The ester formed= methyl butanoate: the alcohol takes the first part of the name and the carboxylic acid the later. The newly formed ester bond = C-O-C=O