92 CC-94.] 



ACETIC ALDEHYDE 



181 



Or from methyl alcohol through 

 ethane (see under ethyl alcohol [14 ; D]), 

 and then as above under B. 



[DD.] Isohutylene glycol [47] on treat- 

 ment with hydrochloric acid gives a 

 chlorhydrin which, on oxidation with 

 nitric acid, yields a-chlorisobutyric acid 

 (Henry, Bull. Soc. [2] 26, 2,4). From 

 the latter through a-hydroxyisobutyric 

 acid as above under K. 



[EE.] Methylisoeugenol [80] gives 

 aldehyde among the products of oxida- 

 tion by potassium permanganate (Kolo- 

 koloff, Journ. Russ. Soc. 29, 23; Ch. 

 Centr. 1897, 1, 915). 



[FP.] From isobutyl alcohol [18], or 

 tertiary butyl alcohol [19], through iso- 

 butylene [18; A; 19; B] and acetic 

 acid [Vol. II]. Isobutylene and acetyl 

 chloride or acetic anhydride condense in 

 presence of zinc chloride to form mesityl 

 oxide (Kondakoff, Journ. Russ. Soc. 26, 

 12; 232). Subsequent treatment as 

 above under S, &c. 



NOTE : Generators of isobutylene are given 

 under isobutyl alcohol [18 ; B ; C] and under 

 butyric aldehyde below [94]. 



93. Acetal ; Etkyliclenedietliyl Ether. 

 CH 3 .CH(O.C 2 H 5 ) 2 



NATURAL SOURCES. 



Occurs in raw spirit after filtration 

 through animal charcoal (Geuther, Ann. 

 126, 63) ; also in fusel oil of whisky 

 (Allen, Journ. Fed. Inst. 3, 38). Has 

 been found in forerunnings from spirit 

 rectification (Kramer and Pinner, Ber. 

 2, 402 ; 4, 788 ; Kekule, Ber. 4, 719). 



It is doubtful whether the acetal is 

 a biochemical product or due to secon- 

 dary reactions. 



SYNTHETICAL PROCESSES. 



[A.] From ethyl alcohol [14] by 

 oxidation (Dobereiner, Gmelin's Handb. 

 d. org. Ch. IV, 805 ; Liebig, Ann. 5, 25 ; 

 14, 156; Stas, Ann. Chim. [3] 19, 

 146 ; Wurtz, If/ul. 48, 370 ; Ann. 108, 

 84). By electrolysis (Renard, Ber. 8, 



[B.] From aldehyde [92] and ethyl 

 alcohol [14] by passing hydrogen 

 chloride into a mixture, and acting on 

 the monochlorethyl ether (CH 3 . CHC1 . 

 OC 2 H 5 ) thus formed with sodium ethyl- 

 ate (Wurtz and Frapolli, Comp. Rend. 

 47, 418; Ann. 108, 223). Or by 

 passing hydrogen chloride into a mixture 

 of alcohol and aldehyde, and allowing 

 to interact at ordinary temperatures 

 (Fischer and Giebe, Ber. 30, 3053). 



Also by converting aldehyde into 

 ethylidene dibromide by the action of 

 phosphorus pentabromide, and the 

 interaction of the dibromide with so- 

 dium ethylate (W. and F., loc. cit.}. 



Or from aldehyde by heating with 

 alcohol and acetic acid at 100 (Geuther, 

 Ann. 126, 63), or by passing hydrogen 

 phosphide into a cold mixture of alde- 

 hyde and absolute alcohol (Engel and 

 Girard, Comp. Rend. 91, 692 ; Jahres- 

 ber. 1880, 694). 



Also from aldehyde through a-chlor- 

 ethyl acetate (Wurtz, Ann. 102, 94), 

 or by the action of acetyl chloride on 

 aldehyde (Simpson, Ann. 109, 156). 

 By the action of bromine at 100-103 

 a-chlorethyl acetate gives bromethyl 

 bromacetate (Kessel, Ber. 10, 1994 ; 

 11, 1916), and the latter (CH Br. CO. 

 O.CHBr.CH,), when heated with 

 alcohol, yields acetal among other pro- 

 ducts (Ibid. 11, 1918). 



Hydrogen chloride passed into a cooled 

 mixture of alcohol and hydrogen cyanide 

 [172] gives formimino-ethyl ether (Pin- 

 ner, Ber. 16, 354, 1644). The hydro- 

 chloride of the latter interacts with 

 acetic aldehyde to form acetal (Claisen, 

 Ber. 31, 1014). 



Acetal is best prepared by acting on 

 aldehyde with a I per cent, solution of 

 hydrogen chloride in alcohol (Fischer 

 and Giebe, loc. cit.}. 



94. Butyric Aldehyde ; Butanal. 

 C 3 H 7 . CHO 



NATURAL SOURCES. 



A butyric aldehyde is said to occur 

 in the oil of Eucalyptus glolndus and in 

 oil of cajeput from Melaleuca leucaden- 



