these compound types according to the relative crowding of the nitrogen atom, as in the classification scheme of Table XI. Similarly, nonortho alkyl substitution increases So for these compounds much more than in the case of the aromatic hydrocarbons of similar ring number, and pure compound data (39) were used to estimate the additional contribution to as0 in excess of that given by Figure 2. Given values of aA,and of AP for the effect of aliphatic substitution on the original So and A , values of a parent molecule, it may be shown that ti
= [ ( A , / A+ , AA,)](c,)’+ A S ” / ( A ,+ AA,)
€ 1 refers to the value for the aliphatic substituted derivative-i.e., petroleum component-and (e# is the value of t l for the original parent compound. With the exception of basic nitrogen compounds, compounds of the same type fall into reasonably narrow adsorptivity ranges, as illustrated in Figure 3.
ACKNOWLEDGMENT
The authors are grateful for the gift of the various porphyrin samples of Table I11 by J. M. Sugihara of the North Dakota State University and to E. C. Copelin of this laboratory for editing the original manuscript. LITERATURE CITED Albert, A., Serjeant, E.P., “Ionization Constants of Acids and Bases,” Wiley, New York, 1962. Albert, A., Goldacre, R.J., Phillips, J., J . Chem. SOC.1958, p.2240 Braude, E.A., Nachod, F.C., Eds., “Determination of Organic Structures by Physical Methods,” Academic Press, New York, 1955. Britton, H., “Hydrogen Ions,” Vol. 1, Academic Press, New York, 1963. Cohen, L.A., Jones, W.M., J. Am. Chem. SOC.85, 3397 (1963). Copelin, E.C., Anal. Chem. 36, 2274 (1964). Cundiff, D.H., Markunos, P.C., Ibid., 28, 792 (1956). Deal, V.Z., Weiss, F.T., White, T.N., Ibid., 25, 426 (1953). Drushel, H.V., Somners, A.L., Ibid., 38, 19 (1966). Gusinskaya, S.L., Khim. Seraorgan. Soedin., Sodenhashch. u Neft. i Neftepmd., Akad. Nauk SSSR Bashkirsk. Filial 6, 87 (1964). Hall, N.F., J . Am. Chem. SOC.52, 5115 (1930). Hartung, G.K., Jewell, D.M., Anal. Chim. Acta 26,514 (1962). Ibid., 27, 219 (1962).
Horton, A.W., Burton, M.J., Tye, R., Bingham, E.L., 145th Meeting, ACS, New York, September 1963; Petroleum Div. Preprints 8, No. 4, C-59. Jewell, D.M., Hartung, G.J., J. CHEM.ENG. DATA9, 297 (1964). Katritzky, A.R., Ed., “Physical Methods in Heterocyclic Chemistry,” Vol. I, Academic Press, New York, 1963. Latham, D.R., Ferrin, C.R., Ball, J.S., Anal. Chem. 34, 311 (1962). Lemarie, H., Lucas, H.J., J . Am. Chem. SOC.73, 5198 (1951). Lochte, H.L., Littman, E.R., “The Petroleum Acids and Bases,” Chemical Publishing, New York, 1955. Lochte, H.L., Proc. Am. Petrol. Inst., Sect. VIII, 42,32 (1962). Lumpkin, H.E., Johnson, R.N., Anal. Chem. 26, 1719 (1954). Nicksic, S.W., Judd, S.H., Ibid., 32, 998 (1960). Nixon, A.C., Thorpe, R.E., J. CHEM.ENG.DATA7,429 (1962). Sauer, R.W., Melpolder, F.W., Brown, R.A., Ind. Eng. Chem. 44. 2606 (19521. --, Snyder,L.R., Admn. Anal. Chem. Instr. 3, 251 (1964). Snyder, L.R., Anal. Chem. 33, 1538 (1961). Ibid., 36, 774 (1964). Ibid., 37, 713 (1965). Snyder, L.R., Chap. 4 of “Chromatography,” E. Heftmann, Ed., 2nd ed.,Reinhold, New York, 1967, in press. Snyder, L.R., J. Chromatog. 6, 22 (1961). Ibid., 8, 319 (1962). Ibid., 12, 488 (1963). Ibid., 16, 55 (1964). Ibid., 17, 73 (1965). Ibid., 20, 463 (1965). Ibid., in press. Snyder, L.R., J. Phys. Chem., 67, 234 (1963). Ibid., p. 240. Ibid., p. 2344. Snyder, L.R., Buell, B.E., Anal. Chem. 36, 767 (1964); Anal. Chim. Acta 33, 285 (1965). Snyder, L.R., Buell, B.E., Proc. Am. Petml. Inst., Sect. V I I I , 42, 95 (1962). Snyder, L.R., Fett, E.R., J. Chmmatog. 18, 461 (1965). Snyder, L.R., Warren, H.D., Ibid., 15, 344 (1964). Snyder, L.R., Howard, H.E., Ferguson, W.C., Anal. Chem. 35, 1676 (1963). Streuli, C.A., Ibid., 30, 997 (1958). Sugihara, J.M., Bean, R.M., J. CHEM.ENG. DATA7, 269 (1962). Thompson, C.J., Coleman, H.J., Hopkins, R.L., Rall, H.T., “Hydrocarbon Analysis - ASTM STP 389,” American Society for Testing Materials, Philadelphia, 1965, p. 329. Wimmer, D.C., Anal. Chem. 30, 77 (1958). Yates, K., Stevens, J.B., Can. J . Chem. 42, 1957 (1964). Yew, F.F., Mair, B.J., Anal. Chem. 38, 231 (1966). RECEIVED for review January 24, 1966. Accepted May 13, 1966. ~~~
Thermodynamic Functions of Cyanogen Bromide JOHN S. GORDON Astrosystems International, Inc., Fairfield, N.J.
THERMODYNAMIC
DATA for BrCN are required in the analysis of combustion of high density oxygen deficient systems with various amine fuels. As a result of recent higher resolution infrared studies, Maki and Gott (7) have determined the rotation-vibration interaction term, a3, and the doubling coefficient, gzz. Maki ( 6 ) has determined the anharmonic terms, x22, XB, and VOL. 1 1, No. 4, OCTOBER 1966
( V I + ~ ~ 3 )Burrus . and Gordy ( I ) determined the rotational constant, BO and the rotational stretch constant, DO. Townes, Holden, and Merritt (9) have determined the a2 value. Freitag and Nixon ( 4 ) have determined the observed fundamentals, 0 , ; their older values of ~ 2 2 , x Z 3 , and gz, when used in a comparison calculation led to less satisfactory values of the thermodynamic functions. Maki
553
Table I. Thermodynamic Functions for BrCN(g) (H' - H i ) T 298.15 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 3100 3200 3300 3400 3500 3600 3700 3800 3900 4000 4100 4200 4300 4400 4500 4600
4700 4800 4900 5000 5100 5200 5300 5400 5500 5600 5700 5800 5900 6000
50.447 50.502 53.162 55.361 57.245 58.896 60.371 61.704 62.923 64.047 65.091 66.065 66.979 67.840 68.655 69.428 70.164 70.865 71.536 72.179 72.796 73.390 73.961 74.512 75.045 75.560 76.058 76.541 77.010 77.465 77.907 78.338 78.757 79.165 79.563 79.951 80.331 80.701 81.063 81.417 81.764 82.103 82.435 82.761 83.080 83.393 83.700 84.001 84.297 84.588 84.874 85.155 85.431 85.702 85.970 86.232 86.491 86.746 86.997
8.887 8.902 9.592 10.119 10.540 10.890 11.191 11.454 11.688 11.897 12.086 12.257 12.414 12.558 12.690 12.812 12.925 13.030 13.129 13.221 13.308 13.389 13.466 13.539 13.608 13.674 13.737 13.796 13.854 13.909 13.961 14.012 14.060 14.107 14.153 14.197 14.239 14.280 14.320 14.359 14.397 14.434 14.469 14.504 14.538 14.572 14.604 14.636 14.667 14.698 14.728 14.757 14.786 14.815 14.843 14.870 14.897 14.924 14.950
Table II. Molecular Constants of BrCN, Cm.-' Natural Isotopic Mixture = 575 = 342.5 OS = 2200 a l = 5.17 x a2 = -3.84 x lo-' a3 = 6.77 X lo-' Bo = 0.13705 Do = 2.929 x lo-' 61
02
Molecular weight = 105.934 Heat of formation AH?" = +44.87 kcal./mole (3).
554
So 59.334 59.403 62.753 65.480 67.784 69.786 71.561 73.158 74.611 75.944 77.176 78.322 79.393 80.398 81.345 82.240 83.089 83.896 84.665 85.400 86.104 86.779 87.427 88.051 88.653 89.234 89.795 90.338 90.863 91.373 91.868 92.349 92.817 93.272 93.716 94.148 94.570 94.981 95.383 95.776 96.160 96.536 96.904 97.265 97.618 97.964 98.304 98.637 98.965 99.286 99.602 99.912 100.217 100.517 100.812 101.102 101.388 101.670 101.947
C;, Cal. Mole-' Deg. -' 11.263 11.280 11.983 12.451 12.826 13.150 13.433 13.680 13.895 14.081 14.244 14.386 14.511 14.621 14.720 14.809 14.890 14.965 15.033 15.096 15.155 15.211 15.263 15.313 15.361 15.406 15.450 15.492 15.533 15.573 15.612 15.650 15.687 15.723 15.758 15.793 15.828 15.861 15.895 15.928 15.961 15.993 16.025 16.057 16.088 16.119 16.150 16.181 16.212 16.242 16.273 16.303 16.333 16.363 16.392 16.422 16.452 18.481 16.510
HF
- H&,
Kcal. Mole-' 0.0 0.021 1.187 2.410 3.674 4.973 6.303 7.659 9.038 10.437 11.853 13.285 14.730 16.187 17.654 19.130 20.615 22.108 23.608 25.115 26.627 28.145 29.669 31.198 32.732 34.270 35.813 37.360 38.911 40.467 42.026 43.589 45.156 46.726 48.301 49.878 51.459 53.044 54.631 56.223 57.817 59.415 61.016 62.620 64.277 65.837 67.451 69.067 70.687 72.310 73.935 75.564 77.196 78.831 80.468 Q8.109 83.753 85.400 87.049
PfRT 50.345 49.850 29.696 17.300 8.826 2.619 -2.155 -5.962 -9.085 -11.703 -13.938 -15.876 -17.576 -19.085 -20.436 -21.655 -22.763 -23.776 -24.708 -25.569 -26.368 -27.113 -27.810 -28.463 -29.079 -29.659 -30.209 - 30.730 -31.225 -31.697 -32.147 -32.578 -32.990 -33.385 -33.765 -34.130 -34.481 -34.820 -35.147 -35.462 -35.768 -36.064 -36.350 -36.628 -36.898 - 37.160 -37.414 -37.662 -37.903 -38.138 -38.367 -38.590
-38.806 -39.021 -39.228 -39.431 -39.630 -39.824 -40.014
and Gott (7) list an a1 value which is ascribed to Tetenbaum (8) and is used in preference to the older value (3.77 x given by Townes, Holden, and Merritt (9). It is necessary to estimate values for the anharmonic terms xll, 2 3 3 , x12, and 2 1 3 in a reasonable manner based on data for related linear molecules (ClCN, COS, C 0 2 , N20), since there appears to be considerable difficulty in obtaining accurate values for these terms from the observed BrCN spectra. Thermodynamic functions were computed over the temperature range 298" to W K . , for an ideal gas of BrCN molecules at 1 atm. using the program described previously (5). In these calculations, R is 1.98726 cal. per mole degree, h c l k is 1.4388, and the Sackur-Tetrode constant, k g , is -7.28353 (2). Previous tables for BrCN were based on the rigid rotorharmonic oscillator (RRHO) approximation. JOURNAL OF CHEMICAL AND ENGINEERINGDATA
Consideration of the anharmonicities and rotational effects raises c,O ( 6 W K . ) 11%beyond the RRHO result. NOMENCLATURE rotation-vibration interaction coefficient, cm. -' B = rotational constant, cm.-' c, = specific heat capacity, cal. mole-' deg.-' D = rotational stretching coefficient, cm.-' AH, = heat of formation, kcal. mole-' F = free energy, cal. mole-' g = doubling coefficient for degenerate vibration, cm. -' H = enthalpy, cal. mole-' R = gas constant, 1.98726 cal. mole-' deg.-' a = vibrational fundamental energy, cm.-' s = entropy, cal. mole-' deg.-' T = temperature, K. anharmonicity term, cm. -' a
=
x =
Superscript 0
-
-
ideal gas standard state (1atm.)
VOL. 1 1, No. 4, OCTOBER 1966
Subscript
0, 1 , 2 , 3 = vibrational identification Subscript
0 = zerodeg. K. LITERATURE CITED (1) Burrus, C.A., Gordy, W., Phys. Reu. 101, 599 (1956).
(2) Cohen, E R . , DuMond, J., Layton, T.W., Rollett, J.S., Reu. Mod. Phys. 27, 363 (1955). (3) Jaiiiaf Thermochemical Tables, Dow Chemical Co., Thermal Laboratory, Midland Mich., June 30,1963. (4) Freitag, W.O., Nixon, E.R., J. Chem. Phys. 24, 109 (1956). (5) Gordon, J.S., J. CHEM.ENG.DATA6, 390 (1961); 7, 82 (1962). (6) Maki, A.G., J . Chem.Phys. 38, 1261 (1963). (7) Maki, A.G., Gott, C.T., Ibid., 36, 2282 (1962). (8) Tetenbaum, S.J., Phys. Reu. 86, 440 (1952). (9) Tomes, C.H., Holden, A.N., Merritt, F.R., Ibid., 74, 1113 (1948). RECEIVEDfor review April 4, 1966. Accepted June 28, 1966.
555
