GLYCEKIN. 171 



Tribromhydrine (Tribromallyl), C 3 H 5 Br 3 . Is also 

 formed by bringing allyl iodide or bromide together 

 with bromine. Colorless, lustrous prisms ; fusing point, 

 16; boiling point, 219-220. When heated with 

 potassium cyanide and alcohol, it is converted into 

 tricyanhydnne (tricy anally 1) C 3 H 5 (CN) 3 . 4 



Hydriodic acid and phosphorus iodide convert gly 

 cerin into allyl iodide and pseudopropyl iodide (p. 66). 



Glycerindisulphuric acid, C 3 H 5 1 (go 2 .OH) 2 . Tlie 

 potassium salt is obtained by heating dichlorhydrine 

 with a concentrated solution of potassium sulphite. 

 The free acid is a deliquescent syrup. Its salts crys 

 tallize well. 



Glycerintrisulphuric acid, C 3 H 5 (S0 2 .OH) 3 . Is 

 obtained from trichlorhydrine, like the previous acid. 

 Tribasic. 



( (OH&quot;) 2 

 Glycerinsulphuric acid, C 3 H 5 j ^ g( j 2 Q H Is 



formed by mixing glycerin and concentrated sul 

 phuric acid. Very easily decomposed. Monobasic 

 acid. 



The sulphur compounds, analogous to mercaptan, 

 monothioglycerin C 3 H*0 2 S, diihioglycerin C 3 H 8 OS 2 , and 

 trithioglycerin C 3 H 8 S 3 , are produced by the action of 

 potassium sulphydrate on mono-, di-, and trichlorhy 

 drine. They are viscid bodies, very slightly soluble in 

 water, more easily in alcohol. They combine with 

 metals like mercaptan. 



Compound ethers. Glycerin nitrate (Nitro- 

 glycerin). C 3 H 5 (0.^0 2 ) 3 . Glycerin is added drop 

 by drop to a mixture of concentrated nitric and sul 

 phuric acids immersed in a freezing mixture, and the 

 mixture afterward poured into water. Colorless oil, 

 heavier than water, and insoluble in it. Exceeedingly 

 explosive and poisonous. 



Fats. The fats, which occur in nature, are par 

 tially solid (tallow, lard) and partially liquid bodies 



