1 24 Biological Chemistry. 



first stage (the formation of the ethyl sulphate) will not 

 then take place. A part of the sulphuric acid, further- 

 more, is reduced to sulphur dioxide, and a certain amount 

 of charring takes place during the reaction. 



The ether which is prepared by this process is con- 

 taminated by water and alcohol. These can, for the most 

 part, be removed by distillation over calcium chloride. 

 The last traces of alcohol can be removed by treatment of 

 the distillate with metallic sodium ; the alcohol forms 

 sodium ethoxide and remains behind as a residue when 

 the ether is again distilled. 



Ethers are somewhat inert chemical substances and 

 enter into comparatively few chemical reactions. For 

 this reason they are of great value as solvents in various 

 chemical processes. 



The only member of the series of any importance is 

 ethyl ether, boiling point 35, which is largely used as an 

 anaesthetic. It is soluble in about ten times its own 

 volume of water and in most organic solvents. It has a 

 characteristic smell, and is highly inflammable. 



Part XIII. The Alkyl Derivatives of Nitrogen. 



An important series of organic compounds is known, 

 which may be considered as derived from ammonia by the 

 substitution of a hydrogen atom by alkyl group. Such 

 substances may be represented by the general formulae 



NH 2 R-, NHR 2 , NHR 3 



Where one hydrogen only is substituted by an alkyl 

 radicle, the substance is known as a "primary amine," 

 where substituted by two as a " secondary amine," and 

 where by three alkyl radicles as a " tertiary amine." 



Like ammonia, all these substances are strongly basic, 

 giving solutions alkaline to litmus, and forming salts of 



