276 MM. Wurtz and FrapoUi on Acetal. 



hydrogen were replaced by one equivalent of the biatomic ethy- 

 lene C^H'*, the ether of glycol, (-;4 jj4 rO^, would be formed. 

 This would stand in the same relation to glycol, gs ?-0^ as 



does ordinary ether, ^4 Ss \o^ to ordinary alcohol, j^ J-O'^. 

 The action might take place in accordance with the equation 



^'J^2|04 + C''H4Br2=3NaBr + c!H4l0^ 



T»- V 1 1 Bromide of Bromide of nyr „, i-;; ,„ 

 Disodium-glycol. ethylene. sodium. ^^w body. 



But a recent experiment* made by Wurtz has shown that 

 the action of bromide of ethylene on sodium -glycol is not in 

 accordance with this equation. The substances produced are 

 glycol and bromide of acetyle, C^ H^ Br. 



When glycol is treated in the oil-bath at 350° with thrice its 

 weight of recently-fused chloride of zinc, a brisk action is set up, 

 abundant vapours are disengaged, which condense to a liquid, 

 forming three layers, — the lower one of which consists of hydro- 

 carbons, a middle and aqueous one of aldehyde, and an upper 

 one of a volatile substance, the nature of which has not been 

 determined. That the middle layer contained aldehyde was 

 proved by preparing from it aldehyde-ammonia. Propyl ic glycol 

 treated in the same manner, yields propylic aldehyde. The 

 chloride of zinc acts simply as a dehydrating agent, 



Q4H6 04=C4H''02 4-2H0; 



Glycol. Aldehyde. 



and if the ethers are simply dehydrated alcohols, then the alde- 

 hydes are the true ethers of glycol. 



Wurtz and Frapollif have succeeded in transforming aldehyde 

 into acetal. According to the eqviation 



C4 114 cp + 2 (C4 H^ NaO^) = 3 NaCl + C^ H^ (C* H^)^ 0^ 

 it might be expected that the chloride of aldehydcne, C^ H"* CF, 

 the isomer of chloride of ethylene obtained by Geuther by the 

 action of pentachloride of phosphorus on aldehyde, and which 

 had previously been obtained by Wurtz by the same method, by 

 acting on sodium-alcohol, would yield acetal. But Wurtz and 

 Frapolli have found that, although these substances act energeti- 

 cally on each other, the action is not in accordance with the 

 above equation — no acetal is formed, the principal product being 

 a gas, C"* H.^ CI, which was found to be identical in all its pro- 



* Repertoire de Chimie, November 1858. 

 t Comptes Rendus, Sei)tember 1858. 



