February 1952
INDUSTRIAL AND ENGINEERING CHEMISTRY
331
Equation 1 may be written in a more convenient form
Within the limits of accurac$ of Figure 3, AEband AE” may be assumed the same and Equation 2 may be used to estimate AE”. CONCLUSIONS
The heats of combustion of nine nitro alcohols, including three sets of isomers, have been determined experimentally with an average precision of about 2 parts in 1000. Standard heats of formation have been calculated from the experimental heats of combustion, the heats of combustion of the solid nitro alcohols have been shown to be a linear function of the oxygen balance of the molecules, and an equation has been derived to correlate these two variables. ACKNOWLEDGMENT
The authors wish to express their appreciation to J. P. Kispersky who prepared and purified some of the experimental samples. NOMENCLATURE
A&
= heat of combustion under bomb conditions, kg.-cal. per
mole
AE” = standard change in internal energy a t 25” C., kg.-cal. per
OXYGEN
mole AHo = standard change in enthalpy at 25’ C., k .-cal. per mole AH,” = standard heat of formation at 25’ C. and 1 atmosphere pressure, kg.-cal. per mole M = molecular weight OB = oxygen balance X = number of carbon atoms in the molecule = number of hydrogen atoms in the molecule Y 2 = number of oxygen atoms in the molecule
BALANCE
Figure 3. Heats of Combustion us. Oxygen Balance for the Nitro Alcohols CORRELATION O F HE4TS OF COMBUSTION WITH OXYGEN BALANCE
LITERATURE CITED
Oxygen balance (OB)is defined as the negative of 100 times the weight of external oxygen required for the complete combustion of a unit weight of a compound to carbon dioxide, water, and nitrogen. A plot of the data given in Table I1 for calculated oxygen balances and heats of combustion of the solid nitro alcohols indicates an apparently linear relationship as shown in Figure 3. The points on Figure 3 are numbered to correspond to the nomenclature of Table 11. Heats of combustion of isomers have been averaged before plotting.
TABT,E 11. HEATOF COMBUSTION AND OXYQEN BALANCE FOR NITROALcoHoLs NO.
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Oxygen 14, Compound Balances Cal./Cr;m 4917.71 - 100,651 127.602 2-Nitro-2-methyl-1-propanol 4037.56 2-Nitro-2-methyl-13-propanedioi - 123.369 4700.48 2-Nitro-2-ethyl-l,3~propanediol 6264.17 - 142.181 6266.96 2-Nitro-2-propyl-13-propanediol 142.181 2-Nitro-2-isopro A-1 3 propanediol -192.619 6704.74 2-Nitro-2-methy~-l-phanyl-l-propanol 6667.74 192.619 2-Nitro-2-methyl-3- henyl-1-propanol 3376.23 -79.407 Tris(hydroxymethy1~nitromethane
-
(1) American Society for Testing Materials, A.S.T.M. Manual on Presatatim of Data, Supplement A, Philadelphia, 1940. (2) Baxter, G.P., etal., J . Ant. Chem. SOC.,63,845 (1941). (3) Daniels, F., Ibid., 38, 1473 (1916). (4) Glasgow, A. R., Streiff, A. J., and Rossini, F. D., J . Research Natl, Bur. Standards, 35, 355 (1945). (5) Holcomb, D. E., and Dorsey, C. L., IND. ENG.CREM.,41, 2788 (1949). (6) Jessup, R. S., J . Research Natl. Bur. Standards, 36,421 (1946). (7)Lewis, G. N., and Randall, M., ”Thermodynamics and the Free Energy of Chemical Substances,” New York, MeGraw-Hill Book Co., 1923. (8) Mueller, E. F., and Rossini, F. D., Am. J . Phys., 12, 1 (1944). (9) Perry, J. H.,“Chemical Engineers’ Handbook,” New York, McGraw-Hill Book Co., 1941. (10) Prosen, E.J., Jessup, R. S., and Rossini, F. D., J . Research Natl. Bur. Standards, 33,447 (1944). (11) Richards, T. W., and Barry, F., J . Am. Chem. SOC.,37, 993 (1915). (12)Rossini, F. D., and Deming, W. E., J . Wash. Acad. Sci., 29, 416 (1939). (13)Wagman, D. D.,et al., J . Research Natl, Bur. Standards, 34, 143 (1945). (14) Washburn, E.W., Ibid., 10,525 (1925). (16) White, W. P., “The Modern Calorimeter,” New York, Reinhold Publishing Corp., 1928. RECEIVED April 30, 1961.
The following equation has been fitted to the data by the method of least squares . A E b = 28.981(0B)
- 1129.8
(1)
where A E b is expressed in calories per gram or kg.-cal. per kg. The average deviation between experimental and calculated values is 0.7% of the experimental value. Whereas the correla tion coefficient for a perfect linear relationship is 1.0000, the correlation coefficient for the present data is 0.9993.
Correction In an article on “Coking of Heavy Residual Oils” [Leo Garwin and B. E. Steinkuhler, IND.ENG. CHEM.,43,2586 (1951)], the broad oven employed in the pilot plant studies was incorrectly described as a “Knowles oven.” It should have been referred to as “the Hughes oven, which is a modification of the LEOGARWIN Knowles oven.”
