48 DERIVATIVES OF ETHYL ALCOHOL. 



alcohol at a temperature of 140 ; by means of the 

 double decomposition of sodium ethylate C 2 H 5 .ON"a 

 and ethyl iodide C 2 H 5 I. For its preparation a mixture 

 of 9 parts of concentrated sulphuric acid and 5 parts 

 of 85-90 per cent, alcohol is heated to boiling, i.e. up 

 to 140, in a retort connected with a good condensing 

 apparatus. During the operation just as much alcohol 

 is allowed to flow into the retort, through a tube 

 passing to the bottom of the retort, as liquid distils 

 off. The distillate consists of ether and water. The 

 formation of the ether in this reaction takes place in 

 two phases. At first, from one molecule of alcohol 

 and one molecule of sulphuric acid, water and ethyl- 

 sulphuric acid are formed ; the latter then acts on a 

 second molecule of alcohol, the result being ether and 

 sulphuric acid. Hence a small quantity of sulphuric 

 acid can transform a large (theoretically an unlimited) 

 amount of alcohol into ether. 



Ether prepared in this way contains alcohol, which 

 has distilled over unchanged, especially when the too 

 rapid addition of alcohol to the mixture caused the 

 temperature to sink much below 140; it also often 

 contains sulphurous acid, when, the addition of the 

 alcohol having been too slow, the temperature in the 

 retort has risen much above 140. Both impurities 

 may be removed by shaking the distillate with water 

 containing an alkali and rectifying the ether, after 

 separating from the water, over calcium chloride or 

 quicklime. Ether can be obtained perfectly anhy- 

 drous and free from alcohol by being allowed to stand 

 for some time in contact with metallic sodium. 



Colorless, limpid liquid, strongly refracting, of a 

 peculiar penetrating odor and taste. Specific gravity 

 at + 20 = 0.713, at = 0.736. Very volatile, boil- 

 ing at 35. 5. At 31 congeals, forming a crystalline 

 mass. Easily inflammable, burning with a luminous, 

 sooty flame. Mixed with air in the form of vapor it 

 is exceedingly explosive. Inhaled as vapor it causes 

 unconsciousness and insensibility. Does not mix with 

 water; ether, however, does dissolve some water -f s 



