As the alkyl chain gets longer, the molecule becomes more nonpolar and less soluble in water. Dicarboxylic and Tricarboxylic Acids Compounds that contain two CO 2 H functional groups are known as dicarboxylic acids . Tartaric acid, for example, is a by-product of the fermentation of wine, and succinic, fumaric, malic, and oxaloacetic acid are intermediates in the metabolic pathway used to oxidize sugars to CO 2 and H 2 O. Common Dicarboxylic Acids oxalic acid malonic acid malic acid succinic acid maleic acid fumaric acid tartaric acid oxaloacetic acid Several tricarboxylic acids also play an important role in the metabolism of sugar. The most important example of this class of compounds is the citric acid that gives so many fruit juices their characteristic acidity. Acetic acid, for example, reacts with ethanol to form ethyl acetate and water.
Chemists tend to synthesize esters in a two-step process.
They then react the acyl chloride with an alcohol in the presence of base to form the ester. The base absorbs the HCl given off in this reaction, thereby driving it to completion. As might be expected, esters are named as if they were derivatives of a carboxylic acid and an alcohol. The term ester is commonly used to describe the product of the reaction of any strong acid with an alcohol. Sulfuric acid, for example, reacts with methanol to form a diester known as dimethyl sulfate.