V O L U M E 23, NO. 8, A U G U S T 1 9 5 1
1095
had the minimum optical density value, calculate the total amount of phenol present by using the following equation:
with a glass rod. The packing consisted of 27.3 grams of silicic acid and 15 ml. of water. COh-CLU SION
yo phenol
=
11.1
where A = absorbance (optical density), v = volume of fraction in milliliters, e = specific extinction coefficient for phenol in cyclohexane, and ?y;r = weight in milligrams of original sample in aliquot.
This method provides two essential techniques required in the quantitative analysis of phenol in cresylic acid: a rapid and convenient means of quantitatively separating phenol from its homologs, and a precise and accurate means of determining the quantity of phenol that has been separated. 1.0
RESULTS
To illustrate the precision of the method, data covering the analysis of a series of samples of known phenol content are presented in Table 1. These data indicate a precision of approximately 2Yc.
t'41
CHROMATOGRAM OF CRESYLIC ACID USING AN 8' COLUMN
1.2
0 0.8
CRESYLIC A C I D FORTIFIED WITH PHENOL
- -- ---7---- -- ---
r
0.4
0.2
1' 40
i
I
60
80
I
100
120 LAL.
Figure 4.
ML.
Figure 3.
OF
140 160 180 OF PERCOLATE
200
I
,
I
220
240
0
Chromatogram of Cresylic Acid
The use of a spectrophotometer for the final phenol estimation is recommended because of the convenience and accuracy afforded. If an inqtrument of thii type is not available, one of the current colorimetric methods for determining phenol may be employed, as there 1% ill he no interfering substances present.
PERCOLATE
Typical Sample Curve LITERATURE CITED
(1) Chapin, R. AI., U. S.Dept. -4gr., Bur. dnimal Ind., Bull. 1308
Table I. Comparative Results Obtained on Known Samples of Cresylic Acid by Partition Chromatography Sample Purified phenol Phenol-m-cresol blend Petroleum cresylic acid Known blend A B C D E
Phenol, 5% W t . Known Found 99 100 3J 54 83 83 10 11 42 50
40
52 60 68 81
59 67 83
RESOLUTION OF HIGHER HOMOLOGS
Although the present work was not concerned n-ith the determination of other phenolic compounds, the jnherent possibilities of the method nia) be showi by the graphical chromatogram in Figure 4. This resolution n-as produretl by the passage of a cresylic acid sample through an 8-inch column. The coniponents of the mirture were separated into four distinct bands: Band 1
2 3
4
Percolate, 311. 45- 65 66- 80 80-133 165-245
Component Higher boiling phenolic materials o-Cresol m- and p-cresol Phenol
The column was prepared in a manner analogous to that of the 6-inch column, except that it was packed tighter by tamping
( S o v . 22, 1924). (2) Craig, L. C., J . Bid. Chern., 150, 33 (1943). (3) Ibid., 155, 519 (1944). (4) Craig, L. C., Golumbic C., llighton, H., and Titus, E., Ibid., 161,321 (1945). ( 5 ) Hogeboom, G. H., and Craig. L. C., Ibid., 162, 363 (1946). (6) &filler, J. K., and Urhain, 0. RI., ISD.ESG. C H n f . , hrua~.ED.,2, 123 (1930). (7) Sato, P., Barry, G. T., and Craig, L. C.. J . B i d . Chem., 170, 501 (1947). (8) JVarshon-sky, B., and Schanta, E. J., AXAL. CHEM., 20, 951 (1948). (9) T~illiamson, B. and Craig, L. C., J . B i d Chem., 1 68, 687 (1947). RECEIVEDFebrriary 23, 1951. Presented before the .Inalytiral Section of t h e Meeting-in-Miniature, Philadelphia Section, AJIERICAS CHEJIICAL S o c m r y , January 18, 1951.
Techniques and Reactions- for Paper C hro m atography-torr e ct io n In the article on "Techniques and Reactions for Paper Chromatography" [ h s a ~C.H m r , 23, 823 (19Sl)I the second line of the first column should read the use of formeous hydrochlcric acid," instead of "the use 3f hydrochloric acid." I n the thirteenth line of the seccnd cclumn the address should read Yonkers 5 , S . Y. On page 824, fourth line from bottom of second column, "chloroplatinic acid" should have been used instead of "platinochloric acid." GERRITT O E N S I E S
