maleic acid

maleic acid
/meuh lee"ik/, Chem.
a colorless, crystalline, water-soluble solid, C4H4O4, isomeric with fumaric acid, having an astringent, repulsive taste and faint acidulous odor: used in the manufacture of synthetic resins, the dyeing and finishing of textiles, and as a preservative for fats and oils.
[1870-75; < F maléique, alter. of malique MALIC]

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also called  cis-butenedioic acid (HO2CCH=CHCO2H) 

      unsaturated organic dibasic acid, used in making polyesters for fibre-reinforced laminated moldings and paint vehicles, and in the manufacture of fumaric acid and many other chemical products. Maleic acid and its anhydride are prepared industrially by the catalytic oxidation of benzene.

      Maleic acid shows reactions typical of both olefins and carboxylic acids. Commercially important reactions of the acid groups include esterification with glycols to polyesters and dehydration to the anhydride. The double bond is involved in conversions to fumaric acid, to sulfosuccinic acid (used in wetting agents), and to Malathion (an insecticide).

      Maleic acid melts at 139–140° C (282–284° F); at higher temperatures it forms the anhydride, which, like the acid, is irritating to the skin and toxic.

      Maleic anhydride is interchangeable with the acid in most applications.

       fumaric acid, or trans-butenedioic acid, the geometrical isomer of maleic acid, occurs in fumitory (Fumaria officinalis), in various fungi, and in Iceland moss. Like maleic acid, it is used in polyesters, and since it is nontoxic, unlike maleic acid, it is used as an acidulant in foods. It is produced by isomerization of maleic acid or by fermentation of molasses. Its reactions are generally similar to those of maleic acid, although it cannot form an intramolecular anhydride. It is very much less soluble in water and most other solvents than its isomer.

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Universalium. 2010.

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  • maleic acid — n. (Chem.) An unsaturated dicarboxylic acid ({HO.CO.CH=CH.CO.OH}) of cis conformation, having various uses in the manufacture of artificial resins, the dyeing and finishing of wool, silk, and cotton, and also combined with certain drugs to make… …   The Collaborative International Dictionary of English

  • maleic acid — [mə lē′ik] n. [< Fr maléique, altered (1834) by T. J. Pelouze (1807 67), Fr chemist < malique,MALIC (ACID), to indicate a relationship between the two acids] a colorless, crystalline, poisonous acid, HOOCCH: CHCOOH, an isomer of fumaric… …   English World dictionary

  • Maleic acid — Not to be confused with Malic acid or malonic acid. Maleic acid …   Wikipedia

  • maleic acid — maleino rūgštis statusas T sritis chemija formulė HOOCCH=CHCOOH atitikmenys: angl. maleic acid rus. малеиновая кислота ryšiai: sinonimas – (Z) buteno dirūgštis …   Chemijos terminų aiškinamasis žodynas

  • maleic acid — [mə leɪɪk] noun Chemistry a crystalline acid made by distilling malic acid, used in making synthetic resins. Origin C19: maleic from Fr. maléique, alt. of malique (see malic acid) …   English new terms dictionary

  • maleic acid — noun an unsaturated organic dicarboxylic acid, HOOCCH=CHCOOH, the geometric isomer of fumaric acid; it is found in unripe fruit, and is used industrially in the production of polyester resins See Also …   Wiktionary

  • maleic acid — Butenedioic acid; the cis isomer of fumaric acid; used for preparing maleate salts of antihistaminics and similar drugs. SYN: toxilic acid. * * * ma·le·ic acid mə .lē ik , .lā n a crystalline dicarboxylic acid C4H4O4 that is isomeric with fumaric …   Medical dictionary

  • maleic acid — noun Etymology: French acide maléique, alteration of acide malique malic acid; from its formation by dehydration of malic acid Date: 1857 a crystalline dicarboxylic acid C4H4O4 that is isomeric with fumaric acid and is used especially in organic… …   New Collegiate Dictionary

  • maleic acid — /məˌliɪk ˈæsəd/ (say muh.leeik asuhd) noun an unsaturated dibasic acid, butenedioic acid, C2H2(COOH)2, the cis isomer of fumaric acid …  

  • maleic acid — n. a colourless crystalline organic acid used in making synthetic resins. Etymology: F maleacuteique (as MALIC ACID) …   Useful english dictionary

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