E. R. WASHBURN, C . E. BROCKWAY, C. L. GRAHAM AND PHILIP DEMING
1886
meters and minutes appearing in column 7 of Table 11-C. The low value for the one run with a 3-1 initial ratio of hydrogen to cyanogen is understandable since by the end of the run practically all the cyanogen has reacted. BodensteinLind constants, however, fit the variation with respect to total pressure a t 675O, and the fit would be better if a lower value of m were taken for this temperature; but they are totally unsatisfactory at 625'. Since there is no reason to suppose that the steps in chain propagation are any different in the clean bulb, the increased rate a t low temperatures along with the lower temperature coefficient argues for a different method of chain starting on the surface. The possibility
VOl. 64
nor was any extensive polymerization observed. This must mean that the reactions
+ H*+HCN + H CN + CN + W(CN)z f W CN
and
are much faster than the addition of radical to molecule. It may well be that the (CN)s complex is unstable at these temperatures since it is known that cyanogen does not polymerize a t elevated temperatures and that paracyanogen begins to regenerate cyanogen in the region 700-800°.
Summary
The thermal reaction of hydrogen and cyanogen to yield hydrogen cyanide has been studied in a silica vessel over the temperature range 550-675'. WH2 W(CX)s +WHCN H CN The reaction proceeds without undue complicawhich results in the foregoing kinetic expression tions, but the nature of the surface of the reaction suggests itself since Hadow and Hinshe1woodl1 bulb has some influence on the rate. The product, obtained evidence of strong adsorption of cyano- hydrogen cyanide, inhibits the reaction. Packing gen on clean silica in their oxidation studies. increases the rate at low temperatures but has Hogness and T'sai'O found that CN radicals dis- little effect above 625'. appear at room temperature by addition to cyanoThe simplest expression which fits the kinetics gen molecules to form a postulated (CN)Bwhich a t 625' reasonably well is that developed by acts as a nucleus for further polymerization with Bodenstein and Lind for the combination of the ultimate formation of paracyanogen. WhiteY hydrogen and bromine. Evidence is presented concluded that the radicals formed during an which favors a radical chain mechanism involving electric discharge combine with complex ions gas phase propagation by hydrogen atoms and simultaneously produced in the discharge as a cyanide radicals with chains starting and breaking first step in polymerization. In the present in- on the walls. The steps in this process would be vestigation a t temperatures of 625' or higher analogous to those in the hydrogen-bromine such an addition reaction was not indicated by reaction .with the cyanogen assuming the role kinetic analysis of the results in the aged bulb, of bromine.
+
+ +
(11) H. J. Hadow and C. N. Hinshelmood, PYOC. Roy. SOC.(London), A132, 375 (1931)
lCONTRIBUTION FROM THE BVERY
PRINCETON, NEWJERSEY
LABORATORY OF CHEMISTRY
RECEIVEDMAY6, 1912
OF THE UNIVERSITY OF NEBRASKA]
The Ternary Systems Involving Cyclohexane, Water, and Isopropyl and Normal Propyl Alcohols BY E. ROGERWASHBURN, CHARLES E. BROCKWAY, c. LORENGRAHAMAND PHILIPDEMING
The ternary systems' made up of cyclohexane, water, andk methyl andlb ethyl alcohols have been described previously. The systems2involving water, isopropyl alcohol andza benzene,2b toluene andzc cyclohexene have been described. (1) k:
K. Washburn,
[ w 8 4 , 4 2 1 7 (1932).
e1 a2.. THISJ O U X N A L , (a)
56, 361 (1934);
(21 E . R. Washburn, et d.,ibzd , (a) 57, 303 (lY36); , e ) 62, 1454 (1940)
;1810),
( 1 ) ) 62,
579
This report adds normal propyl and isopropyl alcohols to the first group and cyclohexane to the second group. Materials.-Cyclohexane from Eastman Kodak Company was carefully fractionated, dried with sodium and recrystallized several times. The alcohols were the best grades obtainable from the same company. They were dried with active lime and carefully fractionated. Some physical
hug., 1942
TERNARY S Y S T E M S OF
constants for the materials used in this investigation are recorded in Table I. TABLE I Material
Specific gravity, d %
Refractive index, nuD
Freezing point, OC.
Cyclohexane 0.7746 1.4232 6.1" 1.3838 .. n-Propyl alcohol .SO00 .7808 1.3749 .. Isopropyl alcohol a A small amount of cyclohexane resulting from many recrystallizations had a freezing point of 6.33" and a specific gravity, d26, of 0.7744, and a refractive index not measurably different from that recorded above. This more highly purified material was employed in four solubility measurements with n-propyl alcohol and water a t 35". The differences in the results obtained with the 6.1" and the 6.33" cyclohexane, both for the solubility determinations and the refractive index-composition relationships, were well within the experimental errors.
Procedure and Results.-The experimental procedures were essentially the same as those which have been described.'v2 The results are presented in the following tables and graphs. Since the concentrations are presented in weight per cent., it will be enlightening to state that in each solubility determination and in each disTABLE I1
58.73 1.3825 7.30 1.4192 17.77 57.60 1.3788 14.98 1.4152 12.91 6.56 49.52 1.3708 22.55 1.4114 43.01 1.3660 29.87 1.4071 4.29" 1.4027 2.16" 35.63 1.3608 37.94 0.72" 27.42 1.3550 45.22 1.3974 1.3930 18.49 1.3488 51.50 0.08" 0.06" 9.40 1.3408 56.68 1.3880 Water saturated with cyclohexane 1.3322 Cyclohexane saturated with water 1.4233 a Mixtures of n-propyl alcohol and water were titrated with cyclohexane, 92.41 84.09 75.60 66.73 56.64 46.57 36.81 26.95
TABLE I11 ALCOHOL,CYCLOHEXANE AND WATERAT 35.0"
92.06 84.21 75.60 67.04 57.29 46.54 37.31 26'96
7.62 14.86 22.54 29.81 37.48 45.27 51.40
s'''
Refractive index
Cyclohexane, wt. %
%Propyl alcohol, wt. %
Refrap tive index
1.4137 1.4101 1.4062 1.4026 1.3982 1.3937
18.05 13.14 7.42" 4.19' 2.21' 0.85" O.ll'
58.91 57.99 51.60 42.96 34.87 27.46
1.3792 1.3758 1.3692 1.3692 1.3579 1.3528
9'21 Water saturated with cyclohexane 1.3311 Cvclohexane saturated with water 1.4177 Mixtures of n-propyl alcohol and water were titrated with cyclohexane,
0'074
TABLEIV ISOPROPYL ALCOHOL, CYCLOHEXANE AND WATER AT 25.0' IsoIsoCyclopropyl RefracCyclopropyl Refrac";.an& alcohol, tive hexane, alcohol, tive wt. % index wt. % wt. 7 0 index
0.14 0.32 1.08 4.81 10.46 16.27
8.80 23.88 36.80 48.29 53.88 55.57
1.3400 1.3531 1.3616 1.3687 1.3739 1.3777
18.97 26.85 35.97 43.56 55.02 71.40 86.98
55.74 53.53 49.29 45.08 37.86 25.78 12.82
1.3778 1.3848 1.3897 1.3936 1.3995 1.4066 1.4144
TABLE V CON JUGATE --Water Refractive index
1.3377 1.3403 1.3450 1.3480 1.3494 1.3505 1.3513 1.3521 1.3636
SOLUTIONS CONTAINING %-PROPYL ALCOHOL AT 25.0" layer-Cyclohexane layerAlcohol, Water, Refractive Alcohol, Water, wt. % wt. % index wt. % wt. %
5.8 8.6 13.9 17.5 19.3 20.8 21.9 23.0 39.6
94.1 91.1 85.6 81.9 79.9 78.5 77.3 75.9 57.2
1.4228 1.4225 1.4208 1.4167 1.4120 1.4002 1.3922 1.3862 1.3680
0.9 1.4 4.4 12.1 21.3 41.6 52.6 57.8 45.7
0.0 0.0 0.0 0.7 1.7 6.7 12.4 18.5 49.2
TABLE VI CON JUGATE SOLUTIONS CONTAINING n-PROPYL
1Z-PROPYI ALCOHOL, CYCLOHEXANE AND WATER AT 25.0" Cyclon-Propyl RefracRefracCyclo- n-Propyl hexane, alcohol, tive alcohol, tive hexane, wt. % index wt. % wt. % index wt. %
n-PRoPyL Cyclo- n-Propyl hexane, alcohol, wt. % wt. %
188i
C Y C L O H E X A N E , W A T E R A N D P R O P Y L ALCOHOLS
AT
--Water Refractive index
layerAlcohol wt. % '
Water, wt. %
1.3365 1.3384 1.3426 1.3448 1.3460 1.3470 1.3480 1.3494 1.3588
6.2 8.3 13.3 16.1 17.7 19.0 20.3 22.3 36.4
93.7 91.6 86.7 84.0 82.4 81.0 79.6 77.4 61.2
CONJUGATE SOLUTIONS
--
4.4 7.1 15.4 25.9 32.6 41.6 52.1 55.5
-Cyclohexane layerRefractive Alcohol, Water, index wt. % wt. %
1.4172 1.4168 1.4142 1.4105 1.4050 1.3954 1.3875 1.3812 1.3664
1.1 1.8 6.7 14.1 25.0 42.6 53.6 58.6 48.0
0.0 0.1 0.2 0.8 2.3 6.8 13.0 20.3 46.6
TABLE VI1 CONTAININGPROPYL ALCOHOL AT 25.0'
Water l a y e r - - - - - - Refractive Alcohol, Water, index wt. % wt. %
1.3356 1.3383 1.3465 1.3545 1.3590 1.3647 1.3718 1.3789
ALCOHOL
35.0"
95.4 92.8 84.1 73.9 66.5 55.7 39.9 26.7
-Cyclohexane layer-Refractive Alcohol, Water. index wt. % wt. %
1.4233 1.4231 1.4223 1.4190 1.4154 1.4117 1.4066 1,4021
0.0 0.2 1.3 5.9 11.2 17.2 25.8 33.5
0.0 0.0 0.1 0.2 0.3 1.0 2.8 5.4
tribution study the total weight of liquids employed was of the order of 13 to 15 g. The earlier investigations2 of ternary systems isopropyl alcohol, water and the hydrocarbons benzene, toluene and cyclohexene showed
E. R . WASHRURN, C. E. BROCKWAY, C. L. GRAHAM AND PHILIPDEMING ---
'
VOl. 64
point. Attention has been called to the fact that in several ternary systems such convergence is to be observed.* The system methyl alcohol-cyclohexane and water when studied at 25.0°h not only shows such convergence but the point a t which the tie lines converge is practically the cyclohexane vertex of the ternary diagram. The solubility of methyl alcohol in cyclohexane is not only limited but very small. As would be expected, ethyl alcohol'b is between methyl alcohol and the propyl alcohols in its distribution. It is not much different from methyl alcohol. 0 20 411 (it I The systems in which the tie lines change direcIsopropyl alcohol in water layer, wt.70. tion of slope represent extreme cases of non-conFig. I.--A, Benzene; N, toluene: C, cyclohexene; D, vergence. In one of the earlier studies the discyclohexane. tribution of isopropyl alcohol between water and cyclohexeneZcwas investigated a t three different , temperatures, 15, 25 and 35'. The slopes of the 4 tie lines and the positions of the plait points 4 changed to a marked extent with the change in temperature. Larger proportions of the alcohol Q 1 entered the hydrocarbon layer at the higher temperatures. If the present system behaves in a similar manner it might be expected that a change in direction of slope of the tie lines would be observed a t a temperature somewhat higher than 23'. The other system, described in this report, involving n-propyl alcohol shows such a change in J the direction of slope of the tie lines a t 23 and 0 20 -Iu 60 Alcohol in water layer, wt.%. 3.5'. The change causes the plait point to appear Fig. 2 - 4 , Methyl alcohol; B, ethyl alcohol; C, isopropyl on the opposite branch of the binodal curve from alcohol; D. n-propyl alcohol. that which would be predicted by the tie lines obtained with the smaller total proportions of the that the greatly increasing proportions in which It was possible to determine the plait alcohol. the alcohol entered the hydrocarbon layer as the point quite accurately with this system; it aptotal amount of alcohol in the system was inpeared a t about 92% alcohol on the water branch creased caused a change in the direction of slope The change of temperature to 35' did not 25'. a t of the tie lines. I t will be noted in the present as large a change in plait point as was obcause study that, while the proportion of alcohol in the served in the former system. cyclohexane layer increases as the total amount The proportions in which these alcohols are of alcohol increases, it does not ever become equal distributed between the water and the hydroto the proportion of alcohol in the conjugate layer carbon layers for these and related systems are which is rich in water. The tie lines never become clearly shown in Figs. 1 and 2 . horizontal and the plait point is some distance down on the cyclohexane branch of the binodal Summary solubility curve. Experimental difficulties preThe solubility relationships for the ternary vented a very close approach to the plait point and system containing water, cyclohexane and isoa study of the conjugation curvesa did not greatly propyl alcohol have been determined a t 25'. improve the situation. It is probably not far from The system containing water, cyclohexane and 48% alcohol on the cyclohexane arm of the curve. n-propyl alcohol has been studied a t 23 and 3 5 ' . It should be mentioned that extensions of the LINCOLN,NEBRASKA RECEIVED JUNE 3, 1942 tie lines for this systeni do not converge a t a single (4) A. V. Brauckar, 'I G . Hunter and A W Nnah, I n d E;tp T---T--
13) "Iotemotionrrl ('ritiral 'Tahlr;," Vol I l l . p 388
C h e ~Awal. , E d , 12, X5 11010)
