OLEIN. 229 



CH 3 

 Palmitic acid, (CH 2 ) 14 , crystallizes from an alcoholic solution in tufts 



COOH 



of fine needles. It melts at 62 C.; still the admixture with stearic acid, 

 as HEINTZ has shown, essentially changes the melting- and solidifying- 

 points according to the relative amounts of the two acids. Palmitic 

 acid is somewhat more soluble in cold alcohol than stearic acid; but 

 they have about the same solubility in boiling alcohol, ether, chloro- 

 form, and benzene. Its barium salt contains 21.17 per cent barium, and 

 silver salt contains 29.72 per cent silver. 



CH 2 .O.C 18 H 33 O 



Olein, or triolein, 57^0^6, = CH.O..C 18 H 33 O, is present in all animal 



fats, and in greater quantities in vegetable fats. It is a solvent for 

 stearin and palmitin. The oleic acid (elaic acid), Ci 8 H 34 O2, as soaps, 

 probably has about the same occurrence as the other fatty acids. 



Olein is, at ordinary temperatures, a nearly colorless oil of a specific 

 gravity of 0.914, without odor or marked taste, and solidifies in crystalline 

 needles at 6 C. It becomes rancid quickly if exposed to the air. It 

 dissolves with difficulty in cold alcohol, but more easily in warm alcohol 

 or in ether. It is converted into its isomer, ELAIDIN, by nitrous acid. 

 CH 3 



(CH 2 ) 7 



PTT 



Oleic acid, , is an unsaturated acid of the series C re H n _ 2 O 2 , and 

 CH 



(CH 2 ) 7 



COOH 



correspondingly takes up two halogen atoms, i.e., iodine, at the double 

 bondage, a factor which is the basis of v. HUBL'S method for determining 

 the iodine equivalent. On taking up hydrogen, which can be accomplished 

 by heating with hydroiodic acid and amorphous phosphorus, it is trans- 

 formed into the corresponding saturated acid, namely, stearic acid. On 

 oxidation the double bonds are satisfied by 2HO groups, and dioxystearic 

 acid, CH 3 (CH 2 ) 7 CHOH.CHOH(CH 2 ) 7 COOH, is formed. Oleic acid readily 

 undergoes oxidation in the air with the formation of acid products, and 

 the occurrence of monoxy stearic acid, found in animal fats in certair 

 instances, can be explained by this oxidation. Oleic acid on heating 

 yields, besides volatile fatty acids, sebacic acid, Ci Hi 8 O 4 , which melts 

 at 127; and with nitrous acid it is transformed into its isomer, solid 

 elaidic acid, which melts at 45 C. 



Oleic acid forms at ordinary temperature a colorless, tasteless, and 

 odorless oily liquid which solidifies in crystals at about 4 C., which 



