C. U. C. p. ALUMNI JOURNAL 



249 



Conducted by Prof. George C. Diekman. 



Shark Liver Oil. 



M. Tsujimoto, in /. Ind. Eng. Chem., 

 1 916, calls attention to a highly unsat- 

 urated hydrocarbon present in shark 

 liver oil. This hydrocarbon, named 

 "squalene," is found in some shark-liver 

 oils, and can be produced in Japan in 

 commercial quantities, by distilling the 

 oils which contain it, under reduced 

 pressure, or with superheated steam, and 

 treating the distillate with alkali to re- 

 move free fatty acids. The hydrocarbon 

 is readily soluble in ether, acetone, 

 petroleum ether and carbon tetrachloride. 

 It is only sparingly soluble in alcohol 

 and glacial acetic acid. When mixed 

 with I per cent, of cobalt resinate, it 

 produces, even at low temperatures, a 

 smooth, colorless film, in about 10 days. 

 This film was much firmer than one ob- 

 tained from fatty oils. Complete hydro- 

 genation of squalene results in the pro- 

 duction of an oil-like substance, re- 

 sembling liquid paraffin. When sub- 

 jected to a temperature of — 80° C. this 

 oil-like product becomes a transparent 

 jelly, resuming its mobile character at 

 about — 35° C. 



J' 



Detection of Arachis Oil. 



The presence of arachis oil, in quan- 

 tity as low as 5 per cent, in olive oil, 

 cottonseed oil, soya bean oil and corn 

 oil, may be detected as follows : About 

 20 grammes of the suspected oil are 

 saponified by aid of alcoholic potassium 

 hydroxide solution, and the excess of 



alkali neutralized by aid of a 25 per cent, 

 solution of acetic acid in 95 per cent, 

 alcohol, phenolpthalein being employed 

 as indicator. The mixture is then treated 

 with 50 mils of a 5 per cent, solution of 

 magnesium acetate in a mixture of equal 

 parts of water and 95 per cent, alcohol. 

 After heating to boiling, it is allowed to 

 cool to room temperature with occasional 

 shaking, and then set aside for about 

 24 hours at a temperature of about 10 

 to 15° C. The resulting precipitate is 

 then removed by filtration, and washed 

 twice with 50 per cent, alcohol and three 

 times with distilled water. It is then 

 mixed with 100 mils of hot water and 

 a sufficient quantity of diluted sulphuric 

 acid to insure complete decomposition 

 of the magnesium salts. The separated 

 fatty acids are now washed with water, 

 dissolved in 90 per cent, alcohol, and set 

 aside, when arachidic acid separates in 

 crystal form. 



Detection of Benzoic Acid. 



W. Stadlin, in Chem.-Zeit., 1916, 770, 

 recommends the following method for 

 the detection of benzoic acid in edible 

 fats : From 20 to 30 grammes of the 

 fat, in a semi-melted condition, are 

 spread evenly over the parchment dia- 

 phragm of a Kreis dialyser, and covered 

 with 50 per cent, alcohol. The outer 

 chamber of the dialyser is also filled with 

 alcohol of the same strength. After 24 

 hours the dialysate is made slightly alka- 

 line and heated on a water-bath to re- 



