Online Encyclopedia

Search over 40,000 articles from the original, classic Encyclopedia Britannica, 11th Edition.

FUMARIC AND MALEIC ACIDS

Online Encyclopedia
Originally appearing in Volume V11, Page 300 of the 1911 Encyclopedia Britannica.
» Make a correction to this article.
» Add information or comments to this article.
Spread the word: del.icio.us del.icio.us it!

FUMARIC AND MALEIC ACIDS , two isomeric unsaturated acids of See also:

composition C4H4O4. Fumaric See also:acid is found in See also:fumitory (Fumaria officinalis), in various See also:fungi (Agaricus piperatus, &c.), and in See also:Iceland See also:moss. It is obtained by See also:heating malic acid alone to 150 C., or by heating it with hydrochloric acid (V. Dessaignes, Jahresb., 1856, p. 463) or with a large quantity of hydrobromic acids (A. See also:Kekule, See also:Ann., 1864,130, p. 21). It may also be obtained by boiling monobromsuccinic acid with See also:water; by the See also:action of dichloracetic acid and water on See also:silver malonate (T. Komnenos, Ann., 1883, 218, p. 169) ; by the See also:cyanide See also:synthesis from See also:acetylene di-iodide; and by heating maleic acid to 210 C. (Z. Skraup, Monats. f.

Chemie, 1891, 12, p. 112). It crystallizes in small prisms or needles, and is practically insoluble in See also:

cold water. It sublimes to some extent at about 200° C., being partially converted into maleic anhydride and water, the reaction becoming practically quantitative if dehydrating agents be used. Reducing agents (See also:zinc and See also:caustic See also:alkali, hydriodic acid, See also:sodium See also:amalgam, &c.) convert it into succinic acid. See also:Bromine converts it into dibromsuccinic acid. See also:Potassium permanganate oxidizes it to racemic acid (A. Kekule and R. Anschutz, Ber., 1881, 14, p. 713). By See also:long-continued heating with caustic soda at loo° C. it is converted into inactive malic acid. Maleic acid is obtained by distilling malic or fumaric acids; by heating fumaric acid with acetyl chloride to oo° C.; or by the See also:hydrolysis of trichlorphenomalic acid ((3-trichloracetoacrylic acid) [A.

Kekule, Ann., 1884, 223, p. 18s]. It crystallizes in See also:

monoclinic prisms, which are easily soluble in water, melt at 130° C., and See also:boil at 16o° C., decomposing into water and maleic anhydride. When heated with concentrated hydrobromic or hydriodic acids, it is converted into fumaric acid. It yields an anilide; oxidation converts it into mesotartaric acid. Maleic anhydride is obtained by distilling fumaric acid with See also:phosphorus pentoxide. It forms triclinic crystals which melt at 6o° C. and boil at 196° C. Both acids are readily esterified by the action of alkyl halides on their silver salts, and the maleic ester is readily transformed into the fumaric ester by warming with See also:iodine, the same result being obtained by esterification of maleic acid in alcoholic See also:solution by means of hydrochloric acid. Both acids yield acetylene by the See also:electrolysis of aqueous solutions of their alkali salts, and on reduction both yield succinic acid, whilst by the addition of hydrobromic acid they both yield monobromsuccinic acid (R. See also:Fittig,Ann., 1877, 188, p. 98). From these results it follows that the two acids are structurally identical, and the See also:isomerism has consequently to be explained on other grounds.

This was accomplished by W. See also:

Wislicenus [" Uber See also:die raumliche Anordnung der Atome," &c., Trans. of the Saxon Acad. of Sciences (Math. Phys. See also:Section), 1887, p. 14] by an See also:extension of the See also:van't Hoff See also:hypothesis (see STEREO-ISOMERISM). The formulae of the acids are written thus: HC•CO2H HC•CO2H HC•CO2H Maleic acid. HO2C:6H These See also:account for maleic acid readily yielding an anhydride, whereas fumaric acid does not, and for the behaviour of the acids towards bromine, fumaric acid yielding See also:ordinary dibromsuccinic acid, and maleic acid the isomeric isodibromsuccinic acid.

End of Article: FUMARIC AND MALEIC ACIDS

Additional information and Comments

There are no comments yet for this article.
» Add information or comments to this article.
Please link directly to this article:
Highlight the code below, right click, and select "copy." Then paste it into your website, email, or other HTML.
Site content, images, and layout Copyright © 2006 - Net Industries, worldwide.
Do not copy, download, transfer, or otherwise replicate the site content in whole or in part.

Links to articles and home page are always encouraged.

[back]
FUM, or FUND HWANG 		[next]
FUMAROLE

Site © 2006 - Net Industries