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octane numbers and lead susceptibility. Fuels of higher octane number might be obtained by proceeding in at least three different ways: (I) segregating the desired hydrocarbons of high antiknock value from all others in the gasoline, (2) segregating and combining not only the high octane number types but also those of high octane blending value and combining these with other hydrocarbon type$ of only fair octane number to make available a greater volume of fuel, and (3) segregating and combining the high octane number types as well as those very reponsive to tetraethyllead. I n this way fuels of very high octane number could be produced, for the recent work of Boyd and co-workers (1) has shown certain hydrocarbons-for example, the branched paraffins and the substituted benzenes-to permit marked increases in critical compression ratio upon the addition of 1 cc. of tetraethyllead, in comparison with other hydrocarbon types. The patent of Henderson and Ferris (5) relates to a process for obtaining gasoline of high antidetonating quality by fractional distillation. This patent relates to the separation of the paraffinic hydrocarbons from the aromatic and naphthene types, the paraffinic types being considered undesirable as high-antiknock fuel. It is now known that certain paraffinic types are highly desirable, in many instances more so than the aromatic hydrocarbons, such as benzene, which are available commercially for blending with motor fuels. The fractions or hydrocarbons suitable for the high-antidetonating fuel according to this patent are those of high specific gravity and low aniline point. It now appears in view of the recent work on the octane numbers of various hydrocarbons and their physical constants ( I , @ that the only sure way to recognize the desirable hydrocarbons resulting from efficient fractional distillation of gasoline is either to know definitely their chemical formula, or else have available reliable and rather extensive tests of their antiknock qualities a t high engine temperatures, as well as their octane blending value and susceptibility to tetraethyllead. The apparent parallelism between density and refractive index curves and knock rating that was thought to exist earlier, no longer holds on more efficient fractionation or for gasolines from different sources. This is apparent in the case of the Michigan straight-run gasoline shown in Figure 3 where, in the low- as well as in the
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high-boiling fractions, high octane number and high refractive index do not necessarily coincide. There may be several reasons for this: (1) because of efficient fractionation, the isolation of the constituents in the gasoline has been sharper and ( 2 ) the boiling points of the hydrocarbons themselves may have been responsible. I n certain portions of the gasoline the boiling points of the aromatics and the most highly branched paraffins do not coincide, and in gasolines where the aromatic content is small the effect is even more pronounced because of naphthenic hydrocarbons. This has been found in other gasolines to be described later. It is now possible to produce by fractional distillation fuels containing concentrated portions of branched hydrocarbons, particularly paraffins, but also naphthenes and aromatics where the proportions are several fold greater than in the original gasoline; these materials are characterized as having high octane number, high blending value, and high lead susceptibility. By combining efficient fractional distillation and efficient fractional extraction, it is possible to extend further the scale of knock ratings and the volume of suitable fuel. In this way marked progress can be made toward reducing gasoline, partially a t least, to a list of chemical substances. As this work progresses it is quite probable that greater quantities of gasoline will find use in special solvents and in chemical manufacture.
Literature Cited (1) Campbell, J. M., Signaigo, F. K., Lovell, W . G., and Boyd, T. A , IND. ENQ.CHEW,27, 593 (1935) ; other references are cited. ( 2 ) Edgar G., Calingaert, G., and Marker, R. E., J. Am. Chem. Soc., 51, 1483-1540 (1929). (3) Fenske, M. R., Quiggle, D., and Tongberg, C. O., IND. ENO. CHEM.,24,542 (1932). (4) Garner, F. H., Evans, E. B., Sprake, C. H., and Broom, W. E. J., World Petroleum Congr., London, 1933, Proc. 2, 170. (5) Henderson, L. M., and Ferris, 5. W., U. S. Patent 1,868,102 (July 19,1932). (6) Lovell, W. G., Campbell, J. M.,and Boyd, T. A., IND.ENQ. CHEM.,23,26 (1931). (7) Quiggle, D., Tongberg, C. O., and Feneke, M. R., IND.ENO. CHEM.,Anal. Ed., 6,466 (1934).
RECEIVED July 24, 1935. Presented before the Division of Petroleum Chemistry a t the 89th Meeting of the American Chemical Society, New York, N. Y , April 22 t o 26, 1935.
ZINC-INDIUM ALLOY SYSTEM CURTIS L. WILSON A N D ETTORE A. PERETTI Montana School of Mines, Butte, Mont.
NDIUM alloy systems which have been investigated and reported in the literature aye: lead-indium ($), thallium-indium (4), tellurium-indium (2), copper-indium ( B ) , and silverindium ( 7 ) . Certain alloys of gallium ( I ) , zinc (5), and selenium (8) have been studied, but the equilibrium diagrams of these elements with indium do not appear to have been published. I n preparing the alloys, electrolytically purified indium obtained from zinc-roaster flue dust was used. The metal was first extracted by dissolving the flue dust in hydrochloric acid, separating group I1 with hydrogen sulfide, and treating the filtrate with zinc dust. Zinc and copper were removed with ammonia, and after repeated treatments the indium was
recovered as indium hydroxide or sulfide, taken into solution and then deposited eleEtrolytically upon 'steel cathodes (8). The zinc used was Anaconda electrolytic zinc. The alloys were made by melting the correct proportion of eachmctalseparately and then pouring them together, constantlystirring the mixture, and remelting in carbon crucibles to obtain cooling curves. At the lower temperatures there was practically no loss by oxidation or volatilization. At higher temperatures the melts were protected from oxidation by charcoal. Readings were obtained by means of mercury thermometers, calibrated by the U. S. Bureau of Standards to read to the closest 0.2"C., and an iron-constantan thermocouple. Thirty alloys were made and examined. The combined cooling curves show the equilibrium diagram as represented in Figure 1. Figure 2A is a photomicrograph of electrolytic zinc etched with a 10 per cent solution of nitric acid; the grain boundaries are very sharp. This can be compared with Figure 2B, a photomicrdgraph of a n alloy containing 1.98 per cent indium and 98.02 per cent zinc. It
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c o n s i s t s of z i n c g r a i n s surrounded b y i n d i u ni-sin e eutectic. Upon heating this specinien for 2 hours at 135" C., no change in s t r u c t u r e was noted, so t.liat the soliihility of indium in zinc at this temp e r a t u r e was kssuined to be close to zero. Figure 2C shows an alloy containing 10 per cent indium and 00percent zinc. The lirht .---- colored crystals are of zinc, and the dark material is the eutectic. Figure 2 0 shows a 76 per cent zinc-24 per cent indium alloy. The eutectic alloy, with 96 per cent indium and 4 per cent zinc, showed grayish black; it contained (~ii1.V 4 per cent of the light-etching zinc. All the alloys etched darker as the indium content increased. Two specimens of the eutectic alloy were obtained by heating the 54 per cent indium alloy a t 14ja C. Thismadethe alloy "sweat" beads of eotectio which were collecied and analyzed for both indium and zinc. They were found to contairi 90 per cent indium and 4 per cent zinc, which compsition Nas also confirmed by the euteetir-timc?s intcrpo~ation ~ticthod. These alloys bccoinc softer as the indium content is increased; the 54 per cent indium alloy can be scratched vith t,Iic finger nail. All of the alloys have a silvery white color. ~~~~
Literature Cited Browning arid Uhlar. Am. J . Sci.. 41, 351 (1916). Klemm and Vosel, Z.anma. allaem. Chem., 219,45 (1934) Kurriskov and Pusohin, Ihid.. 52,430 (1907). Ihid.. 52, 445 (1907). Richards and White. J. Am. C h e m Soc., 50, 3290 (1928). Weibko and Eggem. Z.anow. allgem. Chem., 220, 273 (1934). rbid.. 222. 145 (1935). ( 8 ) Westbrook, T~ans.Am.. Elediochem. Snc., 57, 289 (1930).
(1) (2) (3) (4) (5) (6) (7)
r indium ( X 415) B . 48.03 per ornt i i n ~~1 . O R~ e oent
Rmcsrvro August ?!I, 1815.
D.
a;
per oent aino-24 per cant indium FIGURE
2 ( A , B,
( x 98)
c, D). PAOTOMICROGRAPBB OF
C. YO per oent sin*-I0 per cent indium ( X $8) ZIXC AND ZINC
10 PER CENT NITRIC ACID
ALGOYB&'CUED
WITH
