876
NOTES
data are of importance in connection with the handling and administration of this agent. Cyclopropane has become extremely important as an inhalation anesthetic and since a survey of the literature reveals that similar data have not been published, it seems worthwhile to make the data obtained in this study available at this time. Experimental The critical constants and vapor pressures of cyclopropane at high pressures were investigated utilizing a very accurate type of apparatus described by Booth and Swinehart.* The procedure was t o transfer fractionally distilled cyclopropane which exhibited a constant density at constant temperature and pressure to a manifold to which Cailletet tubes were sealed. The manifold and cells were rinsed 20 times with dry air and 15 times with cyclopropane, and the tubes finally were filled to a pressure of slightly less than one atmosphere. The cells were then broken under mercury and placed in the pressure well which was connected to the pump and dead weight gauge. The assembly was placed in the thermostat and a determination was made. The critical temperature was determined by raising the temperature of the sample gradually, keeping the pressure high enough to maintain a liquid until the meniscus disappeared on stirring. The temperature was held constant a t this point for 15 to 20 minutes to attain equilibrium. The temperature was t,hen lowered and the pressure raised to liquefy the sample and the process was repeated. The highest temperature at which there were two phases visible and at which the meniscus did not reform after disappearing on stirring was taken as the critical temperature. The critical pressure was determined a t this temperature as the pressure a t which the mercury thread in the capillary did not move after standing for a long enough period to assure equilibrium.
Vol. 62 log P,,
= ___ - 1063.8
+ 7.261
This expression is in good agreement with the results of Ruehrwein and Powell6 who determined the vapor pressure of cyclopropane at pressures below one atmosphere. (5) R. A. Ruehrwein and T. Powell, ibid.. 68, 1063 (1946). ~~~
HEAT OF FUSION AND HEAT CAPACITY OF INDIUM ANTIMONIDE BY NORMAN H. NACHTRIEB AND NORIKOCLEMENT Institute for the Study of Metals, University of Chicago, Chicago, Illinoia Received February $6, 1968
The latent heat of fusion of indium antimonide is sufficiently large that it could be determined with fairly high accuracy and precision by a simple drop calorimetric method. The heat capacity was also determined for several temperature intervals in the range 20-500", although with lower accuracy. Analysis of the material for antimony gave 51.44 f 0.16%, as compared with the theoretical value of 51.48%. Semi-quantitative spectrographic analysis revealed Fe (0.001%), Pb (0.001%), Sn (O.OOl%), Mg (0.001%), Si (0.0001%) and Cu (0.0001%). A weighed quantity of InSb, sealed in an evacuated Vycor bulb of known weight, was heated in a tube furnace; the temperature was controlled by a Leeds and Northrup Micromax with four chromel-alumel thermocouples in series to permit regulaResults.-The critical temperature and critical tion to h0.5". For the latent heat of fusion, drops were made from temperatures just above and just pressure of cyclopropane are given in Table I. below the melting point (525").' (The melting point of the material was verified to lie within 1' TABLE I Critical Critical of its reported value by trial inspections on withSample temp., pressure drawing it quickly from the furnace at temperaOC. atm. No. tures close to 525O.) The calorimeter was a 11 124.65 54.22 liter glass Dewar vessel equipped with a stirrer, 2 124.66 54.24 Beckman thermometer, and a brass tube for guid3 124.65 54.22 ing the specimen from the furnace. A copper Av. 124.65 54.23 gauze liner in the calorimeter gave protection The vapor pressure of cyclopropane as a func- against breakage even though the specimen fall tion of temperature was determined during the was almost free. About 825 g. of water was used critical constant experiments on the same samples in the calorimeter, and weight losses by evaporation of cyclopropane. The results of these determina- did not exceed 0.2 g. The water equivalent was determined by mixing weighed quantities of water tions are given in Table 11. of different temperature, and found to be 86.8 g. Two series of runs were made, with 0.2104 and TABLE I1 0.1620 mole of InSb. The average of six determiVAPORPRESSURE OF CYCLOPROPANE nations was 11.2 h 0.4 kcal.mole-' and the enSample Temp., Pressure, Sample Temp., Pressure, no. OC. atm. atm. no. OC. tropy of fusion is accordingly 14.1 cal.mole-'deg.-'. C 115.34 16.66 45.26 C 61.32 Measurements of the heat capacity were made in 15.25 B 40.98 110.02 B 52.42 a similar manner for the temperature intervals 12.15 105.30 39.20 A C 43.28 20-go", 90-170', 170-350" and 350-500'. CorB 9.60 34.14 101.31 B 36.25 rections for the heat capacity of Vycor were made 7.82 A 91.10 A 32.42 30.13 from runs with an evacuated bulb filled with 5.30 88.29 B 27.18 B 16.78 crushed Vycor. The measurements are of lower 4.01 81.19 25.79 A A 11.02 accuracy than the heat of fusion because the heat 3.62 76.38 C 23.48 B 7.56 content of the Vycor was about equal to the heat 71.42 B 2.38 22.32 A 3.00 content of the InSb. For the four temperature 64.92 A 18.08 intervals above the heat capacity of InSb was When the data in Table I1 are plotted as a func- found to be 0.052, 0.056, 0.062 and 0.062 ca1.g.-'deg. -l, respectively. tion of temperature they yield the expression Acknowledgments.-The work described was in (4) H. 6. Booth and C. F. Swinehart, J . A m . Cham. Sac., 67, 1337 (1935).
(1) T. S. Liu and E. A. Peretti, Trans. J . Metals, 3, 791 (1951).
July, 1958
NOTES
877
part supported by the Air Force Office of Scientific was a pinkish-orange colored salt. This reaction Research under Contract No. AF- 18(600)-1489 may have taken place with the University of Chicago. The indium 3WOCla 2AlCla 3W, AlzOa 9C1z +Red White antimonide was provided by the Chicago Midway Laboratories. The boiling points of the two salts are not too far separated: WOCL, b.p. 227.5" and AlCL b.p. TRANSPORT OF METALS BY GASEOUS 178". A mixture of the salts could give the pinkish orange color. A subhalide reaction may also CHLORIDES AT ELEVATED have occurred to a small extent since 0.5% A1 (as TEMPERATURES determined by hydrogen evolution) was condensed in one portion of the salt, Tungsten was conBYM. F. LEE tained in a graphite boat to produce the chloride. Contribution from Alcoa Research Laboratoriee, New Kensington, Pa. The conditions for Type 1 reactions are given in Received February 88, 1968 Table 11. The metal chlorides were passed slowly The purpose of these experiments was to de- over a heated Alundum boat containing the metal. termine the transport of several metals by chlorides The transported metal and salts were condensed on at elevated temperatures. The subhalides back an air-cooled silica tube and tube walls. react at lower temperatures to deposit the metal TABLE I1 and to regenerate a normal halide. For example, REACTIONS OF M' + M'Cl when aluminum chloride is passed slowly over metalTemp., Pressure, Metal lic aluminum a t 800" and 0,001 atmosphere, 50% of OC. mm. produot Metal Chloride the AICla reacts to form AlC1.l The AlCl 0.4 No reaction 1000 Cb CbCls vapor back reacts in a cooler zone of the reaction 0.2 Cr CrClr 1250 Cr tube to deposit aluminum and regenerate AICla. 1250 0.2 Cr Cr CrClz The effect of these reactions is to transport alumi2.3 Fe Fe FeClz 1300 num from a hot zone to a cold zone. The transGa GaClz 800 0.2 Ga ported aluminum can be purified by this process. Ge GeClr 1250 5.0 Ge In the work to be reported, reduced pressures 0.1 No reaction Mn MnCla 1000 were used to avoid the relatively high temperatures 0.05 No reaction NiClz 1010 Ni required at atmospheric pressure. Two types of SiC1, 1000 3.0 Si Si reactions were investigated: (1) a metal with its Ti TiC14 1300 2.5 Ti anhydrous gaseous chloride, and (2) a metal with a Ti Ticla 1.5 Ti 1250 dissimilar anhydrous gaseous chloride. Zr ZrCl, 1225 0.2 Zr Most of the anhydrous chlorides (Table I) were In each of these reactions, the transported metal prepared from the metal and chlorine immediately before use. Silicon tetrachloride was purchased product was separated and identified by appearfrom Fisher Scientific Co. The tantalum chloride ance and chemical analysis. Although Gr0ss~8~ listed in Table I was not used in the distillation reported subhalides of manganese (MnF) and nickel (NiBr, NiCl), there was no evidence of experiments. metal under the conditions of these experiments. TABLE I Appreciable amounts of metallic condensed products resulted when chlorides of iron, gallium, PREPARATION OF CHLORIDES OF M + Clz Tyw., Probable silicon and zirconium reacted with the corMetal C. product How identified responding metals. CrC12 produced a larger Cb 1000 CbC16 Orange salt yield of chromium than CrC13, and Tic13 produced Cr 1000 CrCla Light lavender salt a larger yield of titanium than TiC14. The yield Fe 925-1050 FeClz Purple salt of germanium was very small a t 1250". CrC13, Ga 675 GaCL M.p. 160-170' GeC14and TiCL, on the basis of color and appearGe 800 GeC14 M.p. approx. -50" ance, appeared to form the lower valence chlorides Mn 900-1070 MnClz Pink salt CrC12, GeCL and TiCb, while in all other experiNi 1010 NiCla Yellow salt ments the deposited chlbride appeared to be the Ta 730 TaCls Pale yellow salt same as the starting material. Ti 1250 TiCL M.p. approx. -30' The conditions and products for Type 2 reactions W 950 WCla Deep purple salt are given in Table 111. Zr 1250 ZrClr White salt X-Ray analysis of the deliquescent chlorides In the preparations chlorine gas was passed over condensed on the cold region of the reactor tube an Alundum boat containing the metal surrounded were not conclusive. The elements in the chlorides by a quartz tube. Temperature was raised until were verified by analysis. A Ga-A1 alloy free from salt was produced in the a reaction took place. The salts condensed on the cold wall of the quartz tube and were removed in a heated boat when GaClg4vapor was passed over aluminum. The aluminum in the alloy increased dry air room. When chlorine gas was passed over metallic from 35.3% at 800" to 68.3% at 1000". Results (2) P. Gross, Proe. Chem. SOC.Eng., 26, (Feb., 1958). tungsten in an Alundum boat a t 950", most of the (3) P. Gross, U. S. Patent 2,470,305-6 (to International Alloy8 Alundum boat was volatilized and the condensate Ltd.) M a s 17. 1949.
+
(1) A. S. Russell, K. E. Martin and C. N. Cochran, J . Am. Chem. Soc., 73, 1466 (1951).
+
+
(4) A. W. Laubengayer and F. B. Shirmer, J. A m . Chem. Soe., 6 2 , 1578 (1940).
