176 



ALDEHYDES AND KETONES : FATTY GROUP [92 C-P. 



ether, the latter giving acetaldehyde 

 among the products of its photochemical 

 oxidation (Berthelot, Comp. Rend. 129, 

 627), or by passing through a hot tube 

 (Liebig, Ann. 14, 134; Tistschenko, 

 Journ. Russ. Soc. 31, 784; Ch. Centr. 

 1900, 1, 586). 



From alcohol by chemical, aided by 

 electrolytic, oxidation (Darmstadter, 

 Germ. Pat. 109012 of 1897; Ch. 

 Centr. 1900, 2, 151); or by electrolysis 

 in presence of sulphuric acid (Elbs and 

 Brunner, Zeit. Elektroch. 6, 604). 

 Among the products of photo-oxidation 

 of alcohol by ferric chloride (De Coninck, 

 Comp. Rend. 131, 275), and among the 

 products of pyrogenic decomposition 

 (Ipatieff, Ber. 34, 598): the yield is in- 

 creased by the pyrogenic ' contact ' 

 influence of certain metals, such as iron 

 or zinc, &c., or certain metallic oxides 

 (Ibid. 34, 3579 ; 35, 1047). 



Ethyl alcohol is oxidised to aldehyde 

 by quinones, ketones, benzaldehyde, and 

 anisaldehyde in presence of light (Ciami- 

 cian and Silber, Ber. 34, 1530). 



Magnesium ethylate gives aldehyde 

 when acted upon by dry chlorine (Meu- 

 nier, Comp. Rend. 134, 472). 



Ethyl hypochlorite decomposes spon- 

 taneously into aldehyde and hydrogen 

 chloride (Schmitt and Goldberg, Journ. 

 pr. Ch. [2] 19, 393; 24, 106). ^ 



[D.] From formic and acetic acids 

 [Vol. II] by distilling a mixture of the 

 dry calcium salts (Ritter, Ann. 97, 



3 6 9)- 



Or from acetic acid through acetyl 



cyanide and pyroracemic acid (see under 

 benzyl alcohol [54; I]), and then as 

 below under E. 



Formylacetic ethyl ester (see under 

 cymene [6 ; IX]), when boiled with di- 

 lute sulphuric acid, gives aldehyde 

 among other products (Wislicenus and 

 Bindemann, Ann. 316, 18). 



[E.] From propionic acid [Vol. II], 

 being among the products of electrolysis 

 of sodium propionate in presence of 

 sodium perchlorate (Hofer and Moest, 

 Ann. 323, 284). 



Or from propionic acid through 

 ethane by photochemical decomposition 

 in presence of uranium salts, or through 

 ethylene by electrolysis (see under 



ethyl alcohol [14; H]). Ethane yields 

 aldehyde as under B, and ethylene as 

 under A. 



Or from propionic acid and methyl 

 alcohol [13] through tertiary amyl al- 

 cohol by the interaction of propionyl 

 chloride and zinc methyl (Popoff, Ann. 

 145. 293 ; Jermolajeff, Zeit. [2] 7, 275 ; 

 Wischnegradsky, Ann. 190, 336), the 

 corresponding iodide, and amylene (tri- 

 methylethylene) by the action of alco- 

 holic potash on the latter. According to 

 Wagner (Ber. 21, 1235), acetic aldehyde 

 is among the products of oxidation of 

 this amylene. 



Or from propionic acid through the 

 a-bromo-acid by bromination (Friedel 

 and Machuca, Comp. Rend. 53, 408 ; 

 Ann. 120, 286; Bischoff, Ann. 206, 

 319; Zelinsky, Ber. 20, 2026 ; Michael 

 and Graves, Ber. 34, 4044), the a-cyano- 

 acid by the action of potassium cyanide 

 [172], and hydrolysis of the latter to iso- 

 succinic (methylmalonic) acid (Wichel- 

 haus, Zeit. [2] 3, 247 ; Byk, Journ. 

 pr. Ch. [2] 1, 19; Cohn, Ann. 251, 

 335; Pusch, Arch. Pharm. 232, 188). 

 Acetic aldehyde (trace) is among the 

 products of electrolysis of the potassium 

 salt of this latter acid (Petersen, Ch. 

 Centr. 1897, 2, 519; Zeit. physik. Ch. 

 33, 702). 



Or from propionic acid through pyro- 

 racemic acid (see under benzyl alcohol 

 [54; O]). The latter, on heating with 

 dilute sulphuric acid at 150, gives 

 aldehyde (Beilstein and Wiegand, Ber. 

 17, 840). Pyroracemic acid also yields 

 aldehyde among the products of its 

 electrolytic oxidation (Rockwell, Journ. 

 Am. Ch. Soc. 24, 719). 



Or a/3-dibrompropionic acid can be 

 converted into acrylic acid by treatment 

 with zinc and sulphuric acid (Caspary 

 and Tollens, Ann. 167, 241 ; Melikoff, 

 Journ. Russ. Soc. 13, 156), and the 

 latter into /3-chlorlactic acid by the 

 addition of hypochlorous acid (Melikoff 

 loc. cit. 157). /3-Chlorlactic acid gives 

 aldehyde on heating with water, or by 

 boiling a strong solution of the sodium 

 salt (Erlenmeyer, Ber. 13, 309 ; Reisse, 

 Ann. 257, 337). 



[F.] From malonic acid [Vol. II], 

 methyl and ethyl alcohols [13 ; 14], 



