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INDUSTRIAL AND ENGINEERING CHEMISTRY
(4) Dourson, Sage, and Lacey, Zbid., 151, 206 (1943). (5) Hadden, Chem. Eng. Progress, 44, [ l ] , 37 (1948). (6) Xvalnes and Gaddy, J. Am. Chem. Soc., 53,394 (1931). (7) Lewis, Zbid., 30,668 (1908). (8) Marker and Oakwood, Zbid., 60,2598 (1938). (9) Olds, Reamer, Sage, and Lacey, IND.ENG. CHEM.,35, 922 (1943). (10) Ibid., 36,282 (1944). (11) Reamer, Korpi, Sage, and Lacey,Zbid., 39, 206 (1947). (12) Reamer, Olds. Sage, and Lacey, Zbid., 34,1526 (1942). (13) Reamer, Sage, and Lacey, Zbid., 38, 986 (1946). (14) Zbid., 39,77 (1947). (15) Sage, Budenholzer, and Lacey, Zbid., 32,1262 (1940).
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(16) Sage, Hicks, and Lacey, Zbid., 1085. (17) Sage and Lacey, Am. Inst. Mining Met. Engrs., Tech. Pub. 2269, Petroleum Technol. (September 1947). (18) Sage and Lacey, Rev. Sci. Instruments, 18, [9], 650 (1947). (19) Sage and Lacey, Tram. Am. Znst. Mining Met. Engrs., 136, 136 (1940). (20) Sage, Lavender, and Lacey, IND. ENG.CHEM.,3 2 , 7 4 3 (1940). (21) Shepard, Henne, and Midgley, J. Am. Chem. Soc., 53, 1948 (1931). RECEIVED May 19, 1949. Paper 51 in the series "Phase Equilibria in Hydrocarbon Systems." Previous articles have appeared in INDUSTRIAL AND ENQINEBRINQ CABMISTRY during 1934-40 and 1942-46, in January and February 1947, and in March 1949.
Physical Data on Some Organic Compounds -
R. R. DREISBACH AND R. A. MARTIN T h e Dow Chemical C o m p a n y , Midland, Mich.
Four tables are given, listing for 96 organic compounds the freezing point, mole per cent purity, densities at 20" and 25" C., refractive indexes at 20" and 25" C., the C value of the Eylrman equation, the density at 25" C. calculated from the C value and the ny, the A and B values of the Antoine equation, the A* and B* values of the DreisbachSpencer orthobaric vapor density equation, the a and b parameters of the law of rectilinear diameters, boiling point at 760 mm., and the d t l d p values at 760 mm., the rate of change of boiling point with pressure.
I
*
N OBTAINING data for the calculation of the infinite points of Cox chart families, a good many compounds were purified for a determination of their vapor pressure a t several temperatures. The literature data on vapor pressure-temperature relation of these compounds were either lacking or of insufficient accuracy. Inasmuch as these purified compounds were available it was considered advisable to obtain the density and refractive indexes at 20" and 25" C., as well as the boilingpoint, freezing point, and mole per cent purity; these data are recorded here. For the use of pressure-temperature relations in obtaining the infinite points of Cox chart families, a purity of 99.5 mole yowas considered sufficient, since in most cases the impurity consisted of one or more isomers, the value of whose physical properties was not very different from the compound in question. I n each case, however, an attempt was made t o refine the product t o t h e highest degree possible without a t the same time consuming more time and effort than was justified. As can be seen from the tables, some of the compounds were not even 99.5% pure. I n general, distillation was the method used for the purification; the compounds which are the most impure are those which could not be improved by distillation. For the most part the listed compounds were made and purified in the Dow laboratories, but a number, those not of the type made by DOW,were Eastman Kodak products which were further purified. The two cresols were supplied by the Barrett Company with the purity as given in t h e tables. The alkyl halobenzenes were made by halogenation of benzene and the alkyl benzene, using iron as the halo carrier. These compounds were then purified by distillation. Most of the styrenes were made by starting with a bromobenzene or bromoalkylbenzene and making the p-phenylethyl alcohol by means of the Grignard reaction, purifying the alcohol by distillation, dehydrating the alcohol by dropping onto hot caustic soda, and fractionating
the styrene. The m-divinylbenzene was made by dehydrogenating mdiethylbenzene and fractionation. The p-phenylethyl alcohols were made by the Grignard reaction. The a-phenylethyl alcohols were produced by either chlorinating the side chain and hydrolyzing the (Y compound with water or hydrochlorinating the styrene and hydrolyzing the chloro compound. The first property determined was always the freezing point and the purity by means of the freezing point. If the purity was unsatisfactory, the product was further purified before any other properties were determined. The method of determining the freezing point and calculating the degree of purity by an inspection of the time-temperature freezing point curve was as outlined by Mair, Glasgow, and Rossini ( 7 )and later by Stull(9). A platinum resistance thermometer was used, either one calibrated by the Bureau of Standards or another compared t o t h a t standard. The refractive indexes were obtained by means of a five-place Valentine refractometer of the Abbe type and a n accurately controlled temperature bath. This determination and freezing point and purity were carried out by the East General Laboratory of The Dow Chemical Company, Midland, Mich., under the direction of E. N. Luce. The boiling point at various pressures was determined by S. A. Shrader in the apparatus elsewhere described ( I O ) , except that the points for controlling the pressure were placed on the atmospheric side instead of on the pressure side. The results obtained on the boiling points checked the bureau's results to within ==0.Ol0c. The density determinations were carried out by V. A. Stenger and 0. L. Daniels. The pycnometer used was of a shape described elsewhere ( 6 ) , from which it was patterned. However, several modifications were made to permit greater accuracy. Two pairs of pycnometers were used, one pair with a 25-ml. capacity and one of 10 ml. I n each case the sample in one pycnometer was weighed against the other as a tare. The larger size was always used when enough material was available. A second improvement was the use of a smaller capillary in t h e pycnometer. The readings on t h e calibrated capillary were made b y means of a cathetometer while the pycnometer was in the bath. The bath was controlled t o within *0.02" C. T h e mercury thermometer used was calibrated against a thermometer certified by the National Bureau of Standards. As noted in the senior author's paper (S), densities and refractive indexes are abstract values whose accuracies are often indeterminable. In order t o check t h e values of both the density
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December 1949
INDUSTRIAL AND ENGINEERING CHEMISTRY
mw
d
p
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and refractive index, the Eykman equation as given jn the paper mentioned was used. This equation is:
AT-1 0.4
n
+
1
xa
where n is refractive index a t same temperature as d, the density, and C is a constant for each compound. C was determined from the values obtained for n and d a t 20" C., and it was then used to calculate the density a t 25' C. using the value of n determined at 25" C. It nil1 be seen by referiing to the tables that inpractically all cases the error between the determined value of d at 25 O C. and that calculated is less than 0.0003 and in many cases is much less. This, for the first time, gives an indication of the accuracy of published density and refiactive index data. The C value of the Eykman equation has a characteristic value for each type of compound. For the alkyl benzenea it is around 0.75, for the alkyl styrenes 0.78, for alkyl chloiobenzenes 0.65, and for alkyl bromobenzenes 0.53. This value along with density gives a good method of determining the structure of an unknown compound if a series of C values is known for various structures. I n the cases of all the unsaturated compounds listed and in a few of the others, determination of the atmospheric boiling point was impossible. I n the case of the styrenes, for instance, they would polymerize below the boiling point. The temperatures corresponding t o a number of pressures--123.76 mm., 75.86 mm., 57.04 mm., etc.-were experimentally determined and from a series of these it was found t h a t they formcd a Cox chart family with a n infinite point of T, = 1063.4" C. and P , = 0.916 X lo8mm. The A and B values of the Antoine equation were then obtained by means of one value and the infinite point, and then these A and B values mere used to find what the boiling point mould be, for instance a t the pressure of 57.04 mm. where an actual determination was made. These values always checked even better than is usual with the Xritoine equation and the infinite point above seems to be an especially good one. From the A and B value the boiling point a t 760 mm. was calculated and is the one given in the tables. For a complete description of this procedure t h e reader is refer red to the Dieisbach-Spencer paper
(4).
Tables I t o I V give the data considered and check the values by means of the Eykman equation. Tables I to IV further include the A and B values of the Antoineequation ( 4 ) ,the A * and B * values of the Dreisbach-Spencer orthobaric vapor density equation ( 6 ) ,the values of the a and 6 parameters of the Cailletet-Mathias law, or law of rectilinear diameters ( 6 ) ,and the d t / d p values a t 760 mm., the rate of change of boiling point with pressure. The Dreisbach-Spencer orthobaric vapor density equation is expressed by the equation : log dv
=
A*
-t ~
+ dr.
=
u
However, the b parameter in Equation 3 is iiidcpendent of tern-. peratures-that is, it does not vary wit'h temperature, whereas the a value in Equation 4 is accurate for only small ranges of temperature and can be used only in that narrow range. As the density determinations in the accompanying tables are very wcurate, as shown by the comparison of the dct,ermiiied and calcu1at)ed values at' 25' C., the liquid densities calculated by means of Equation 3 should be accurate to about +0.0002 gram per ml. a t t'he boiling point. Equation 2 will not' hold for compounds which are associated in the vapor st.ate a t the temperature used, but will hold if the amount of association is known and t'he correction applied. I n Equation 3 only the dc term is affected by association, and if this term is correct,ed for this, as noted, then Equation 3 will hold. I n the Dreisbach-Spencer reference ( 5 )t'he method of obtaining t l , the temperature a t which the vapors of the compound obey t h e perfect gas law, was to calculate this value of tI, which is the temperature corresponding to a reduced pressure ( P R ) of 0.00072, from the Antoine equation. This is, of course, only possible where the critical pressure is known. In the present paper this value is arrived a t in a different manner where the critical pressure is unknoLm. If the gas law is obeyed, then
RT/PVt,X
B*
+ bt
=
1
(51
where Vu is the volume of the vapor, M is the molecular weight, and R, the gas constant, is equa,l to 62,370 ml.-mm. per C. If now a pressure and its corresponding temperature (obtained by means of the Antoine vapor pressure equation) are substituted in Equation 5 and the quotient lies between 0.9906 and 1.0004, i t is assumed t h a t the vapor obeys the gas law closelyenough to give values of A * and B * which are well lvithin expcrimental error. It is not difficult to select a pressure which with its corresponding teniperature will satisfy Equation 5 within the above limits, as the values of P range from approximately 15 mm. for low boiling compounds t o 50 to 60 mm. for high boiling conipounds. For example, anisole, with a boiling point of 153.75' C. a t 760 min., gives a quotient of 1.0008 a t a pressure of 20.0 mm. and a temperature of 53.7" C.; phenetole, with a boiling point of 170.00 a t 760 mm., has a quotient of 1.00013 a t 25.5 mm. and 71.65' C.; while n-propyl phenyl ether with a boiling point of 189.9" C . a t 760 mm. results in a quotient of 0.9996 at 32.0 mm. and 92.7" C. If the result obtained from Equation 5 is more than *0.0004 from unity, then a different pressure and its corresponding temperature must be tried until a result is obtained which falls within the above limits.
+ 230
ACKNOWLEDGMENT
and the Cailletet-Mathias law (5)by dv
Vol. 41, No. 12
(3)
= orthobaric vapor density, grams per ml. a t t o C . where dv dL = liquid density, grams per nil. a t t o C . a and b = parameters where b is the slope and a is the in-
The authors wish to express their thanks t,o 6 . P. lCliller of the Barrett Company for his kindness in supplying them with the two cresols. LITERATURE CITED
where VO= volume at 0" C., ml. per gram VI = volume at t l 0 C., ml. per gram a = coefficient of cubical expansion
(1) Beilstein, "Handbuch der organischen Chemie," 1st ed., Supplement Vol. I , p. 149, New York, G . E. Stechert & Co., 1925. (2) Ibid., 2nd ed., Vol. I, p. 285, 1941. (3) Dreisbach. R . R . . IND.ERG.CHEW.40.2269 (1948). (4j Dreisbach, R. R.1 and Spencer, R.S'., Ibid., 41;176 (1949). (5) I b i d . , 41,1363 (1949). (6) Lipkin, M.R., Davidson, J. A , , Harvey, W. T., and Kurtz, S. S., J r . , IXD. ENG.CHEX., ANAL. ED., 16,55 (1944). (7) Mair, B. J., Glasgow, A. R., and Rossini, I?. D., J. Research Nail. BUT.Standurds, 26,591 (1941). (8) Natl. Bur. Standards, Circ. C461 (1947). (9) Stull, D. R., ISD. EXG.CHEM.,ANAL.E D . ,18,234 (1946). (10) Willingham, C . B., Taylor, W. J., Pignocco, J. M., and Itossini, F. D., J . Research S a t l . Bur. Standards, 35, 219 (1945)
except t h a t i t has t o do with density, the reciprocal of volume.
RECEIVED Y a y 9, 1949.
A * , B"
tercept a t 0" C.
= constants dependent on the
A and B values of
the Antoine equation T h e b parameter corresponds to the coefficient of cubical expansion, a , in the volume equation
