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FURFURANE (3r FURANE, C4H40, a colourless liquid boiling at 32° C., found in the distillation products of pine wood. It was first synthetically prepared by H. Limpricht (Ann., 1873, 165, p. 281)
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FURFURANE, (3r FURANE, C4H40, a colourless liquid boiling at 32° C., found in the distillation products of pine wood. It was first synthetically prepared by H. Limpricht (Ann., 1873, 165, p. 281) by distilling barium mucate with soda lime, pyromucic acid C4H3O•CO2H being formed, which, on further loss of carbon dioxide, yielded furfurane. A. Henniger (Ann. chim. phys., 1886 [2], 7, p. 220), by distilling erthyrite with formic acid, obtained a dihydrofurfurane C4H6(OH)4+2H2CO2= C4H60+CO+CO2+4H2O, which, on treatment with phosphorus pentachloride, yielded furfurane. Furfurane is insoluble in water and possesses a characteristic smell. It does not react with sodium or with phenylhydrazine, but yields dye-stuffs with isatin and phenan- threnequinone. It reacts violently with hydrochloric acid, producing a brown amorphous substance. Methyl and phenyl derivatives have been prepared by C. Paal (Ber., 1884, 17, p. 915). Paal prepared acetonyl acetophenone by condensing sodium acetoacetate with phenacylbromide, and this substance on dehydration yields aa'-phenylmethylfurfurane, the acetonyl acetophenone probably reacting in the tautomeric " enolic "form, CH3•CO•CHNa•COOR-I-C6H6•CO•CH2Br = CH3•CO•CH(CH20006H6)•COOR. This ester readily hydrolyses, and the acid formed yields acetonyl acetophenone (by loss of carbon dioxide), which then on de-hydration yields the furfurane derivative, thus CH—CH CH—CH CH3•C<OH HO>C.C6H1=H2O-f-CH3•C< O>C.C6HE. L. Knorr (Ber., 1889, 22, p. 158) obtained diacetosuccinic ester by condensing sodium acetoacetate with iodine, and by de-hydrating the ester he prepared aa'-dimethylfurfurane f3,6'-dicarboxylic acid (carbopyrotritaric acid), which on distillation yields aa'-dimethylfurfurane as a liquid boiling at 94° C. Paal also obtained this compound by using monochloracetone in the place of phenacylbromide. By the distillation of mucic acid or isosaccharic acid, furfurane-a-carboxylic acid (pyromucic acid), C4H3O•CO2H, is obtained; it crystallizes in needles or leaflets, and melts at 134° C. Furfurol (furol), C4H3O •CHO, is the aldehyde of pyromucic acid, and is formed on distilling bran, sugar, wood and most carbohydrates with dilute sulphuric acid, or by distilling the pentoses with hydrochloric acid. It is a colourless liquid which boils at 162° C., and is moderately soluble in water; it turns brown on exposure to air and has a characteristic aromatic smell. It shows all the usual properties of an aldehyde, forming a bisulphite compound, an oxime and a hydrazone; whilst it can be reduced to the corresponding furfuryl alcohol by means of sodium amalgam, and oxidized to pyromucic acid by means of silver oxide. It also shows all the condensation re-actions of benzaldehyde (q.v.); condensing with aldehydes and ketones in the presence of caustic soda to form more complex aldehydes and ketones with unsaturated side chains, HC—CH>O