ANALYTICAL EDITION
November, 1944
693
30, 70, 80, and 90% A.S.T.M. distillation temperatures-might be preferred to the 50% dietillation temperature. Among the straight-run naphthas described in Tables I and 11, however, in no case do the 50% points and average boilinp points differ by as much as 2’ C. Thus the 50% temperature, T,has been chosen for convenience POSSIBILITY OF WIDER APPLICATION
The present estimates are limited to conmercially available solvent naphthas, or hydrocarbon thinners. It nevertheless appears possible to extend the method to include mixtures of hydrocarbons and oxygen-containing solvents, wherein latent heat of vaporization may vary rapidly with composition during the time of evaporation. Additional data covering volume changes upon mixing, together with evaporation rates of individual components, will then be required. Meanwhile, the present rough method is suggested as a subatitute for routine control tests.
MINUTES
Figure 5
Table
LITERATURE CITED
IV. Aromatic Solvent Naphthas (1)
CoalTar Hi-
2’ 5012’ 10’ dolRolBen- vesso Tolu- Xyl- vesso vesso ene 2 Flash sene 1 ene 3 29.5 39.3 31.8 32.8 33.6 31.1 29.5 Gravity, * A.P.I. 0 , 8 7 9 0 , 8 2 9 0.868 0 . 8 8 2 0 , 8 5 7 0 , 8 7 0 0 , 8 79 Sp. gr. at 6Oo/8O0F. A.S.T.M. distillation 174 78 99 108 134 137 152 Initial b.p.. O C . 187 80 111 110 137 14i 171 507’ off 14* 83 138 E n 8 point 177 196 209 Evaporation time at 25* C., minutes l!:: 21 15.2 27.3 37 92 122 390 670 21 36.0 46 I20 170 604 .
:
i!
ig
l:! 3yh ..
Bansene
Solveaao i
Toluene Xylene Solvesao 2 Hi-Flash 8olvenso 3
Specific Gravity Difference 0.187 0.088 0.125 0.097 0,087 0.085 0.086
Table C. Added
5 4.5 4.5 4.6
Committee D-2. D8€-40. (2) Bent, F. A., and Wik, S. N . , IND.ENO.CHEM.,28, 312 (1936). (3) Bogin, C., and Warnpner, H.L., Ibid., 29, 1012 (1937). (4) Dorsch, J. B., and Stewart, J. K.,IND. ENCI.CHEM., 30, 825 (1938).
(5) Ddsa, M. P., “Physical Constants of the Prinripal Hydrorrrr bons”, 4th ed., New York, Texas Co., 1943. (6) Dunstan, A. E . . Nash, A. W., Tizard, Henry, and Brooks. B. T. “Science of Petroleum”. Vol. 11, D. 1136. New York. Oxford University Press, 1938. (7) Fallon, J. F., and Watson, K. M., p. 136, Petroleum Division Preprints, A.C.S. Meeting, Pittsburgh, Sept., 1443. (8) Institute of Petroleum, Suhrornmittee 9, J Inat. Petroleum, 30, No. 242, 49 (Feb.. 1444) ---,.
V. Aromatic Solvent Naphthas
to B . P . 8.5 4.5 8
A.S.T.M. Standards on Petroleum Products and Lubricants
Estimated Evaporation Points, by Weight 1 . 9 at 1 8 . 1 % 5 . 2 at 4 0 . 4 % 1 0 . 2 at 6 4 . 5 % 14 at 7 6 . 5 % 5 . 2 ut 18% 5.5atli.l% 15at 17.7% 21 at 18 52 a t 94 a t 18% ...
Myodiscillation temperature) parallel each other in evaporation rate in both actual and estimated values; although agreement between these va!ues for the individual solvent leaves something to be desired. Concordance in the cme of benzene is poor, alahough the 76oJ, point is close to actual. Benzene, however, is unique in a number of ways, and it evaporates much faster than other commercial aromatic solvents. VARNISH SPIRITS
In the section above on “Evaporation Rate Curves”, diucussion of varnish spirits was postponed. The difference in specific gravity between the varnish spirits in Table I and the lower solvency mineral spirits-viz., 0.023-necessitates the use of the gravity correction, 50 (f3- Gp),and therefore there must be added 1’ C. to its already 2’ C. higher 50% distillation temperstwe. In this connection it may appear, particularly in the case of the large number of mineral spirits commercially available, that an error in reading the 50% distillation temperhture will bulk large in estimating evaporation rate. In such an event, the popular “average boiling point”-the arithmetic average of the 10, 20,
(9) McArdle, E. H.,IND.ENO.CHEM..ANAL ED., 11, 450 (1939). (10) Metringer, E. F., Paint. Oil Chem. Reo.. 99. No. 10. 9 (Mav. 1937). (11) Rubek, D. D., and Dahl, D. W., IND. ENO CHEM..ANAL.ED., 6, 421 (1934).
(12) Stewart, J. K., Dorsoh, J. B., and Hopper C. B . , IND.ENQ.CHEM.,29, 899 (1937) (13) Sweeney, W. J., and McArdle, E . H., Ib&j.. 33. 787 (1941). (14) Wetlaufer; L. A.,and Gregor, J. B., IND. ENQ.CHEM.,ANAL.ED., 7, 290 (1935)
PREBENTBD before the Division of Paint, Varnish, and Plastics Chemlltrr of the AMERICAN CHEMICAL SOCIETY. New York, N. Y
nt the 108th Meeting
Corrections In the article on “Determination of Formaldehyde” [IND.ENQ CAEM.,ANAL.ED.,16,496 (1944)],reference 50x1page 496 should read: Boyd, M. J., and Rambach, Karl, IND.ENO.CHEM.,ANAL ED., 15, 314-15 (1943). G.C.WECXTNACK I n the note on “An Observation of Possible Value for Sugar Determinations” [IND.ENO.CHEM.,ANAL.ED.,16,537 (1944)], an error occurs in lines 15 and 33, where “grams” should read “milligrams”. The possibility of iodometric determination of Ihe cuprous iodide has been discussed in detail by Shaffer and Hartman [ J . B h l . C h m . , 45, 365 (1920-21)l. DANIELI,UZONMORRIE
