CONTROL OF SAPONIFIED SOLUTIONS 13 
any evidence of the presence of true acids. Whether the addition of 
sodium bicarbonate need be made a matter of routine in the assay 
of commercial cresols for " total phenols " will have to be determined 
by some one with access to a wider variety of such products than are 
likely to come into the hands of the writer. 
The foregoing study on the assay of commercial cresol points the 
way toward a practical method for the determination of total phenols 
in saponified* cresol solutions. If sodium bicarbonate is added to a 
kerosene solution of the sample, then on distillation any original 
excess of sodium hydroxide which would otherwise tend to hold back 
phenols should be converted into innocuous sodium carbonate, while 
any original excess of fatty acid which might otherwise contaminate 
the distillate should be neutralized and held back. 
EXPERIMENT 6 
A saponified cresol solution was prepared from cresol H B as 
follows : 
Soybean oil, 290 grams, was emulsified with a solution containing 
42.3 grams NaOH in about twice its weight of water by stirring in 
a beaker. After several hours at room temperature saponification 
was completed by heating overnight on the steam bath with occasional 
stirring. The soap was then transferred to a flask together with 
520 grams of cresol H B and sufficient water to bring the total weight 
of the mixture to 1,000 grams. Complete solution of the soap was 
effected in the stoppered flask at room temperature. The specific 
gravity of the completed " saponified cresol solution H B " was 
950 
1.0259 at ^5- C, so that the 1,000 grams occupied a volume of 979 
cubic centimeters. The specific gravity of the cresol was 1.0225, and 
its purity had been shown by experiment 5 to be 96.3 volume per 
cent. Therefore there must have been 511 cubic centimeters of cresol 
H B, or 492 cubic centimeters actual phenols present, which makes 
the theoretical content of the saponified cresol solution 50.3 volume 
per cent of total phenols. 
Portions of 40 cubic centimeters of saponified cresol solution H B 
were distilled in a 300 cubic centimeter flask provided with a ther- 
mometer with the addition of 75 cubic centimeters of kerosene, besides 
other additions later noted. The distillate in the tar-acid funnel was 
extracted twice with 20 cubic centimeter portions of sulphuric-acid 
solution, specific gravity 1.505, then three times with sodium- 
hydroxide solution, as in the assay of commercial cresol. To the de- 
crease in volume of the kerosene layer was added a correction of 0.10 
cubic centimeter to compensate for half the phenols extracted in the 
approximately 50 cubic centimeters of the acid layer, and the sum 
was divided by 0.4 to obtain the apparent volume per cent of phenols 
in the sample. The essential data are given in Table 3. The " maxi- 
mum temperature " was that noted, without corrections, on a 16-inch 
thermometer graduated from —30° to 400° C. 
