AMINES I27 



(4) Carbylamine Reaction. Dimethylamine and secondary amines 

 do not yield' isocyanides with chloroform and alcoholic potash. 



(5) Reaction with Acetyl Chloride. Secondary amines form with 

 acetyl chloride, etc., crystalline substituted amides which are useful for 

 purposes of identification : 



CH 3 COC1 + HN(CH :$ ) 2 = HC1 + CH 3 CO-N(CH,) 2 . 



Reactions of a Tertiary Amine (Trimethylamine). 



(1) Trimethylamine is evolved on adding excess of alkali to a 

 solution of its hydrochloride : 



(CH 3 ) 3 : N : HC1 + NaOH = (CH 3 ) 3 : N + NaCl + H 2 O. 



It is a gas like the primary and secondary amines with a fishy 

 ammoniacal odour and is combustible. 



(2) Double salts are formed on adding v alcoholic solutions of gold 

 chloride, etc., to an alcoholic solution of trimethylamine hydrochloride. 



(3) Action of Nitrous Acid. Trimethylamine does not react with 

 nitrous acid. 



(4) Carbylamine Reaction. This reaction is not given by trimethyl- 

 amine and tertiary amines. 



(5) Reaction with Acetyl Chloride. Tertiary amines do not react. 



(6) Quaternary Ammonium Salts. Tertiary amines combine with 

 alhyl iodides to form a quaternary ammonium salt : 



/CH, 

 (CH 3 ) 3 ;N+CH 3 I 



In this compound the halogen atom can be replaced by the 



hydroxyl group : 



/CH 3 /CH 3 



(CH 3 ) 3 : N( + AgOH = Agl + (CH 3 ) 3 | N/ 



\I \OH. 



Choline. 



Choline, or hydroxy-ethyl-trimethyl-ammonium hydroxide is a 

 trimethylamine derivative of ethyl alcohol, 



CH 2 OH 



CH 2 N ;(CH 3 ) 3 



OH. 



It occurs in the free state in most animal tissues and is widely distri- 

 buted in plants. It is a constituent of lecithin, which is present in 

 e og ylk, nervous tissue, and in seeds of plants from which it arises by 

 hydrolysis. 



Preparation. 



Cnoline is usually prepared from egg yolk. The lecithin is extracted with 

 ether or alcohol. The residue left on evaporation of the solvent is hydrolysed 

 by boiling with baryta. The barium soaps (p. 99), which are formed, are 

 filtered off and the solution evaporated to dryness. The choline is extracted 



