Online Encyclopedia

PIPERONAL (heliotropine, protocatechu...

Online Encyclopedia
Originally appearing in Volume V21, Page 635 of the 1911 Encyclopedia Britannica.
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PIPERONAL (heliotropine, protocatechuic aldehyde methylene ether), C8H6O3, an aromatic aldehyde. It is prepared by oxidizing piperic acid with potassium permanganate (R. Fittig, Ann., 1869, 152, p. 35); by condensing methylene iodide with protocatechuic aldehyde (R. Wegscheider, Monats., 1893, 14, p. 388) ; or by oxidizing isosafrol with chromic acid. It forms long colourless crystals which melt at 370 C. and boil at 263° C. It has an agreeable smell, resembling that of heliotrope, and is much used in perfumery. It is only slightly soluble in cold water, but is readily soluble in alcohol and in ether. When heated with dilute hydrochloric acid to Zoo° C. it yields protocatechuic aldehyde, C7H6O3, and carbon. It readily combines with sodium bisulphite and with various bases (ammonia, aniline, methylamine, &c.).
End of Article: PIPERONAL (heliotropine, protocatechuic aldehyde methylene ether), C8H6O3
PIPERNO (anc. Privernum)
PIPIT (cognate with the Lat. Pipio; see PIGEON)

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