880 ETHAL. 



Ethal is deposited from an alcoholic solution in crystalline 

 plates; it fuses above 118, and solidifies at that temperature, 

 forming a white crystalline mass. It is volatile, and may be 

 distilled without decomposition. It is insoluble in water, 

 soluble in alcohol and ether, neutral and does not combine with 

 acids or alkalies. It is decomposed by nitric acid, and combines 

 with sulphuric acid. 



Chloride of cetyl; C 32 H 33 ,Cl=CtCl. An oily liquid, formed 

 by the action of perchloride of phosphorus on ethal. 



Acid sulphate of oxide of cetyl; HO.CtO,S 2 O 6 . This com- 

 pound is formed when ethal is heated with strong sulphuric 

 acid. It forms double salts when neutralised with bases. Sul- 

 phate of oxide of cetyl and potasfr, KO.CtO,S 2 O 6 , is prepared 

 by adding an alcoholic solution of hydrate of potash to the 

 preceding compound, sulphate of potash precipitates, and the 

 salt in question remains dissolved in the alcohol, from which 

 it is deposited in white pearly scales. (Dumas and Peligot, 

 Annales de Chimie, &c., Ixii, 5.) 



Ethalic acid, HO- L C 32 H 31 O 3 . * This compound, the acetic 

 acid of the cetyl series, was formed by M. Dumas, by mixing 

 1 part of ethal with 5 or 6 parts of the mixture of hydrate of 

 potash and quicklime, and heating to 410 or 428 (210 or 

 220 centig.), for five or six hours. Hydrogen gas is evolved, 

 and the ethalate of potash formed. The last is decomposed by 

 hydrochloric acid, and the ethalic acid, which separates in flocks, 

 purified by boiling it with the acid liquid, and repeatedly with 

 water, converting it into ethalate of barytes, and treating the 

 last with boiling alcohol, to dissolve out undecomposed ethal. 

 The ethalate of barytes is then decomposed by hydrochloric 

 acid, and the liberated ethalic acid purified by solution in 

 ether. 



Ethalic acid is solid, white, inodorous, tasteless, lighter than 

 water. Fused by heat, it solidifies at 101, and then presents 

 itself in the form of small brilliant needles, in groups radiating 

 from a centre. It is insoluble in water, but is dissolved largely 

 by alcohol and ether. When heated in a little capsule, it boils 

 like ethal, and is volatilised without leaving any residue. 



All the ethalates are insoluble in water or alcohol, except 

 those of potash, soda, and ammonia. The insoluble ethalates 

 are prepared by precipitating the metallic salts dissolved in 



