LESSON X 



SEPARATION OF PTOMAINES 



173 



(c) Separate the ethereal extract. 



(d) Repeat this three times and 

 collect the ethereal extracts. 



(e) Distil off the ether. 



(/) Neutralise the residue, before 

 it sets, with 12 per cent caustic 

 soda : turbid liquid. 



(g) Mix with three to four times 

 its volume of 12 per cent caustic 

 soda, and keep in the cold for 

 twelve to twenty-four hours. 



(ti) Remove the liquid from the 

 crystals which have formed and 

 wash the crystalline residue with 

 cold caustic soda. 



(i} Now wash thoroughly with 

 water. 



(k) Dissolve the crystals in warm 

 spirit. 



(1} Add a large excess of water : 

 the crystals are reprecipitated. 



(m) Allow to settle and filter. 



(c) Pour this into thirty times 

 its volume of cold water. 



(d) Allow to stand for several 

 days : crystals appear. 



(e) Filter. 



(/) Wash crystalline residue with 

 water, until the washings are quite 

 clear. 



(g) Press out as much of the 

 water as possible. 



(h) Dissolve the crystalline resi- 

 due in the least possible quantity 

 of absolute alcohol. 



(i) Pour this solution into a 

 large excess of water : precipitate. 



(k) Filter again and redissolve 

 the residue in the least possible 

 quantity of warm alcohol : crystal- 

 line precipitate will appear. 



(8) Mix the two crystalline precipitates, and dissolve 

 them in the least possible quantity of warm alcohol. 



(9) Pour the alcoholic solution into twenty times its 

 volume of ether. 



(10) Shake, and allow to crystallise. 



(11) Filter: residue consists of the benzoyl compound 

 of tetmmeihylene-diamine or putrescine. 



(12) Filtrate : distil off the alcohol and ether. 



(13) Crystals appear: benzoyl compound of penta- 

 methykne diamine or cadaverine. 



