98 METHODS OF ANALYSIS. 



stand for one hour in water that is kept at 15 C. turning occasionally to 

 hasten the settling of the chloroform, and note the volume of the chloroform. 

 After thoroughly cleansing and drying the apparatus repeat this operation, 

 using the diluted distillate from the sample under examination instead of the 

 fusel-free alcohol. The increase in the chloroform volume with the samples 

 under examination over that with fusel-free alcohol is due to fusel oil, and this 

 difference (expressed in cubic centimenters) multiplied by the factor 0.663 gives 

 the volume of fusel oil in 100 cc, which is equal to the percentage of fusel oil 

 by volume in the 30 per cent distillate. This must be calculated to the percent- 

 age of fusel oil by volume in the original liquor. 



Example. A sample of liquor contains 50 per cent of alcohol by volume. The 

 increase in the chloroform volume with the 30 per cent fusel-free alcohol is 

 1.42 cc. The increase in the chloroform volume with the distillate from the 

 liquor under examination diluted to 30 per cent is 1.62 cc ; difference, 0.20 cc.' 

 The volume of fusel oil in 100 cc of the 30 per cent distillate is then 

 0.20X0.663=0.1326, and the percentage of fusel oil by volume in the original 



. 50X0.1326 

 liquor is go =0.221. 



(b) ALLEN-MARQUARDT METHOD. PROVISIONAL. 



Add to 100 cc of whisky 20 cc of half-normal sodium hydroxid, and saponify 

 the mixture by boiling for one hour under a reflux condenser. 6 Connect the 

 flasks with a distilling apparatus, distil 90 cc, add 25 cc of water, and continue 

 the distillation until an additional 25 cc is collected. 



Approximately saturate the distillate with finely ground sodium chlorid and 

 add a saturated solution of sodium chlorid until the specific gravity is 1.10. 

 Extract this salt solution four times with carbon tetrachlorid.e using 40, 30, 

 20, and 10 cc, respectively, and wash the carbon tetrachlorid three times with 

 50 cc portions of a saturated solution of sodium chlorid and once with saturated 

 solution of sodium sulphate. Then transfer the carbon tetrachlorid to a flask 

 containing 5 cc of concentrated sulphuric acid, 45 cc cf water, and 5 grams of 

 potassium bichromate, and boil for eight hours under a reflux condenser. 



Add 30 cc of water, and distil until only about 20 cc remain ; add 80 cc of 

 water, and distil until but 5 cc are left. Neutralize the distillate to methyl 

 orange, and titrate with sodium hydroxid, using phenolphthalefn as indicator. 

 One cubic centimeter of tenth-normal sodium hydroxid is equivalent to 0.0088 

 gram of amyl alcohol. 



Rubber stoppers can be used in the saponification and first distillation, but 

 corks covered with tinfoil must be used in the oxidation and second distillation. 

 Corks and tinfoil must be renewed frequently. 



11. Sugar. Provisional. 

 Proceed as directed under " XIII. Wine," page 87. 



The temperature must be held as nearly 15 C. as possible. If any variations occur, 

 the chloroform must be increased or decreased 0.040 cc for every degree above or below 

 that temperature (Gebek und Stut/n-. 7,ts. angew. Chom.. is-.i::. I:;LI. 



Or 100 cc of the liquor may be mixed with 20 cc of half-normal sodium hydroxid. 

 allowed to stand overnight at room temperature, and distilled directly. 



Purify 5 liters of carbon tetrachlorid by boiling for several hours under a reflex con- 

 denser with 200 cc of sulphuric acid and 25 grams of potassium bichromate in 200 cc of 

 water ; separate from the oxidizing mixture by distillation, and redistil over barium 

 carbonate. 



