0.1685 gm. substance gave 0.0557 gm. H 2 and 0.1054 gtn. C0 2 . 



0.1693 gm. substance gave 0.1363 gm. Mg 2 P 2 O r . 



Found: C=17.06; H=3.69; P=22.44 per cent. 



For inosite triphosphoric acid C 8 H 15 O 15 P 3 =420. 



Calculated: C=17.14; H=3.57; P=22.14 per cent. 



In the above combustion a slight residue of unburned carbon re- 

 mained enclosed in the fused metaphosphoric acid. It was mixed with 

 some fine copper oxide and again burned when a few additional milli- 

 grams of carbon dioxide was obtained. 



PROPERTIES OF INOSITE TRIPHOSPHORIC ACID 



The reactions of this acid differ in several particulars from phytic 

 acid or inosite hexaphosphoric acid. 



The concentrated aqueous solution gives no precipitate with 

 ammonium molybdate either in the cold or on warming. The cold 

 aqueous solution of inosite hexaphosphoric acid gives a white crystal- 

 line precipitate with ammonium molybdate. 



The aqueous solution of the acid is not precipitated with silver 

 nitrate. Inosite hexaphosphoric acid gives a white amorphous precipi- 

 tate with silver nitrate in excess. However, a solution of inosite 

 triphosphate neutralized with ammonia gives a white amorphous preci- 

 pitate with silver nitrate. 



An aqueous solution of inosite triphosphoric acid when added to a 

 solution of egg albumin causes only a slight turbidity ; on longer stand- 

 ing a white precipitate separates slowly. Inosite hexaphosphoric acid 

 precipitates egg albumin immediately. 



The acid is very soluble in water and readily soluble in alcohol 

 and absolute alcohol ; from the latter solution it is precipitated by 

 ether in small, oily drops. 



The acid is not precipitated by barium or calcium chlorides but 

 alcohol produces in these solutions white amorphous precipitates ; 

 these salts are likewise precipitated with ammonia. 



CLEAVAGE OF INOSITE TRIPHOSPHORIC ACID INTO 

 INOSITE AND PHOSPHORIC ACID 



One gram of the acid, dissolved in a little water, was heated with 

 10 cc. of 5N/1 sulfuric acid in a sealed tube for three hours to 150 to 

 155° The contents of the tube were then slightly yellowish brown in 

 color. The sulfuric and phosphoric acids were precipitated with 

 barium hydroxide and the inosite isolated in the usual way. Unfor- 

 tunately a portion of the solution was lost but from what remained 0.1S 

 gram inosite was obtained. After twice recrystallizing from dilute 

 alcohol with addition of ether, 0.12 gram of inosite in the characteristic 



42 



