PETROLEUM SOLVENTS Correlation of Kauri Butanol Solvency with Gravity and Aniline Point W. T. HARVEY
AND
I. W. MILLS, Sun Oil Company, Marcus Hook, P a .
A correlation has been developed which relates the A.P.I. gravity, 50% boiling point, and aniline point with kauri butanol solvency values. This relation is expressed mathematically by two equations, one applying to solvents below 50 kauri, the other applying to higher solvency materials.
T
HE kauri butanol solvency test, originally developed by Kiehl (4)and later officially adopted by the Paint and Varnish Superintendents Club of the Philadelphia District ( 6 ) , has been widely used by the industry as an aid in evaluating the solvency power of hydrocarbon mixtures for different applications. Various modifications for standardization of this test procedure have been proposed by other investigators (1, I,S ) , but as yet the procedure has not been officially standardized as a uniform test procedure for all laboratories. Since the kauri butanol solvency test is rather tedious to perform and requires precise laboratory technique, a correlation is desirable t o predict th? kauri butanol solvency values of petroleum spirits from other easily determined, standardized physical tests. McArdle and Baldeschwieler (6) indicated that kauri butanol values can be correlated nith A.P.I. gravity, mixed aniline point, and other properties, but did not completely develop or evaluate these relations. The purpose of this paper is to show that kauri butanof solvency can be predicted accurately from physical properties. The correlation which was developed, as shown in Figure l , relates the -4.P.I. gravity test (.4.S.T.X D278-39) and aniline point test (A.S.T.M. D61146T) n-ith kauri solvency values as determined in this laboratory. The procedure is based on samples having mid-boiling points varying not more than 10" F. (5.5" C.) from340'F. (171.1' C.). The relation expressed in the graph is represented bv the following equation: K =
123.5 - G - 0.22(A) 1.24
G = A.P.I. gJavity at 60" F./60° F., and -4 = aniline point, F. Deviations were encountered in applying this relation to sapples having mid-boiling points (A.S.T.N. D86-46) substantially different from 340' F. The deviation appeared to be proportional to the difference in mid-boiling point. For this reason boiling point correction terms were incorporated into the original equation t o extend its range of application. The improved equation is as follows: K = 99.6 - 0.806G - 0.177d 0.0755 (340 - B ) (2) where K = kauri butanol solvency G = .4.P.I. gravity at 60" F./60" F., A = aniline point, F., and B = mid-boiling point, ' F.
+
Table I. Accuracy of Correlation for Solvents Having' Mid-boiling Points of 340" =t10" F. and Kauri Values Less Than 50
Sample 1
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
(1)
where K = kauri butanol solvency
3500
110
120
130
140
150
160
ANILINE. POINT "F. Figure 1. Correlation of Gravity, Aniline Point, and Kauri Butanol Solvency for Petroleum Solvents of 330° to 350' F. Mid-boiling Point
a
207
A.P.I. Initial,, Gr.160 O F.
50% Boiling E n d Aniline Point, Point, Point, F. O F. O F. 342 157.1 345 150.3 335 148.5 149 . O 339 345 152.6 347 140.4 346 130.9 348 138.2 338 136.8 340 136.8 349 138.0 341 153.3 344 135.3 335 136.3 336 134.6 132.5 338 129.6 336 338 130.1 131.2 340 342 128.7 341 131.5 336 128.1 126.7 333 844 127.2 133.0 347 125.0 338 129.5 338 336 125.9 333 131.9 123.0 345 335 123.4 340 118.4 121.3 342 336 115.7 333 115.0 336 120.0 105.1 331 338 113.5 342 119.0 337 120.9 340 120.9 333 105.0 341 113.2 33 1 120.0 106.7 333 109.6 333 119.6 342 112.1 346 114.2 345 99.5 340 99.0 341 102.0 336 102.2 333
Calculated by Equation 2.
Kauri Butanol Solvency, M1. Deter- Calcu- Dev., mined lateda ml. 30.4 29.1 -1.3 30.4 29.4 -1.0 -0.6 30.5 29.9 -0.7 30.5 29.8 31.7 30.7 -1.0 33.8 34.7 +0.9 f1.4 34.4 35.8 -0.2 35.1 34.9 35.4 35.6 +0.2 35.7 35.9 +0.2 -0.5 35.9 35.4 -2.9 36.0 33.1 36.2 36.4 +0.2 36.3 36.5 +0.2 36.5 36.9 +0.4 37.0 37.3 +0.3 37.0 38.0 +1.0 37.0 37.7 +0.7 37.2 37.5 +0.3 37.5 38.6 +1.1 38.0 37.7 -0.3 38.1 38.6 +0.5 38.2 39.6 +1.4 38.2 38.5 +0.3 38.4 37.6 -0.8 38.5 39.3 +0.8 -0.2 38.6 38.4 38.7 38.9 $0.2 -0.4 38.8 38.4 39.2 40.1 $0.9 40.0 40.0 0.0 40.8 41.6 +0.8 41.8 41.9 +0.1 42.0 42.2 -0.2 42.1 42.6 $0.5 42.2 43.2 $1 .o 43.0 44.6 +1.6 43.1 43.2 +0.1 43.4 43.7 f0.3 43.7 43.7 0.0 43.9 44.0 +O.l 44.0 44.4 +0.4 44.1 44.1 0.0 44.2 44.8 +0.6 44.3 44.7 +0.4 44.4 44.3 -0.1 45.0 48.1 +0.1 45.1 45.1 0.0 -0.4 46.0 45.6 +0.3 46.4 46.7 +0.4 46.4 46.8 46.9 47.1 +0.2 -0.2 47.5 47.3 Av. deviation 0.55 Deviation of av. t0.14
ANALYTICAL CHEMISTRY
208 Table 11. Accuracy of Correlation for Solvents Having Mid-boiling Point above or below 340 * 10' F. and Kauri Values Less Than 50
A.P.I. Saniple Gr./6O 1 52.5 48.8 2 48.7 3 42.6 4 5 58.8 66.2 6 7 46.0 56.1 8 56.3 9 47.9 10 56.6 11 37.2 12
Initial 50% Boiling Boiling E n d Point, Point, Point, F. O F. F. 370 353 353 408 244 193 359 254 241 324 210 362
Aniline Point, O
F.
152.9 140.2 140,9 140.7 130.8 125.2 130.1 127.8 120.2 118.2 109.4 124.3
Kauri Butanol Solvency, Ml. DeviDeter- Calcu- ation, mined lateda ml. -1.4 29.5 28.1 $0.1 34.4 34.5 -0.3 34.7 34.4 -0.2 35.4 35.2 +0.1 36.2 36.3 -2.2 37.4 35.2 37.7 d-0.4 38.1 37.9 +0.4 38.3 40.4 0.0 40.4 42.1 41.3 -0.8 43.6 44.4 f0.8 45.3 46.0 +0.7 Av. deviation 0.6 Deviation of av. -0.2
Calculated by Equation 2.
Equation 2 has been applied t o a variety of samples to establish its accuracy. Table I shows the accuracy for 53 commercial spirits ranging from approximately 30 t o 50 kauri value and having mid-boiling points of 340' =t10' F. The average deviation for these samples is 0.55 ml., and the deviation of the average is +0.14 ml. Six of this number show deviations greater than one unit, and one sample has a deviation greater than 2.0 ml. of kauri. Table I1 shows the accuracy of this correlation for commercial solvents having mid-boiling points which differ from 340" F. by more than 10' F. For this group of samples the average deviation is 0.6 ml., and the deviation of the average -0.2 ml. Two of these samples show deviations greater than 1.0 unit of kauri butanol. The accuracy of this correlation for a group of miscellaneous samples is shown in Table 111. The data given in this table were not obtained in the authors' laboratories, or necessarily by their procedure for kauri solvency. They represent data presented in sales pamphlets and similar literature, and in some cases they may represent product specifications rather than data on individual samples. For such data, as would be expected, the accuracy of the correlation is not so good as shown in Tables I and 11. The average deviation for these data is 1.2 ml. and the deviation of the average is $0.27 mi. Twenty of the thirty-six samples show deviations greater than 1.0 ml.; nine have deviations greater than 2.0. The data presented show the accuracy of the correlation is satisfactory for kauri butanol values up to 50. However, in applying this correlation t o samples above this range, abnormal deviations were encountered which increased with increasing kauri butanol value. This indicates a change in the relationship involved and necessitated the development of a new equation, involving the same properties, to be applied in the range above 50. This modified equation is as follows:
K
117.7 - 1.06G
- 0.2498
+ 0.10 (340 - B )
(3)
Data presented in Table IV sho-x the deviations encountered using Equations 2 and 3 for samples having kauri values above 50. Whereas Equation 2 gives almost entirely negative deviations, in some cases as high as 7.0 units, Equation 3 gives random deviations with a maximum of about 2.0 units. The equation is limited to approximately 75 kauri butanol value, since the freezing point of aniline occurs in this solvency range. It may be possible to develop a correlation for higher kauri butanol solvency materials by replacing straight aniline points with mixed aniline point determination. There may be other complicating factors in this range, however, since solvents are encountered that are completely miscible with the kauri butanol solution, indicating infinite solvency. As an example, a solvent
rich in polycyclic aromatics was blended with a solvent having a low kauri butanol value. It was found that the kauri butanol values followed a linear relationship up to 80 (75% of the higher solvency component). Above this concentration, a sharp break in the curve occurred and the kauri values approached 100% concentration as an asymptote. I t will be extremely difficult for a correlation to predict such behavior as this. It is recommended that Equation 2 be used for all samples having calculated kauri values below 50 and that Equation 3 be used for samples above 50 kauri and up to the freezing point of aniline. KAURI BUTANOL SOLVENCY TEST PROCEDURE
Apparatus. A 250-ml. extraction flask (similar to ART 4955). A 50-ml. buret. An analytical balance. A suitable water bath. A clear glasR jar, 11.4 cm. in diameter and 7.6 cm. deep, half filled with distilled water, is convenient. Reagents. Kauri Butanol Solution. Weigh 400 grams of clean, powdered No, 1 kauri gum into a 3-liter flask, and add with considerable agitation 2000 grams of n-butyl alcohol,
Table 111. Accuracy of Correlation on Miscellaneous Data ' Having Kauri Values Less Than 50"
1
A.P.I. Gr./6O 43.0 51.0 48.5 71.6 46.4 49.0 07.8 55.0 70 5 58.4 48.9 53.5 70.0 43 0 62.9 56.9 55.5 54.9 57.9 59.7 56.4 58.0 69.0 00.5 47.5 46.5 50.4 59.4 54.0 55.4 60.5 59.0 55.9 56.2 50.3 38.0
Entimated 50% B.P.,
~ ~ i Point,
, l Kauri i ~ Butanol ~ Solvency, MI.
CalouGiven lstedb 445 29.5 158.0 28.3 348 154.0 30.0 30.6 2 355 31.8 143.6 34.0 3 184 31.8 4 138.0 29.2 390 32.0 147.0 32.4 5 352 140.0 , 3 2 . 2 34.4 6 192 137.3 32.3 7 31.8 290 141.8 32.6 34.0 8 170 129.0 32.7 32.8 9 247 135.5 33.5 35.6 10 358 139 .O 33.5 11 34.2 306 141.8 33.9 34.0 12 166 124.4 34.0 34.3 13 425 142.0 34.5 33.4 14 139.3 34.6 31.9 239 15 152.6 260 34.9 32.8 16 2 50 34.9 138.0 37.2 17 134.0 253 35.2 38.2 18 121.0 245 35.2 38.7 19 126.5 233 35.8 37.2 20 133.0 270 36.9 35.9 21 261 37.0 36.0 129.0 22 126.0 165 37.0 34.9 23 37.1 122.9 230 37.4 24 349 37.5 36.7 135.0 25 363 37.8 37.6 129.0 26 122.9 311 3 8 . 0 39.4 27 120.0 225 38.5 39.2 28 122.0 265 39.0 40.2 29 256 40.0 40.3 118.4 30 207 1 1 3 . 0 4 1 . 5 40.9 31 218 112.1 42.8 41.4 32 43.0 221 106.0 44.8 33 211 45.0 109.0 44.8 34 258 49.0 49.0 92.0 35 98.3 360 50.0 50.1 36 Av. deviation Deviation of av. a Taken from sales pamphlets and other similar literature. b Calculated by Equation 2.
Sample
a
F.
Deviation,
F.
ml.
-1.2 $0.6
+2.2 -1.4 +0.4 12.2 -0.5 +1.4 +0.1 +2.1 +0.7 +0.1 +0.3 -1.1
-2.7
-2.1
c2.3 +3.0 +3.5 +1.4 -1.0 -1.0 -2.1 +0.3 -0.8 -0.2 f1.4 +0.7 +1.2 +0.3 -0.6 -1.4
+1.8 -0.2 0.0 f0.1 1.2 + O , 27
Table IV. Accuracy of Correlation for Solvents Having Kauri Values above 50 Kniiri Riitnnol Solvencv. ..__.. " , MI. Aniline Equation 2 Equation 3 4 . P . I . Gr. B . P , Point, Experi- Calcu- Devia- Calcu- DeviaSamule 60/60 ' F. O F. mental lated tion lated tion 41.4 49.3 49.6 t 0 . 3 p0.2 $ 0 . 1 342 94.6 51.5 03.3 -2.1 49.7 55,4 -3.9 80.6 256 2 51.5 52.0 + 0 . 5 53.4 + 1 . 9 41.7 83.4 333 3 5 3 . 4 +1.0 52.4 52.6 +0.2 39.9 341 88.2 4 5 2 . 2 -3.4 5 3 . 8 -1.8 33.7 55.6 81.3 420 5 55.7 53.3 - 2 . 4 55.7 0.0 50.0 77.9 236 6 59.6 5 5 . 9 -3.7 59.1 -0.5 31.9 423 66.2 7 57.5 -2.5 61.5 f 1 . 5 46.8 58.6 60.0 260 8 59.4 67.2 64.0 f 0 . 5 -4.1 63.5 47.2 235 9 5 9 . 4 -6.0 63.9 -1.5 30.0 52.5 65.4 429 10 6 9 . 1 +0.1 44.3 6 3 . 4 -5.6 69 .O 263 35.6 11 65.8 72.7 -6.9 0.0 44.4 34.9 72.7 232 12 33.0 68.4 76.3 +1.3 76.0 -6.6 355 20.0 13 28.0 20.0 76.5 +1.5 75.0 14 68.6 -6.4 405 Av. deviation 3.8 1.0 Deviation of av, -3.6 +0.2 ~~~~
70
~~
~
V O L U M E 2 0 , NO. 3, M A R C H 1 9 4 8 water-free (refined grade, boiling point 117" C.), Fit the flask with a reflux condenser and heat on a steam bath until the kauri is all dissolved. The solution may then be clarified by filtering through a Buchner funnel with the aid of suction. Adjust the filtrate, using a blend of 2870 C.P. toluene and 72% n-heptane, so that a titration of 41.4 ml. is obtained with the toluene-heptane blend. Procedure. meigh 20 * 0.1 grams of the kauri butanol solution into the 250-ml. flask, and from the buret make small additions of sample with constant agitation of the flask. hlaintain the temperature of the kauri butanol solution and sample in the flask a t 77" F. (25" C.) * 2 " F. by means of the water bath. Take the end point as the point a t which a sufficient cloud has developed in the mixture in the flask to obscure the sharp outlines of IO-point print which has been placed directly beneath the water bath and observed through the liquid. Correct number of milliliters of sample added to the standard temperature of the test by means of the following equation: M1. correction = 0.0005 X ml. titration X (77" F. - temperature of sample)
209
Report the corrected number of milliliters added as the kauri butanol solvency. Accuracy. Duplicate determinations should agree within 0.5 ml. LITERATURE CITED
Baldeschwieler, E. L., Morgan, M. D., and Troeller, W. J., IND. ENQ.CHEM.,ANAL.ED.,9,540(1937). Baldeschwieler, E. L., Troeller, W. J., and Morgan, M. D., Ibid., 7,374(1935).
Beard, L. C., Shipp, V. L., and Spelhouse, W. E., Ibid., 5, 307 (1933).
Kiehl, S. R.,Sci. Section, Am. Paint and Varnish Manufacturers' Association, Circ. 319,585-98 (1927). McArdle, E. H., and Baldeschwieler, E. L., ISD. ENG.CHEM., ANAL.ED.,13,301(1941). Stewart, J. R., Sci. Section, Am. Paint and Varnish Manufacturers' Association, Circ.378, 143-53 (1931;. RECEIVED August 4, 1947.
Determination of Ethylacetylene and Vinylacetylene in C4 Hydrocarbon Gases PAUL R. THOMAS, LEON D O"', AND HARRY C. BECKER The Texas Company, Beacon, N . Y . A method is described for the determination of ethylacetylene and vinylacetylene in an over-all C, hydrocarbon fraction. Total acetylenes are determined from the acidity produced upon treatment of a sample with 2.5% silver nitrate solution. Catalytic hydrogenation is used to differentiate between ethylacetylene and vinylacetylene after corrections have been made for the hydrogen consumed by the olefins and 1,3-butadiene. Olefins plus 1,3-butadiene are determined by bromine addition and 1,3butadiene by the use of maleic anhydride. Ethyl-
D
URING recent years many processes involving the catalytic
treatment of hydrocarbon fractions have been studied, and these processes have resulted in the formation of some rather complex mixtures. It became necessary t o determine the amount of individual acetylenes in the CChydrocarbon fraction of such a mixture, and the simple methods of low-temperature fractional distillation and catalytic hydrogenation (4) were incapable of giving sufficient analytical data. Such a fraction, boiling between -17" and +14" C., could contain ethylacetylene (1butyne), vinylacetylene (l-buten-&yne), and diacetylene (1,3butadiyne) as well as n- and isobutane, isobutene, the 2-butenes, 1-butene, 1,3-butadiene, and 1,a-butadiene. A number of methods have been developed for the determination of acetylene (ethyne). Most of them depend on the formation of a metal acetylide or a complex involving a metal acetylide. However, relatively few of these methods have been applied to the determination of higher acetylenes. Peregud (7) used oxidation with iodine pentoxide, absorption in an alkaline solution of mercurous cyanide, and absorption in 80% sulfuric acid as a means for determining acetylene, vinylacetylene, and divinylacetylene in mixtures. S o method is described for the determination of individual C, a-acetylenes in a mixture. The most widely used acetylene methods employ Chavastelon's procedure ( d ) in which acetylene reacts with silver nitrate to form silver acetylide and liberates 2 moles of nitric acid for each mole of acetylene. The liberated acid is then titrated as a measure of 1
Present address. Jefferson Chemioal Co., New York, N. Y.
acetylene and vinylacetylene are determined with an average deviation of 0.8q0 on the basis of the total sample over a concentration range from 1 to 100%. Methylamine and methylmercaptan (methane thiol) interfere and, if present, must be remmed before the determination is made. 1,2-Butadiene also interferes, but no chemical method is available for its determination. The percentage of vinylacetylene will be increased and consequently the ethylacetylene will be decreased by the amount of 1,2-butadiene that is present.
the acetylene content. Ross and Trumbull (10) modified the method somewhat and obtained excellent results on synthetic acetylene-ethylene mixtures. Hillyer and Webber (3) applied the same reaction t o the determination of total acetylenes in C4 hydrocarbons. This method is limited to a-acetylenes and will give one mole of nitric acid for each mole of monosubstituted acetylene. I n working out a method for determining the individual acetylenes in a C, fraction (-17' t o $14" C.), it was found that only ethylacetylene and vinylacetylene need be considered. Diacetylene was found, through numerous attempts to prepare it, to be extremely unstable. This instability was so great that there appeared t o be little likelihood of its ever being present in a sample, so it was given no further consideration in the development of the method. The other C4 acetylene, 2-butyne, boils at 27" and so is not included in the C, fraction. This left only the vinylacetylene, which is also unstable, and ethylacetylene t o be determined in the admixture with saturates, olefins, and diolefins. If the total acetylene content, the total unsaturation, the diene content, and the mono-olefin content of the sample could be determined, sufficient data would be available for calculating the amount of ethyl- acd vinylacetylene by the difference in their unsaturation. The method finally developed is a systematic procedure in which acetylenes are determined individually over a range of 1 to 1007, in admixture with olefins and l,3-butadiene. Total acetylenes are determined by a modification of the Hillyer and
