Dl P J.] 



FORMIC ALDEHYDE 



171 



132, 1495), or by incomplete combustion 

 (Mulliken, Brown, and French, Am. Ch. 

 Journ. 25, in). 



Or from acetone through diacetona- 

 mine (see under aldehyde [92; S]), 

 the latter giving- trioxymethylene 

 (among other products) when the sul- 

 phate is oxidised by chromic acid mix- 

 ture (Heintz, Ann. 198, 45). 



Or from acetone through chloroform 

 by the action of bleaching powder (see 

 under methane [l ; J] ), and then, with 

 sodium methylate, through methylal as 

 above under D and C. Or from acetone 

 through iodoform (see under methane 

 [l ; J]), and then as above under D. 



[G.] ~From formic acid [Vol. II], the 

 aldehyde being among the products ob- 

 tained by the dry distillation of the 

 calcium salt (Mulder, Zeit. [3] 4, 365 ; 

 Ann. 159, 366 ; Linnemann, Ann. 157, 

 119; Lieben and Rossi, Ann. 158, 107). 



[H.] From acetic acid [Vol. II] by 

 incomplete combustion (Mulliken, 

 Brown, and French, Am. Ch. Journ. 

 25, in). Or from acetic and (jlycollic 

 acid [Vol. II] ; formic aldehyde is 

 produced when an. electric current is 

 passed through a solution of potassium 

 acetate (positive electrode) and potassium 

 gly collate (negative electrode) (v. Miller 

 and Hofer, Ber. 27, 467 ; 28, 2437). 

 Or by the electrolysis of sodium acetate 

 in presence of sodium perchlorate (Hofer 

 and Moest, Ann. 323, 384). 



Also from acetic acid through acetyl 

 cyanide and pyroracemic acid (see under 

 benzyl alcohol [54 ; l]). The latter, on 

 heating with acetic anhydride and 

 sodium acetate at 160-180, gives a- 

 crotonic acid (Homolka, Ber. 18, 987), 

 which can be converted into /3-methyl- 

 glyceric acid and formic aldehyde as 

 below under J. 



Or from acetic acid and methyl alco- 

 hol [13] through methylglycollic acid 

 by the action of chloracetic acid on 

 sodium methylate (Heintz, Jahresber. 

 1859, 358). The methylglycollic acid 

 gives formic aldehyde among the pro- 

 ducts of electrolysis of the sodium salt 

 (v. Miller and Hofer, Ber. 27, 469). 



Calcium glycollate on heating with 

 dilute sulphuric acid at 170-180, or 

 the acid itself on heating to 330-240, 



gives 'trioxymethylene'' (Heintz, Ann. 

 138, 43 ; Jahresber. 1861, 444), which 

 is related to formic aldehyde as under D. 



Silver glycollate gives formic alde- 

 hyde when decomposed by iodine (Her- 

 zog and Leiser, Monats. 22, 357). Or 

 glycollic ester interacts with hydrazine 

 to form a hydrazide, which by the 

 action of nitrous acid gives glycolazide 

 (CH 2 [OH] CO . N 3 ) (Curtius and Hei- 

 denreich, Journ. pr. Ch. [3] 52, 335). 

 The azide on heating with alcohol 

 gives glycolurethane, and this by the 

 action of mineral acid is resolved into 

 formic aldehyde and other products 

 (Curtius and Miiller, Ber. 34, 3795). 



Or from acetic acid through mono- 

 chloracetic acid and ' trioxymethylene/ 

 the latter being among the products 

 formed by passing the vapour of the 

 chloro-acid through a hot tube (Grassi- 

 Cristaldi, Gazz. 27, 503). 



[I.] Lactic acid [Vol. II] gives iodo- 

 form by the action of iodine and alkali 

 (Lieben, Ann. Suppl. 7, 218 ; 377), and 

 this can be converted into methylene 

 iodide, chloride, methylal, &c., as under D. 



Or from lactic acid through pyro- 

 racemic acid (see under benzyl alcohol 

 [54 ; P]), a-crotonic acid, &c., as above 

 under H, and then as below under J. 



Potassium lactate gives crotonic alde- 

 hyde [102] on electrolysis, the positive 

 electrode being kept alkaline (v. Miller 

 and Hofer, Ber. 27, 468). Sarcolactic 

 acid [Vol. II] also yields crotonic alde- 

 hyde under these conditions (Ibid.}. 



[J.] From normal butyric acid [Vol. II] 

 through a-crotonic acid [54 ; K], a/3- 

 dibrombutyric acid by bromination 

 (Korner, Ann. 137, 334 ; Michael and 

 Norton, Am. Ch. Journ. 2, 13; Ber. 

 14, 1 203 : see also Kolbe, Journ. pr. Ch. 

 [3] 25, 396), and /3-methylglyceric (a/3- 

 dihydroxybutyric = 3:3- butanediol- 

 carboxylic) acid by boiling the latter 

 with water (Kolbe, loc. cit* 390). 

 Formic aldehyde is among the products 

 of the electrolysis of potassium /3- 

 methylglycerate (Pisarjevsky, Journ. 

 Russ. Soc. 29, 389). 



Crotonic acid also gives /3-methyl- 

 glyceric acid by oxidation in alkaline 

 solution with barium permanganate 

 (Fittig and Kochs, Ann. 268, 8). 



