INDUSTRIAL AND ENGINEERING CHEMISTRY
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Literature Cited Carrier, W. H., J. Am. SOC.Heatang V e n t i l a t i n g Engrs., 24, 25 (1918). Coffey, B. H., and Horne, G . A., Am. SOC.R e f r i g . Engrs. J., 3, 32 (1916). Davis, A. H., Phil. Mag., 47, 972, 1057 (1924). Ferrel, Ann. Rept. of Chief Signal Officer, Appendix 24, p. 233 (1886). Himus, G. W., Trans. Inst. Chem. Engrs. (London), 7 , 166 (1929). Himus. G. W.. and Hinchlev. J. W.. Ibid.. 2. 57-64 (1924). Karnei; S., Mizuno, S., and Shioni, S., J. Soc'. Chem. Ind. Japan, 37, Suppl. binding 626 (1934). Lurie, M., and Michailoff, N., IND. ENG.CHEW,28, 345 (1936). McAdams, W. H., "Heat Transmission." P. 220, New York, McGraw-Hill Book Co., 1933. Mark. J. G., Trans. Am. Inst. Chem. Engrs., 28, 110 (1932)
VOL. 30, NO. 10
(11) Powell, R. W., and Griffiths, E., Trans. Inst. Chem. Engrs. (London), 13, 175 (1935). (12) Sharpley, B. B., and Boelter, L. M. K., IND.ENG. CHEM.,30, 1125 (1938). (13) Shepherd, C. B., Hadlock, C., and Brewer, R . C., I b i d . , 30, 388 (1938). (14) Sherwood, T. K., Ibid., 25, 314 (1933). (15) Sherwood, T. K., Trans. Am. Insl. Chem. Engrs., 32, 152 (1936). 116) Stanton, T. E., in W. H. McAdams' "Heat Transmission," pp. 105 and 108, New York, McGraw-Hi11 Book Co., 1933. (17) Thiesenhusen, H., G e s u n d h . - I n g . , 53, 113-19 (1930). (18) Wahlen, F. G., Univ. Ill. Eng. Expt. Sta., B u l l . 120, 5-17 (1921). (19) Walker, W. H., Lewis, W. K., McAdams, W. H., and Gilliland, E . R., "Principles of Chemical Engineering," 3rd ed., facing p. 720, New York, McGraw-Hill Book Co.. 1937. RECEIVED July 18, 1938
SodiumlLead Alloys by Carbon Reduction GARTH L. PUTNAM' University of Washington, Seattle, Wash.
A
LTHOUGH Castner (3) reported that the distillation of sodium (boiling point, 883"C . ) from a sodium hydroxide-carbon mixture requires a temperature of 100OO C., Rossiter's patent (6) states that the reduction takes place a t the surprisingly low temperature of 750" C., and that the sodium can be efficiently extracted from its solution in the melt. Halla and Tompa (4) showed that sodium reacts reversibly with sodium hydroxide to give a mixture of sodium hydride and sodium oxide. Into wrought-iron crucibles, of 30-ml. capacity and with closely fitting covers, were placed charges consisting of 10 grams of lead, 10 grams of anhydrous sodium hydroxide, and 1.6 grams of pulverized petroleum coke (99.8 per cent carbon). Parallel experiments were made in which lead was omitted. The crucibles were heated to 750" C. in a calibrated electric resistance furnace until the evolution of hydrogen became negligible. The reduction proceeds according to the equation (7) 6NaOH
+ 2C -+- 2NazCOa + 2Na + 3H2
As estimated by the relative sizes of the vigorously burning jets of hydrogen, lead did not lower the temperature of reduction. This was an unexpected result, since the heat of solution of one gram-atomic weight of sodium in an excess of lead is 39.1 kg.cal. 6).a value greater than the heat of formation of an eauivalent weight of iater. When the charge from which the lead had been omitted was dissolved in water, hydrogen was produced in volumes corresponding to a 3 per cent sodium content. After being washed thorou hly with cold dilute nitric acid, the lead alloys were dissolve% in 4 N nitric acid, evaporated to dryness, and analyzed for sodium by the zinc uranyl acetate method ( 1 ) ; it had previously been determined that large amounts of lead nitrate have little effect on the accuracy of the determination. Typical analyses were 4.31, 4.04, and 5.83 per cent sodium, corres onding t o yields of about 50 per cent, based on the amount o?sodium carbonate produced.
With 15-minute heating a t 750" C., the conversion of sodium hydroxide to sodium carbonate was more than 90 per cent complete, as determined by phenolphthalein and methyl orange titrations. It is believed that the reason for the higher yields when lead was present was the exclusion of air from the alloy by the layer of molten sodium carbonate. The carbonate of sodium was more difficultly reducible 1 Present address, Division of Electrochemistry, Columbia University, New York, N. Y .
than the hydroxide. Uniform charges, consisting of 7.5 grams of anhydrous sodium carbonate, 2.5 grams of pulverized petroleum coke, and 25 grams of lead, were heated at 1000" C . The following results indicate that the reaction is a slow process: Time of heating, hr. Na, found in alloy, %
0.25
0.01
1.0
0.38
4.0 0.79
With sodium carbonate, finely ground coke was a more efficient reducing agent than the coarse material. The reaction mixtures evolved small amounts of combustible gases when treated with water. These observations indicate that sodium can be held in solution a t temperatures considerably above the boiling point of sodium and that the reaction proceeds in the stages (a) reduction of the carbonate and (b) combination of the alkali metal with lead. All attempts to prepare alloys of the alkaline earth metals by carbon reduction of calcium oxide, barium carbonate, or strontium carbonate at 900" to 1100" C. Were unsuccessful, the lead containing less than 0.01 per cent of the alkaline earth metal. However, potassium compounds were found more easily reducible than those of sodium. Five to ten per cent sodium-lead alloys are used for the manufacture of tetraethyllead (I). As a simple method requiring a low capital investment, the Rossiter process might be found suitable for the production of sodium-lead alloys. The author wishes to thank Kenneth A. Kobe for his very generous assistance and encouragement.
Literature Cited (1) Barber, H. H., and Kolthoff, I. M., J . Am. Chem. SOC.,52, 2654-
65 (1930). (2) Calcott, W. S., Parmelee, A. E., and Meschter, H. F. (to E. I du Pont de Nemours & Co., Inc.), U. S. Patent 1,944,167 (Jan. 23, 1934). (3) Castner, H. Y . , J . FrankEin Inst., 92, 347 (1886). (4) Halla, F., and Tompa, H., 2. anorg. allgem. Chem., 219, 321-31 (1934). (5) Kraus, C. A., Trans. Am. Electrochem. Soc., 45, 175 (1924). (6) Rossiter, E. C., U. S. Patent 1,073,523 (Sept. 16, 1913). (7) Thorpe, E., "Dictionary of Appliad Chemistry," Vol. VI, p. 233, London, Longmans, Green and Co , 1926.. RECEIVED M a y 18, 1938.
