Tartaric Acid

Tartaric acid is an organic acid. Tartaric acid is also known as 2,3-dihydroxysuccinic acid or Racemic acid. It is in use to generate carbon dioxide. Tartaric acid is a diprotic aldaric acid. Tartaric acid is an alpha-hydroxy-carboxylic acid and is a dihydroxyl derivative of succinic acid. It is widely in use in the field of pharmaceuticals. A High dose of tartaric acid can affect our body to a great extent.

Tartaric acid is a white and crystalline that occurs naturally in many fruits and vegetables and most notably in grapes. It is also present in bananas, tamarinds, and citrus. The salt i.e., potassium bitartrate also called cream of tartar, develops naturally in the process of fermentation. It is commonly mixed with sodium bicarbonate and is sold as a baking powder that is in use as a leavening agent in food preparation. The tartaric acid is added to foods being an antioxidant i.e., E334 and to impart its distinctive sour taste.

Properties of Tartaric Acid

• The molecular weight or molar mass of tartaric acid is 150.087 gram per mole.
• The density of tartaric acid is 1.79 g/mL.
• Also, the boiling point of tartaric acid is \(275^oC\).
• The melting of tartaric acid is \(171^oC\) to \(174^oC\).

Derivatives of Tartaric Acid

Derivatives of tartaric acid consist of its salts, cream of tartar i.e., potassium bitartrate, Rochelle salt i.e., potassium sodium tartrate, a mild laxative, and tartar emetic i.e., antimony potassium tartrate. Diisopropyl tartrate is in use as a co-catalyst in asymmetric synthesis.

Tartaric acid is a muscle toxin. It works by prohibiting the production of malic acid and in high doses, it causes paralysis and death. The median lethal dose is about 7.5 grams/kg for a human, 5.3 grams/kg for rabbits, and 4.4 grams/kg for mice. As a food additive, it is used as an antioxidant with E number E334. Tartrates are additives serving as antioxidants or emulsifiers.

Production of Tartaric Acid

• The L-(+)-tartaric acid isomer of tartaric acid is obtained from lees. It is a solid byproduct of fermentations. The former by-products consist of potassium bitartrate. This potassium salt is converted to calcium tartrate upon treatment with milk of lime:

\(KO_2CCH(OH)CH(OH)CO_2H + Ca(OH)_2 \rightarrow Ca(O_2CCH(OH)CH(OH)CO_2) + KOH + H_2O\)

Higher yields of calcium tartrate are produced with the addition of calcium chloride. Calcium tartrate converts into tartaric acid by treating the salt with aqueous sulfuric acid

\(Ca(O_2CCH(OH)CH(OH)CO_2) + H_2SO_4 \rightarrow HO_2CCH(OH)CH(OH)CO_2H + CaSO_4\)

• Racemic tartaric acid is prepared in a multiple-step reaction from maleic acid. Firstly, the maleic acid is epoxidized by hydrogen peroxide. It is done using potassium tungstate as a catalyst.

\(HO_2CC_2H_2CO_2H + H_2O_2 \rightarrow OC_2H_2(CO_2H)_2\)

Later, the epoxide is hydrolyzed.

\(OC_2H_2(CO_2H)_2 + H_2O \rightarrow (HOCH)_2(CO_2H)_2\)

Uses of Tartaric Acid

• To improve the taste of oral medications.
• To chelate metal ions such as magnesium and calcium.
• In recipes as a leavening agent along with baking soda.
• As an antioxidant.
• As one of the important acids in wine.
• In foods to give a sour taste.
• To induce vomiting.
• To make silver mirrors.
• In Tartaric acids ester form, Tartaric acid is in use in the dyeing of textiles.
• In the tanning of leather.
• It is also in use in candies.
• In Tartaric acids cream form, Tartaric acid is in use as a stabilizer in food.

FAQs on Tartaric Acid

Question 1: Is tartaric acid a strong acid?

Answer: Tartaric acid is the acid most prescribed for modifications. It is a stronger acid than malic and citric acid, and but less susceptible to microorganism breakdown during alcoholic and malolactic fermentations. Tartaric acid is a potassium salt that easily tends to precipitate.

Question 2: What is the difference between tartaric acid and citric acid?

Answer: The distinction between tartaric acid and citric acid is that tartaric acid occurs in grapes while citric acid occurs in citrus fruits. Tartaric acid and citric acid are two different types of plant acids that are in use as natural additives to food.