D-(-)-Tartaric Acid

Chemical properties

D-Tartaric acid is a white crystalline dicarboxylic acid found in many plants, particularly tamarinds and grapes. It is an acidulant that occurs naturally in grapes. It is hygroscopic and rapidly soluble, with a solubility of 150 g in 100 ml of distilled water at 25°c. It has a slightly tarter taste than citric acid, with a tartness equivalent of 0.8–0.9. It augments the flavor of fruits in which it is a natural constituent. It is used in grapeand limeflavored beverages and grape-flavored jellies. It is used as an acidulant in baking powder and as a synergist with antioxidants to prevent rancidity.

The Uses of D-(-)-Tartaric Acid

D-(-)-Tartaric acid is used as a resolving agent in organic synthesis. It is used as a precursor for the preparation of its ester derivatives like D-tartaric acid diethyl ester, D-tartaric acid dimethyl ester and D-tartaric acid diiso-propyl ester. It finds application in the synthesis of chiral aziridine derivative, a common intermediate for the preparation of hydroxyethylamine class HIV protease inhibitors viz. as saquinavir, amprenavir and nelfinavir. It is widely used in the food industry as a beer foaming agent, for food acidity regulations and as a flavoring agent.

Definition

ChEBI: D-tartaric acid is the D-enantiomer of tartaric acid. It has a role as an Escherichia coli metabolite. It is a conjugate acid of a D-tartrate(1-). It is an enantiomer of a L-tartaric acid.

Biotechnological Production

Tartaric acid is generally produced from crude tartar and lees, which are byproducts of wine production. However, there are a few reports of fermentative production of tartaric acid by Gluconobacter suboxydans growing on Glucose or sorbitol. Vanadate plays a central role in this process. The microorganism forms 5-keto-D-gluconic acid, which is oxidized to tartaric acid. The vanadium catalyzes this reaction. Product concentrations up to 2.96 g.L-1 have been observed after 3 days of fermentation.

General Description

D-(-)-Tartaric acid is a polycrystalline solid, widely used as food additive. It has been reported to exhibit piezoelectric effect.

Purification Methods

Crystallise the acid from distilled H2O or *benzene/diethyl ether containing 5% of pet ether (b 60-80o) (1:1). Soxhlet extraction with diethyl ether has been used to remove an impurity absorbing at 265nm. It has also been crystallised from absolute EtOH/hexane and dried in a vacuum for 18hours [Kornblum & Wade J Org Chem 52 5301 1987]. [Beilstein 3 IV 1229.]