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(organic chemistry)
C4H5N Water-insoluble, yellowish oil, with pungent taste; soluble in alcohol, ether, and dilute acids; boils at 130°C; polymerizes in light; used to make drugs.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a heterocyclic compound; colorless liquid that darkens rapidly upon exposure to air. Melting point, — 23.42°C; boiling point, 130°C; density, 0.9698 g/cm3 at 20°C. Moderately soluble in water. Pyrrole is a very weak acid; it forms a salt with potassium or anhydrous caustic potash. It resinifies under the influence of acids, and it oxidizes readily. It hydrogenates with H2 over Ni at 200°C to pyrrolidine.

Pyrrole was first isolated from coal tar. It is produced commercially

by dry distillation of the ammonia salt of mucic acid or by passing a mixture of furan and NH3 over Al2O3 at 400°–450°C. The pyrrole nucleus is a structural fragment of porphyrin molecules. Pyrrole is used in the production of pyrrolidine and in the synthesis of pharmaceuticals—for example, the antiseptic Iodol (2,3,4,5-tetraiodopyrrole).

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.