95 777 B-96 III B.] 



VALERIC ALDEHYDE 



185 



the latter on heating- with very dilute 

 sulphuric acid yields the above valeric 

 aldehyde (Ibid. 154). 



NOTE: Forvaleral from methylethyl methyl- 

 carbinol (active amyl alcohol of fusel oil) see 

 Bemont, Comp. Rend. 133, 1222 ; also Etard and 

 Vila, Ibid. 134, 122. For trimothacetaldehyde 

 = dimethylpropanal from trimethacetic and 

 formic acids see Tissier, Ann. Chim. [6] 29, 

 353- 



96. Hexoic Aldehyde ; Caproic 

 Aldehyde. 



C 6 H n .CHO 



NATURAL SOURCES. 



Hexoic aldehyde occurs in small 

 quantity in oil of Eucalyptus globulus 

 (Bouchardat and Oliviero, Bull. Soc. 

 [3] Q, 429). A caproic aldehyde occurs 

 in rancid fat, probably a bacterial pro- 

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



SYNTHETICAL PROCESSES. 



/. Normal Caproic Aldehyde ; Hexanal. 



CH 3 . CH 2 . CH 2 . CH 2 . CH 2 . CHO 



[A.] From normal caproic = hexoic 

 and formic acids [Vol. II] by distilling 

 a mixture of the calcium salts (Lieben 

 and Janecek, Ann. 187, 130). 



77. Isocaproic Aldehyde ; Isobutylacet- 

 aldehyde ; ^.-Methylpenfanal. 



CH 3 . CH(CH 3 ) . CH 2 . CH 2 . CHO 



[A.] From isofaitylacetic and formic 

 acids [Vol. II] by distilling a mixture 

 of the calcium salts (Rossi, Ann. 133, 

 178). 



777. Methylpropylacetaldehyde ; 

 2 -Methylpen tanal. 



CH 3 . CH 2 . CH 2 . CH(CH 3 ) . CHO 



[A.] From normal propyl alcohol [15] 

 through the aldehyde (propanal) by 

 oxidation (Chancel, Ann. 151, 301 ; 

 Przybytek, Journ. Russ. Soc. 8, 335 ; 

 Lieben and Zeisel, Monats. 4, 14). Pro- 

 panal on heating with sodium acetate 

 solution gives methylethylacrolem = 2- 



methyl-2-pentenal (L. and Z., loc. cit. 

 16; Hoppe, Ibid. 9, 637), and this, on 

 standing in contact with iron and acetic 

 acid for four weeks in the cold, is con- 

 verted into the above hexoic aldehyde 

 (L. and Z., loc. cit. 23). 



Or indirectly from propyl (or iso- 

 propyl) alcohol through propylene, the 

 bromide and cyanide, and hydrolysis of 

 the latter to pyrotartaric acid (Simpson, 

 Ann. 121, 161). Subsequent steps as 

 under I and C below. 



Or through propylene chloride or 

 bromide and glycol, and then as below 

 under B. According to Michael (Journ. 

 pr. Ch. [2] 60, 417 : see also Beilstein 

 and Wiegand, Ber. 15, 1496) propanal 

 is among the products of the action 

 of water and silver oxide on propylene 

 bromide. 



Or propylene chlorhydrin by the 

 action of potash gives propylene oxide, 

 and this yields propanal on heating with 

 zinc chloride more readily than the 

 glycol (Krassusky, Journ. Russ. Soc. 

 34, 537)- 



NOTE : Generators of propylene (see under 

 glycerol [48 ; B to G, &c.) thus become 

 generators of the above hexoic aldehyde. 



[B.] From glycerol [48] through allyl 

 alcohol (see under ethyl alcohol [14 ; 

 G-]). The latter gives methylethyl- 

 acrolein among other products when 

 heated with 10 per cent, hydrochloric 

 acid at 100 (Solonina, Journ. Russ. 

 Soc. 19, 306). Subsequent reduction as 

 above under A. 



Or allyl chloride from allyl alcohol 

 gives a chlorhydrin which is decomposed 

 by heating with water with the forma- 

 tion of acetone and propanal (see under 

 acetone [106 ; P]). 



Or from glycerol through glyceric 

 acid and pyrotartaric acid (see under 

 benzyl alcohol [54; F]), or through allyl 

 cyanide and pyrotartaric acid (Ibid.). 

 Pyrotartaric acid is converted into citra- 

 dibrompyrotartaric acid and then treated 

 as below under C. Or pyrotartaric acid 

 gives propanal among the products of 

 electrolysis of the potassium salt (Peter- 

 sen, Zeit. physik. Ch. 33, 704). 



Or from glycerol through propylene 

 glycol by distilling with sodium hy- 



