92 L-S.] 



ACETIC ALDEHYDE 



179 



This acid on dry distillation also breaks 

 down into acetaldehyde and diethyl- 

 acetic acid. 



NOTE : This synthesis of aldehyde from dial- 

 kyl-/3-hydroxybutyric acids is general what- 

 ever the alkyls may be (Keformatsky, Journ. 

 pr. Ch. [2] 54, 477). 



Or from acetoacetic ester through 

 ' oxymesitenedicarbonic ' acid and its an- 

 hydride (lactone) which is formed by the 

 action of hydrochloric or sulphuric acid 

 on the ester (Duisberg, Ann. 213, 177 ; 

 Polonowska, Ber. 19, 2403 ; Anschutz, 

 Bendix, and Kerp, Ann. 259, 153). 

 The lactone on distillation with lime 

 gives mesityl oxide (Hantzsch, Ann. 

 222, 21), and this can be converted 

 into hydroxyisobutyric acid as below 

 under S, and aldehyde as above under K. 



[M.] From fi-hydroxybutyric acid 

 [Vol. II] through a-crotonic acid (see 

 under benzyl alcohol [54; L]), or 

 through /3-methylglyceric acid (see 

 under formic aldehyde [91 ; K]), and 

 then as under J and K. 



[N.] From eryt/iritol [50] and formic 

 acid [Vol. II] through a-crotonic alde- 

 hyde [102] and acid, or through /3-methyl- 

 glyceric acid (see under formic aldehyde 

 [91 ; B]), and then as under J and K. 



[O.] From allyl isothiocyanate [166] 

 through /3-methylglyceric acid [91; 

 P], and then as under J. 



[P.] From fumaric or male'ic acids 

 [Vol. II] through acetylene (see under 

 methane [l ; U]), and then as above 

 under A. 



Or from fumaric acid through di- 

 bromsuccinic acid by the addition of 

 bromine (Kekule, Ann. 117, 123; 

 Suppl. 1, 131 ; Baeyer, Ber. 18, 676), 

 and then as under G. 



Or from maleic acid through iso- 

 dibromsuccinic acid by the addition of 

 bromine (Kekule, Ann. Suppl. 2, 89), 

 and decomposition of the isodibrom- 

 succinabes by boiling with water (Lossen 

 and Reisch, Ann. 30O, 5). 



[Q.] From malic acid [Vol. II], being 

 formed in small quantity by the electro- 

 lysis of a strong solution of the potas- 

 sium or sodium salt (Bourgoin, Bull. 

 Soc. [2] 9, 427 ; v. Miller and Hofer, 

 Ber. 27, 470). 



Also by boiling the aqueous solution 

 of the acid with manganese dioxide 

 (Liebig, Ann. 113, 14), by heating with 

 dilute sulphuric acid at 135 (Weith, 

 Ber. 10, 1744), or by oxidation with 

 potassium permanganate (Denige's, 

 Comp. Rend. 130, 32). 



[B.] Tiglic acid [Vol. II] gives alde- 

 hyde on oxidation with potassium 

 permanganate (Beilstein and Wiegand, 

 Ber. 17, 2262). 



[S.] From acetone [106] through the 

 dibromide or diiodo-derivative (see under 

 glycerol [48 ; E]), acrolein [lOl], acrylic 

 acid, /3-chlorlactic acid, &c., as above 

 under J. 



Or from acetone and hydrogen cyanide 

 [172], which condense in the presence 

 of hydrochloric acid to form hydroxy- 

 isobutyric acid (Staedeler, Ann. Ill, 

 320; Markownikoff, Ann. 146, 339). 

 The latter gives aldehyde as above 

 under K. 



Or from acetone and chloroform\\; D], 

 which condense in the presence of caus- 

 tic alkali to form c acetone-chloroform ' 

 (see under tertiary butyl alcohol [19 ; 

 D]). The latter gives hydroxyiso- 

 butyric acid on heating with water or 

 dilute alkali (Willgerodt, Ber. 15, 2307 ; 

 Willgerodt and Schiff, Journ. pr. Ch. 

 [2] 41, 519). 



Acetone by the action of sulphuric 

 acid, of lime, or of hydrogen chloride 

 followed by caustic alkali or water 

 gives mesityl oxide = 2-methyl-2- 

 pentenone-4 (Kane, Phil. Trans. 44, 

 475 ; Fittig, Ann. 110, 32 ; Kasanzeff, 

 Journ. Russ. Soc. 7, 173; Baeyer, 

 Ann. 140, 297 ; Claisen, Ann. 180, 4; 

 Freer and Lachman, Am. Ch. Journ. 

 19, 887, note). Or mesityl oxide results 

 from the action of zinc methyl or ethyl 

 (Pawloff, Ber. 9, 1311; Ann. 188, 

 130), or of acetyl chloride on acetone 

 (Beilstein and Wiegand, Bull. Soc. [2] 

 38, 167). Mesityl oxide gives hydroxy- 

 isobutyric acid on oxidation with potas- 

 sium permanganate (Pinner, Ber. 15, 



591)- 



Acetone and ammonia condense in 

 the presence of acids to form diaceton- 

 amine (Heintz, Ann. 174, 154; 189, 

 214). The latter (or its salts) gives 

 mesityl oxide on dry distillation (Soko- 



