December, 1928
INDUSTRIAL AND ENGINEERING CHEMISTRY
D.P.G. as an accelerator was more than two years before the filing date of the Weiss patent, the Supreme Court held the defense to be good and the claims in suit, directed to D.P.G. as an accelerator for vulcanization of rubber, to be invalid. Anybody is now free to utilize the subject matter of the invalidated claims. It is to be observed in passing that if one public use of the invention or one sale of an embodiment of the invention can be proved to have occurred more than two years before the filing date of the patent, claims in the patent covering the invention in question will be declared to be invalid. Weiss, in addition to claiming D.P.G. as a vulcanization accelerator, claimed a process of treating rubber by combining with the rubber compound “a disubstituted guanidine.” It was shown that the class of disubstituted guanidines contains between fifty and one hundred substances in addition to D.P.G. The experts testified that many of these substances are not accelerators a t all. Weiss made no disclosure in his patent that there is a general quality common to disubstituted guanidines which made them all effective as accelerators, and, therefore, could not make claims covering a broad class of substances many of which are not effective or useful as vulcanization accelerators. A patentee can only make claims which are directed to his invention and which include things that are effective for carrying the invention into practice. The doctrine enunciated by the Supreme Court in the Incandescent Lamp Patent Case (159 U. S. 465) prohibits the sustaining of claims which are not supported by a description in the specification shorn-ing that there is some quality running through the members of the family or class of substances which the patentee seeks to monopolize. I n view of the Supreme Court’s holding, the public is free to utilize the subject matter of the invalidated process claims. The Weiss process claims in suit were also invalid because they were anticipated by an article published by one DuBosc on July 15,1919. This publication constituted a valid
1363
anticipation because it was printed more than two years before the filing date of the Weiss patent, which was November 12, 1921. For a full appreciation of the defense of prior publication as well as other defenses, reference should be had to Section 4920 of the Revised Statutes, which enumerates the defenses available to an infringer in actions for infringement. This section states, in essence, that when a person is charged with infringing a patent he may plead as a defense that: 1-The description and specification filed by the patentee was made to contain less than the whole truth relative to his invention or discovery, or more than is necessary to produce the desired effect. 2-The patentee had surreptitiously and unjustly obtained the patent for that which was in fact invented by another who was using diligence in adapting and perfecting the same. 3-The invention was patented or described in some printed publication prior to the patentee’s supposed invention or discovery thereof, or more than two years prior to the application for a patent therefor. 4-The patentee was not the original and first inventor or discoverer of any material and substantial part of the thing patented. 5-The invention had been in public use or on sale in this country for more than two years before the application for a patent, or had been abandoned to the public.
From a perusal of the foregoing, it will be observed that, in view of the evidence, the Supreme Court was correct in its decision because (I) Kratz and not Weiss was proved to be the original and first inventor or discoverer of D.P.G. as a vulcanization accelerator; ( 2 ) D.P.G. was used as an accelerator and was sold in inner tubes for automobile tires more than two years before the filing of the Weiss patent application; and (3) Du Bosc described in a printed publication more than two years prior to the supposed Weiss invention or discovery that disubstituted guanidines had been used as accelerators.
Vapor-Pressure Chart for Paraffin Hydrocarbons’ 0. G . Wilson, Jr. GULF REFININGCOMPANY,PORTARTHUR, TEXAS
c
OX2 gave an empirical method for plotting vapor-
pressure data so that the resulting curve became essentially a straight line over a limited range of temperature. Calingaert and Davis3 improved this method by showing that it was applicable to very large ranges; that the straight-line curves of a homologous series intersect a t a common point; that, with the point of intersection of the series known, a complete vapor-pressure curve for any member of the series could be drawn with the experimental determination of a single vapor pressure a t any one convenient temperature. Such a series of curves for normal paraffin hydrocarbons has been drawn on a large scale, similar to the one shown by them, using various data in the literature, particularly those of Francis and Wood,* with the intention of using it in the preparation of engineering estimates. However, it was found that the chart has several limitations as regards its direct application to petroleum engineering. For example, petroleum products rarely have average boiling points which place them directly on one of the lines so that interpolation 1 Received January 20, 1928. I N D E N O . CHEM, 15, 592 (1923). I b i d , 17, 1287 (1925). 1 J . Chem. Soc , 1936, 1120. J
has to be made between lines, a procedure particularly inaccurate when dealing with logarithmic and reciprocal scales; the number of lines close together is large enough to be bewildering when reading in the necessary three directions. Therefore, an empirical equation has been developed which gives the vapor pressures of normal paraffin hydrocarbons in terms of the temperature and of the boiling points under atmospheric pressure (assuming no decomposition). Also, a nomographic chart has been prepared which affords quick and easy solutions of the unwieldy equation. As shown by Calingaert and Davis, the temperature (ordinate) scale of their chart is in reality the function, 1/(T 230), where T is the temperature in degrees Centigrade and the vapor pressure (abscissa) scale is the function, log p , where p is the absolute vapor pressure in millimeters of mercury. A straight line can be represented by the equation
+
which becomes
x = A-by
(1)
when the functions of the scales of this chart are substituted for z and y in the general equation. Therefore ( 2 ) is the form of the equation of all the straight lines on the chart.
INDUSTRIAL A N D ENGINEERING CHEMISTRY
1364
If the temperature is converted to degrees Fahrenheit, ( 2 ) becomes log$ = '4
B -f + 382
(3)
where t = temperature in O F. and A and B are constants. Let to = boiling point of the hydrocarbon in O F. and po = atmospheric pressure, or 760 mm. mercury. Putting these values in (3), log$, = A
B -t o -t 382
(4)
Subtract b > t h sides of equation (4) from both sides of (3) to obtain B B log p - log pe = -- -
or
to+382
t+382
log PlPo
B
VOl. 20, No. 12
(L1-) (5) to + 382 t + 382
Obviously, one unknown quantity, A , has now been eliminated, so that if B can be expressed in terms of to,the formula will be reduced to sufficiently few variables to chart conveniently. It is first necessary to determine B separately for each line on the chart, or a t least enough of the lines to determine later the nature of its general relation to 6. This is easily done, as equation (4)contains two constants and any two points on each curve may be substituted to obtain values. Of course, one point to use in every case is the poixt of intersection of the series of the curves, which is3 t = 2264 and p = 1,300,000, for which log p = 6.1139 The other is any convenient point; an experimentally determined one, according to the published data, is used in every
INDUSTRIAL A N D ENGINEERING CHEMISTRY
December, 1928
case. For instance, for pentane, using t mm., equation (3) becomes
98" F. and p
=
760
~
B
6.1139 = A -
2264
+ 382
.*.
-- 2646
(4iO
B
B1
= 1896
Table I
FOR-
EXPTL.DATA
M m .Hg
6.1139log9
or
I+
1 --1
382
I
+ 382
(10) (11)
+ 0.0007634d
I+389
1 2646
B =
0.3091 +to + 382
-0.0001165
+
to 382 0.3091 - 0.0001165 (to
(12)
+ 382)
(13)
Insert this value of B in equation (5), which then becomes log
IN
MULA Press. Temp. CnHm+* (0) (1) log$
+ 0.002083d
Subtract (11) from (10) and solve, finding d = 0.3091, and c = -0.0001165. Putting these numerical values of the constants in (9) gives
Similar details of the calculations for the value of B for every second hydrocarbon from pentane (CPHI1)to pentatriacontane (C35H~2) are given in Table I. n
0.0006274 = c 0.0001195 = c
(7)
Subtracting (6) from (7), 3.2331 = B
when the functions of the scales of Figure 1 are substituted for 2 and y in the general equation. Introduce the first and last numerical values of 1/B and l / ( t o 382) from Table I1 as follows:
+
- 98 +B 382
2.8808 = A
and
=
1365
*'*'
to
= 0.3091
+ 382
+ 382)
- 0.0001165 it" \
to
B
,
-
-I- 382
,
1
t
+ 382
(14)
This equation apparently gives the vapor pressure of any normal paraffin hydrocarbon from pentane to pentatriacontane a t any temperature in terms of the temperature and of the boiling point a t atmospheric pressure. However, it must be employed with due consideration for the following factors: (1) Its derivation is based on the assumption that the vaporpressure curves on the Calingaert and Davis chart are straight lines, whereas there is some slight curvature, especially in the case of the lower members of I the series; (2) the boilI Having obtained values of B for each of the vapor-pressure ing points e m p l o y e d I l l equations of the various individual hydrocarbons of interest, were the temperatures it is next necessary to find a general relation between B and noted a t the intersecto, the boiling point under normal pressure. Of several tions of the vapor-prespossible relations, the most convenient is a hyperbolic one s u r e c u r v e s with the 8 which is demonstrated by a graph of 1/B vs. l / ( t o 382) 760-mm. line on the 3 giving a straight line, as shown in Figure 1, which was plotted same chart, which, in from the values given in Table 11. The boiling points a t the case of the higher u atmospheric pressure were read directly from the above- members of the series, LLmentioned Calingaert and Davis type chart of the vapor implies extrapolations pressures of the individual hydrocarbons, which values are from experimentally --____ theoretical in that no allowance is made for decomposition determined v a l u e s a t I l l which would make the actual figures somewhat lower, es- 10 or 15 mm. pressure ' ii 13 ,S '7 13 Z/ pecially for those that are shown higher than 700 O F. Lx ,do00 and makes no allowt, r 362 Table I1 a n c e for c r a c k i n g , Figure 1 n IN which would reduce FORMULA considerably the actual boiling point; (3) it is not applicable CnHm+a B toa f o + 382 1/B l / ( f o f 382) 5 IS96 480 98 0 0005274 0 002083 above or close t o the critical temperature of any hydrocarbon 7 2485 212 594 0 0004025 0 001684 under consideration. I n applying equation (14) to petroleum 9 3007 305 687 0 0003325 0 001456 11 3492 386 768 0 0002864 0 001302 distillates other factorsenter which further reduce the accuracy. 13 3952 457 839 0 0002530 0 001192 I n the first place, petroleum products are not normal paraffin 15 4456 525 907 0.0002244 0.001103 17 4903 582 964 0.0002039 0.001037 hydrocarbons, but mixtures of many series, so that the vapor 19 5333 632 1014 0.0001875 0.0009862 21 5744 680 1062 0.0001741 0.0009416 pressures of the fractions from different crudes show different 23 6141 728 1110 0.0001628 0.0009009 types of variations from those of the paraffins, which must be 766 25 6510 1148 0.0001536 0.0008711 27 6871 798 1180 0.0001455 0.0008475 learned by experience. Furthermore, petroleum products 830 29 7258 1212 0.0001378 O.OOOS251 are very rarely fractions cut so close as to exhibit vapor-pres31 7635 870 1252 0.0001310 0.0007987 33 7988 893 1275 0.0001252 0.0007843 sure properties like a single pure substance. However, the 35 8366 928 1310 0.0001195 0,0007634 Boiling-point temperatures, lo, a t atmospheric pressure are from equation possesses some utility for making estimates, espeCalingaert and Davis type of vapor-pressure chart. These values are cially as it can be charted nomographically so that it can be theoretical in t h a t no allowance is made for decomposition, which would make the actual figures somewhat lower, especially those t h a t areishown solved by inspection. higher than 700' F. The method used in making the nomographic chart, which To find the general equation connecting B and to, again is described by Lipka,6 is not given here, as being outside the scope of this paper. The accuracy of the chart is esstart with the general form of a straight-line curve, sentially the same as that of equation (14) from which it was y = c + d x made. Two examples of its use follow: which becomes 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35
760 20 15 15 10 15 15 15 15 15 15 15 15 15 15 15
O F .
98 2.8808 50 1.3010 113 1.1761 176 1.1761 216 1.0000 291 1.1761 340 1.1761 38.5 1.1761 426 1.1761 464 1.1761 498 1 1761 530 1 1761 563 1 1761 594 1 1761 622 1 1761 651 1 1761
3.2331 4.8129 4.9378 4.9378 5.1139 4.9378 4.9378 4.9378 4.9378 4.9378 4 9378 4 9378 4 9378 4 9378 4 9378 4 9378
480 432 495 558 598 673 722 767 808 846 880 912 945 976 1004 1033
0.002083 0.002315 0.002020 0.001792 0.001672 0.001486 0,001385 0.0013038 0.0012376 0.0011S20 0 0011364 0 0010965 0 0010582 0 0010246 0 0009960 0 0009681
0.001705 0.001937 0.001642 0.001014 0.001294 0.0011OS 0.001007 0.0009259 0.0008597 0.0008041 0 0007585 0 0007186 0 0006803 0 0006467 0 0006181 0 0005902
1896 2485 3007 3492 3952 4456 4903 5333 5744 6141 6510 6871 7258 7635 7988 8386
+
./i++T~ , ] 1-
i
1 B - = cf-
d
to
+ 382
6 "Graphical and Mechanical Computation," p. 107, JohnIWiley and Sons, Inc., 1918.
1366
Vol. 20, No. 12
INDUSTRIAL A N D ENGINEERING CHEMISTRY
1-To find the vapor pressure a t 300' F. of a normal paraffin hydrocarbon having a boiling point under normal atmospheric pressure of 250' F : Place a straight edge across the chart so that it connects the 300' F. point on the left side of the right (temperature) axis and the 250' F. point on the left side of the middle (boiling point) axis; read the vapor pressure a t the intersection of the straight edge with the left (vapor pressure) axis as 1550 mm. of mercury, absolute pressure, or as 14.5 pounds per square inch gage pressure.
2-To find the boiling point under normal atmospheric pressure of a normal paraffin hydrocarbon which has an absolute vapor pressure of 500 mm. of mercury at 300" F.: Place a straight edge across the chart connecting the 500 mm. point on the left side of the left (vapor pressure) axis and the 300" F. point on the left side of the right (temperature) axis; read the boiling point under normal atmospheric pressure a t the intersection of the straight edge with the middle (boiling point) axis as 327' F. or 164' C.
Solubility of Sodium Benzene Sulfonate in Water and in Solutions of Sodium Sulfate' F. H. Rhodes and A. W. Lewis CORNELLUNIVERSITY, ITHACA,hT.Y.
ESPITE the importance of sodium benzene sulfonate as an intermediate product in the manufacture of synthetic phenol, there is but little published information as to the properties of this salt. Norton2 has made measurements of the solubility at two temperatures. He states that sodium benzene sulfonate crystallizes as the anhydrous salt from water. This is true under some conditions, but not always. Beilstein3 says that a monohydrate crystallizes from aqueous alcohol, but gives no reference for this statement. The investigation described in the present article was undertaken for the purpose of determining the solubility of sodium benzene sulfonate in water a t various temperatures. Since the salt as prepared commercially is contaminated with more or less sodium sulfate, the effect of the presence of sodium sulfate upon the solubility was also determined. Some experiments were made to determine the composition of the hydrate formed a t ordinary temperatures and the inversion temperature a t which this hydrate decomposes.
D
until equilibrium was reached. A portion of the clear saturated solution was then removed and weighed and the amount of dissolved salt was determined by evaporating the water and weighing the dried residue. I n each case duplicate determinations were made. In determining the , solubility of the sodium b e n z e n e s u l F/G. 2 fonate a t the boiling 56~%p o i n t , a weighed a m o u n t of the dry salt was placed in a weighed Erlenmeyer which was provided with a r e f l u x condenser. A small amount of water or of a solution of sodium I / , I sulfonate of k n o w n added c o n c e nand t r a tthe i o n mixwas 7/
'
~
ture was heated to 6 9 $ boiling. Water or sodium sulfate solution 67 was added in small k increments until the 6 f h s o l i d s a l t j u s t dis-
1
8
PURE
/p
~
8
-66
l
'C
NG.3 D/L ATOflE 7ER RLADNGJ
5 NaaSO;
10 NazSO4
20 NazSO4
TEMPERATURE WATER 95 WATER 90 WATER 80 WATER Grams S.B. S. i n 100 grams solution c.
The sodium benzene sulfonate was purified by repeated recrystallization from water. Sulfone was removed by extracting the diluted solution with benzene. In making the solubility determinations, a mixture of the salt with water or with a solution of sodium sulfate of known concentration was sealed in a bulb and agitated a t constant temperature
1
Received July 14, 1925. J . Am. Chem. Soc., 19, 835 (1897). a "Handbuch der organischen Chemie," 4th ed., Vol. 11, p. 28.
1 9
0 30 35 40 45 50 60 70 75 80 (105)
26.8 35.8 37.4 38.6 40.4 41.9 45.1 48.0 49.4 51.1 58.5
32.2
27.7
38.6
34.4
25.8
45.2
42.1
31.9
These results are shown graphically in Figure 1. Figure 2 shows the effect of varying amounts of sodium sulfate upon the solubility of sodium benzene sulfonate a t the boiling point of the solution. In determining the composition of the hydrate of sodium
