OLEIC ACID. 55 



products. For the same reason there is some doubt as to its 

 properties. 



The following properties are assigned to oleic acid : — A colour- 

 less liquid free from smell, which moistens the skin, solidifies 

 at 4° C, and melts at 14° C. Specific gravity at 14° C. 0-898, 

 and at 100° C. 0'876. It cannot be distilled under atmospheric 

 pressure, but boils under 100 mm. pressure at 286° C. It can 

 be easily distilled below 270° in a current of superheated steam. 



Oleic acid is insoluble in water, but very soluble in alcohol 

 even if considerably diluted. To a solution of 1 c.c. of oleic acid 

 in 95 per cent, alcohol 2-2 c.c. of a mixture of equal parts of acetic 

 acid and water can be added without causing precipitation ; 

 further quantities, however, throw the oleic acid out of solution. 



On exposure to the air it turns yellowish, and becomes rancid ; 

 it then reddens blue litmus paper, while pure oleic acid is said 

 not to do so. 



By the oxidation of oleic acid dioxystearic acid is formed. 



By the action of bromine di-brom-stearic acid is formed : this 

 is a heavy yellow oil, which has not been crystallised. By 

 reduction with zinc and hydrochloric acid oleic acid is aiiain 

 formed. Oleic acid also absorbs iodine from Hubl's reagent, 

 and is said to form chlor-iodo-stearic acid. 



Strong sulphuric acid acts on oleic acid, forming stearo-siil- 

 phonic acid or sulpho-stearic acid ; on boiling with watiT, sul- 

 phuric acid is split off and hydroxystearic acid is formed, with 

 other products. 



When oxidised by alkaline potassium permanganate di-oxy- 

 stearic acid is formed. 



The salts of oleic acid behave with water in much the same 

 way as the salts of stearic and palmitic acids. All the oleatc-s 

 are soluble in alcohol, and those of copper, lead, and zinc are 

 soluble in ether. 



By the action of fused alkalies oleic acid is split up into salts 

 of acetic and palmitic acids. 



Nitrous fumes act on oleic acid in a characteristic manner; 

 the liquid oleic acid is transformed into the isometric solid elaidic 

 acid melting at 45° and boiling at 288° C. at 100 mm. pressure. 



Baruch has proposed the following formulae for oleic and 

 elaidic acids : — 



Oleic Acid. Elaidic Acid. 



CgHi7— C— H CgHu— C— H 



H-C-(CH2)7-COOH COOH-(CH„)r-C-H 



Acids of the Series, CH-i.-sCOOH — Linolic Acid, 

 C,-H„COOH.— It is not known whether this acid exists nor- 

 mally in butter fat ; if so, the proportion is probably not large. 



