182 



ALDEHYDES AND KETONES: FATTY GROUP 



[94-E 



(Iron (Voiry, Bull. Soc. [2] 40, 106 ; 

 50, 108 ; Comp. Rend. 106, 1419; 

 1538). A butyric aldehyde occurs in 

 rancid fat, probably a bacterial product 

 (Nagel, Am. Ch. Journ. 23, 173). 



SYNTHETICAL PROCESSES. 



The constitution of the natural pro- 

 duct has not been determined, so the 

 synthetical methods for both normal 

 and iso-aldehydes are given : 



[A.] Butyric and formic acids [Vol. 

 II] give the n-aldehyde on distilling 

 a mixture of the dry calcium salts (Lie- 

 ben and Rossi, Ann. 158, 146; Linne- 

 mann, Ann. 161, 186 ; Lipp, Ann. 211, 

 355 ; Kahn, Ber. 18, 3364). 



Or n-butyric acid can be converted 

 into the chloride, and the latter reduced 

 in moist ethereal solution with sodium 

 amalgam (W. H. Perkin, junr., and 

 Sudborough, Proc. Ch. Soc. 10, 216). 



[B.] Isobutyric acid [Vol. II] gives 

 the iso-aldehyde by distilling the cal- 

 cium salt per se, or with calcium formate 

 [Vol. II] (Popoff, Ber. 6, 1255 ; Bar- 

 baglia and Gucci, Ber. 13, 1572 ; Linne- 

 mann and Zotta, Ann. 162, 7). 



[C.] Isobutyl alcohol [is] gives the 

 iso-aldehyde on oxidation with chromic 

 acid mixture (Pfeiffer, Ber. 5, 699 ; 

 Michaelson, Ann. 133, 182-; Pierre and 

 Puchot, Comp. Rend. 7O, 434 ; Lipp, 

 Ann. 205, 2 ; Fossek, Monats. 2, 614 ; 

 W. H. Perkin, junr., Trans. Ch. Soc. 

 43, 91). Also by pyrogenic decomposi- 

 tion (Ipatieff, Ber. 34, 598) ; especially 

 by the contact action of certain heated 

 metals (Ibid. 35, 1052), or by passing 

 the vapour mixed with air over heated 

 platinum (v. Stepski, Monats. 23, 773). 



Isobutyl hypochlorite is decomposed 

 by hydrochloric acid with the formation 

 of isobutyric aldehyde (Tiesenhold : 

 Krassusky, Journ. Russ. Soc. 34, 556). 



[D.] Tertiary butyl alcohol [19] can 

 be converted into isobutylene by acting 

 on the iodide with alcoholic potash, or 

 on the alcohol with sulphuric acid or 

 zinc chloride (Wurtz, Ann. 93, 107; 

 De Luynes, Comp. Rend. 56, 1175; 

 Butleroff, Ann. 144, 1 9 ; Zeit. [2] 6, 

 236 ; Konowaloff, Bull. Soc. [2] 34, 

 333; Nevole, Bull. Soc. [2] 24, 122; 



Lermontoff, Ann. 196, 117; Puchot, 

 Ann. Chim. [5] 28, 508 ; Scheschukoff, 

 Bull. Soc. [2] 45, 181). Isobutylene 

 bromide, when heated with water at 

 1 60, gives isobutyric aldehyde (Linne- 

 mann and Zotta, Ann. 162, 36). 



Or from isobutylene through the 

 chlorhydrin, which gives isobutyric 

 aldehyde on heating with water or by 

 passing over heated zinc oxide (Kras- 

 susky, Journ. Russ. Soc. 34, 287). Iso- 

 butylene oxide (from the chlorhydrin) 

 gives the aldehyde when heated with 

 zinc chloride (Ibid. 537). 



Or isobutylene by chlorination gives 

 (with an isomeride) isobutenyl chloride = 

 2-methyl-3-chlorpropylene (Scheschu- 

 koff, Journ. Russ. Soc. 16, 495), which, 

 by potassium carbonate and water, is 

 converted into isopropenyl carbinol 

 = i-hydroxy-2-methylpropylene (Ibid. 

 499). The latter, on heating with water 

 acidified with sulphuric acid, gives iso- 

 butyric aldehyde (Ibid. 502). 



[E.] Isovaleric acid [Vol. II] gives 

 isobutylene among the products of the 

 electrolysis of a strong solution of the 

 potassium salt (Kolbe, Ann. 69, 259), 

 and this can be converted into isobutyric 

 aldehyde as above under D. 



Or from isovaleric acid through /3- 

 dimethylacrylic acid and isobutylene 

 (see under isobutyl alcohol [18 ; C]). 



Or /3-dimethylacrylic ester on nitra- 

 tion gives an a-nitro-derivative (Bou- 

 veault and Wahl, Comp. Rend. 131, 687), 

 which, on reduction by sodium in moist 

 ether, or by heating with sodium hy- 

 droxide solution, yields nitroisobutylene 

 (Ibid. 121 1). The latter, on reduction 

 with aluminium amalgam or zinc dust 

 and acetic acid, gives the oxime of iso- 

 butyric aldehyde, from which the alde- 

 hyde can be obtained by hydrolysis 

 (Ibid. 134, 1145). 



NOTE: Other generators of #-dimethylacrylic 

 acid given under isobutyl alcohol are acetone 

 [106] and glycerol [48], or acetone, malonic acid, 

 and acetic anhydride. 



Or isovaleric acid can be brominated 

 or chlorinated (Cahours, Ann. Suppl. 

 2, 78 ; Borodin, Ann. 119, 1 21 ; Fittig 

 and Clark, Ann. 139, 199; Ley and 

 Popoff, Ann. 174, 63; Schmidt, Ann. 



