August, 1957
THERMODYNAMIC PROPERTIES OF SUBSTITUTED NAPHTHALENES
tion t o saturated vapor in any way which differs from the changes undergone by these materials in going from the pure liquids t o the pure saturated vapors, (2) that the actual effective number of individual molecules in the solution is equal t o the sum of the effective number of molecules in the pure liquids before they were mixed, (3) that the effective number of molecules in the gaseous mixture is the same as if the gases were unmixed, and (4) that the gas phase obeys the ideal gas law. Subject to these assumptions and the additional assumption of no change in volume on mixing, the seventh column in Table I11 gives the apparent heat of mixing of sufficient quantities of pure components to give one total "mole" of solution. The changes in the apparent heat of mixing with composition may be explained in terms of two major effects with opposite sign. The dissociation of (HF)i into hydrogen fluoride monomer and lower polymers requires the absorption of heat while the association of hydrogen fluoride monomer and chlorine trifluoride to form the weak complex, ClF4*HF, reported by Pemsler and Smith,s liberates 3.9 kcal. per mole of complex produced. Since significant quantities of the complex can only be produced if the partial pressure of hydrogen fluoride monomer is relatively high, dissociation of (HF)i induced by
1105
the addition of chlorine trifluoride to hydrogen fluoride rich solutions would be more pronounced than the formation of the complex, whereas the formation of the complex is more important in the chlorine trifluoride rich solutions. If, as is reasonable, the change in volume of the liquids on mixing is small, then the variations in the.apparent heat of mixing with composition are in the same sense as would be predicted. The shape of the activity coefficient curves in Fig. 5 tend to lend further credence to this explanation. The rapid initial increase in the activity coefficient of hydrogen fluoride with the addition of a small amount of chlorine trifluoride results from depolymerization of hydrogen fluoride polymer, and the subsequent leveling out of the activity coefficient of hydrogen fluoride a t 0.25 formula fraction chlorine trifluoride results from increased importance of the formation of the complex between chlorine trifluoride and hydrogen fluoride. It should be noted that there is no way of knowing the quantity of solution which constitutes one total "mole" without further experimental measurements. Acknowledgment.-The authors wish to thank J. W. Grisard and G. D. Oliver for performing the thermal analyses of the pure chlorine trifluoride and hydrogen fluoride.
THE LOW-TEMPERATURE THERMODYNAMIC PROPERTIES OF NAPHTHALENE, I-METHYLNAPHTHALENE, %METHYLNAPHTHALENE, 1,2,3,4-TETRAHYDRONAPHTHALENE, t~ans-DECAHYDRONAPHTHALENE AND cis-DECAHYDRONAPHTHALENE BY J. P. MCCULLOUGH, H. L. FINKE, J. F. MESSERLY, S. S. TODD, T. C. KINCHELOE AND GUYWADDINGTON Contribution No. 63from the Thermodynamics Laboratory, Pelrolum Experiment Station, Bureau of Mines, U.S. Department of the Interior, Bartlesville, Oklahoma Received April $8, 1967
As part of a program to provide basic thermodynamic information for important petroleum constituents, low temperature calorimetric investigations were made of the following six bicyclic hydrocarbons: naphthalene, I-methylnaphthalene, 2methylnaphthalene, 1,2,3,4-tetrahydronaphthalene,trans-decahydronaphthalene and cis-decahydronaphthalene. For each compound, measurements were made of the heat capacity in the solid and liquid states between 12 and 370"K.,the heat of fusion, the triple-point temperature, the cryoscopic constants, and the purity of the sample. Isothermal transitions that occur in 1-methylnaphthalene, 2-methylnaphthalene and cis-decahydronaphthalene were studied, and values of the heats and temperatures of transition were determined. Unusual effects of impurity on the thermal pro erties of l-methylnaphthalene and cis-decahydronaphthalene in the remelting" and melting regions were observed. #he absence of a reorted thermal anomaly in liquid cis-decahydrona'khalene was demonstrated. From the low temperature thermal data for each compound, values of the following thermognamic functions in the solid and liquid states were computed at selected temperatures from 10 to 370°K.: (Faatd - H0o)/T, (Hsatd - H"o)/T, Hsatd H'o, Saaaand C6atd.
-
An important fraction of the compounds found in the 180 to 230" boiling range of petroleum is composed of bicyclic hydrocarbons. Naphthalene and its derivatives probably comprise the bulk of this group of compounds. To provide basic information needed in the calculation of thermodynamic properties of bicyclic hydrocarbons, low temperature calorimetric studies were made of the following substances: naphthalene (I),1-methylnaphthalene (11), 2-methylnaphthalene (111), 1,2,3,4-tetrahy(1) F. D. Roesini, B. J. Mair and A. J. Streiff, "Hydrocarbona from Petroleum," ACS Monograph No. 121, Reinhold Publ. Corp., New,
York, N. Y., 1953.
CHs
03 03 03-cHa I
I1
0{111;CH2
IV
I CH2
I11
/CH2\/CHz\ CH2 CH
CH2
(!!HZ \CH/\CH/ (!XI
(!!€I2
V (trans) V I (cis)
1106
MCCULLOUGH, FINKE, MESSERLY, TODD, KINCHELOE AND WADDINGTON
Vol. 61
sults reported here in their calculations of the thermodynamic functions of alkylnaphthalenes in the ideal gaseous state. Experimental
TEMPERATURE.
O K
Fig. 1.-The heat capacity curves of (1) naphthalene, (2) ]-methylnaphthalene, (3) 2-methylna hthalene, (4) 1,2,3,4 tetrahydronaphthalene, (5) trans-decaRydronaphthalene and (6) cis-decahydrona hthalene. Solid curves indicate values for thermodynamica\y stable phases; dashed curves indicate values for supercooled phases; the dotted curve indicates an extrapolation; and light vertical lines indicate a phase change. Premelting corrections have been applied to the data represented in this figure.
dronaphthalene (IV), trans-decahydronaphthalene CV), and cis-decahydronaphthalene (VI). Measurements were made of the heat capacity in the solid and liquid states and of the latent heats and temperatures of phase changes. From the resulting data, values of the following thermodynamic properties were calculated at selected temperatures between 10 and 370°K.:( p s a t d Hoo)/T,( H s a t d Hoo)/T, H s a t d - Hoe, &atd and
-
Csatd.
Milligan, Becker and Pitz;gr2used some of the re-
(2) D.E. Milligen, E.D.Beaker end 16, 2707 (1956).
K.8. Pitser, J . Am. ch8'hsm.8oc.
Physical Constants.-The 1951 International Atomic Weights' and the 1951 values of the fundamental physical constants4 were used. Measurements of temperature were made with platinum resistance thermometers calibrated in terms of the 1948 International Temperature Scale6 and, bclow 9O"K., the rovisional scale* of the National Bureau of Standards. Cefsius temperat,ures were converted to Kelvin temperatures by addition of 273.16'. Measurements of mass, energy and resistance were made in terms of standard devices calibrated at the National Bureau of Standards. Energy in international joules was converted to calories by the relation 1 cal. = 4.1840 abs. j . = 4.1833 int. j . Materials.-The materials used in this investigation were A.P.I. Research samples' courteously loaned by F. D. Rossini from the hydrocarbon bank of the API Samples and Data Office, Carnegie Institute of Technology. The purities of the samples, determined in calorimetric melting point studies described in a later section of this paper, ranged from 99.83 to 99.99 mole %. The samples were received in glass ampoules with internal break-off seals and were transferred to the calorimeter by vacuum distillations. The Apparatus.-All measurements were made in the adiabatic low temperature calorimetric system described by Huffman and co-workers.* In each study about 55 ml. of material was sealed in a copper calorimeter under 3 cm. helium pressure (at room temperature). Heat Capacities in the Solid and Liquid States.-Measurements were made of the heat capacity in the solid and liquid states, Caatd, between 11 and 370'K.; the results are given in Table I and Fig. 1. With a few exceptions (indicated by footnotes), the temperature increments used in the experiments were small enough to obviate the need of correction8 for non-linear variation of Ceatdwith T. The precision of the heat capacity data was usually within = t O . l % . Above 30'K., the accuracy uncertainty should not exceed 0.2% except near phase changes, where greater Uncertainty may be caused by rapid variation of COsa+d with T,slow equilibration, or the presence of impurities. For example, the data for crystals 1 of I-methylnaphthalene, which were stable only in a 1.9' range, are subject to uncertainty much larger than 0.2%. Empirical equations were obtained to represent the heat capacity of each of the six compounds in the liquid state. The constants for these equations are listed in Table 11. The Heats and Temperatures of Transition.-Isothermal phase transformations were found to occur in 1- and 2methylnaphthalene and cis-decahydronaphthalene. The temperatures a t which the transitions occur were determined for each com ound by transposing a portion of crystals I1 to crystals ?9 and observing the temperature with both solid phases present. The results obtained are: 1methylnaphthalene, 240.79'K. with 857, transposed to crystals I; 2-methylnaphthalene, 28854°K. with 61.70 transposed; and cis-decahydronaphthalene, 216.04"K. wlth 36% transposed and 216.05'K. with 45% transposed. (3) Edward Wichers, ibid., 74, 2447 (1952). (4) F. D.Rossini, F. T. Gucker, Jr., H. L. Johnston, L. Pauling and G. M. Vinal, ibid., 74, 2699 (1952). (5) H. F. Stimson. J . Research Null. Bur. ~!?tandards,42, 209 (1949). (6) H. J. Hoge and F. G. Brickrvedde, ibid., 22,351 (1939). (7) These API Research hydrocarbons have been made available b y the American Petroleum Institute through the API Research Project 44 a t the Carnegie Institute of Technology. The samples were purified b y the API Research Project 6 from material supplied by the following laboratories: Naphthalene by the American Cyanamid Company, Calco Chemical Division. Bound Brook, New Jersey; 1-methylnaphthalene, 2-methylnaphthalene, 1,2,3,4-tetrahydrona~hthalene, trona-decahydronaphthalene and cis-decahydronaphthalene b y the American Petroleum Institute Research Project 6 a t the Carnegie Institute of Technology. (8) R. A. Ruehrwein and H. M. Huffman, J. Am. Chem. Soc., 66, 1620 (1943); G. D. Oliver, M. Eaton and H. M. Huffman, ibid., 70, 1502 (1948); H. M. Huffman, Chem. Reus., 40, 1 (1947). (9) The allotrope in equilibrium with the liquid a t the triple point is designated "crystals I," and that stable at temperatures below the solid-solid transition point is designated "crystal8 11."
THERMODYNAMIC PROPERTIES OF SUBSTITUTED NAPHTHALENES
August, 1957
TABLE I THEMOLALHEATCAPACITIES OF SIX NAPHTHALENE HYDROCARBONS IN THE SOLIDAND LIQUIDSTATES, CAL.D E Q . - ~ T,
OK."
ATb
cBatdc
T , OK."
ATb
Csstd"
Naphthalene Crystals 11.81 13.36 13.42 14.53 14.82 15.75 16.33 17.14 18.02 18.73 19.80 20.44 21.75 22.28 23.84 24.44 26.30 27.27 30.54 34.00 37.62 41.40 45.85 51.05 54,36 56,68 59,65 64.93 70.20 75.51 80.85 85.98 86.24 91.98 97.69 103.15 108.83 114.72 121.03 128.81 137.34
1.810 1.231 1.413 1.134 1.373 1.310 1.649 1.469 1.677 1.695 1.856 1.729 2.033 1.936 2,125 2.389 2.794 3.275 3.262 3,648 3.601 3 I955 4,946 5.440 5.068 5.816 5.506 5.055 5.483 5.139 5.533 6.163 5.238 5.836 5.578 5.354 6.005 5.776 6.84G 8.728 8.331
0,659 .969 ,988 1.227 1.306 1.513 1.669 1.860 2.091 2.287 2.561 2.735 3.079 3.220 3.633 3.784 4.251 4.483 5.245 6.015 6.748 7.456 8.194 8.990 9.455 9.757 10.149 10.804 11.388 11.947 12.518 13.069 13.095 13.643 14,175 14.702 15.251 15.840 16.480 17.270 18.163
145.49 7.986 19.042 152.26 5.831 19.794 158.47 6.601 20.498 164.98 6.403 21.253 171.29 6.232 21.978 6.914 22.769 177.87 184.68 6.717 23.593 191.31 6.535 24.408 6.365 25.222 197.76 6.206 26.028 204.04 210.24 6.182 26.840 216.84 7.027 27.714 6.846 28.630 223.78 230.54 6.672 29.567 237.13 6.516 30.464 244.02 7.262 31.443 5.799 32.260 250.12 256.42 6.795 33.212 6.638 34.183 263.12 271.80 10.730 35.496 282.33 10.352 37.103 292.49 10.002 38.719 9.636 39.877 299.84 9.535 41.054 306.99 9.838 41.443 309.32 316.36 9.235 42.672 321.90 8.998 43.614 325.44 8.959 44.272 327,9B 8.840 44.729 330.76 8.720 45.277 336.66 8.568 46.461 339,35 8.454 47.017 8.303 48. 257d 345.10
Liquid 357.00 361. 63 363.84 366.23 368.44 370.79
4.646 4.613 4.611 4.578 4.581 4.548
1-Methylnaphthalene Crystals I1 27.38 2.902 11.94 13.33 13.58 14.80 15.02 16.27 16.81 17.99 18.56 19.97 20.61 22.08 22.95 24.54 25.42
1.250 1.545 1.154 1.411 1.804 1.526 1.775 1.911 1.735 2.067 2.355 2.149 2.329 2.774 2.615
1,015 1.364 1.426 1.741 1.814 2.134 2.282 2.603 2.767 3.172 3.352 3.757 3.997 4.426 4.653
28.12 31.11 34.56 38.39 42.84 47.06 53.45 54.72 59.82 64.92 70.29 75.94 81.21 86.44 86.66 93.20
2.782 3.209 3.681 3.987 4.904 5.336 5.(ill 4.891 5.312 4.807 5.873 5.440 5.108 6.975 5.776 6.537
52.260 52.690 52.941 53.129 53.319 53.528
5.158 5.338 6.068 6.860 7.666 8.524 9.455 10.392 10.602 11.435 12.234 12.980 33.773 14.534 15,273 15.307 16.129
99.57 6.198 105.62 5.912 111.42 5.672 116.98 5.462 122.87 6.310 129.06 6.078 135.04 5.875 140.33 5.709 140.82 5.694 145.95 5.541 151.77 6.103 158.37 7.089 165.35 6.866 171.56 5.565 177.60 6.504 184.02 6.333 190.27 6.176 196.37 6.029 203.21 7.663 208.29 7.469 210.77 7.450 215.64 7.256 218.11 7.242 221.24 5.988 222.79 7.054 224.66 5.895
16.930 17.712 18.450 19.174 19.938 20.756 21.529 22.221 22.290 22.974 23.761 24.657 25.597 26.451 27.299 28.192 29.057 29.911 30.903 31.620 31.978 32.739 33.105 33.584 33.869 34.106
5.848 5.746 5.692
227.15 230.47 232.92
0.872 1.139 1.410 1.489 1.764 1.882 2.234 2.318 2.618 2.875 3.085 3.515 3.662 4.193 4.356 4.876 5.053 5.586 5.736 6.491 7.329 8.183 8.984 9.790 10.665 11.277 11.568 12.128 12.956 13.716 14.466 15.246 16.030 16.735 16.866 17.530 18.171
34.547 35.190 35.71Sd
Crystals I 241.38 241.71
0.365 63.6 .301 79.Sd
Liquid 247.97 5.339 48.891 7.045 49.427 254.16 257.51 8.716 49.716 8.692 50.119 262.03 9.434 50.535 266.59 276.36 10.118 51.469 286.39 9.946 52.440 9.779 53.429 296.26 299.90 10.434 53.816 306.36 10.412 54.482 310.24 10.251 54.888 320.41 10.078 55.958 330.80 10.668 57.036 341.39 10.491 58.132 352.19 11,043 59.259
2-Methylnaphthalene 109.48 6.036 Crystals I1 11.14 0.993 12.19 1.150 13.03 1.239 13.46 1.472 14.41 1.475 14.88 1.378 15.94 1.584 16.48 1.849 17.55 1.624 18.44 2.072 19.18 1.651 20.67 2.388 21.15 2.288 23.02 2,321 23.59 2.596 25.49 2.606 26.14 2.504 28.18 2.780 28.74 2,695 31.67 3,132 35.03 3.594 38,79 3.909 42.48 3.470 46.41 4.405 51.07 4.910 54.50 5.202 56.17 5,292 59.47 4.731 64.55 5.436 69.79 5.049 75.15 5 . 6 6 1 80.63 5,312 86.21 5.845 91.90 5.557 92.95 5.683 98.51 5.441 103.84 5.231
1107
115.40 121.11 126.63 131.99 135.39 141.18 146.81 152.83 159.22 165.43 171.97 178.82 185.50 192.00 193.19 198.72 200.86 205.65 208.33 212.40 215.59 219.00 219.78 222.68 226.25 229.60 232.56 232.67 236.36 238.75 239.39 242.98 244.81 245.23 245.71 246.00 250.76 252.25
5.809 5.614 5.434 5.278 5.886 5.711 5.556 6,481 6.299 6.132 6.959 6.768 6.589 6.427 7,786 7.016 7.567 6.840 7.368 6.676 7.179 6.522 6.547 7.004 6.390 6.837 6.253 6.797 6.694 6.122 6.647 6.560 6.005 7.104 7.054 6,588 5,899 6.938
18.844 19.562 20.234 20.909 21.550 21.958 22.671 23.344 24.086 24.865 25.626 26.450 27.318 28.188 29.023 29,149 29.910 30.174 30.822 31.172 31.743 32.176 32.629 32.715 33.147 33.644 34.11 34.52 34.39 35.01 35.39 35.36 35.85 36.21 36.23 36.43 36 :40 36.98 37.28
MCCULLOUGH, FINKE, MESSERLY, TODD, KINCHELOE AND WADDINGTON
1108
I (Continued)
T.
“K.G
ATb
TABLE CentdC
252.45 6.354 37.35 252.67 6.883 37.47 253.11 13.719 37.40 259.10 6.775 38 36 250.48 6.534 38.44 264.99 10 070 39.61 265.78 6.816 39.49 272.31 6.454 40.68 272.47 4.917 40.72 277.31 4.792 42.06 278.66 6.248 42.33 281.91 4.475 45.8
T,‘K.Q
ATb
CaatrlC
Crystals I
293.31 294.07 291 I 1 296.07 297.07 298.79 299.93
2.769 46.103 5.920 46.378 2.069 46.487 2.740 46.663 2.945 46.965 2.714 47.160 5.810 47.373d Liquid
312.08 3.067 54.852 315.91 4.579 55.175 316.91 9 070 55.300 273.49 5.384 43.466 321.22 6.057 55.693 278.83 5.300 44.245 326.47 9.708 56.224 282.0.5 6.121 44.646 336.10 9.559 57.182 284.52 6.080 45.105 345.96 10.142 58.156 288.11 6,018 45.518 356.02 9.982 59.176 366.63 11.228 60.204 lJ2,3,4-Tetrahydronaphthalene Crystals 110.50 6.217 17.480 116.59 5.967 18.206 12.13 1,181 1.009 122.45 5.754 18.886 13.31 1.208 1.312 128.56 6.474 19.607 14.62 1.407 1.646 134.92 6.246 20.374 15,45 1.652 1.863 141.07 6.045 21.113 16.08 1.512 2.028 147.02 5.863 21.829 17.27 1.994 2.352 151.32 5.691 22.324 17,61 1.553 2.449 152.80 5.698 22.551 19.31 1.849 2.930 157.47 6.617 23.106 19.32 2.107 2.935 163.99 6.416 23.937 21.23 1,980 3.478 170.31 6.233 24.750 21.45 2.156 3.539 176.46 6.066 25.547 23,46 2.491 4.100 182.93 6.874 26.439 23.6P 2.179 4.146 189.70 6.661 27.394 25.91 2.404 4.762 196.26 6.467 28.378 26.05 2.,683 4.795 202,64 6.285 29.372 28.41 2,592 5.407 208.84 6.111 30.386 31.21 3.011 6.120 214 61 8.748 31.438 34.47 3.476 6.885 220 99 6.581 32.531 38.11 3,794 7.672 227.44 6.366 33.70Sd 42,Ol 4.018 8.447 Liquid 46.14 4.226 9.206 50.63 4.750 9.960 54 86 4.352 10.623 248.42 4.856 46.604 55,58 5.149 10.730 250.11 0.549 46.580 59,82 5.564 11.357 253.26 4.811 47.089 65.39 5.571 12.139 259.57 9.371 47.748 71.26 6.178 12.873 268.85 9.198 48.729 77.23 5.752 13,609 274.90 9.672 49.379 82.81 5.408 14.313 284.49 9.491 50.442 85.84 4.395 14.692 288.43 10.361 50.872 298.68 10.145 52.032 88.08 5.130 14.954 91.04 6.005 15.281 308.71 9.927 53.184 97.47 6.838 15.992 318.54 9.735 54.307 104.14 6.503 16.756 Crystals I,supercooled
’
trans-Decahydronaphthalene Crystals 14.34 1.285 1.190
11.54 1.377 0,633 12.94 1.456 ,901 13.44 0.862 J.011
14.57 1.408 1.234 15.71 1.457 1.493 16.10 1.623 1.584 17.14 1,397 1.835
17.76 18.68 19.49 20.47 21.48 22.43 23.03 24.70 26,69 27.33 29.61 30.16 32.62 35.63 35,85 42.87 47.50 52.44 54.06 57,82 59,27 64,83 70.68 76.37 82.10 87.95 93.90 95.11 99.86 105.24 111.18 116.94 122.70 128.74
1.697 2.003 1.713 2.224 1,727 2,455 1.871 2.713 2.236 2.996 2.054 3.252 2.651 3.663 2.499 3.874 2.867 4.410 2,756 4.572 2.983 5.165 2.898 5.299 3.039 5.929 2.970’ 6,653 3.480 7.377 4.549 8.221 4.699 9.107 5.191 9.909 5.002 10.276 5.560 10.903 5,405 11.148 5.707 12.052 5,978 12.935 5.411 13,776 6,039 14,669 5.659 15,552 6.239 16.393 4.416 16.578 5.078 17.231 5.675 18.006 6.194 18.864 5.343 19.702 6.170 20.540 5.922 21.416
Vol. 61
5.703 22.242 5.520 23.075 5.419 23,727 5.362 23,844 6.995 24,625 8.427 25,743 7.732 26.008 7.456 28.014 8.245 29,189 7.954 30.443 7.712 31.637 7,468 32.840 7.102 34.040 6.954 35.081 6.761 36.292 6.614 37.02Sd 6,581 37.578
134.56 140.16 144,76 145,60 150.96 158.67 166.75 174.34 182.20 190.30 198.14 205.72 213.01 219,25 226.11 229.97 232.78
Liquid
248.75 254.11 256.52 265.76 275.66 285.76 294.97 295,63 305.26 315.34 325.19 334.83 344.27
5.356 48.156 5.315 48.786 8.902 49.088 9.579 50.248 10.223 51.548 9.985 52.905 10.422 54.162 9.768 54.262 10.184 55.616 9.964 57.098 9.737 58.529 9.537 59.960 9.350 61.348
cis-Decahydronaph thalene 73.23 6.351 13.766 Crystals I1
12 50 12 71 13 98 14 11 15 24 15 58 16 58 17 03 18 10 18 72 19 87 20 65 21 92 22 70 24 44 24 77 27 00 27.18 29 90 33 23 37 23 41 44 45 84 50 59 55 78 56 25 61.30 61 31 67.10
1.713 1.239 1.234 1.521 1.226 1.404 1.304 1.499 1,622 1,848 1,886 1.998 2.211 2.070 2.831 2,077 2,389 2.651 2.788 3.870 4.126 4.301 4.494 4.998 5.374 4.445 5.658 5.670 5.906
0 958 1 000 1 337 1 345 1 677 I 745 2 034 2 165 2 480 2 674 3 086 3 267 3 654 3 806 4 413 4 505 5 126 5 177 5 859 6 758 7 6GO 8 536 9 381 10 232 11 098 11 173 11 996 11 999 12 887
79.82 86.84 89.98 93.82 96.27 100.79 102.81 109.60 116.06
122.74 129.65 134.78 136.29 140.35 142.00 143.13 145.76 147.62 148.21 150,18 154,36 155.09 155,87 160.88 161.75 162.91 170.76 179.10 183,97 185.18
6.828 14.738 7.215 15.797 6.469 16.235 6.757 18.540 6.118 17.072 7.167 17.G95 6.958 17.965 6.610 18.895 6 316 19.794 7.053 20.715 6.764 21.647 5,665 22,330 6.510 22.557 5.483 23.119 5.417 23.316 7.172 23.501 5.327 23.864 6.855 24.077 7.000 24.178 6.919 24.473 6.631 25.021 6.764 25.139 6.745 25.240 6.432 25.922 6.555 26.057 7.334 26.223 8.505 27.279 8.198 28.464 6.112 29.110 6.098 29.259
*
THERMODYNAMIC PROPERTIES OF SUBSTITUTED NAPHTHALENES
August, 1957
TABLE I (Continued) T. OK."
187.16 188.26 189.99 191.18 193.23 197.02 198.56 204.2%
ATb
cssstdc
T, 'K.a
7.934 5.028 5.956 5.925 4.915 5.780 5.772 5.643
29.613 29.798 30.023 30.167 30.543 31.096
120.80 126.58 132.79
11.72 12.2G 13.03 13.54 14.44 14.94 15.86 16.51 17.38 18.19 19.18 20.19 21,26 22.46 23,69 24.85 26.49 27,47 30.40 33.78 37.56 41.95 47.04 52.05 55.11 57,OO 61.01 66. 96 72.94 $8.99 84.63 86.07 no.37 92 34 92.79 97.97 98.83 103.76 109.30 114.98
1,180 1,203 1,460 1.345 1.364 1.460 1.479 1.674 1.560 1.694 2.044 2.309 2.108 2.250 2.747 2.531 2.865 2.707 3.151 3.614 3.932 4.861 5.305 4.732 5.555 5.150 6.236 5.673 6 ,277 5,823 5.458 6.465 6.014 6.073 4.419 5.926 6.902 5.653 5 ..422 5.947
139.61
31.383
143.56 150.32 156.86
32.276
363.18
Crystals I, supercooled 1 ,070 1,225 1.438 1.559 1.829 1.986 2.233 2.458 2.685 2.952 3.241 3.573 3.890 4.264 4.618 4.952 5.404 5.660 6.415 7.241 8.067 8.954 9 898 10.761 11.266 11.567 12.221 13,140 ,13.999 14,903 15.771 15.976 16.597 16,861 16,923 17.639 17.749 18.316 19,232 20,052
Liquid ATb
lti(i.63 169.83 175.83 176.84 181.28 186 17 188.97 196.59 211.25
5.679 5.884 6.537 7.109 6.897 6.628 6.451 6.18G 8.364 7.121 10.041 6.904 7.844 10.643 7.542 10.183 19.135
CsatdC
3.246 4.014 3.273 3.177 3.109 3.086
38.10 38.51 39.13 39.21 40.76 40.7d
92 13 66 74 79 16
25 64 87
3 257 3.172 3 280 2 257 2 909 2 639 3 072 2 796 3 152
82 04 30 23 36 40 59 40 58 41 08 41.11d
37 39 39 39 39
Crystals I-C" 218 41 219 42 219.74 219 88 221.47 222 GO 222 65 222 89
3 113 3 247 2 96F 3 076 3 018 3 112 2 847 2.946
58.18 58.29 58.37 58.45 58.51 58.46 58.74 58.85 58.84 58.92 59.09 59.10 59.08 59.23 59.35 59.648 59.794 60.664 62.038
The heat of transition of each compound was determined from measurements of the total enthalpy increase over a temperature range (about 20') that included the transition temperature. To obtain values of the latent heats of transition, the energy absorbed non-isothermally was computed from the heat capacity data and subtracted from the total enthalpy change. Corrections for the effect of premelting were applied. Two determinations of the heat of transition of each compound yielded the results given in Table 111. The Heats of Fusion, Triple Point Temperatures, Cryoscopic Constants and Purity of the Samples.-The heats of fusion of the six hydrocarbons were determined in the manner described for the heats of transition. The results are presented in Table IV. A study of the melting temporature of each compound as a funrtion of the fraction of sample melted was made by the method outlined in an earlier piiblication from this Laboratory.I0 The results are given in Table V. The observed temperatures, Tobsd, were plotted as a function of 1/F, the reciprocal of the fraction of total sample in the liquid phase. The triple point temperatures, T T . ~, were . determined by linear extrapolations to zero value of l / F . If the impurities present form ideal solutions in the liquid phase and are insoluble in the solid phase, the relation between mole fraction of total impurity! N*2, and melting point depression, A T = TT.P. - Tobsdr 1s'' -ln(l - N z ) = AAT(1 +BAT . . . ) (1) where N Z = N*2/F. Values of the cryoscopic constants, A = AHfusion/RTT.P.2andB = ~/TT.P. ACitusion/2AHfusion,
Crystals I-Be 215 219 216 219 219 222 222 222 222
1.028 1.956 1.025 4.217 1.022 1.955 1.019 1.017 1.939 1.018 4.176 1.013 1.932 1.010 1.923 4.139 4.108 9.615 9.994
234.19 6,781 47.716 241.35 7.549 48.390 244.55 7.190 48.716 249.24 8,238 49.255 251.68 7.081 49.525 258.21 9,696 50.272 267.82 9.515 51.440 ,277.23 9,302 52.637 284.32 9.112 53.561 286.44 9.126 53.833 293.71 9.680 54.845 302.96 10.136 56.114 303.65 10.190 56.221 311.58 7.100 57.333 313.02 8.560 57.406 315.50 1,032 57.88 316.11 1.963 57.95 316.62 1.030 58.05 a T is the mean temperature of each heat capacity meaaurement. AT is the temperature increment of each measurement. Csatd is the heat capacity of the condensed phase at saturation pressure. Heat capacity values for the solid have not been corrected for premelting. eCorrected for curvature.
21.100 22.049 23.347 24.751 25.591 26.87 27.66 29.09 29.63 30.21 31.04 31.31 31.49 32.36 32.88 34.06 37.06
Crystals I-A" 217.08 218.33 220.15 220.29 223.37 223.43
317.65 318.07 318.68 319.41 319.70 320.02 320.72 321.74 321.97 322.76 323.61 323.77 323.91 324.79 325.83 327.77 328.86 334.64 344.45
1109
39.08 39.53 39. 67 39.65 40.68 41.54 41.63 41. SOd
+
-
(10) S. 9. Todd, G. D. Oliver and H. M. Huffman, J . Am. Chem. Soc., 69, 1519 (1947).
(11) A. R. Glasgow, Jr., A. J. Streiff and F. D. Rossini, J . Re-search Nall. Bur. Sfandards, 36, 355 (1945).
TABLE I1 EQUATIONS REPRESENTING THE MOLAL HEATCAPACITIES IN THE LIQUIDSTATE,CAL.DEG.- 1 Csatd(liq.) = a f bT cT2 d P a Range, '1Z.a Compound b c x 103 d x 107 Naphthalene 19.212 0.092572 .... ....... 357-371 I-Meth ylnaphthslene 67.196 .31472 1.3098 - 13.642 248-352 2-Methylnaphthalene 23.663 .09972 .... .. . . . . , 312-366 1,2,3,4-Tetrahydronaphthalene 44.376 .12879 0.74003 - 7.467 248-319 trans-Decnhydronaph thalene 51.845 .20789 1.0156 - 9.6296 248-344 cis-Decahydronaphthnlcne 70.245 .37560 1,5554 - 15,494 234-345 a I n the indicated temperature range,'these equations fit the experimental ds,ta with an average deviation of less than 0.050/;, and, except for cis-decahydronaphthalene, with a maximum deviation of less than 0.1%. The equation for cis-decahydronaphthalene deviates slightly more (less than 0.2%) from some of the points near 320°K.
+
-
+
MCCULLOUGH, FINKE, MESSERLY, TODD, KINCHELOE AND WADDINGTON
1110
TABLE I11 THEMOLALHEATSO F TRANSITION O F 1- AND !&METHYLNAPHTHALENE AND
&-DECAHYDRONAPHTHALENE IN CAL. MOLE-1 Tt.W
Compound
1
OK.
I-Methylnaphthalene 2-hlethyln~phthalcne cis-Decahydronaphthalene See text.
240.79 288.5
AHtr8.S
Av.
2
1177 1192 1190" 1340.0 1341.1 1341"
Vol. 61
2-Methylnaphthalene (impurity = 0.01 mole %) 307.603 14.67 307.6570 6.818 .687 4.866 ,6951 20.55 ,7093 44.70 2.237" a. 7093" ,7149 .7151 63.67 1.571 ,7180 ,7180' 82.18 1,217" ,7198 100,oo 1.om . 7283c Pure 0
1,2,3,4-Tetr~hydronaphthalene(impurity = 0.03 mole yo) 237.272 8.290 237.2816 12.06 .318 3.797 ,3205 26.34 TABLE IV .3367" .3367 50.21 1,992" THE MOLALHEATSOF FUSION, TRIPLEPOINT TEMPERA.3424 69.31 1.443 ,3425 TURES AND CRYOSCOPIC CONSTANTS ,3455 .3455" 88.44 1,131" TT.P., AHfuslonta A, B, ,3469 100.00 1,000 Compound OK. cal. mole-1 deg.-l deg.-l ,3571" Pure 0 Naphthalene 353.43 f 0.05 4536 * 1 0.01827 0.00261 216.1
510.4
510.9
510.6
(I
1-Methylnaph-
thalene 242.70 rt 2-Methylnaphthalene 307.73 i: 1,2,3,4-Tetrahydronaphthalene 237.26 i: trans-Decahydronaphthalene 242.78 f. cis-Deoahydronaphthalene 230.18 f
.05 1660
* 2b
.01418
.O062Zb
.05 2898 f l . g b
,01540
,00216
.05 2975
0.1
.02657
,00248
.05 3445 f 0.3
.02941
.00292
* 1.5
,02154
.00299
.05 2268
3z
The uncertainty intervals given indicate the maximum deviation from the mean of 2 to 7 determinations of the heat of fusion. See text. a
were calculated from the values of AHruaionand TT.P.in Table IV and values of ACfusionobtained from data in Table VI (discussed in the following section). The values of A nnd B are included in Table IV. Application of eq. 1 in its simplified form (for N*2
