Tartaric acid

• BPTartaric Acid
• JPTartaric Acid
• Ph. Eur.Tartaric Acid
• USP–NFTartaric Acid

L-(+)-tartaric acid; acidum tartaricum; d-tartaric acid; 2,3-dihydroxybutanedioic acid; dihydroxysuccinic acid; E334

(2R,3R)-2,3-Dihydroxybutanedioic acid · [87-69-4]

UNII 4J4Z8788N8 · PubChem CID 444305

C4H6O6 · 150.09

pH adjuster, buffering agent

Typical concentrations: — · Dosage forms: Solid

Used as the acid component of effervescent tablets, granules and powders, where it reacts with sodium bicarbonate or carbonate to release carbon dioxide. It is also used as an acidulant and flavour enhancer in oral liquids, as a buffering and sequestering agent, and to form salts of basic drugs. It is widely used in foods and beverages.

Colourless, transparent crystals or a white, fine to granular crystalline powder. It is odourless and has a strongly acid taste. The pharmacopoeial material is the naturally occurring L-(+) isomer.

Melting point

168–170 °C

Dissociation constants

pKa1 ≈ 3.0; pKa2 ≈ 4.3 (25 °C)

Density

≈ 1.76 g/cm³

Specific rotation

+12.0° to +12.8° (20% w/v aqueous solution)

Solubility

very soluble in water; freely soluble in ethanol (95%)

Stable in the solid state. It is slightly hygroscopic, which matters in effervescent products. Store in a well-closed container in a cool, dry place.

Reacts with carbonates and bicarbonates (the basis of its effervescent use) and with bases. Incompatible with silver salts and strong oxidising agents; it forms complexes with many metal ions.

Obtained from potassium hydrogen tartrate (argol or wine lees), a by-product of wine making, which is converted to calcium tartrate and then treated with sulfuric acid; the liberated acid is purified by crystallisation.

Widely used in foods and oral products and generally regarded as non-toxic at normal intakes, although strong solutions are irritant. Large oral doses can cause gastrointestinal upset. JECFA and EFSA have set acceptable daily intakes for L-(+)-tartaric acid and its salts.

Observe normal precautions for the quantity handled. The powder and solutions irritate the eyes and mucous membranes; eye protection and gloves are recommended.

GRAS listed. Accepted as a food additive in Europe (E334). Included in the FDA Inactive Ingredient Database (oral, intramuscular and intravenous preparations) and in parenteral and non-parenteral medicines licensed in Europe.

Citric acid monohydrate; fumaric acid; malic acid; potassium hydrogen tartrate; sodium tartrate.

Tartaric acid is less hygroscopic than citric acid, which makes it attractive in effervescent formulations, but low humidity during manufacture and moisture-proof packaging are still essential. Complete neutralisation needs 2 mol of sodium bicarbonate per mole of tartaric acid, that is about 1.1 parts by weight per part of acid.