DAVIDL. CAMIN,A. F. FORZIATI AND F. D. ROSSINI
440
Vol. 58
PHYSICAL PROPERTIES OF n-HEXADECANE, n-DECYLCYCLOPENTANE, 12-DECYLCYCLOHEXANE, I-HEXADECENE AND n-DECYLBENZENE' BY DAVIDL. CAMIN,ALPHONSE F. FORZIATI AND FREDERICK D. ROSSINI Carnegie Znstitiite of Technolog!], Pitbsburgh, Pennsylvania Received February 16, 1964
For n-hexadecane, n-decylcyclopentane, n-decylcyclohexane, 1-hexadecene and n-decylbenaene, highly purified hydrocarbons of the API Research series, th,e following properties were measured: densities a t 20, 25 and 30"; refractive indices a t seven wave lengths at 20, 25 and 30 ; and boiling points and vapor pressures from 50 to 760 mm. The data on refractive indices were correlated by means of modified Cauchy and Hartmann equations, and values of the constants are given for each compound, to permit precise evaluation of the refractive index as a function of wave length. The data on vapor pressures were correlated with the three-constant Antoine equation and values of the constants are given for each compound. Also included are calculated values of the specific dispersions, ( n ~ nc)/d and (n, nD)/d.
-
The American Petroleum Institute Research Project 6 has so f8r reported data on the densities, refractive indices and boiling points and vapor pressures for 76 different API Research hydrocarb o n ~ . ~ - ' In this paper are reported similar data for an additional 5 API Research hydrocarbons representing different normal alkyl series, namely, nhexadecane, n-decylcylopentane, n-decylcyclohexane, 1-hexadecene and n-decylbenzene.
-
process of publicationS by other workers. The purity of the samples measured was as follows, in mole per cent.: n-hexadecane, 99.96 f 0.04; ndecylcyclopentane, 99.80 f 0.18, n-decylcyclohexane, 99.88 f 0.11; 1-hexadecene, 99.93 f 0.06; and n-decylbenaene, 99.88 f 0.10. The measurements of density were made a t 20, 25 and 30°, with a density balance previously de~ c r i b e d . ~The experimental values of density are
TABLE I VALUESOF DENSITY Compound
a
Formula
25'
30'
Temp. coefficient of density a t 25O
0.76996 ,80739 .a1517 ,77759 ,85189
0.76643 .a0383 .81183 .77409 ,84833
0.000701 .000714 .000675 .000703 .000720
Densitya 200
0 I77344 n-Hexadecane C1eH34 Cl5H30 .a1097 n-Decylcyclopentane CieHn ,81858 n-Decy lcyclohexane Cl6H32 .78112 1-Hexadecene CieHta ,85553 n-Decylbenzene For air-saturated hydrocarbons in the liquid state a t 1 atm.
These API Research hydrocarbons were made available by the American Petroleum Institute through the API Research Project 44 a t the Carnegie Institute of Technology. The samples were purified by the API Research Project 6 from material supplied by the following laboratories: nhexadecane and I-hexadecene by the API Research Project 6 a t the Carnegie Institute of Technology: n-decylcyclopentane, n-decylcyclohexane and ndecylbenzene by the API Research Project 45 at The Ohio State University. Description of the purification and purity of these compounds is in (1) This investipation was performed as part of the work of the American Petroleum Institute Research Project 6 in the Petroleum Research Laboratory of the Carnegie Institute of Technology, Pittsburgh, Pennsylvania. A portion of the work described was completed before June, 1950, when the Project was moved from the National Bureau of Standards to the Carnepie Institute of Technolopy. One of the authors, A. F. F., remained with the Nat,ional Bureau of Standards, transferring to the American Uental Association Research Fellowship there. (2)C. B. Willingham, W. J. Taylor, J. M. PignocOo and F. D. Rossini. J . Research Nall. Bur. Standards, 81,219 (194.5). (3) A. F. Forziati and F. D. Rossini, ibid., 43, 473 (1941)). (4) A. F. Forziati, W. R. Norris and F. D. Rossini. ibid., 43, 555 (1949). (5) A. F. Forziati, ibid., 44, 373 (1950). (6) A. F. Forziati, D. L. Camin and F. D. Rossini, ibid., 41, 406 (1950). (7) F. D. Rosslni, B. J. Mair and A. J. Streiff, "Hydrocarbons from Petroleum," Reinliold Publ. Corp., New Ymk, N. Y.,1953.
7
given in Table I. Individual measurements were reproducible within 0.00003 g./ml. The accuracy of the tabulated values is estimated to be *0.00005 to ~ 0 . 0 0 0 1 0g./ml. The refractive index was measured by means of the apparatus and procedure previously described.6 The calculations and correlations were similarly made as described p r e v i ~ u s l y . ~Table I1 gives the values of refractive index a t 7 wave lengths a t 20, 25 and 30" and the values of the constants of the modified Cauchy and Hartmann equations. The fourteenth and last columns of Table I1 give the root mean square values of the deviations of the observed from the calculated points. Individual measurements were reproducible within f0.00002 to f0.00003. The accuracy of the tabulated values is estimated to be rt0.00005 to A0.00008. Table I11 gives the values of the specific dispersions, 1 0 4 ( n ~- n,)/d and 104(n, - nD)/d, calculated from the values of refractive index in Table I1 and of density in Table I. In previous reports,6.6it was indicated that some correlation exists between the values of the con'
(8) Unpublished data of the API Research Project 6, Petroleum Research Laboratory, Carnegie Institute of Terhnology, Pittsburgh, Pennsvlvania, Attention of Frederick D. Rossini. (9) A. F. Forziati, B. J. Mair and F. D. Rossini, J . Research Nall. Bur. Standards, 36, 613 (1945).
1
d
PHYSICAL PROPERTIES OF SOME HYDROCARRONS
May, IF),%
I
0
11
3
3
3
3
. . . . . . . . . . . . . . .
3
4 3 3 3 3 4 3 4 3
3 3 3
4 3 4
3 3 3
3 3 3
3 3 3
3 3 4 3 3 H
44 1
stants n, and C of the Hartmann equation and the number of carbon atoms in the normal alkyl radical for the normal paraffins, the l-alkenes, and the normal alkylbenzenes. The values of n, and C for n-hexadecane, l-hexadecene and n-decylbenzene from the present investigation are found to be in good accord with those previously reported for the lower members of these series.6e6 The measurements and caIculations of vapor pressures and boiling points were made as previously' d e s ~ r i b e d , ~with . ~ . ~the samples being introduced into the apparatus without contact with the air of the atmosphere.6 Because of a break in the multicontact mercury manometer, a new one was made for the apparatus, with resulting pressures for the given contacts that were slightly different from those of the previous manometer.2 Due to the relatively high normal boiling points for the compounds of this investigation, it became necessary to use a procedure which minimized the time a given sample was kept a t elevated temperatures (above 200"). This was done as follows: two samples of each compound were used, with one sample being used for the lower range of pressure (50 to 403 mm.) and the second sample being used for the higher pressures (403 to 760 mm.). For the measurements from 50 to 403 mm. the boiler and jacket were preheated to 100" before the sample was introduced. After introduction, the sample was quickly brought to equilibrium and temperature measurements were made a t selected pressures from 50 to 403 mm. The first sample was then withdrawn and the apparatus was thoroughly cleaned. Before introducing the second sample, the boiler and jacket were preheated to 200" and the sample itself was preheated to 100". When the sample had been introduced into the boiler, it was quickly brought to equilibrium and temperature measurements were made a t selected pressures from 403 to 760 mm. After the measurement a t 1 atmosphere, the pressure was reduced t o 403 mm. and the temperature was remeasured as a check. Table I V gives the experimental data on the temperature and pressures of the liquid-vapor equilibrium for the 5 compounds. Table V gives the values of the three constants of the Antoine equation, the normal boiling point at 760 mm., the pressure coefficient of the boiling point a t 760 mm., and the range of measurement in pressure and in temperature. The last column of Table V gives the root mean-square value of the ratios of the deviations of the observed points from the Antoine equation t o the expected standard d e ~ i a t i o n . ~ Individual measurements of boiling points were reproducible within *0.002 to *0.003". The accuracy of the tabulated values of the normal boiling point is estimated to be *0.008 to 10.015'. I n earlier report^,^^^^^ it was pointed out that some correlation exists between the values of the constants B and C of the Antoine equation for vapor pressures and the number of carbon atoms in the normal alkyl side chain for the members of the several normal alkyl series of hydrocarbons, as normal paraffins, normal alkylcyclopentanes, normal alkylcyclohexanes and normal alkylbenzenes, and the 1alkenes. The values of the B and C constants for
DAVID L. CAMIN,A. F. FORZIATI AND F. D. ROSSINI
442
Vol. 58
TABLE 111 CALCULATED VALUESOF THE SPECIFIC DISPERSION T$mp., C.
-
104(ng nn)/d
104(n~ nd/d
-
-
104(n~ nd/d
-
104(n~ nd/d
l,O;YTd-
lO4(ng nD)/d
-
l O d ( n ~nd/d
n-Hexadecane n-Decylcyclopentane n-Decylcyclohexane 98.00 124.90 96.55 123.19 97.73 124.48 98.19 125.07 96.86 123.48 97.77 124.51 97.16 123.78 97.80 124.53 98.38 125.26
20 25 30
1O"ng nd/d
-
I-Hexadecene 107.03 136.73 107.25 137.09 107.48 137.45
l O 4 ( n ~nd/d
-
lO4(ng nd/d
n-Decylbenaene 136.99 177.32 136.40 176.67 136.62 176.04
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EXPERIMENTAL DATAO N t, o c .
P. mm.
1,
n-Hexadecane 286.704 758.50 285.337 736.32 278.333 630.54 268.540 503.11 259.336 403.36 250.605 323.81 242.432 261.15 235.145 214.20 227.336 171.66 221.780 145.87 215.000 118.69 208.962 98.24 203.437 82.14 199.273 71.49 195.301 62.48 190.054 52.09
THE
oc.
TABLEIV TEMPERATURES AND PRESSURES OF THE
P , mm.
oc.
LIQUID-VAPOR P , mm.
EQUILIBRIUM t,
P, mm.
oc.
n-Decylcyclohexane 297.507 758.50 296,058 736.32
I -Hexad ecene 284.768 758.24 283.402 736.10
n-Decylbenzene 297.799 758.41 296. 370 736.16
260.943 251.676 242.859
503.23 403.47 323.76
503.01 403.38 323.84
503.12
403.47 323.79
266.590 257.440 248.690
278.950
268.976 259,864
260.372
323.82
227.251 219.377 213,782
214.10 171.73 145.93
243.758 235.626 229.848
214.15 171.71 145.88
233.203 225.397 219.806
214.17 171.68 145.81
244.331
214.18
230.476
145.83
200.861
98.25
216.465
98.22
206.981
98.06
217.156 211.392
98.17 82.04
191.085
71.48
206.361
71.50
197.257
71.56 202.987
62.47
181.867
52.01
196.812
52.08
188.152
52.06
THE
TABLE V CORRELATION OF THE EXPERIMENTAL DATAWITH PRESSURE
Constants of t h e Antoine equation log10P = A - B / ( C t) or t = B/(A loglo P) - C P in mm. Hg; 1 in O C . A B C
-
Compound
t,
n-Decylcyclopentane 279.283 758.55 277.907 736.33
SUMMARY OF THE RESULTS OF
n-Hexadecane n-Decylcyclopentane n-Decylcyclohexane 1-Hexadecene n-Decylbenzene
P, mm.
t, o c .
Formula
+
THE
ANTOINEEQUATION
Normal boiling point a t 700 mm., "C.
Pressure coefficient dt/dP a t 760 mm., OC./mm.
Range of measurement Pressure, Temp., mm. OC.
FOR
VAPOR
Measure of precision, P
7.03044
1831.317
154.528
286.793
0.06077
52-760
190.0-286.8
1.30
C1.5H30 7.00349
1825.748
163.479
279.376
.06138
52-760
181.8-279.4
1.04
7.01640 7.04437 C1eH26 7.03642
1896.974 1843.581 1904.132
161.106 157.917 160.318
297.589 284.873 297.890
.06338 .06077 .06301
52-760 52-760 62-760
196.8-297.6 188.1-284.8 202.9-297.9
1.55 1.71 1.50
CleH34
CieH32
CIeH32
each of the five compounds of the present investigation are found to be in good accord with those pre-
viously reported for the lower members of these serie~.~~~~~
