tartaric acid(redirected from E334)
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tartaric acid,HO2CCHOHCHOHCO2H, white crystalline dicarboxylic acid. It occurs as three distinct isomersisomer
, in chemistry, one of two or more compounds having the same molecular formula but different structures (arrangements of atoms in the molecule). Isomerism is the occurrence of such compounds. Isomerism was first recognized by J. J. Berzelius in 1827.
..... Click the link for more information. , the dextro-, levo-, and meso- forms. The dextro- and levo- forms are optically active; the meso- form is optically inactive, as is racemic acid, a mixture of equal parts of the dextro- and levo- forms. Tartaric acid is found in many plants, e.g., grapes; this natural acid is chiefly the dextrorotatory d-tartaric acid, called also d-2,3-dihydroxysuccinic acid or l-2,3-dihydroxybutanedioic acid. This form can be partially converted to the others by heating it with an aqueous alkali, e.g., potassium hydroxide. Tartaric acids can be synthesized from maleic acids or fumaric acidsfumaric acid
or trans-butenedioic acid,
HO2CCH=CHCO2H, unsaturated dicarboxylic acid that melts at 287°C;. Maleic acid, or cis-butenedioic acid, is a geometric isomer of fumaric acid; it melts at about 140°C;.
..... Click the link for more information. by reaction with aqueous potassium permanganate. The various isomeric forms differ in such physical properties as boiling point. Tartaric acid is used chiefly in the form of its salts, e.g., cream of tartarcream of tartar,
white crystalline powder. Chemically it is potassium hydrogen tartrate, KC4H5O6, the acidic potassium salt of tartaric acid. It is used as the leavening agent in baking powders.
..... Click the link for more information. and Rochelle saltRochelle salt,
colorless to blue-white orthorhombic crystalline salt with a saline, cooling taste. It is also called Seignette salt after Pierre Seignette, an apothecary of La Rochelle, France, who was the first to make it (c.1675).
..... Click the link for more information. .
tartaric acid[tär′tar·ik ′as·əd]
HOOC(CHOH)2COOH Water- and alcohol-soluble colorless crystals with an acid taste, melts at 170°C; used as a chemical intermediate and a sequestrant and in tanning, effervescent beverages, baking power, ceramics, photography, textile processing, mirror silvering, and metal coloring.
a colourless or white odourless crystalline water-soluble dicarboxylic acid existing in four stereoisomeric forms, the commonest being the dextrorotatory (d-) compound which is found in many fruits: used as a food additive (E334) in soft drinks, confectionery, and baking powders and in tanning and photography. Formula: HOOCCH(OH)CH(OH)COOH