INDUSTRIAL AND ENGINEERING CHEMISTRY
1474
Vol. 39, No. 11
ACKNOWLEDGMEhT LEGEND
T h e cooperation of the Kendall Refining Company, who performed many of the tests described in this paper, and the uermission of the Selenium Development Committee t o publish the results of this investigation, are gratefully acknowledged. T h e authors also wish to thank H. L. Hemmingway for his assistance.
ADDITIVE
LITERATURE CITED
SOC. Testing MateriaZs, 42, 326 (1942). ( 2 ) Astin, S., Moulds, L. de V., and Riley, H. 1935, 901. L., J . Chem. SOC., (3) Am. SOC.Testing Materials, Standards, 1940 Supplement, Part 111, p. 72. (4) C.R.C. Test Procedure L-4. ( 5 ) Georgi, C. W., S.A.E. Journal, 51, 52 (1943). ( 6 ) Guillemonat, 9.,Ann. Chim., 11, 143 (1939). (7) Hinsberg, Ann., 260, 40 (1890). (8) Lamb, G. G., Loane, C. >I., and Gaynor, J. W.,IND.ESG. CHEX., A s ~ L .ED., 13, 317 (1941). (9) Linstead, R. P., Chem. SOC.Ann. Repts., 34, 238 (1937). (10) Long, J. S., and Mecarter, \IS. . IF'.'., IND. EIZG.CHEW.23, 786 (19311. (11) Matthijsen, H. L., J . Znst. Petroleum, 26, 72 (1940) (12) Mizushima, S., and Yamada, T., J . SOC. Chem. Ind. Japan, 32, 848 (1929). (13) Siebeneck, H., Petroleum Z., 18, 281 (1) A m .
I
(1922).
(14) Stein, G.. Angew. Chem., 54. 146 (1911) (15) Underwood, A. F., S.A.E. Transactions, 43, 385 (1938). (16) Waitkins, G. R., and Clark, C. W , Chem. Rezs., 36, 235 (1945). Figure 7
RECEIVED December 26, 1946.
Vapor Pressure Data for Phenols K. B. GOLDBLUM, R. W. ,MARTIN, AND R. B. YOUNG General Electric Company, Pittsfield, Muss. Vapor pressure data for phenol, o-cresol, m-cresol, p cresol, four mixtures of m- and p-cresol, o-phenylethylphenol, and p-phenylethylphenol were determined by a modified Ramsay-Young procedure. The data show that
there is no evidence of a constant boiling mixture of mand p-cresol which boils lower than the ,components. Data on the vapor pressure of 0- and p-phenylethylphenol are presented for the first time.
T
T h e materials used in the investigation were purified, 11-here possible, by a distillation in which the foreruns and residues were discarded and only t h e middle fraction boiling over a narrow range of a f w tenths of a degree was collected. T h e p-phenylethylphcnol was purified by a recrystallization from a petroleum ether of 30-60" C. boiling range until a maximum melting point of 57" C. was reached. T h e mixtures of m- and p-cresol were prepared b y weighing the purified components. T h e composition of the mixtures is given in Table 11. The apparatus used is a modification of the Ramsay-Young equipment (1). The change consists in shortening the neck of the distilling flask so t h a t the more difficultly volatile phenols and cresols distill into the cooled flask and do not condense back.
HE vapor pressure d a t a for phenol, o-cresol, m-cresol, pcresol, and four mixtures of m- and p-cresol were obtained in
1941 during a n investigation of t h e possibility of the existence of a constant boiling mixture of m-and p-cresol. T h e boiling points of these t n o materials are very close together (Table I). T h e close proximity of the boiling points does not preclude the eaistence of a constant boiling mixture of the two materials. The d a t a for 0- and p-phenylethylphenol were determined in 1943. T h e structural formulas for the latter compounds arc:
H
oH
H
CH, o-phenylet h ylphenol
p-phenylethylphenol
November 1947
INDUSTRIAL AND ENGINEERING CHEMISTRY
1475
TABLE I. BOILI\GPOI\TI S
O C i r 760 RIv. ~CRE~OLS
rn-Cresol 202 8 201 0 202 8 202 7 202 2
TO ATMOSPHERE
p-Cresol 202 202 202 202 202
OF
m-
4\1)
Reference
5 32
(8)
(6)
(4)
32 1
(3)
(a
TABLE 11. CO\IPO~ITIO\ OF ~ I I X T L R E ~ p-Cresol, % 19 23 39 93 59 94 79 27
m-Cresol, % 80 77 60 07 40 06 20 73
Mixture No 1 2 3
4
000
700
Figure 1.
0
Vapor Pressure Apparatus
J
eo0
I
Figure 1 shows the vapor pressure apparatus; the distilling flask on the left is equipped with a dropping funnel, to which is attached a calibrated thermometer. This thermometer is placed so that the bulb, \$rapped with several turns of cloth, is located a t approximately the center of the flask. An oil of high flash point was used for the heating medium in some of the earlier n o r k ; however, it is more convenient to use concentrated phosphone acid which has been previously heated to about 250" C. to removc water, and which can be kept water-white for ease in reading the thermometer by the periodic addition of a few erystals of potassium nitrate. The second flask can be cooled with ice, although air cooling : : xas found satisfactcry for these high boiling materials. The cooled flask is connected to a 21/2-gallon suige vessel nhich acts as a reservoir. T h e surge vessel has connections to a manometer, a vacuum pump, and the atmosphere. While both open- and
i 300 W
5 400 m Y
E 300 e 00
M, - CRESOLS, MIXTURES l,2,3,4 o
l
140
110
180
170
TEMPERATURE,
Figure 2.
180
I90
200
"0.
Data of Table I11
TABLE 111. YAPORPRESSURE DATAFOR PHENOL AKD CRESOLS Phenol Temp.,
Pressure, mm. Hg 214 317 458
c.
141.1 152.6 164.4 168.3 173.5 181.0
515 601 740
140 2 145.1 171.4 176.6 181.1
207 246 564 653 739
Tyw., C. 142.3 153,3 164.5 171.2 183,3 189.8
O
c.
Temp.,
149.5 164.3 172.0 179.6 187.4 192.1 196.3 201.1
145.7 163.6 171.6 179.2 187.2 193.7 200.8
Pressure, mm. Hg 132 245 317 400 504 605 738
149.6 154.1 176.4 183.4 201.1
153 178 366 461 742
153.0 183.8 190.8 197.1 200.9
172 468 557 664 738
Temp.,
' c.
146.0 179.5 189.5 196.8 200.8
p-Cresol
c.
Mixture 1 Pressure, mm. Hg 180 251 319 411 515 609 733
:%
177.1
Pressure, mm. Hg 152 25 1 32 1 404 505 577 649 742
c.
Temp.,
182 385 460
m-Cresol Temp.,
o-Cresol Pressure, mm. Hg 173 253 358 439 615 734
Temp.,
c.
l50,4 164.0 172.0 181.3 188.1 194.0 200.8 146.9 176.8 184 0 190.5 196.7 200.8
Mixture 3 Pressure, mm. Hg 156 247 319 424 515 609 736 138 371 459 552 660 735
Mixture 2 Pressure, mm. Hg
132 401 562 659 732
Mixture 4 Temp., Pressure, " c. mm Hg 149 2 148 163 9 247 172 7 328 180 5 414 188 5 521 194 1 612 200 8 734 146 9 136 176 4 367 183 6 454 191 0 55 1 197 0 662 200 8 734
INDUSTRIAL AND ENGINEERING CHEMISTRY
1476
100
I20
160
140
Figure 3.
200
I60
T E Y P E R ATU RE,
220
240
260
OC.
Data of Table I\’
closed-leg mercury manometers ere uscd, the former type is preferred as being more reliable. I n this case, however, a simultaneous barometer reading is necessary. I n practice, the surge vessel should be w a p p e d in a large towel to minimize the Fffect of temperature changes in the room and also to act as a safety guard in case of brcakage. PROCEDURE
T o determine the pressure-temperature data foi a pal ticulai material, the bath is heated to about 20” C. above the temperature to be investigated. A vacuum is drawn on the system, and the vacuum pump is cut off with the stopcock. The manometei is then observed for 10 to 15 minutes to see if the Evsteni ic vacuum-tight. If no leaks occur, the stopcock of the dropping funnel containing the molten phenol or cresol is opened and 50 regulated that the cloth around the thermometer is always vet and the bottom of the first flask always dry Several reading& of temperature and pressure are then obtained over a long enough period t o ensure equilibrium (usually 5 t o 10 minutes). The pressure is then increased or decreased; the system i q again alloived to come to equilibrium; and a further set of data it. taken. The complete data taken consist of time, equilibrium temperature in the first flask, barometric pressure, ambient temperature of the barometer, manometer readings and ambient temperature of the manometer, bath temperature, and emergent stem temperature of the thermometer In the first flask, when necessary. DATA
Corrections in the manometer readings N ere found necessary when the closed-leg manometer was used (probably because of a bmall amount of trapped air in the closed leg). The barometer and manometer readings were corrected to standard conditions. Emergent stem (when necessary) and calibration corrections were applied t o the readings,of the thermoqeter in the first flask. The corrected temperature and pressure data are presented in Tables I11 and 1V and Figures 2 and 3. CALCL-LATED D ~ T A .The d a t a covering the relation of thrx reciprocal of the absolute temperature to the logarithm of tho pressure may be expressed by the following formula: logP n here
=
-M
-
1 ‘
+c
P = pressure, mm. mercury T = temperature, ’ K. = slope of log pressure LS. reciprocal of absolute temperature line C = intercept of this line a t 1 ’1’= 0
M
Vol. 39, No. 11
o-Phenylethylphenol p-Phenylethylphenol Temp., Pressure, Temp., Pressure, c. mm. Hg c. mm. H g 193 1 20.1 216.0 31.5 202.4 31.5 216.5 32.1 217.4 51.7 32.5 217.0 52.3 211.6 228.9 50.2 227.6 74.8 229.3 50.6 228.2 76 2 74.7 241.8 234.8 91.6 75.7 242,o 235 4 92.6 246,2 86.7 241.9 109.8 246.5 87.1 242.1 250 4 111.6 98.1 250 3 250.5 98.9 140.9 196 8 22.8 199 8 16.4 195.6 200 3 23.7 17.0 211.6 215 4 42.7 31.6 212.2 43 5 223 8 42.4 223.8 63 8 238 2 63.7 224 3 64.1 238 4 65.6 225 0 79.7 243 4 63.0 234.6 243 7 87.7 80.1 235.6 88.9 239.7 174 4 4.2 102.4 239 6 176 0 l o a ,0 4.8 17.1 217.2 201 6 128.1 247.6 128.2 194 0 12.0 169 2 6.1 131 0.580 177 2 9.3 126 0 41“ 10 4 179 1 183 2 12.9 187.6 14 9 122 0 57” These d a t a were obtained duriiig il. Siediuaii roluinn distillstion of the pure materials and are inrluded for coniparison.
A summary of the constants for the various materials is givcn in Table Y. The graphs and calculated data show that, within thc. experimental limits of +1 mm. of mercury for pressure and +=0.15”(7. for temperature, there is no evidence of a constant boiling mixture of m- and p-cresol which boils lower than either constituent or any other mixture of the two. Although no special attributes are claimed for these data, a comparison with the literature (8-6) for the vapor pressure of phenol and of 0-, m-, and p-cresol reveals that, except for m-cresol which is in disagreement by less than 5 % a t 140” c.,the rest of the data are in agreement by 2.5% or less over the range 140” to 200” C . There are no data for comparison with 0- and p-phenylethylphenols in the literature.
T4BI.E
Y.
M
AND
c v.4,LUES
Material
24
Phenol o-Cresol m-Cresol p-Cresol Mixture 1 Mixture 2 Mixture 3 Mixture 4 Composite of mixtures 1 , 2 , 3 ,4. a n d m- a n d p-cresol o-Phenylethylphenol p-Phenylethylphenol
2510 2520 2650 2680 2650 2690 2690 2700 2680
C 8.395 8.308 8.457 8,524 8,457 8.545 8.545 8.566 8.521
3800 3940
9.531 9.427
LITERATURE CITED
(1) Dahiel, F., Mathews, J. H., and Williams, J. W.,”Experimental Physical Chemistry,” 1st ed., pp. 14-17, Sew York, McGrawHill Book Co., Inc., 1929. (2) Hodgman, C. D., “Handbook of Chemistry and Physics,” 27th ed., pp. 718-20, Cleveland, Ohio, Chemical Rubber Pub. Co.. 1943. (3) Huntress, E. H., and Jlulliken, S. P., “Identification of Pure Organic Compounds, Order I,” pp. 208, 258, New York, John Wiley & Sons, Inc., 1941. (4) Lange, A . N . , “Handbook of Chemistry,” 5th ed., pp. 398-9, Sandusky, Ohio, Handbook Publishers, Inc., 1944. (5) Pardee, W. A , , and Weinricii, W.,ISD. ENO.CHEM.,36, 595 (1944). (6) Perry, J . H., “Chemical Engineers’ Handbook,” 1st ed., p. 287, New York, McGraw-Hill Book To., Inc., 1934. RECEIVED August 17, 1946.
