( 859 ) 



acid, also a small pioportion of tho nioiio-acid. It' to this mixture 

 is added palmitic acid dissolved in H^SO, a suhstance is obtained 

 with an ester nnmher of 205.1 ; the estei- luimbers of tripalmitin 

 and dipalmitin are respectively 208.8 and 197.6. Hy one single reci-ys- 

 tallisation fi-om absolute alcohol, nearly chemically pure tripalmitin 

 with an ester number of 208.1 and m.p. 64 — 65° could be isolated. 

 Thei'efore, a mixture of dipalmitin and tripalmitin has l)een the 

 main product. The barium salt prepared by me according to their 

 method possesses another composition as stated by them; it should, 

 howevei-, be observed that CjH^ OgS, Ba -j- 2 H^O does not require 

 7.63„/„ of H,0 but 8.50°. 



One part of chemically pure glycerol D 1.261 was dissolved in 

 4 parts of 98.57o sulphuric acid. After 15 minutes an equal volume 

 of water was added, the liquid was neutralised with barium carbo- 

 nate and after j-emoval of the bai-ium sulphate by'filtration the liquid 

 was evaporated in vacuum. After adding a little alcohol it is again 

 evaporated so as to get rid as much as possible of the water. 



If now, an excess of absolute alcohol is added, a thick white 

 preciptate of syrupy consistence is formed, which is shaken several 

 times vigorously with alcohol to remove any free glycerol. The 

 precipitate solidifies after a while and is then dried in vacuum 

 over P2O5 to constant weight. 



3.132 grams of the dried salt gave on evaporation with sulphuric 

 acid 1.7380 grams of Ba SO, = 55.497„ of sulphate or 32.657„ of 

 barium 0.7740 grams gave 0.4295 grams of sulphate = 55.49" „ or 

 32.657„ of barium. 



Calculated for the Ba salt of the anhydrous di-acid 60.24^ , ^ ^^ 

 ,, „ ,, ,, ,, ,, ,, ,, mono-acid 48.67 " ^ "• 



t)n heating the dried compound for IVs hour at 105" in an aii-- 

 bath it turns brown and evolves acrolein. In this operation 1.059 

 grams lost 0.011 grams- or 1.037o- 



Therefore, a mixtui-e of barium salts has formed wliich may be 

 readily explained by the fact that on diluting the mixture of glycerol 

 and sulphuric acid, the tri-acid already formed passes into lowei- acids. 



Claesson '), who was the first to jn-epare glycerolsulphuric acid 

 also obsei-ved this conversion of the tri-acid into the lower acids. 



He prepared the tri-acid from anhydrous glycerol and chlorosul- 

 phonic acid; his statement that this tri-acid, on boiling with water 

 or dilute acids, is readily and completely resolved into glycerol and 

 sulphuric acid is, however, incorrect ; at least after boiling for one 



1) Journal fur praktische Chemie [2] Bd. 20. p. 1. 1879. 



