April, 1946
389
INDUSTRIAL AND ENGINEERING CHEMISTRY ACKNOWLEDGMENT
The cooperation of the operating and technical staff of the Western Sugar Refinery on plant tests is appreciated. Many persons in the laboratory of The Dicalite Company aided in these tests; t o them thanks are extended for valuable assistance. LITERATURE CITED
(1) Brown, J. M., and Bemis, W. A,, IND.ENG.CHEW,34, 419-22
(1942). (2) Brown, C. A., and Zerban, F. W., "Physical and Chemical
Methods of Sugar Analysis", 3rd ed., p. 1075, New York, John Wiley & Sona, 1941. cHnM., 34, 398-402 (1942). (3) cummins, A , B., (4) Frankenhoff, C. A., Ibid., 34, 742 (1942). ( 5 ) Knowles, H. I., Ibid., 34, 422-4 (1942). S W G r Cane Tech., Baton Rouge, (6) Meade, h o c . 6th C O W T . Intern. 1938, 1032.
(7) Spencer, G. L., and Meade, G. P., Cane Sugar Handbook, 8th ed., p. 297, New York, John W h y & Sons, 1945. (8) Wright, Arthur, MD.ENG.CHEM.,34, 425-9 (1942). PRESENTED on the program of the Division of Sugar Chemistry and Technology of the 1945 Meeting-in-Print, AMERICAN CHEMICAL SOCILTY.
Vapor-Liquid Equilibria in Three Hydrogen-Paraffin Systems d
M. R. DEAN AND J. W. TOOISE T h e solubilities of hydrogen in isobutane were determined for temperatures from 100' to 250' F. and pressures from 500 to 3000 pounds per square inch. Solubilities in 2,2,4trimethylpentane were found for temperatures from 100" to 302.5" and in a mixture of isomeric dodecanes for 200' and 300" F. with pressures ranging from 500 to 5000 pounds per square inch. The compositions of the equilibrium vapor phases were also determined. The solubility of hydrogen increases with temperature and pressure but decreases as the solvent molecular weight inareases. The solubility of hydrogen follows Henry's law only in isobutane at 150' F. and lower. The hydrogen solubilities in. the two heavier hydrocarbons increase more rapidly with pressure at low pressures than at high pressures. Correlation with literature data shows that hydrogen is more soluble in paraffins than in aromatics of similar molecular weight. Vaporization equilibrium constants are computed from the data for both solvent and solute. The constants vary widely with pressure and to a lesser extent with temperature. The constant for hydrogen increases with an increase in solvent mQlecularweight.
T
HE solubility of hydrogen a t high pressures in several pure hydrocarbons was reported by Frolich (8)for 77" F. and up to 100 atmospheres, by Ipatieff (3) at higher temperatures for several petroleum fractions, and by Ipatieff (4) i n several pure aromatic hydrocarbons. More recently solubilities to 106 atmospheres in n-butane were reported by Nelson (7). I n none of these investigations was a comprehensive study of the composition of the equilibrium vapor phase made. Kelson, however, did present some data on the vapor phase. The purpose of this work was t o determine the solubility of hydrogen in a narrow-boiling mixture of isomeric dodecanes and in two relatively pure hydrocarbons-isobutane and 2,2,4-trimethylpentane-for a range of temperature and pressure. I n addition, the compositions of the equilibrium vapor phases were to be found, and a study made of the vaporization equilibrium constants of the components and the effect of temperature and pressure on these values. The hydrogen used was the commercial electrolytic waterpumped grade. The impurity, oxygen, was less than 0.2%. R a t e r vapor was removed by contacting with anhydrous calcium sulfate. The isobutane, with a tested purity of 99.5%,
Phillips P e t r o l e u m Company, Bartlesville, Okla. was obtained from the Phillips Petroleum Company, The major portion of the impurity was n-butane. The iso-octane, obtained from Rohm & Haas Company, was considered to be essentially pure 2,2,4-trimethylpentane. The physical properties were determined by the National Bureau of Standards: p ~ ; ~ i ~ g FSp. Gr.,
.
2,2,4-Trimethylpentane Isomerio dodecane mixt.
210.5; 350-2
d:" 0.691~a 0.756
Refractive Index, n v
Mol. Weight
1.3915a 1.4227C
114;22b 170
Determined by National Bureau of Standards. C Experimental.
b Calculated.
The mixture of isomeric dodecanes was specially prepared for this work by polymerizing isobutylene, hydrogenating the resulting product, and fractionating in a 1/2-inch i.d. column, 36 inches long and packed with l/a-inch glass helices. A cut boiling between 350" and 352' F. was collected for use in this work. The particular combination of polymerization and fractionation was believed t o have yielded a product which was a mixture of isomeric dodecanes. This final product will be referred t o as dodecanes. The determined physical properties of the dodecanes are also listed in the table. The molecular weight was obtained by a method utilizing the principle of the freezing-point lowering of benzene. Vapor pressures of the hydrocarbons are useful in the correlations of experimental data. The vapor pressures of isobutane and 2,2,4-trimethylpentane were determined up to their critical temperatures by Sage (8) and Smith (Q), rekpectively. Since comparable data for the dodecanes were lacking, the vapor pressure curve was determined t o 300" F. The apparatus used was based on the principle of balancing a column of mercury against the vapor pressure of the air-free hydrocarbon confined in a Utube over mercury. The technique was developed by measuring the vapor pressure of our iso-octane and comparing results with values by Smith. Bridgeman ( I ) described this type of apparatus in detail. The dodecanes vapor pressures are believed to be in error by no more than t 0 . 0 2 pound per square inch a t the higher temperatures and less a t the lower temperatures: Temp., O F. 32.0 77.0 173.7 200.0
Vapor Pressure Lb./Sq. In. Abs.' 0.04 0.11 0.67 1.04
Temp., ' F. 228.7 233.6 297.1 300.0
Vapor Pressure, Lb./Sq. In. Abs. 2.00 2.15 6.49 6.52
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
390
. i w . m ~ rsu The experimental work on the hydrogen-isobutane system was carried out in the apparatus described by Kat2 ( 5 ) . Some difficulty was experienced with that style of equilibrium cell due to the difficulty of making a seal for the lead-in wire to the electric stirring motor which xould hold hydrogen a t high pressures and temperatures. I n addition, the nonlubricating atmosplicre in xhich the motor had to operate made its proper lubrication impossible. The consequent low operating speeds resulted in extreme time requirements for obtaining equilibrium bctrvecn t>hevapor and liquid phases.
8
A B C D E F G
EQUILIBRIUM CELL ROCKING MOTOR CRANK ARM INSULATED OIL-FILLED BATH LIQUID-PHASE SAMPLING VALVE VAPOR-PHASE SAMPLING VALVE MERCURY-FILLED LINE TO PRESSURE GAGES
C
Figure 1.
Vol. 38, No. 4
was measured with mcrcury-in-glass thermometers with 0.2" IC divisions and calibrated ngainst thermometers of the same t y p ~ ~ having a Bureau of Standards certificate. Bath tempcr:ituri:i were held constant to h0.2" F. Special glass traps and calibrated glass balloons were prov~tlctl for handling and annlyzing t h c p l m c samples. I n the wo~,liO J I the hgdrogen-isobutnne systcm a Podbielniak-type lowtempiwlure fractionating column was nlso used, together rritli ill(: ii-.i1:11 Orsat apparatus for hydro..cn ;mal I'ROCEDUIIE
ing for a11 expcrimt:rit vias tcj C V : ~ ( : I : L ~ C the equilibrium cell with a r:icuuni punip to a pi.cssurc icse h i r 1 nim. mercury. Three to four hundred milliliters of the dwired hydrocarbon were pressured in. Sufficient hydrogen was tliciii pressured in until t,lie prcssurc' in thc ccll TVRH sci than the planncd cqui ,ium prcssurc for tho experi tion of the contents T bcgun, cit>herby stirring ary cell m r e used, or rocking thc ccil in t h c case of unit. The tcmpcraturc JV:M ndjustctl to tho ~li:?~i agitation of tlic cc.11 mntcrits cxintiriucd until thc. prcssiii'c: l i t ! cnmc constant. Since tile proswrc as hi:,her than dc4rcli!, portions of t,hc vapor phsc? IYCI'C bled off uritil the equilibi~iuni pressure was loncretl t o ilic clcsirctl value. TYhen no f i i i ~ ! l i t ~ i pressure change took place with inucd agitat,ion oE tiit' i,i-li contents, the vapor and liquid p s were considered to t)c i i i equilibrium. I n the cirue of tho ing cell, tests sho~vedI 1 i : r r 10 minutes of rocking a t const nut pressure and tcinpt:r:itiirc would attain equilibrium. Thc sampling and analysis of iI M phases were combincd into wlrut iv:is cssenti:illy a single tion. The analysiq of tlic samples consisted of the phy-it.:il scparation of the liydrogcn from Chc hydrocarbon by f out the hydrocarbon from tlic sample as it wiis withdr:in-ii il.oln the cell. I n sampling t h c 5 liquid 1111 of the isohutanc system, :I ~ I O I tion was conducted from the equilibrium cell through an U I I heated steel line terminating in a needle valve to the sampliiilr connection of a Podhic.lniak-type low-tcmperature fractioixil
Dingram of Equilibriunl Apparatiis
Tlic hydrogen-iso-octane and 1iydrogc:n-dodecanes systcms were tested in a n equilikwium cell niountcd in a n oil-filled bath in which it was rocked at 30 cycles a minute. Figure 1 is a diagram of the cell and bath. The cell was circular in cross scction with hemispherical ends and approxinlately 700 i d . in capacity. A coil of 1/8-inch steel tubing was connected into the bott,om of the cell and led to pressure gages through a manifold. h t the upper end of the cell one valve n'us attached with a n induct,ion tube for withdrawing liquid-phasc samples. Anotlicr valve was providcd for taking vapor-pliasc samples. The ccll was roclicd by a crank arm powrred by a n electric motor. The crank arni linkage was desipnccl to ciiusc tlic ccli to rock to :in angle 30" above and belorv the horizontal. The cranli arm ~ v n sdctachable from the motor in order that tlic cell could be placed in R vcrtical position lor sampling the phascs. Tho rocking equjlibriuin cell alloJved equilibrium of the phases to be attained quickly. The two gages were Hourdon-tube type of 1000 and 6000 pound capacities and graduated in divisions of 170of tlic rapacity, and the pressures w r e read to 0.2% of capacity. The gages were calibrated with n dead-weight testcr before work was begun and a t intervals during the work. I n rccording t,he pressure in the equilibrium rcll, appropriate correction was made for the head of mercury to the gage. The volume of thc ccll was adjustcd as required by the introduction or withdrarval of mercury through the steel tubing with a hand-operated piston pump. The temperature of the oil bat'li
3000 2500 2000 1500 1000 500
17.9 14.2 11,12 8.79 5.92 2.75
'I'cmperature 100' F. 95.51 149 5.34 95, 71 0.74 4.29 8.56 05.21 4 79 94.23 91.21 3.77 10.7 94.08 91.91 8 OD 15.5 87.23 80.31 1 3 . 09 31.4
8 % .1 85.8 88.88
I .
3000 2500 2000 1500 1000 500
19.7 16.9 12.9 8.47 6.76 2.74
l o m p e r a t u r e 1.50' 80.3 90.18 0.82 8i3.1 87.9 12.1 88.7 11.3 87.1 13.3 01.55 86.7 93.24 82.4 17.6 97.26 6'1.7 30.3
3000 2500 2000 1500 1000 500
24.7 19.2 15.6 10.9 7.09 2.25
75.3 80.8 84 4 89.1 92.91 97.75
(2
'32
io
52 i; 40.t i 2 6 I.,
11.9
F. 4.58 5.20 6.88 10.2 12.2
25.4
Ternperaturr 200' I". 2.29 313.5 43.3 3.95 73.8 24.2 4.8 75.8 24.2 6.60 71.9 28.1 8.67 i38.3 6l.G -10.7 50.3 18.1
Temperature 250' F. T5.2 24.4 75.6 2-1.8 16.2 42.4 07.0 83.8 11.7 40.6 69.4 88.3 6:j.O 8.20 91.8 37.0 Hydrogen gas a t 77' l?. arid 1 atmoapherc. b In the single-phase region.
2000b 1500 1250 1000
0,0547 0.0500 0,0539 0.0633 0.0860 0.141
1.02
2.62
3.47 4.51
0.122
0.146 0.130 0.145
0.180 0.312 0.578 0.299 0.287 0.315 0.414 0.607
0,995 0.687 0.673 0.686
lo:( 86 02
38.9
30 5 11.9
138
100 7
51 3Ll >! . 7
13rj
%
38
INDUSTRIAL AND ENGINEERING CHEMISTRY
April, 1946
TOTAL
Figure 2.
P.SIA.
PRESSURE
Solubility of Hydrogen in Isobutane TOTAL
distillation column. The liquid was kept at equilibrium pressure up t o the needle valve, and then the sample was flashed into the kettle of the column. The kettle, immersed in liquid nitrogen, acted as a trap and froze out the greater part of the isobutane. The effluent hydrogen gas containing a small concentration of isobutane was collected in glass balloons for measurement. A significant volume of hydrogen remaining in the frozen isobutane was collected by boiling the isobutane in the closed off column, then freezing it again. The undissolved hydrogen was Collected and combined with the rest, This operation was repeated until the pressure of the kettle contents was less than 2 mm. mercury at liquid nitrogen temperature. The vapor volume of the hydrogen-free isobutane was found by vaporizing
TABLE11. EXPERIMENTAL DATA
FOR
HYDROGEN-
2,2,4-TRIMETHYLPENTANESYSTEM
5025 4010 3025 2020 1020 525 176
19.8 16.6 13.2 9.71 5.17 2.72 0.90
80.2 83.4 86.8 90.29 94.83 97.28 99.10
Temperature 100° F. 99.832 0.168 5.04 99.840 0.160 6.01 99.838 0.162 7.56 99.831 0.169 10.31 99.764 0.236 19.3 99.602 0 . 3 9 8 36.6 98.950 1.050 110
0.00209 0.00192 0.00187 0.00185 0.00249 0.00409 0.0106
52.9 42.6 32.6 23.0 11.7 6.0 1.9
5055 4010 3025 2070 1520 1035 583 248
25.8 21.8 17.4 13.0 9.74 7.10 4.04 1.65
74.2 78.2 82.6 87.0 90.26 92.90 95.96 98.35
Temperature 200° F. 99.36 0.64 3.85 99.30 0.70 4.56 0.78 5.70 99.22 7.62 99.10 0.90 98.88 1.12 10.2 98.55 1.45 13.9 97.65 2.35 24.0 94.90 5.10 57.5
0.0086 0,0090 0.0094 0.0103 0,0121 0.0156 0,0245 0.0519
74 60 45.1 32.0 23.1 16.4 9.0 3.6
0.0391 0.0388 0,0426 0.0479 0.0561 0,0733 0,108 0.314
118 88 67 42.9 31.7 21.4 10.5 ' 2.6
5065 35.5 3990 29.2 3025 23.8 2045 16.7 1540 12.9 1020 9.10 550 4.68 185 1.22 a Hydrogen gas
391
Temperitture 302.6" 64.5 97.48 2.62 70.8 97.25 2.75 76.2 96.76' 3.24 83.3 96.01 3.99 87.1 95.11 4.89 93.34 6.66 90.90 95.32 89.69 10.31 98.78 68.97 3 1 . 0 3 a t 77' F. a n d 1 atmosphere,
F. 2.75 3.33 4.07 5.75 7.37 10.3 19.2 56.5
PRESSURE
RSLA.
Figure 3. Solubility of Hydrogen in 2,2,4-Trimethylpentane and in a Mixture of Isomeric Dodecanes
into the calibrated balloons. The isobutane in the effluent gas was determined by passing a known volume of the mixture over copper oxide a t 300" C. in the usual Orsat apparatus t o convert the hydrogen to water. The gas volume remaining was assumed t o be isobutane. The isobutane i n the vapor-phase sample was separated from the hydrogen by passing the gas stream through a specially designed trap immersed in liquid nitrogen where most of the isobutane was frozen out. The effluent gas was then passed into the liquid-nitrogen-immersed kettle of the fractionating column where the remainder of the isobutane was frozen out. The isobutane-free hydrogen effluent was collected and measured in the calibrated balloons. After sufficient sample had been taken, the isobutane in the trap was vaporized into the kettle of the column where i t was denuded of hydrogen in the same manner as in the liquid-phase analysis. The hydrogen-free isobutane was then vaporized into the balloons and its volume measured. Tests proved that this method separated the components almost completely Some changes in the method of s+mpling and separating the components of the hydrogen-iso-octane system were found advantageous. The liquid-phase sample was flashed into a glass trap at atmospheric temperature. The effluent vapors were then passed into a second trap immersed in liquid nitrogen where the remainder of the iso-octane was frozen out. The effluent gas, iso-octane-free hydrogen, was conducted into the balloons for measurement. The steel line connecting the cell with the first trap was heated t o drive all the iso-octane into the trap. Both traps were removed, and the weight of iso-octane was found. The separation of the hydrogen and iso-octane in the vapor-phase sample was effected in the same manner as for the liquid phase. The procedure used in sampling the phases of the hydrogendodecanes system and the manner of separating the components were identical with those in the iso-octane system except that a pentane-dry ice mixture was used as the cooling medium instead of liquid nitrogen. With liquid nitrogen the dodecanes had a tendency t o freeze into minute particles and entrain in the cffluent hydrogen stream.
.
INDUSTRIAL AND ENGINEERING CHEMISTRY
392
Vol. 38, No. 4
HYDROGEN
SOLVENT MOLECULAR
WEIGHT
Figure 4. Solubility of Hydrogen in Paraffinic Solvents at 200' F.
TABLE111.
EXPERIMEXTAL DATA FOR HYDROGEN-ISOMERIC
DODECANE SYSTEM
Composition, Mole % = l/lz HI Soly.b, Pressure, Lb./Ss. Liquid ____ phase Vapor phase . Cc. Gas/ In. Abs. Hz ClzHgsa Hz CizH2aa H2 CizH16~ G . Solven Temperature 200' F. 3 . 9 3 0.00094 9 9 , 9 3 0 0.070 49.0 25.4 74.6 5036 4 . 6 6 0.00089 39.4 78.5 99.930 0.070 4030 21.5 5 . 9 1 0.00082 99.932 0 . 0 6 8 29.3 16.9 83.1 3033 8 . 0 6 0.00081 87.6 99.929 0 . 0 7 1 20.4 2025 12.4 14.6 0.00107 99.900 0 . 1 0 0 10.6 6 . 8 4 93.16 1020 525 3 . 7 3 96.27 99.831 0 , 1 6 9 26.8 0.00176 0.6 Temperature 300' 1'. 3.33 70.1 99.652 0.348 5035 29.Y 3.99 99.633 0.367 75.0 4030 25.0 4.98 80.0 99.602 0 , 3 9 8 3035 20.0 6.77 85.3 99.520 0 . 4 8 0 2025 14.7 12.6 99.227 0 . 7 7 3 1020 7 . 8 9 92.11 525 4 . 4 2 95.58 98.68 1.32 22.3 a A mixture of isomeric dodecanes. b Hydrogen gas at 77' F. and 1 atmosphere.
0.00498 0,00489 0.00498 0.00563 0.00839 0.0138
61.4 48.0 36.0 24.8 12.3 6.7
Mercury was pumped into the bottom of the cell while the $ phase samples were being withdrawn to maintain a constant pressure. DATA FOR THREE SYSTEMS
The experimental data consist of the determined compositions of equilibrium vapor and liquid phascs and the associated conditions of pressure and tcmpcraturc. A conv~nicntway t o express the vaporization cliaractcristics of the components of a mixture is the vaporization equilibrium conitant K,defined as
K = y/x (1) where y = mole fraction of component in vapor phase 1: = mole fraction of same component in liquid phase The K constants were calculated by Equation 1 from the experimental data and are included in Tables I, 11, and 111. Figure 2 shows the solubility of hydrogcn in isobutanc a t various temperatures. It is noteworthy that the solubility is a straight line-function of the total pressure up to 150' F.; a t 200" F., however, the solubility tends to increase more rapidly with pressure than would be indicated by a straight line originating at the lower pressures.
.$~~q--J .O
100
Figure 5.
300 500
PRESSURE
1000
F1SI.A.
Z o o 0 3000
K Constants for HydrogenIsobutane System
The solubility of hydrogen i n 2,2,4-trimethylpentane and in dodecanes (Figure 3) is somewhat diffcrent. At the lower prc+ sures and t,emperatures the hydrogen solubiljt'y increases moria rapidly with pressure than a t the higher tempera.turcs and pressures. Frolich (8) reported a similar effect with nitrogen as v,~:ll as hydrogen in various types of solvents to show the limitation in the use of Henry's law. The solubility of hydrogen iri the three solvents a t 200' F. altd a t various total pressures is plotted against molccular m i g h t i n Figure 4 to show the effect of the solvent molecular mcight on thcb solubility. It is apparent that the solubility dccrcascs with iiicrcasing molecular might. Hydrogen solubilities in 11-buta i i o determined by Nelson ( 7 ) and in a petroleum naphtha by K i i j (6) are also plotted. Kay reported the naphtha to be composed almost, eii tiroly r ~ f pcritanes and hexanes; the composition data shoncd thaf t I i ( : sum of the concentrations of all the normal type coniponenis \\-:I> essentially equal to the sum of the concentrations of all the. isumcric types. Siliee the data of Kay are in reasonable agreement ivith the, curves of Figure 4, thc curves could be useful for estininling the. ' solubility of hydrogen in narrow-boiling mixtures of isornc paraffin hydrocarbons. On this b the solubility oi lrydrogrrr in an isomeric paraffin mixture of 95 average molcculm n-ciglit can be compared with solubilities in a gasoline (avcragc molecular k Ipaticff (3)and i i i tolucric. d g h t 99.5) by cross-plotting ~ o r by (molecular weight 92.1) by Ipaticff (4). The comparison shows that the solubility of hydrogen in a solvent is a function of thv molccular structure of the solvent molecules as well as of t h e temperahre and prcssure : Pressure, Lb./Sq. I n . Abs. 500 1000 3000
Go. € I n a t 77' F. and 1 Atm. in 1 G. of Su'vent Paraffinic mixtures Gasoline ( 3 ) Toluene ( 4 ) 4 8 7 19 8 15. 26 59 45
April, 1946
INDUSTRIAL AND ENGINEERING CHEMISTRY
393
critical pressure was approximately 1900 pounds 250' F. Thus, the K curves for hydrogen and isobutane were drawn to meet a t K 1for that pressure. Figure 6 gives K constants for hydrogen in iso-octane and in dode.canes as a function of pressure. The isothermal K constant curves for the two solvents are shown in Figure 7. From the definition of K (Equation 1) it follows that the K constant curves for the solvent must intersect the K = 1 line a t the vapor pressure of the solvent for the temperature represented. Further, since a t pressures below 200 pounds the concentration of the hydrogen in solution becomes quite small, the solvent could be expected to follow Raoult's law. When the components of a solution have vaporization characteristics which follow Raoult's law, the K constant curves plotted as in Figure 7 will be straight (unit slope). By following these rules the K curves for the solvents were extrapolated to low pressures.
-
I
300
I SO0
I I I I I 1000 PRESSURE
I
I
2000 P.S.I.A.
4000
6000
Figure 6. K Constants for Hydrogen in 2,2,4-Trimethylpentane and in a Mixture oflsomeric Dodecanes
The K constants for the hydrogen-isobutane system were plotted as in Figure 5 to show the effect of pressure on K. The determination made at 250' F. and 2000 pounds per square inch. absolute (Table I) showed that the system was i n the critical region. The fact that the pressure was 2000 pounds indicates only that the critical pressure is equal to or below that pressure. Other correlations of the data not shown here showed that the
21 50
I
.I
I
I
90 130 SOLVENT MOLECULAR WEIGHT
I
I
I70
Figure 8. K Constants for Hydrogen in Paraffinic Solvents of Various Molecular Weights at 200' F.
The effect of the solvent molecular weight. on K for hydrogen is demonstrated for 200" F. by plotting the hydrogen K constant against solvent molecular weight as in Figure 8, which shows that K increases with an increase in solvent molecular weight. The plot is useful for estimating K constants for hydrogen a t 200" F. dissolved in a solvent composed of a single highly branched paraffin and might be used with caution for estimating K constants for hydrogen dissolved in a solvent composed of two or more isomeric paraffin hydrocarbons. ACKNOWLEDGMENT
The writers wish to acknowledge the precise analytical work done by Grant Stewart,-Frank C. Gibbs, and Frank W. Melpolder, and their many helpful suggestions. LITERATURE CITED
(1) Bridgeman, 0. C., PTOC. Am. Petroleum Inst., 111, 11, 4 (1930). (2) Frolich, P. K., Tauch, E. J., Hogan, J. J., and Peer, A. A., IXD. EXQ.CHEM.,23, 548 (1931).
PRESSURE
Figure 7.
P.S.I.A.
K Constants for 2,2,$-Trimethylpentane and for the Isomeric Dodecane Mixture
(3) Ipatieff, V. V., and Levin, M. I., Chem. Solid Fuels (U.S.S.R.), 8, No. 10, 866 (1937). (4) Ipatieff, V. V., Jr., and Levin, M. I., J. Phys. Chem. (U.S.S.R.), 6, 632 (1935). (5) Katz, D. L., and Hachmuth, K. H., IND.ENQ.CHEM.,29, 1072 (1937). (6) Kay, W. B., Chem. Rev., 29, 501 (1941). (7) Nelson, E. E., and Bonnell, W. S.,IND.ENG.CHEM.,35, 204 (1943). (8) Sage, B. H., and Lacey, W. N., Zbid., 30,679 (1938). (9) Smith, E. R., J . Research NatZ. Bur. Standards, 24, 229 (1940).
