218 CHEMISTRY 



As mentioned above, ethylether is the chief product when ethyl- 

 halides are treated with alcoholic potash or with dry sodium ethyl- 

 ate; this is also true when dry silver oxide and ethylhalides are used. 

 These reactions, which have been interpreted by Williamson and 

 others on the basis of double decomposition or of minute ionization, 

 must obviously be attributed to the absorption by the ethylidene of 

 alcohol or of water which is set free by the action of the halogen 

 hydride particles on the sodium ethylate or silver oxide respectively, 



+ H-OC 2 H 5 ->CH 3 CH/ 



X OC 2 H 5 , 

 H H 



3 ' . 



\ \ / 



H OH 



or 2CH 3 CH+0 -CH 3 CH' .CHCH 3 . 



We are now able to consider an entirely new explanation of the 

 function of sulphuric acid, or of phenylsulphonic acid, in converting 

 ethylalcohol into ether. Sulphuric acid acts first of all with alcohol 

 at ordinary temperatures to give both mono- and diethylsulphate; 

 the first stage in the reaction cannot be ascribed to the union of 

 ethylidene, formed by dissociation of alcohol, with free sulphuric 

 acid, since ethylether, which is relatively more dissociated than alcohol, 

 acts only very slowly with concentrated sulphuric acid at ordinary 

 temperatures to give primary ethylsulphate. Furthermore since 

 sulphuric acid itself is completely dissociated into its components, 

 sulphurtrioxide and water, at 400 it is extremely probable that 

 monoethylsulphate is formed by the union of sulphurtrioxide, pre- 

 sent by dissociation, H 2 S0 4 <=*SO 3 + H 2 O, with alcohol, 



OH 



OC 2 H 5 



Now it is well known that ether formation in a mixture of sulphuric 

 acid and alcohol begins perceptibly only at 95 and proceeds very 

 slowly at that temperature. The favorable temperature for ether 

 manufacture is 140. This is self-evident in view of the following 

 considerations. Primary and secondary ethylsulphate possess the 

 dissociation-points 160 and 200, respectively; consequently these 

 substances must be dissociated at 140 to a very great extent into 

 sulphuric acid and one or two molecules of ethylidene respectively. 

 Addition of alcohol at 140, therefore, simply necessitates a com- 

 bination with the ethylidene particles, 



