342 CONSIDERATION OF CARBON COMPOUNDS. 



flask a cork with a third aperture through which a glass tube passes into the 

 liquid. The other end of the tube is connected by means of rubber tubing 

 with a vessel filled with alcohol and standing somewhat above the flask. As 

 soon as distillation commences alcohol is allowed to flow into the flask at a 

 rate equal to that of the distillation, keeping the temperature at about 140 C. 

 (284 F.). The flow of alcohol is regulated by a stop-cock. . 



The action of sulphuric acid upon alcohol is not quite so simple as 

 described above in connection with the general methods for obtaining 

 ethers, where the final result only was given An intermediate pro- 

 duct, known as ethyl- sulphuric acid or sulpho-vinic acid, is formed, 

 which, by acting upon another molecule of alcohol, forms sulphuric 

 acid and ether, which latter is volatilized as soon as formed. The 

 decomposition is shown by the equations : 



C 2 H 5 OH + H 2 S0 4 .== C 2 H 5 HS0 4 + H 2 O. 



Alcohol. Sulphuric Ethyl-sulphuric Water, 



acid. acid. 



C 2 H 5 HSO, + C 2 H 5 OH = H 2 S0 4 + (C 2 H 5 ) 2 O. 

 Ethyl-sulphuric Alcohol. Sulphuric Ether, 



acid. acid. 



The liberated sulphuric acid at once attacks another molecule of alcohol, 

 again forming ethyl-sulphuric acid, which is again decomposed, etc. Theo- 

 retically, a given quantity of sulphuric acid should be capable, therefore, of 

 converting any quantity of alcohol into ether ; practically, however, this is not 

 the case, because secondary reactions take place simultaneously, and because 

 the water vhich is constantly formed does not all distil with the ether, and 

 therefore dilutes the acid to such an extent that it no longer acts upon the 

 alcohol. 



Ether thus obtained is not pure, but contains water, alcohol, sulphurous and 

 sulphuric acids, etc. ; it is purified by mixing it with chloride and oxide of 

 calcium, pouring off the clear liquid and distilling it. 



The official ether contains of ethyl-ether 96 per cent, and of 

 alcohol 4 per cent. It is a very mobile, colorless, highly volatile 

 liquid, of a refreshing, characteristic odor, a burning and sweetish 

 taste, and a neutral reaction ; it is soluble in alcohol, chloroform, 

 liquid hydrocarbons, fixed and volatile oils, and dissolves in ten 

 volumes of water. Specific gravity is 0.726 at 15 C. (59 F.); 

 boiling-point 37 C. (98.6 F.). It is easily combustible and burns 

 with a luminous flame. When inhaled, it causes intoxication and 

 then loss of consciousness and sensation. The great volatility and 

 combustibility of ether necessitate special care in the handling of this 

 substance near fire or light. 



cetheris and Spiritus cetheris compositus are mixtures of about one 

 part of ether and two parts of alcohol, 3 per cent, of certain ethereal oils being 

 added to the second preparation. 



