Search over 40,000 articles from the original, classic Encyclopedia Britannica, 11th Edition.
|
MELLITIC See also:ACID (See also:benzene hexacarboxylic acid), C6(000H)6 , was first discovered in 1799 by M . H . See also:Klaproth in the See also:mineral honeystone, which is the See also:aluminium See also:salt of the See also:acid . The acid may be prepared by warming honeystone with ammonium carbonate, boiling off the excess of the ammonium salt and adding See also:ammonia to the See also:solution . The precipitated alumina is filtered off, the filtrate evaporated and the ammonium salt of the acid purified by recrystallization . The ammonium salt is then converted into the See also:lead salt by precipitation with lead acetate and the lead salt decomposed by sulphuretted See also:hydrogen . The acid may also be prepared by the oxidation of pure See also:carbon, or of hexamethyl See also:benzene, in the See also:cold, by alkaline See also:potassium permanganate (F . Schulze, Ber., 1871, 4, p . 802 ; C . See also:Friedel and J . M . Crafts, See also:Ann. chim. ph s., 1884 [6], t, p .
470)
.
It crystallizes in See also:fine silky needles and is soluble in See also:water and See also:alcohol
.
It is a very See also:stable See also:compound, See also:chlorine, concentrated nitric acid and hydriodic acid having no See also:action upon it
.
It is decomposed, on dry See also:distillation, into carbon dioxide and pyromellitic acid, C10H6O3; when distilled with See also:lime it gives carbon dioxide and benzene
.
See also:Long digestion of the acid with excess of See also:phosphorus pentachloride results in the formation of the acid chloride, C6(000I)6, which crystallizes in needles, melting at 19o° C
.
By See also:heating the ammonium salt of the acid to 150-16o° C. as long as ammonia is evolved, a mixture of
Paramide (mellimide), C6 (co > NH) 3, and ammonium euchroate is
obtained
.
The mixture may be separated by dissolving out the ammonium euchroate with water
.
Paramide is a See also: |
|
|
[back] MELLE |
[next] MELLITUS (d. 624) |
There are no comments yet for this article.
Do not copy, download, transfer, or otherwise replicate the site content in whole or in part.
Links to articles and home page are encouraged.