FATTY ACIDS. 21 



dissolves in 100 parts of water to the extent of 12 parts at 11 to 

 12, and the solubility decreases on heating. 



Caprylic Acid, C 7 H 15 COOH. This acid crystallises in plates 

 or needles melting at 16-5 C., and boils at about 236 C. It 

 has a faint unpleasant odour of sweat, and a sharp rancid taste ; 

 it is difficultly soluble even in hot water, from which it crystal- 

 lises in plates. From dilute solutions it distils eight times as 

 fast as water. 



Barium caprylate crystallises in anhydrous plates, and is 

 soluble to the extent of 6 parts in 100 parts of water at 20 C. 

 The calcium salt crystallises in long thin needles, and is less 

 soluble than the barium salt 0-6 part per 100. 



Capric Acid, C 9 H 19 COOH. This acid has a faint goat-like 

 odour, and is only very slightly soluble in water. It crystallises 

 in brilliant plates, melting at 30 C. ; it boils at 268 to 270. 

 The barium and calcium salts are nearly insoluble in water, 

 even on boiling, and the salts of the alkalies are the only ones 

 appreciably soluble. 



Laurie Acid, CnH^COOH. The acid is solid at ordinary 

 temperatures, and is not soluble to any extent in water ; it 

 passes over to a very appreciable extent when distilled with 

 steam. It crystallises from alcohol in needles, melting at 43*6 C. 

 It cannot be distilled without decomposition at the atmospheric 

 pressure, but at 100 mm. it has a boiling point of 225 C. The 

 salts of the alkali metals yielded by the acids previously described 

 are soluble in strong salt solution ; the laurates of sodium and 

 potassium are, however, precipitated by strong sodium chloride 

 solutions, but not by weaker ones. Laurie acid is a leading 

 constituent of coco-nut and palm-nut oils. 



Myristic Acid, GtgH^COOH. This acid crystallises in 

 laminae melting at 53-8 C. and boils at 250-5 under 100 mm. 

 pressure ; it cannot be distilled alone. The acid is insoluble 

 in water and its salts of the alkali metals are precipitated by salt. 



Palmitic Acid, C 15 H 31 COOH. The acid is quite insoluble 

 in water ; it separates from alcohol in tufts of finely crystal- 

 lised needles ; and the melted acid solidifies on cooling to a pearly 

 crystalline mass. The melting point is 62 C., and it boils under 

 100 mm. pressure at 271-5 C. ; it cannot be distilled under 

 atmospheric pressure without decomposition. 



According to Hehner and Mitchell a saturated solution of 

 palmitic acid in alcohol of specific gravity 0-8183 contains 

 from 1-03 to 1-32 grammes per 100 c.c. at C. 100 parts 

 of absolute alcohol at 19-5 dissolve 9-32 parts ; it is, however, 

 readily soluble in boiling alcohol and crystallises out on cooling. 



Stearic Acid, C^H^COOH. This acid is quite insoluble in 

 water ; it crystallises from alcohol in white, nacreous laminae, 



