Arginine hydrochloride from gelatin

1 Kossel and Gross, Z. physiol. Chern., 1924, 135, 167 Felix and Dirr, Z. physiol. Chern., 1928, 176, 38. 

The flavianic acid can be recovered from its sparingly soluble barium salt as follows Decompose the salt with a slight excess of hot 20 per cent sulphuric acid, filter at the pump while hot, add some concentrated hydrochloric add to the clear filtrate, and allow the free sulphonic acid to crystallise. 

The method given by Bergmann1 for the preparation of arginine may also be recommended here. 

In the simplified extraction apparatus (Fig. 27 on p. 35) 100 g. of finely powdered tea or tea dust are extracted for eight hours with 400 c.c. of alcohol. The alcoholic extract is then added to a suspension of 50 g. of magnesium oxide in 300 c.c. of water, and the whole is evaporated to dryness on the steam bath in a porcelain basin with frequent stirring. The pulverulent residue is boiled once with 500 c.c. and then three times with 250 c.c. of water and filtered while hot at the pump. 

After 50 c.c. of dilute sulphuric acid have been added to the combined filtrates, they are concentrated to about one-third of their volume, filtered if necessary while hot from the flocculent precipitate which occasionally forms, and then extracted five times with 30 c.c. portions of chloroform. 

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