126 C-Z.] 



FURFURAL 



225 



[C.] From formic aldehyde [Ol] 

 through a-acrose and a-acrosone (see 

 under mannitol [51; A]). The latter 

 gives furfural on heating with acids or 

 per se (Loew, Ber. 2O, 141; 3039; 

 Fischer and Tafel, Ber. 22, 99). 



[D.] From glycerol [48] through 

 a-acrose (see under mannitol [51 ; B]), 

 and then as above. 



[E.] Tartaric acid [Vol. II] on oxida- 

 tion with hydrogen peroxide in presence 

 of ferrous salts gives dihydroxymalei'c 

 acid, the aqueous solution of which 

 decomposes on heating with the forma- 

 tion of gly collie aldehyde. The latter 

 on heating at 100 in a vacuum poly- 

 merises to a ' sugar/ which yields fur- 

 fural on heating with water at 140 

 (Fenton, Trans. Ch. Soc. 65, 899; 67, 

 48; 774; 69,546; 71,375). 



NOTE; The 'sugar' is a mixture of a- and 

 0-acrose (Jackson, Trans. Ch. Soc. 77, 129). 

 The polymerisation of glycollic aldehyde takes 

 place in presence of dilute caustic soda at o 

 (Ibid.). 



[P.] From acetal [93] through brom- 

 acetal (Pinner, Ber. 5, 149; Fischer 

 and Landsteiner, Ber. 25, 2551), brom- 

 acetaldehyde by distilling bromacetal 

 with dry oxalic acid (F. and L. loc. cit.), 

 glycollic aldehyde by the action of 

 barium hydroxide solution (Ibid. 2552), 

 and then as above under E. 



Or brom- or chloracetal on heating 

 with alcoholic potash gives the acetal 

 of glycollic aldehyde (Pinner, loc. cit. 

 1 50 ; Marckwald and Ellinger, Ber. 

 25, 2984), from which the aldehyde 

 can be obtained by heating with very 

 dilute hydrochloric acid (M. & E. loc. 

 cit.}. 



[G.] From ethyl alcohol [14] through 

 ethylene, ethylene iodide, and 2-iodo- 

 ethyl ether by heating the latter with 

 water (Baumstark, Ber. 7, 1172). The 

 iodo-ether, by the action of sodium 

 ethyl ate, gives vinyl ethyl ether (Henry, 

 Bull. Soc. [2] 44, 458), which combines 

 with bromine to form i : 2-dibromethyl 

 ether (Wislicenus, Ann. 192, in), from 

 which bromacetal is obtained by the 

 action of sodium ethylate (Ibid. 112). 

 Subsequent steps as above under P 

 and E. 



Or from ethyl alcohol through chlor- 



acetal by the action of chlorine (Lieben, 

 Ann. 104, 114), glycollic aldehyde 

 acetal, and the aldehyde, &c., as above 

 under P. 



Or from ethyl alcohol through ethyl 

 ether, 1 : 2-dichlorethyl ether by chlorina- 

 tion (Malaguti, Ann. 32, 15), chloracetal 

 by the action of sodium ethylate or 

 alcohol on the dichlorether (Lieben, 

 Ann. 146, 193 ; Paterno and Mazzara, 

 Ber. 6, 1202; Natterer, Monats. 3, 444), 

 and then as above. 



NOTE : Generators of ethylene thus become 

 generators of furfural through glycollic alde- 

 hyde and the ' sugar ' obtainable from it. 



[H.] From choline [Vol. II] through 

 ethylene glycol [45] (see under isopropyl 

 alcohol [16; NN]), and then as below 

 under Z and above under G. 



[I.] Qlycuronic acid [Vol. II] gives 

 furfural on distillation with acids 

 (Mann, Inaug. Diss. Gofctingen, 1894; 

 IJdranszky, Zeit. physiol. Ch. 12, 389 ; 

 Giinther and Tollens, Ber. 23, 1751 ; 

 De Chalmot, Inaug. Diss. Gottingen, 

 1891). 



[J.] d-Arabinose [153] gives furfural 

 on distillation with dilute sulphuric acid 

 (Wohl, Ber. 26, 735). 



[Z.] From ethylene glycol [45], the 

 glycol ethyl ether by the interaction 

 of ethyl iodide and sodium glycol 

 (Wurtz, Ann. Ch. [3] 55, 429), 2-iodo- 

 ethyl ether by the action of phosphorus 

 triiodide on the glycol ether (Demole, 

 Ber. 9, 746), and then vinyl ethyl ether, 

 i : 2-dibromethyl ether, and bromacetal, 

 &c., as above. 



Or ethylene glycol gives glycollic 

 aldehyde directly by oxidation with 

 hydrogen peroxide and ferrous sulphate 

 (Fenton and Jackson, Trans. Ch. Soc. 

 75, 2). 



NOTE : The alcohol, C 4 H 3 O . CH 3 . OH, corre- 

 sponding to the aldehyde, has been found in 

 the oil (steam distilled) from roasted coffee 

 berries (E. Erdmann, Ber. 35, 1846). It is not 

 strictly a biochemical product. The alcohol 

 can be obtained from furfural by the action of 

 alcoholic or aqueous potash (Ulrich, Jahresber. 

 1860, 269 ; Schiff, Ann. 239, 374 ; Wissell and 

 Tollens, Ann. 272, 293 ; E. Erdmann, Ber. 35, 

 J 855), or by reduction with sodium amalgam 

 (Beilstein and Schmelz, Ann. Suppl. 3, 275; 

 Baeyer, Ber. 10, 357). 



