122 ACRYLIC ACID. 



ver acetate. This precipitate crystallizes from alcohol 

 in needles. 



Allyl-mercaptan, C 3 H 5 .SH, is formed from allyl 

 iodide and an alcoholic solution of potassium sulphy- 

 drate. A liquid, boiling at 90, very similar to ethyl- 

 mercaptan. 



Allylamine, C 3 H 5 .NH 2 . Is produced when allyl 

 mustard-oil is treated with zinc and hydrochloric acid, 

 or, better, with concentrated sulphuric acid. Liquid, 

 boiling at 58. By the action of ammonia on allyl 

 iodide, the principal product formed is tetrallylammo- 

 nium iodide (C 3 H 5 ) 4 ]NT, a crystalline body, which, when 

 heated with silver oxide, yields tetrallylammonium 

 hydroxide (C 3 H 5 ) 4 E".OH, a strongly alkaline liquid. 



C. MONOBASIC MONATOMIC ACIDS, C n H 2n ~ 2 2 . 



1. Acrylic Acid. 

 C 3 H 4 2 = CH 2 :CH.CO.OH. 



Formation and preparation. Is produced from its 

 aldehyde, acrolein, when the latter, mixed with 3 

 parts H 2 0, is left for a few days in contact with silver 

 oxide. The liquid is then heated to boiling, sodium 

 carbonate added until it shows an alkaline reaction, 

 evaporated to dryness, the residue decomposed with 

 dilute sulphuric acid, and filtered. By distilling the 

 filtrate the pure acid is obtained still containing water. 

 Can be prepared in any quantity from allyl alcohol. 

 The alcohol is combined with bromine, the resulting 

 alcohol oxidized, and the dibrompropionic acid thus 

 obtained, freed of bromine by the action of zinc-dust 

 and water. Can only be obtained free of water by 

 the decomposition of its silver or lead salt by means of 

 sulphuretted hydrogen. It is also produced by heat- 

 ing j3-iodopropionic acid with alcoholic potassa or with 

 milk of lime. 



Properties. Clear liquid, boiling above 100 ; has an 

 odor similar to that of acetic acid ; miscible with water 

 in all proportions. Oxidizing agents resolve it into 



