ACKNOWLEDGMENT
The authors are indebted to F. W. Anderson for the chromatographic separations. LITERATURE CITED
(1) Carlaon, E. G., O’Seal, 11. J., “Analysis of Petroleum Oils by Mass Spectrometry,” American Society
for Testing Materials, Research Division IV on Hydrocarbon Analysis, Committee D-2, Kew Orleans, La., February 1957. (2) Field, F. H., Hastings, S. H., ANAL. CHEBI.28, 1248 (1956). (3) Friedel, R. A., Orchin, M., “Ultraviolet Spectra of Aromatic Compounds,’’ Wiley, Kew York, 1951. (4) Honig, R. E., J . Chem. Phys. 16, 105 (1948). (5) Lumpkin, H. E., Johnson, B. H., h A L . CHEM. 26, 1719 (1954).
( 6 ) Meluolder. F. W.. Brown. R. A..
RECEIVEDfor review July 12, 1957. Accepted March 6, 1958. Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy, Pittsburgh, Pa., March 1957.
Carbon-Type Composition of Viscous Fract io ns of Petro Ie um Density-Refractivity Intercept Method S. S. KURTZ, Jr., R. W. KING, W. J. STOUT, and M. E. PETERKIN Sun Oil Co., Marcus Hook, Pa. ,The molecular volume and density of saturated polycyclic hydrocarbons can be calculated with a standard deviation of about 0.008. Density for polycyclic aromatic hydrocarbons can be calculated with a standard deviation of 0.007. Differences of observed density due to differences in number or type of ring structures amount to several units in the second decimal place. Therefore, it is possible to use calculated densities in evaluating carbon-type composition. Molecular volumes and densities for all the basic structures having 15, 20, 26, 30, and 40 carbon atoms have been calculated. A correlation between calculated density and refractivity intercept is presented by which carbon-type composition can be obtained for oils having between 15 and 40 carbon atoms, if the number of carbon atoms is also known. The latter may b e derived from an equation based on molecular weight and viscosity-gravity constant. The correlation can be used for all types of viscous petroleum oils, including very aromatic oils which are rich in polynuclear hydrocarbons. The validity of this analytical procedure confirms the validity of the equation for calculation of molecular volume and density of polycyclic hydrocarbons. HE relation between the physical properties and constitution of the viscous fractions of petroleum has been the subject of a large amount of research in recent years (3-6, 9, 14, 26-29, 31 36, SF). It is believed that the approach prmented in the present paper is particularly well suited for study of the aromatic fractions from petroleum. It is ~
1224
a
ANALYTICAL CHEMISTRY
based on rather general relationships nhich can be extrapolated with a reasonable degree of confidence into the region of polynuclear compounds where good experimental data on pure hydrocarbons are not plentiful. The objective of this paper is to show how the carbon-type composition of polycyclic compounds found in lubricating oil can be determined from density and refractivity intercept. It has been shown (8, 10, 12, 38) that molecular volume (and density) can be calculated for hydrocarbons to a good first approximation, ignoring isomer effects. ilctually, isomer effects seem t o be less in magnitude in hydrocarbons having large molecular volumes (13). The equation for the molecular volume of hydrocarbons a t 20’ C. and 1 atm. is: 1101.v01. = 16.28~~1 $- 13.15~~2 9.7n3 - 6 . 2 7 ~ ~ 31.2 (1)
+
+
n1 = number of carbon atoms in open chain structures n2 = number of carbon atoms in ring structures, except ring junction carbon atoms n3 = number of carbon atoms a t ring junctions n4 = number of double bonds 31.2 = kinetic impact free volume a t 20” C. and 1 atm. (8, 12) This equation has been used by Schiessler and associates on API Project 42 for calculation of the molecular volume of saturated hydrocarbons (2, 32-34). They pointed out in 1943 (32) that there was “close agreement” between calculated and experimental molecular volumes for the saturated hydrocarbons which they synthesized. Equation 1 agrees, on the average, within 1% ( I S , Tables I1 and 111) with data for 139 saturated hydrocarbons for
which data are given by Rossini and associates in API 44 tables (1, $1) and within 0.5y0with data for 90 saturated hydrocarbons of higher molecular 17-eight published by Schiewler and associates of API 42 (2, 53). The molecular volumes calculated by Equation 1 were also compared with e.xperimenta1 data for 11 of the more complex naphthenes synthesized by API Project 42 ( 2 , 33, 3 4 ) . The conipounds used were Pennsylvania State University Compounds 122, 125, 132, 141, 155, 166, 196, 561, 575, 577, and 578. The calculated volume is too small in five cases, too large in five, and exactly right in one. The standard deviation is 2.5 cc. or about O.7yO. I n terms of density the standard deviation is 0.0077. The molecular volumes calculated using Equation 1 vere compared with data for eleven polycyclic and two monocyclic aromatics reported by API 42. The compounds used rrere Pennsylvania State University Compounds 99, 124,126,131, 140,165, 179,517,56i, 568, 571, 574, and 576 (2, 33, $4). For these data the calculated molecular volume a t 20’ C. is in all cases but one a little too small, the standard deviation being 1.7 cc., or 0.0070 in terms of density. Densities have also been calculated (Table 14, 8) for 210’ F. using the temperature coefficient data previously published (22, 16). These data show molecular volumps on the plus side and densities on the minus side for these cyclic compounds, indicating that a readjustment of the coefficients for the effect of temperature on these polycyclic naphthenes and aromatics is desirable. These data also indicate that a t some temperature between 68” and 210” F.
88 c)-}i Q
Q
Po.
ip-4
0
3 c3
Em
Cn W
N
I
Q
Gl 0
clr
3
0
'3
M c3 M
0
cc N
0
cc
c
4
VOL. 30, NO. 7, JULY 1958
* 1225
the calculated volumes for aromatics will agree exactly with the experimental values. Although the agreement between the calculated molecular volume and density and the experimentally observed volumes is not perfect, it is good enough to indicate that the basic concept in-
volved in the molecular volume calculations is probably correct. This concept is that the molecular volume of hydrocarbons can be calculated as the sum of two parts: the sum of the segmental increments and the kinetic impact free volume (8, 12). The segmental increments are thought of as arising from the
Table II. Calculation of Molecular Volume and Density of Saturated and Aromatic Hydrocarbons of Basic Structure Containing 20 Carbon Atoms and Four or More Rings
Saturated vol. Mol. and DenFormula
mol. wt.
sity
omcz 252:;
1.0477
292.3 0.9390 274.5 289.2 0.9492 2i4,5
286.0 0.9596 274.5
03Dc3
Two Aromatic Rings Mol. vol. and DenFormula mol. wt. sity
282.9 0.9iO2 274.5
279.8 0.9810 274.5
AAm-c3
I
1
~
~
~
255.0 1.0369 264.4
c3
251.8 1 0500 264.4
276.0 0.9872 272.5
om?'' ~
;:2;'
0.9985
______-
oav
266.6 1.0219 272.5
Three Aromatic Rings Mol. vol. and DenFormula mol. wt. sity
One Aromatic Ring Mol. vol. and DenFormula mol. wt. sity 270.6 0.9921 268.4
03q3c4%2:: \
1.0037
-
264.3 1.0156 268.4
motions of the atoms in the molecule relative to one another, primarily by rotations around carbon-carbon bonds. These motions can be hindered by structural effects of atoms in the immediate vicinity, which accounts for the lesser volume required by carbon atoms in small rings, a t ring junctions, and in double bonds. The kinetic impact free volume is thought of as resulting from the impact of the mass of a molecule as a whole on its neighbors. These concepts have been discussed in detail (7,8, 13). Simha and Hadden (56) have derived a value from cell theory for the terminal constant of normal paraffins which is 4.4 ml. per gram mole smaller than the terminal constant (kinetic impact free volume) in Equation 1. An explanation for this 4.4ml. correction to the kinetic impact free volume has been developed and will be discussed in another publication, as it is not pertinent to the present paper. It seems reasonable to believe that the basic principles of molecular volume will apply well even for polycyclic structures which are much more complicated than those for which data are now available, and that it is therefore reasonable to extrapolate calculations with Equation 1 into the high molecular weight region. Consideration has therefore been given to the computation of the molecular volume and density of the basic structures in the gas oil and lubricating oil molecular weight range (15 to 40 carbon atoms). By "basic structures" is meant those stmctures whose molecular volume and density can be computed with Equation 1 for the molecular volume of hydrocarbons (7, 10, 12). There are relatively few of these basic structures as compared with the large number of structures which are possible if all isomers are taken into account. For example, if nlolecules containing 20 carbon atoms are considered, the molecular volumes and densities can be calculated for molecules containing no aromatic rings, then for structures with one aromatic ring, two aromatic rings, etc., as shown in Tables I and 11. To simplify the initial calculations, all multiring structures were assumed to be linearly condensed. This is an oversimplification, but it can rather easily be corrected later if necessary. If the total number of carbon atoms per molecule is held constant, the difference between the molecular volume calculated for two condensed rings and that calculated for two noncondensed rings is relatively small. According to the best correlations now available, when two rings are fused (without change in the mimher of carbon atoms in the mole.._~~...~ cule) two ring junction carbon atoms (9.7 ml. each) and two chain carbon atoms (16.28 ml. each) are created in place of four ring carbon atoms (13.15
Four Aromatic Rings Mol. vol. and DenFormula mol. &. sity
03$rc2 om-"' :
Xi
1226
ANALYTICAL CHEMISTRY
1.0277
224.0 256.4
I
I30 p
Table 111.
PER CENT CN
Figure 1. Calculated density v5. per cent CN f o r structures containing 30 carbon atoms
Figure 2. Calculated density lines for compounds with 30 carbon atoms from Figure 1 plotted on a g r a p h o f carbon type composition
100%
c\
Density Line 0.78 0.79 0.80 0.81 0.82 0.83 0.84 0.85 0.86 0.87 0.88 0.89 0.90 0.91 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10
15 carbons 7.4 14.4 19.5 23.5 27.7 31.4 35.0 37.8 40.4 44.0 46.5 49.3 52.4 54.6 57.5 60.0 62.6 64.8 66.6 68.5 70.9 72.7 74.8 76.9 78.7 80.1 81.7 83.3 85.5
1.11
1.12
1.13
1.14 1.15 1.16 1.17 1.18 1.19 1.20 1.21 1.22 1.23 1.24 1.25 1.26 1.27 1.28 1.29
100% CP
Data Necessary to Construct Figure 3
Per Cent Aromatic Ring Carbons ( % CA) 20 25 30 35 carbons carbons carbons carbons
4.0 9.3 14.5 18.8 22.5 25.8 29.2 32.0 35.0 38.1 41.1 43.5 46.1 48.6 51.0 53.4 55.6 57.7 60.0 62.2 64.3 66.4 68.3 70.3 72.1 74.2 76.3 78.2 80.0 81.8 83.4 85.0 86.6 87.9 89.2 90.3
2.2 8.7 13.3 17.2 20.6 23.9 26.7 29.6 32.7 35.5 38.0 40.5 42.8 45.4 47.7 50.0 52.2 54.6 56.7 58.8 60.8 62.9 64.8 66.7 68.6 70.5 72.2 73.7 75.4 76.8 78.5 80.0 81.5 83.0 84.3 85.7 87.0 88.7 90.2 91.6 92.8 94.1 95.5
3.8
9.0 13.4 16.9 20.2 23.0 25.8 28.8 31.5 34.0 36.5 38.8 41.3 43.6 46.0 48.4 50.6 52.7 54.9 57.0 59.0 60.9 62.9 64.7 66.4 68.1 69.8 71.3 72.7 74.4 75.9 76.7 79.1 80.5 81.8
83.4 84.5 86.4 87.7 88.8 90.3 91.7 92.8 94.2 95.4 96.6 97.7 98.8
5.5 10.4 13.8 17.5 20.2 23.1 25.9 29.7 31.0 33.6 36.1 38.5 40.8 43.3 45.7 47.8 49.8 52.0 54.3 56.2 58.2 60.1 61.8 63.7 65.5 67.7 68.6 70.0 71.8 73.4 75.1 76.6 78.0 79.4 80.8 82.4 83.8 85.1 86.4 87.7 89.0 90.2 91.5 92.6 93.8 94.9 96.0
40 carbons
2.3 7.7 11.3 14.8 17.8 20.8 23.5 26.0 28.7 31.3 33.9 35.1 38.5 41.0 43.4 45.7 47.6 49.8 51.9 54.0 55.9 57.8 58.6 61.3 63.0 64.7 61.5 68.0 69.7 71.6 73.1 74.8 76.0 77.5 79.0 80.5 81.8
83.1 84.5 85.8 87.1 88.3 89.5 90.7 91.8 92.8 94.0
ml. each). Four ring carbon atoms = 52.60 cc. Two ring junctions plus two chain carbon atoms = 51.95 cc. The difference] 0.64 cc., resulting from condensation is small. It can become significant] however, when polycyclic structures with large numbers of rings are involved. I n regard to type of condensation, it is believed that the nonlinear ring isomers actually predominate in petroleum oils ( l 7 , 2 4 , SO). The linear representation in the tables is entirely for convenience, as we are not trying to distinguish between linear and nonlinear assemblages of rings. Calculations similar to those outlined in Tables I and I1 for 20 carbcn VOL. 30, NO. 7,JULY 1958
1227
atoms were also carried out for the basic structures of 15, 26, 30, and 40 carbon atoms. When the calculated density data for a particular carbon number (circles in Figure 1) are plotted against the percentage of the total carbon atoms in naphthenic structures (% CN),reasonable lines can be drawn through the data for the compounds n7ith no aromatic rings, one aromatic ring, two aromatic rings, etc. The solid curves in Figure 1 illustrate the lines obtained when
Table IV. Summary of Results O b tained by Using Original Triangular Chart (Figure 4) on Oils in Table XII” % c A %CK %CP Dev. of av. 0.0 -0.9 +0.9 Av. dev. 1 7 3 1 2 2 Std. dev. 2 0 3 7 2 6 a Differences are from Martin analysis (11) data shown in Table XII.
Table V.
Data from Which to Construct Density Lines on Triangular Graph (Figure 5)
% CP on 70 CNon ‘30Ca on Density Line 0.82 0.83 0.84 0.85 0.86 0.87 0.88 0.89 0.90 0.91 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99 1.00 1.01 1.02 1.03 1.04 I .05 1.06 1.07 1.08 1.09 1.10 1.11 1,12 1.13 1.14 1.15 1.16 1.1i 1.18 1,19 1.20 1.21 1.22 1.23 1.24 1.25
1228
the calculated density data for hydrocarbons containing 30 carbon atoms are plotted in such a manner. At equal per cent naphthenic carbons there is a large increase (7 t o 14 units) in the second decimal place of the density for each aromatic ring added. For a 10% increase in naphthene ring carbons there is an increase of from 1.5to 5 units in the second decimal of the density. These differences are large compared with the standard deviations of the calculated densities of polycyclic naphthenes (0.008) and polycyclic aromatics (0.007), based on API 42 data. Therefore, the calculated density data appear to be sufficiently accurate to aid in determining carbon type composition. V i t h this objective in mind, the smoothed data from Figure 1 were transferred to a triangular coordinate system representing carbon-type composition. -4series of parallel, regularly spaced lines of constant density resulted
Ch-CP Base Line
CS-CA Side of Triangle
CA-CP
70 CP on
Triangle
Line
97.5 93.9 90.3 87.3 84.2 81.3 78.2 74.5 71.2 68.0 64.8 61.0 56.9 52.2 49 0 44.7 40.6 36.1 32.9 28.0 24.5 20.9 17.4
3.9 9.1 13.1 16.8 20.1 23.5 26.2 29.0 31.7 34.3 36.8 39.3 41.5 43.7 45.8 48.2 50.4 52.4 54.3 56.3 58.2 60.1 62.1 64.0 65.8 67.5 68.9 70.7 72.4 73.8 75.6 77.4 79.1 80.8 82.3 83.7 85.0 86.6 88.1 89.5 90.8 92.1 93.4 95.6
94 2 86 6 80 5 74 7 69 3 64 4 59 3 50 3 49 4 44 9 40 5 36 0 31 7 27 1 23 6 19 2 15 4 11 8 7 8 4 0 0 4
ANALYTICAL CHEMISTRY
Side of
10% C I
85 6 79 9 74 9 69 9 65 3 60 7 56 1 51 8 47 7 43 5 39 6 35 6 32 5 28 9 25 3 21 8 18 2 15 0 11 5 8 2 4 5 0 4
c/o Cpon 20?q C i me
% Cpon % CP on 405;
‘2.4
Line
60% C.4
Line
i9.9 75.9 70.7 66.3
42.4 39.2 35.7 32.2 28.8 25.3 22.5 19.2 16.1 13.1 10.1 7.0 4.1 1.2
54.3 50.9 47.4 44.1 40.8 37.7 34.8 31.8 29.0 26.4 23.8 21.1 18.2 15.8 13.4 10 i 8 2 5 5 3 1 0 6
(Figure 2). The data for the 15-, 20-, 26-, and 40-carbon atom structures were similarly transferred to triangular coordinatcas. The density lines on all these graphs have the same slope. Therefore, lines which pass through any one point, as at the point of intersection with the paraffin-aromatic side, will be the same at all other points of composition. This striking regularity suggested that it should be possible to interpolate for intermediate numbers of carbon atoms, and possibly to use one density chart for oil fractions with any number of carbon atoms. This will involve calculation of the “equivalent density” to be used on the chosen chart. To facilitate computation, Figure 3 vias constructed by plotting, as a func-
Table VI. Data from Which to Construct Refractivity Intercept Lines on Triangular Graph (Figure 5)
Ri Line 1.038 1.040 1.045 1.050 1.055 1.060 1,065 1.070 1,075 1.080 1.085 1,090 1.095 1.100 1.105 1,110 1.115 1.120 1.125 1.130
NaphNaphthenethene- ParaffinAromatic Paraffin Aromatic BaseSide of Side of Triangle, Line, Triangle, % CN % c P %CA 84.2 74.7 68.4 63.9 60.1 56.3 53.1 49.6 46.6 43.6 40.8 38.1 35.3 32.6 29.6 26.2 22.8 19.6 16.2 12.3
25.0 50.0
39.2 43.5 48.0 51.8 55.8 59.6 63.7 67.8 72.0 76.1 80.5 85.0
Table VII. Basic Refractivity Intercept Data Used in Deriving Table VI“ 39.8 36.9 34.2 31.5 29.0 26.8 24 4 22 0 19 7 17 0 14 6 11 9 9.5 7.0 8.0 2.7 0 3
a
Intercept of Oil
Intercept of hromatic Carbons
1,0350 1,0400 1.0450 1,0500 1.0550 1.0600 1.0650 1.0700 1.0750 i .os00 1 0850 1 0900 1.0950 1.1000 1.1050 1.1100 1.1150 1.1200 1.1250 1.1300
1.0616 1.0695 1.0775 1.0855 1.0926 1.0986 1.1042 1,1094 1.1140 1.1186 1,1235 1.1275 1,1310 1.1340 1.1360 1.1385 1.1405 1.1420 1.1545 1.1585
Extension of Table I11 ( 9 ) .
Figure 4.
AROMATIC
RING
Refractivity intercept lines added to Figure 2
CARBONS
A-
Figure densit)
Figure 5.
Final diagram relating carbon type composition to refractivity intercept and density at
30 carbon atoms
VOL. 30, NO. 7, JULY 1958
1229
’
tion of the number of carbon atoms, the values for the intercept of the density lines with the paraffin-aromatic side of the triangular diagrams to give a series of lines of constant density. This graph shows, for example, that if there are 25 carbon atoms in an oil and the density is 0.960, the per cent aromatic
Table VIII.
% CA
Range
0- 9 . 9
10-19.9 20-29.9 30-35 All
Deviation of Analyses from Best Values for Oils Containing Greater than 35% CNa
Original Diagram (Figure 4) % CA % CN % CP
NO. of oils
Revised Diagram (Figure 5)
% cp
% cN
% c A
Deviation of Average +0.25 +0.24 -0.49 -2.88 +3.99 +0.06 -0.76 +0.70 +4.83 -3.00 -1.22 11.31 -0.09 +4.77 -3.38 -1.68 +2.94 +4.67 -1.26 -3.07 -0.46 +0.42 +4.45 +0.04 -3.02 Standard Deviation 0.91 2.83 2.61 3.47 4.45 2.01 1.19 1.85 2.31 2.20 3.57 5.15 2.29 1.96 1.10 1.70 3.70 4.96 2.62 3.58 3.67 5.14 2.07 2.33 2.32 2.25 2.02 3.52 4.78 1.12 distribution of data points and methods of obtaining “best data.”
75 61 32 9 177
-1.11 -1.83 -1.39 -1.60 -1.43
0- 9 . 9 75 10-19.9 61 20-29.9 32 30-35 9 All 177 a See Figure 6 for Table IX.
carbons on the paraffin-aromatic side of the triangular graph is 50%, and the density of a n oil of the same carbontype composition but having 30 carbon atoms is 0.977. This “equivalent density” at 30 carbon atoms can be used on a density chart drawn on the basis of 30 carbon atoms. This greatly simplifies
Composition of Oils of Rossini and Mair by Refractivity InterceptDensity Method
From Maira Analysis (23)
Ri-Densit y oil B-12 B-16 B-19 C-13 C-20 C-30 C-33 C-35 C-37 C-res
% CN
% CA
% CP
%
%.
%
CA
CN
CP
Difference
’ % CA
% CN
24 24.5 26 23 26 34 33 30.5 28 32
25.5 30.5 33 28 34 44 48.5 52.5 57 68
54 45 41 46 38 23 21 21 19
% CP
$1.0 23 23 -3.5 -5.5 25 0 30 -6.0 27 0 32 -8.0 23 $3.0 31 -8.0 28 +2.0 34 40 -1.0 -3.0 37 -2.5 $2.0 48 31 $3.5 27 52 -4.0 $4.0 57 -4.0 24 75 0 +7.0 0 25 0 -1 . 3 Deviation of average - 1 . 0 5.63 2.67 Standard deviation These numbers were a hlair does not report data on carbon-type basis. directly as possible from his data.
50.5 45 41 49 40 22 18.5 17 15
+2.5 f5.5 +6.0 +5.0 $6.0 +4.0 +0.5 +0.5 0
-7.0 +2.3 4.70 derived as
Comparison of Direct Method Data (23, 28) with Data Obtained Using Figure 5 Standard Deviation CA NO. Of Deviation of Average
Table X. 70
Range 0- 9 . 9 10-19.9 20-29.9 30-39.9 40-49.9 50-59.9 All Table XI.
Oils 41 22 9 7 3 1
83
% c N
%cP
-1.25 -0.20 +O 61 -1.77 -6.50
+0.96 +0.61 +0.91 +2.87 t5.50
1.14 1.34 2.02 1.90 2.12
-0.23
-‘d.’gi
+’l’.’20
1.41
% c A
...
% CN
%cP
2.46 2.21 3.18 3.61 8.08 ... 2.78
2.16 1.68 3.08 3.58 6.74 ...
2.46
Calculation of Number of Carbon Atoms from Molecular Weight and VGC
VGC Group A (0.78-0.82) B (0.82-0.85) C (0.85-0.90) D (0.90-0.95) E (0.95-1.0) F and G (>1.0)
1230
%cA
$0.29 -0.41 -1.52 -1.10 +1.00
No. of
Samples 2 2 9 8
15 3
ANALYTICAL CHEMISTRY
Av. Mol. Wt. 678 406 360 369 326 281
ilv. No. C -4toms 48.55 29.21 29.41 27.07 23.91 20.89
Std. Dev. of Calcd. No. C Atoms 0.45 0.19 0.19 0.13 0.34 0.28
,
Dev. of Av. t o .34 -0.05 +0.02 +0.07
+O. 28
+o I22
the application of density to the determination of carbon-type composition, as a single triangular diagram on which lines of constant density have been placed can be used for a range of carbon atoms. T h a t is, with the aid of Figure 3, one can use a single graph for 30 carbon atoms, and the equivalent density a t 30 carbon atoms, even though the original density is for an oil m-ith as few as 15 carbon atoms or as many as 40 carbon atoms. Table I11 provides data from which Figure 3 may be constructed. It is apparent, however, that density alone cannot uniquely define the carbontype distribution. Another physical property function which will intersect the density lines is needed. It has been shown (9) that refractivity intercept is a suitable function for this type of correlation. It is sufficiently independent of molecular weight so that no correlation curve corresponding to Figure 3 is needed. Figure 4 illustrates a triangular diagram on which both density and refractivity intercept lines appear. The density lines were drawn using the smoothed data calculated for 30-carbon atom structures (Figure 1). The refractivity intercept lines were derived using an extrapolation (Table VII) of the curve previously described (Q), based on data obtained by the Martin method (11 ) . A chart similar to Figure 4 was used in conjunction with Figure 3 to determine the carbon-type composition of 35 oils on n-hich reliable composition data were amilable. Table IV presents in summary form the result of this study. The agreement is in general good. considering the xhole group of oils. However, plotting the data of Lipkin, Martin, and Worthing (16) for a series of hx-drogenated samples revealed that the more naphthenic portion of thp triangular diagram (above about 35% C,) s h o w d substantial deviations in % Cy and % Cp., Study of other data for samples rich in naphthenic carbons confirrrled the need for adjustment of the graph in the region above 35% Cy. A careful inspection of the data indicated that errors of this nature could result if the densities calculated for the basic structures were too high in relation to the percentage of ring carbons. It seemed probable that the assumption of completely condensed polycyclic naphthene structures was responsible for this effect, because condensation reducps the percentage of carbon atoms in rings without changing the density appreciably. It is not unreasonable to suppose that when there is a high proportion of naphthenic carbon in a molecule that some of the naphthene rings will be noncondensed and that the density for a given % CN will therefore be lower, as shown by the dotted lines in Figure 1. Mair and Rossini have found that
single and condensed ring structures occur in about equal amounts in certain saturated fractions (19-91). Miron also discusses the degree of condensation of naphthene rings (26). A preponderance of the mass spectral data in the literature suggests (18, 95) t h a t the saturated portion of lubricating oil contains about equal quantities of noncondensed (including monocycloparafis) and condensed rings. The density data for the saturated structures were, therefore, recalculated assuming completely noncondensed rings. The lowest dotted line in Figure 1 illustrates the results of this calculation for compounds with no aromatic rings. The final densities for the saturated molecules used in preparing Figure 5 were obtained by interpolating between 0 and 100% condensation to give the broken line (second line in Figure 1) representing 50% condensed saturated rings. To correct the densities of structures containing aromatic as well as saturated rings i t was necessary to assume t h a t as the percentage of carbon in aromatic rings increased, the proportion of noncondensed saturated rings diminished. This assumption appears t o be reasonable, if one considers the following:
Table XII.
Comparison of Refractivity Intercept-Density Method (Figures 3 and 5)with Martin Method”
Oil Type Paraffinic
Oil NO. 1
Properties of Oil 698 Mol. wt. 0.798 VGC Ri 1.0446 n
d
N o . carbon
2
atoms Mol. wt. VGC R%n
Ri-d Martin
352 0.818 1.0440 1 ,4748 0.8615 25.0
Ri-d Martin
347 0.846 1.0407 1.4847 0.8879 24.9
Ri-d Martin
464 0.842 1.0419 1.4971 0.9105 33.4
Ri-d Martin
Ri-d Martin
d No. carbon
399 0.883 1.0491 1,5210 0,9439 28.9
Ri-d Martin
n d No. carbon
418 0.879 1.0530 1.5180 0.9300 30.3
N o . carbon
atoms Mol. wt. VGC Ri n d
Relatively paraffinic
4
S o . carbon atoms Mol. wt. VGC Ri
n
d
5
No. carbon atoms Mol. wt. VGC Ri n
1. I n petroleum oils containing two or more aromatic and naphthene rings the aromatic rings are condensed together (11, 21, 23) and it is likely that one or more of the naphthene rings are condensed to the polyaromatic structure. Thus, for molecules containing aromatic nuclei, the probability of the occurrence of noncondensed cycloparaffin rings is considerably reduced. 2. I n viscous oils of petroleum origin, as the percentage of carbon in aromatic structures increases, the contribution from noncondensed structures in saturated molecules decreases, simply because the proportion of totally saturated molecules in the oil becomes less.
d
Naphthenic
6
of
Sac
aromatic fraction of
7
Sf
8
To find the maximum effect possible for noncondensed naphthene rings, the densities for the 30-carbon atom structures containing up to three aromatic rings were calculated, assuming condensed aromatic rings and completely noncondensed cylcoparaffin rings. The dotted line corresponding to the solid line for three aromatic rings in Figure 1 illustrates the maximum effect of this calculation. Interpolation between 0 and 100% condensed cycloparaffins was carried out for the structures containing aromatic rings by arbitrarily assuming that the contribution from noncondensed rings decreased according to a geometrical progression as follows: 50% for no aromatic rings; 25% for one aromatic ring; 12.5% for two aromatic rings; and 6.25y0 for three aromatic rings. KO correction for noncondensed cycloparaffins was applied above three aromatic rings.
No. carbon atoms Mol. wt. VGC Ri n
Aromatic fraction
9
atoms Mol. wt. VGC Ri
atoms 366 Mol. wt. 0.900 VGC Ri 1.0536 1,5269 n 0.9465 d No. carbon 26.7 atoms 442 Mol. wt. VGC 0.842 R, 1.0532 n 1 5332 d
Aromatic fraction of S3c
10
No. carbon atoms Mol. wt. VGC R, n d
No. carbon
11
A
atoms Mol. wt. VGC Ri n d
% CP
% CA
% CN
0 2 -2
26 28 -2
+4
3 -1
32.5 33 -0.5
65.5 64 +1.5
2.5 3 -0.5
33.5 34 -0.5
64 63 +l
1.5 3 -1.5
48.5 47 +1.5
50 50 0
74
70
1.4865 0.8835 52.3
419 0.815 1,0441 1.4793 0.8704 29.9
d 3
Method Ri-d* Martin
A
A
A
A
A
A
Ri-d Martin A
Ri-d Martin A
2
4 5 -1
45 45
51 50
0
+I
19.5 16 +3.5
37.5 42 -4.5
43 42 +1
21.5 24 -2.5
27.5 22 +5.5
51 54 -3
25 24 +1
32 31 $1
43 45 -2
24 25 -1
32.5 30 $2.5
43.5 45 -1.5
25 27 -2
30 27 +3
45 46 -1
22.5 25 -2.5
39.5 30 $9.5
38 45 -7
0 9600 32.2
350 0.898 1.0547 1 5225 0.9355 25 4
Ri-d Martin
365 0.915 1.0501 1.5291 0.9580 26.6
Ri-d Martin
A
A
30. carbon atoms (Continued on page 1232)
VOL. 30, NO. 7, JULY 1958
1231
Table XII.
Comparison of Refractivity Intercept-Density Method (Figures 3 and 5) with Martin Method (Continued) Oil Oil Type KO. Properties of Oil Method % CA % CN % Cp Relatively aro12 1101. wt. 427 Rt-d 34.5 24.5 41 matic S’GC 0.927 Martin 33 26 41 $1.5 Ri 1.0631 A -1.5 0 n 1.5550 d
13
S o . carbon atoms Mol. wt. VGC Ri n d
14
0.9837 31.3
369 0.936 1.0665 1.5556 0.9738 27.1
S o . carbon atoms Mol. wt. 373 VGC 0.936 Ri 1.0639 n 1.5537 d 0.9797 KO.carbon 2 7 . 4 atoms (Continued on page
Rc-d Martin A
Ri-d Martin A
37.5 35 +2.5
22.5 26 -3.5
40 39 $1
35.5 33 $2.5
25.5 31 -5.5
39 36 $3
lI33)
This assumption is justified only by the fact that the correlation derived from the corrected data proved satisfactory. The curves corresponding to these interpolations are represented by the broken lines in Figure 1. A second triangular diagram for 30 carbon atoms was constructed using the corrected density data based on the broken lines in Figure 1. Figure 5 shows the graph obtained. The fact that the density lines now appeared as curves rather than straight lines raised the question as to whether interpolation for intermediate numbers of carbon atoms was still possible. A similar correction for noncondensation was applied to the data for both 15 and 40 carbon atoms. When transferred to triangular coordinates, the corrected data produced curves essentially congruent with those in Figure 5, indicating that Figure 3 could still be used satisfactorily for interpolation.
100 % AROMATIC RING CARBONS
CARBONS
CARBONS
Figure 6.
Composition of oils used in evaluating the refractivity intercept-density method 0 Direct method
X
n-d-M method
0 Martin method 1232
ANALYTICAL CHEMISTRY
Table V gives the data necessary for locating the revised density lines on the triangular diagram for 30 carbon atoms; Table VI, data for placing the refractivity intercept lines on the same diagram; Table VII, the basic intercept values from which Table VI was derived. Enlarged forms of Figure 4 and Figure 5 were used to obtain the carbon-type composition of 177 samples having greater than 3570 CN. Figure 3 was used to get corresponding densities a t 30 carbon atoms for oils having other than 30 carbon atoms. Table VI11 shows these data grouped on the basis of 10% increments of % Ca. It is clear that the use of Figure 5 does give a definite improvement in the determination of YoCNand YoCp for the more naphthenic samples. Actual plotting of the data shows another definite improvement. On Figure 4 many points for the 0% CAsamples fall below the saturated base line by an amount equivalent to -4 or -5% CA. With Figure 5 the 0% Ca samples are never more than 1 or 2% below the base line, which is in line with the expected accuracy for this type of chart. Therefore, we may conclude that the assumptions used in deriving Figure 5 are not far from the truth. Figure 6 shows the distribution of all 369 oil samples used in this study. The dotted triangle shows the area of relatively high naphthenic carbon content in which the revision was needed. This graph also indicates the type of analysis used as the basis of comparison. The adjustment that has gone into Figure 5 is the best that can be made with currently available information, As more and better data become available, it can perhaps be improved. As American Petroleum Institute Research Project 6 (1) has done outstanding work on the composition of petroleum, Figure 5 was used to get the carbon-type composition from physical property data for all the fractions for which API 6 has published enough data to permit a comparison (23). Table I X shows that reasonably good agreement is obtained between the present graphic analysis and the complete analysis of API 6, which includes hydrogenation (23). Van Xes and van Westen (28) have also published reliable data on the analysis of petroleum fractions by a complete hydrogenation procedure, referred t o as the “direct method.” Table X summarizes the agreement between the carbon-type analyses obtained with Figure 5 and the direct analyses of Mair and Rossini and of van Nes and van Westen. For the 83 oils studied, the standard deviations are: 7 0 CA 1.4y0, Yo CN 2.8Y0,70CP 2.570. As one carbon atom equals 5% in an oil with 20 carbon
Table XII.
Comparison of Refractivity Intercept-Density Method (Figures 3 and 5) with Martin Method (Confinued)
Oil Oil Type
Aromatic fraction of Af
So. 15
16
17
18
19
20
Properties of Oil 373 0.943 VGC Ri 1.0654 1.5649 n 0,9990 d Iio. carbon 27.4 atoms Mol. x t . 409 0.957 VGC Ri 1.0705 1,5767 n 1.0124 d N o . carbon 30.2 atoms 278 Mol. mt. VGC 0.985 Ri 1.0700 1.5725 n 1.0050 d S o . carbon 20.8 atoms Mol. n-t. 361 0.970 L-GC 1.0735 Ri 1.5804 n 1.0138 d KO.carbon 26.7 atome 272 Mol. mt. 0.982 VGC 1.0724 Ri 1.5737 n d 1.0026 Yo. carbon 20.3 atoms hlol. Tt. 310 0.977 VGC Ri n hlol. n t .
Jlethod Ri-d Martin A
Ri-d Martin A
Ri-d Martin A
Ri-d Martin A
Rt-d Martin A
% CA
CN 27.5 33 -5.5
% CP
42 42
22.5
0
+l.5
35.5 37 -1.5
0
30 31 -1
26 25 $1
44.5 46 -1.5
23 19 $4
32.5 35 -2.5
45.5 46 -0.5
28 30 -2
26.5 24 +2.5
27 23
38 35 $3
44 44
21
34.5 32 +2.5
Rt-d Martin
47 46
26 31
342 0.996 1.0883 1.5966 1.0166 25.6
R,-d Martin
53.5 50 +3.5
11 17 -6
35.5 33 +2.5
310 1.011 1.0788 1.5952 1.0338 23.3
R,-d Martin
0
24.5 27 -2.5
25.5 23 $2.5
Rt-d Martin
53 51 +2
22.5 29 -6.5
24.5 20 +4.5
?io. carbon
294 1.022 1.0837 1.6006 I.0337 21.8
3101. mt.
314
Rt-d Martin
21.5 23 -1.5
26.5 25
A
52 52 0
$1.5
280d
RS-d Martin
55 54
1 0865 1 6052 1 0375
A
21 5 27 -5 5
23 5 19 +4 5
d S o . carbon
21
atoms Mol. wt. VGC R, n
d S o . carbon
atoms
Very aromatic
22
hlol. wt.
VGC R, n
23
d S o . carbon atoms 1101. wt.
VGC R, n
d
atoms
24
VGC Ri n
d
25
S o . carbon atoms 1101. n t . VGC R, n d Xo. carbon
atoms
1.010
1.0825 1 5997 1 0343 23 6
A
A
A
50 50
+1
20 9
(Conlznued o n page 1834)
VOL. 30, NO. 7 , JULY 1958
1233
Table
XII.
Comparison of Refractivity Intercept-Density Method (Figures 5) with Martin Method (Continued)
Oil Type Extremely aromatic
Oil No. 26
27
Properties Mol. 'wt. VGC Ri n
of Oil 271 1.050 1.0972 1.6261 d 1.0579 KO.carbon 2 0 . 2
Method R,-d Martin
277 1.071 1,1122 1.6465 1.0685 21.3
R*-d Martin
270d
Rt-d Martin
1.1104 1.6421 1 ,0634 20.5
A
Rv-d Martin
n d No. carbon
251 1.084 1.1078 1.6464 1.0773 19.6
4101. wt.
26fjd
R,-d Martin
1 .'ii3i
A
n d
1 6639
atoms Mol. wt. VGC Ri n d
28
No. carbon atoms Mol. wt. VGC R. n d
29
No. carbon atoms Mol. wt. VGC R,
atoms
30
31
VGC R,
No. carbon atoms Mol. wt. VGC Ri n
33
A
KO.carbon
Rt-d Martin
d No, carbon
206 1.052 1.1166 1.6463 1.0535 16,O 260d
Rs-d Martin
1 .'i293 1.6786 1.0987 19.9
A
n d No. carbon
Rc-d Martin
d N o . carbon
215 1.081 1.1251 1.6632 1.0761 16.8
atoms Mol. wt. VGC Ri n atoms Mol. wt. VGC
atoms Mol. wt. VGC Ri n
% CA
% CN
% CP
62.5 61 $1.5
18.5 23 -4.5
19 16 +3
71 68 +3
6.5 10 -3.5
22.5 22 +0.5
70 69 +1
8.5 10 -1.5
21.5 21 $0.5
69.5 69 $0.5
16 18 -2
14.5 13 f1.5
74 72 +2
15 16 -1
11 12 -1
75 77 -2
3 0 $3
22 23 -1
76 79 -3
10 5 +5
14 16 -2
84 82 +2
0 0
16 18 -2
82
4.5 0 +4.5
1.1017 19.9
R,-d Martin
Ri
34
A
259 1.066 1.1177 1.6498 1.0642 19.9
d
32
...
A
3 and
A
A
A
83 -1
0
13.5 17 -3.5
atoms 14 Mol. wt. 220 R,-d 81 5 16 84 VGC 1 081 0 Martin -2 -3 R; 1.1239 A +5 n 1.6617 d 1.0756 No. carbon 1 7 . 2 atoms Dev. of av. for 35 oils. + 0 . 1 9 - 0 . 5 7 +O. 38 1.6 Av. dev. for 35 oils1 3.,. .2 2. A 1.9 4.v 2.0 Std. dev. for 35 oilsp .I11 data obtained by authors. Detailed analyses by Martin method (11). Ri-d = refractivity intercept-density method. Aromatic fraction of oil discussed by Weinstock, Storey, and Sweely (39). Ebulliosco ic molecular wt. Sum of d d r e n c e s observing sign, and dividing by number of data. Sum of differences ignoring sign, and dividing b number of data. Differences squared and summed. Sum dividedlby n - 1, and square root taken. 35
c
1234
ANALYTICAL CHEMISTRY
atoms, 4% in an oil with 25 carbon atoms, and 3.3% in an oil with 30 carbon atoms, the standard deviation corresponds to about l/* carbon atom or less. For these oils a change of 0.1 aromatic ring corresponds to about 2% CA. The standard deviation between the direct method and the densityrefractivity intercept method is acceptable for this type of analysis. The deviation of the average indicates little tendency for the data to deviate systematically. In applying this procedure routinely to lubricating oils and fractions thereof, there will be many occasions when carbon and hydrogen data are not readily available. Therefore the following equation was developed to permit calculation of the average number of carbon atoms per molecule from molecular weight and viscosity gravity constant (6, 7 ) . Number of C atoms = 0.0735 MW 7.00 (VGC)
+
- 6.55
(2)
Table X I shows that this equation is sufficiently accurate for converting from molecular weight to number of carbon atoms. As a further evaluation, carbon-type composition data were calculated for a group of petroleum fractions covering a wide range of molecular weight and composition. Several fractions contained over 80% aromatic ring carbons. These samples had been analyzed using the detailed procedure of Martin (11). Table XI1 compares the composition calculated using intercept and density to that determined by the more detailed analysis of Martin. The agreement is excellent, even for oils containing an extremely large proportion of carbons in aromatic ring structures. The use of Figure 3 to adjust the density data so that a single carbon number chart may be used appears to be sound, as these oils cover a range of from 16 to over 40 carbon atoms. Table XI11 presents a statistical summary of the differences between analyses obtained using the densityintercept method and other currently accepted methods for the 369 oils shown in Figure 6. This comparison includes the direct method data, analyses by the n-d-M method (28, 38), and analyses by the procedure of Martin (11). The statistical data have been arranged in groups according to the percentage of aromatic carbons, and pooled to give a summary for the entire 369 oils. The standard deviation between the densitv-interceDt method and the other curre& accepted methods is 1.4 for % ' CA, 2.6 for % CN, and 2.5 for yo Cp. These data give further confirmation of the method as applied to a large number of oil samples. Some obvious advantages of the method are that it utilizes data
that may be rather cheaply obtained. Furthermore, it is rapid and can be applied over a n extremely wide range of composition. Consideration of data on the highsulfur oils previously studied (9) indicates that the presence of sulfur has less effect on the accuracy of the density-intercept method than on the previously published viscosity-gravity constant-intercept method However, a gain in accuracy can be obtained b y using the following correction equations: Sulfur correction for yoCN = -wt 70 S/O 416 Sulfur correction for Cp = wt. % 8/0.478
+
The correctPd values for % CA can he obtained from the equation % C A = 100 - (7,CN Yo CF). I’sing these corrections. the data shown in Table XIV were obtained. The standard deviations between the best data available and the corrected values for % c 4 , % CH, % ‘ CP a r r 1.13, 1.85, and 1.73, respectively. The corresponding standard deviations before application of the corrcrtion were 1.09,
+
Table XIII.
“Constitution of Mineral Oil Fractions,” Special Publication, Technical University, Institute of Chemical Engineering, Delft, Holland, January 1956; BrennstoffChem. 37,404-8 (1956). Fenske, M. R., Ind. Eng. Chem. 34, 638 (1942). Hill, J. B., Coats, H. B., Ibid., 20, 641-4 (1928). Kurtz, S. S., Jr., “Chemistry of Petroleum Hydrocarbons,” Brooks, B. T., et al., eds., Chap. 11, Reinhold, New York, 1954. Zbid., pp. 294-8. Kurtz, S. S., Jr., King, R. W., Stout, W. J., Partikian, D. G., Skrabek, E. 8., ANAL. CHE?d. 28, 1928
3.42, and 3.28, respectively. The gain in accuracy for 70 CN and 70 CP is sufficient to justify use of the sulfur corrections. The validity of the density-refractivity intercept method for carbontype composition confirms the validity of the general equation for calculating the molecular volume and density of hydrocarbons, and particularly those of polycyclic structure. A comparison of the density-refractivity intercept method for determining carbon-type composition with several other methods will be published elsewhere (37). This study shows the sui& ability of the density-refractivity intercept method for all oils, and its particular advantage for extremely aromatic oils.
(,----,19.56).
Kurtz, S. S., Jr., Lipkin, M. R., Znd. Eng. Chem. 33, 779 (1941). Kurtz, S. S., Jr.. Martin, C. C.. India Rubber ’World 126. 495 119521. Kurtz, S. S., Jr., Sankin, A4.,Ind. Eng. Chem. 46, 2186 (1954). Kurtz, S. S., Jr., Sankin, A., “Physiral Chemistry of Hydrocarbons,” A. Farkas, ed., Chap. 1, Vol. 11, Academic Press, New York, 1953. Lipkin, A I . R., Hoffecker, W. A., Martin, C. C., Ledley, R. E., ANAL. CHEY.20, 130 (1948). Lipkin, M. R., Kurtz, S. S., Jr., Zbid., 13, 291 (1941). Lipkin, M. R., Martin, C. C., Worthing, R. C., Third World Petroleum Congress, pp. 68-79, Section VI, E. J. Brill, Leiden, Holland, 1951. Lipkin, M. R., Sankin, A., Martin, C. C., ANAL.CHEY.20, 598 (1948). Lumpkin, H. E., Ibid., 28, 1946 (1956). Mair, B. J., Eberly, P. E., Li, K., Rossini, F. S., Preprints, Division of Petroleum Chemistry, Symposium on Polycyclic Hydrocarbons, 130th Meeting. ACS, September 1956. Mair, B. J., Rossini, F. D., Znd. Eng. Chem. 48, 1062 (1955). Mair, B. J., Rosqi,ni, F. D., “Science of Petroleum, Vol. 5 , Pt. 1, B. T. Brooks and A. E. Dunstan, eds., Oxford Univ. Press, London, 1950.
LITERATURE CITED
(1) Am. Petroleum Inst., Research Projects 6 and 44, Carnegie Institute of Technology, Pittsburgh, Pa. (2) Zbid., Research Project 42, Pennsylvania State University, University Park, Pa. (3) Boelhouwer, C., Waterman, H. I., J. Znst. Petrol. 40, 116 (1954). (4) Cornelissen, J., Waterman, H. I.,
Deviation of Refractivity Intercept-Density Method from Accepted Values for All 369 Oils Studied“
Deviation of Average Standard Deviation 9; CA x o of Range Oils c/; (”(A % c N %cP %CA % c N %CP 0 - 9 9 +0.03 105 +0.01 -0.04 1.oo 2.81 2.81 -0 40 10 0- 19 9 i Fin $0.50 1.48 -0.10 1.83 1.56 -0,48 20 0--29.9 53 +o. 19 +O. 29 1.40 2.86 3.04 30 0- 39 9 26 +0 .os -2.13 +2.05 1.79 3.32 3.06 40 0- 49 9 -0.91 20 -1.21 +2.12 2.24 3.80 3.28 50 0- 59.9 -0.34 5 -2.84 $3.18 4.67 2.42 3.90 0 60 0-100 0 10 +O. 55 -0.55 2.40 3.73 2.33 All -0.27 -0.25 369 $0.52 1.45 2.61 2.45 ,. In addition to data obtained by authors, data were obtained from (9,6, 88, 18).
Table XIV.
so. c Atoms 28 3 31 5 22 0 29 3 28 7 28 0 24.6 25 6 30 5 30 7 24 I 26 7 32 2 23 6 31 3 34.1 31.5
Ikntlity
0.9441 0.9196 0.9255 0,9264 0,9183
n ,9066 0,8914 0.9055 0 9126 0.9040
1.0061 1,0138
0,9600
1.0343 0.8982
0,9689 0.8933
Application of Figure 5 with Sulfur Correction to Some Oils of High Sulfur Content ( 9 )
Refrac7tivitl Intercept 1 0548 1 0550 1 0515 1 0498 I 0544 1 0534 1 0522 1 0505 1 0468 1 0452 1 0iOc) 1 0735 1 0532 1 0825 1 0441 1 062c) I 0434
%
Sulfur 2.05 1.73 1.70 1.67 1.62 1.51 1.50 1.50 1.35 1.12 1.08 1.03 1.01 0.92 0.89
0.82 0.70
~ % c A
25.0 22.0 22.0 18 0 19 0 20 0
18.0
17.0
12.5 10.0 43.4 46.0 25.0 52.0 7.5 36.7 5.5
Best Analysis _ _ _ %CN 24.0 16 0 31 0 29 0 24 0 ~
18 0
19.0 26.0 32.0 33.5 27.1 19.0 30.0 23.0 35.0 29.2 36.0
%cP st .n
62
6
47 0 53 0 57 0 62 0 63.0 57.0 55.5 56.5 29.5 35.0 45.0 25.0 57.5
34.1
58.5 Dev. of av. Std. dev.
Dev. of av. Std. dev.
Corrected R,,-Density Method us. Best Analysis % CA % CH % CP +o 6 -0.2 -0.4 +0.6 $0.8 -1.4 +1 .o -0.1 -0.9 +0.5 -0.5 0.0 +3.5 -3.9 $0.4 $0.4 +1.4 -1.8 +0.5 $0.6 +1.1 +1 .o -0.1 -0.9 +0.4 -n.7 +0.3 -0.6 +0.3 Jr0.3 -0.1 -4.7 $4.8 -1.2 +1.0 +n.2 -0.2 +1.1 -0.9 -0.7 -2.2 +2.9 -1.3 $0.9 +0.4 -0.4 -2.2 +2.6 -0.8
+0.8
$0.07 1.13
-0.48 1.85
0.0
f0.41 1.73
Before Application of Snlfur Correction -0.30 +2.66 -2.36 1.09 3.42 3.28
VOL. 30,
NO. 7,
JULY 1958
1235
(22) Mair, B. J., Schicktanz, S. T., Znd. Eng. Chem. 28, 1446 (1936). (23) Mair, B. J., Willingham, C. B., Streiff, A. J., J. Research Natl. Bur. Standards 21, 581 (1938). (24) Martin, C. C., Sankin, -4., ANAL. CHEY.25, 206 (1953). (25) Melpolder, F. W., Brown, R. A.,
Washall, T. A., Doherty, W., Headington, C. E., Ibid., 28, 1936
(1956). (26) Miron, S., Zbid., 27, 1917 (1955). (27) Nes, K. van, “Chemist;ry of Petroleum Hydrocarbons, Chap. 16, Vol. 1, Reinhold, Nen- York, 1954. (28) Nes, K. van, Westen, H. A. van, “Aspects of the Constitution of Mineral Oils,” Elsevier, New York, 1951.
(29) OTeiIl, J., “Applied Mass Spectrometry,” pp. 27-46, Report of Conference, Institute of Petroleum, London, 1954.
(30) Rossini, F. D., Mair, B. J., Streiff, A. J.,,,“Hydrocarbons from Petroleum, Reinhold, New York, 1954. (31) Rossini, F. D., Pitzer, K. S., Arnett,
R. L., Braun, R. M., Pimental, G. C., “Selected Values of Physical and Thermodynamic Properties of Hydrocarbons,” Carnegie Press, Pittsburgh, 1953. (32) Schiessler, R. W., Clarke, D. G., Rowland, C. S., Slatman, W. S., Herr, C. H., Proc. Am. Petrol. Inst. 24 (111), 73 (1943). (33) Schiessler, R. W., Herr, C. H., Rytina, A. W., Weisel, C. A., Fischl, F., McLaughlin, R. L., Keuhner. H. H.. Zbid.., 26., (111) \ I
254 (1946).
(34) . , Schiessler. R. W.. Whitmore. F. C.. Znd. Eng. Chem. 47, 1660 (i955). ’ (35) . . Simha, R., Hadden, S. T., J . Chem. Phyk 25, 702 (1956). ‘ (36) Smith, E. E., Eng. Expt. Station,
Ohio State University, Columbus, Ohio, Bull. 152, 1953. Stout, W. J., King, R. W., Peterkin, M. E., Kurtz, S.S., Jr., Am. SOC. Testing Materials, Spec. Tech. Publ. 224, in press. Tadema, H. J., in “Aspects of the Constitution of Mineral Oils,” by van Nes and van Westen, pp. 250, 317, 318, Elsevier. New York. (39) Weinstock, K. V., Storey E. B., Sweely, J. S., Znd. Eng. &hem. 45, 1035 (1953). RECEIVEDfor review June 18, 1957. hccepted March 13, 1958. Division of
Petroleum Chemistry, Symposium on Polynuclear Hydrocarbons, 130th Meeting, ACS, Atlantic City, N. J., September 1956. Complete tables of API42 data may be purchased from the American Documentation Institute, Library of Congress, lT7ashington, D. C., as AD1 4597.
Portable, Automatic Alarm for Detection of Toxic Agents in Atmosphere J. C. YOUNG Chemical Warfare laboratories, Army Chemical Center,
Md.
J. R. PARSONS and H. E. REEBER Radio Corp. o f America, Camden, N. J. ,Because the G series o f chemical w a r f a r e gases (nerve gases) give no sensory warning o f their presence, an automatic alarm was developed which will give warning of sublethal dosages o f these agents. The alarm i s portable, weighs about 25 pounds, will operate automatically f o r 12 hours, will detect 0.02 p.p.m. of GB (isop r o p y l methyl phosphonofluoridate) within 2 minutes, and will alarm t o concentrations above 2 p.p.m. in 5 seconds. It i s believed that this instrument has b r o a d industrial a p p l i cation, in that any single phase colorimetric test for atmospheric polutants can b e a d a p t e d t o the unit.
A
of World War 11, the Germans were found to possess chemical warfare agents which offered no sensory means of detection. These gases, the G-agents or nerve gases, are far more toxic than a n y other known war agent. I n 1953 the Chemical Corps established a project for the development of a portable automatic alarm which would detect sublethal dosages of G-agents in the field. Because this unit was designed for operation by troops in combat, very stringent military requirements were established to govern the final design. The alarm developed will operate T THE CLOSE
1236
ANALYTICAL CHEMISTRY
Table I. Alarm Reliability
Agent Concn. (GB), P.P.M. 0.01 0.02 0.10
2.00 5.00 100 a
KO.of Tests 50 200 50 50 20 5
% response
4v. Alarm Time 5 min. 2 min. 1 min. 5 sec. 5 sec. 5 see.
Response,“
%
58 98 100 100 100 100
=
No. of times alarm occurred in av. alarm time X 100 No. of tests
without attention for 12 hours. It will detect concentrations of GB (isopropyl methyl phosphonofluoridate) as low as 0.02 p.p.m. within 2 minutes and will alarm to higher concentrations (2 p.p.m.) in 5 seconds (see Table I). The unit (Figures 1 and 2) is 17 inches high, l Y / 4 inches wide, fi3/4 inches deep, and weighs 24 pounds complete. It operates from the standard 24volt direct current source used for Army vehicle operation or, because the alarm requires only 19-matt power for operation, it can be operated from a portable power supply. The alarm should have broad application to industrial air pollution problems. Because the detecting system
consists of a chemical solution and plain a-cellulose paper tape, numerous other chemical systems may be substituted for the reagents now used to detect G-agents-e.g., Patty-Petty reagent F a s used in the alarm and concentrations as low as 2.5 p.p.m. of nitrogen dioxide were easily detectable. Using benzidine-type compounds, as little as 1.5 p.p.m. of chlorine was detected. Using other oxidizable amines, as little as 0.02 p.p.m. of ozone was easily detected. It is believed that other simple tests for compounds such as hydrogen sulfide, sulfur dioxide, ammonia, hydrochloric acid and sulfuric acid may be developed. The absorption wave length or color of the compound formed for the detection medium is not critical because the unit does not contain optical filters. The alarm mechanism depends on the amount of total reflected light reduction caused by the colored compound and not of any specific wave length absorption. OVER-ALL OPERATION
The alarm is based upon the red color formed when any G-agent comes into contact with a combined solution of dianisidine (3,3’-dimethoxybenzidine) and sodium pyrophosphate peroxide. An air pump in the alarm samples outside air through a paper prefilter,
