312 TAURINE. [BOOK n. 



capsule. Having been allowed to cool, the acid supernatant liquid is 

 decanted from the hard resinoid mass which adheres to the bottom of 

 the capsule, and is further concentrated by evaporation and then set 

 aside, until the greater part of the sodium chloride in solution has 

 crystallised. The cooled mother liquor is then treated with strong 

 alcohol, which causes a separation of taurine mixed with some sodium 

 chloride. The substance which thus separates is washed with 

 absolute alcohol, dried and dissolved in the smallest possible quantity 

 of boiling water, which on cooling deposits taurine in fine four-sided 

 prisms. By repeated crystallisation the substance is obtained free 

 from all traces of sodium chloride 1 . 



Synthetic Taurine may be obtained by the action of ammonia 



on /3-chlorethylsulphonic acid. 



CH 2 C1.CH 2 .S0 2 .OH 8 + 2NH 3 = CH 2 (NH 2 ).CH 2 .S0 2 .OH 



v. r ; ^ ^ . / 



/3-chlorethylsulphonic Amidoethylsulphonic acid 



acid. or taurin. 



+ NH 4 C1 



It may be also obtained by adding an excess of sulphurous acid 

 to a solution of vinylamin and evaporating on the water bath. 



CH 2 S0 2 . OH CH 2 - S0 a . OH 



II +1 =1 



CH-NH 2 H CH 2 -NH 2 



Vinylamin. Sulphurous Taurine. 



acid. 



Physical and Taurine crystallises in colourless shining prisms, 



Pr " which are often lar e and have four or six sides< li 



is soluble in from 15 to 16 parts of water at ordinary 



FIG. 22. CRYSTALS OF TAURINE. 

 (a) pure, (b) impure. 



1 Drechsel, Anleitung zur Darstellung, &c., p. 35. 



