ANALYTICAL EDITION
February, 1944
The balls may readily be observed by placing a shielded fluorescent light behind the vertical tube holder. More than one ball should be timed to assure an accurate test. The temperature of the viscosity solution is measured t o the nearest 0.1' C. immediately after determining the falling ball time. It is very important that the temperature of the room be relatively stable so that the temperature of the solution does not change during the time of dropping the balls and measuring the temperature. The viscosity of the solution is determined by the following equation:
+
+
tube constant log seconds fall (5"-25' C.)(0.01866) = log viscosity at 23" C. The temperature correction is added above 25' C. and trncted below 25" C.
siib
CONCLUSIONS
The author and his assistants developed this method for use in controlling the preparation of pulp to meet viscosity specifications of the Picatinny Arsenal, These specifications follow the tentative standard A.C.S. method, except that viscosity is expressed in seconds of fall of the standard glass sphere through 20 instead of 15 cm., and for pulp to be used in the manufacture of smokeless powder, the time of fall of the standard glass sphere through 20 cm., instead of centipoises, is used to express viscosity.
107
Figure 1shows the relationship between parallel determinations made by the tentative standard A.C.S. method using a 2.5% cellulose concentration and the cupriethylene diamine modification using a 1% cellulose Concentration. Figure 2 shows the relationship b e b e e n parallel tests made according to Picatinny Arsenal specifications and the cupriethylene diamine method using a 1% cellulose concentration. For very high viscosity it is advisable to use concentrations under lyo,and for very low viscosity to use concentrations above 1%. In order to express the viscosities in terms of 1 % concentration, when concentrations above or below 1% are used, it is necessary to determine the mathematical relationship between concentration and viscosity. So far no universal mathematical relationship has been found which may be used to convert viscosities a t concentrations above and below 1% to the viscosity a t 1% concentration. LITERATURE CITED
(1) Hatch, R.S., Pacific Pulp & Paper Id., p., 13 (Oot., 1942). ( 3 ) Strauss, F. L.,and Levy. R. M., Paper Trade J.. 114, No. 3,
3 1 4 (Jan. 15, 1942). PRESENTED before the Division of Cellulose Chemistry at the 106th Meeting of the AMERICANCHEMICAL SOCIETY. Pittsburgh, Pa.
Furfural Solution Temperatures of Hydrocarbons Evaluation of M i x e d Aniline Point Determination and Application of Furfural H A R R Y T. RICE A N D E U G E N E LIEBER Standard Oil Company of N e w Jersey, Bayonne, The application of furfural for the determination of miscibility solution temperatures of petroleum fractions and the influence of the composition of the 60' diluent on the results of the mixed aniline point test have been studied. Furfural offers considerable promise; it i s nontoxic and is directly applicable to petroleum fractions of high aromatic content, making possible elimination of mixed aniline point determination.
T
HE solvency characteristics of various petroleum fractions of the type of solvent oil, solvent naphtha, Diesel fuels, various gas oils, etc., constitute an important index as to the properties such products will display in use. The determination of these characteristics has been an important task of the petroleum technologist, and various methods have been devised for their evaluation. Of these methods, those based upon the miscibility solution temperature of the oil and a solvent liquid are among the most important. The "miscibility solution temperature" is defined as the minimum equilibrium solution temperature for equal volumes of petroleum product and solvent liquid. Since the different classes of hydrocarbons display different solubilities in various solvents, it is possible to obtain an indication of the nature of a n oil from its miscibility solution temperature. Of the various types of solvents proposed for this determination aniline ( 2 ) has been the most widely used (6). Nitrobenzene ( 7 ) , benzyl alcohol ( 3 ) ,ethyl alcohol (C), mixtures of acetone and amyl acetate ( I C ) , and nitromethane (8) have also been suggested as solvents for this test. Aniline appears to have been accepted as the standard solvent in determining miscibility solution temperatures of petroleum fractions; however, it has a number of defects which make it desirable to find a more widely acceptable substitute. Aniline is a blood poison and its fumes are readily absorbed. JThile indi-
N. 1.
vidual response d s e r s , its high toxicity is generally admitted. Further, aniline cannot be used for the determination of the miscibility temperature of high aromatic content petroleum fractions because of its relatively high freezing point. In an effort to circumvent this shortcoming, the so-called .'mixed aniline point" test has been introduced in relatively recent years in this country as a mode for evaluating these materials. The test represents the minimum, equilibrium solution temperature of a mixture of anhydrous aniline and equal volumes of the material under test and "any naphtha having a straight aniline point of 60' C." (11). It has become increasingly apparent that the results of this test are greatly influenced by the chemical composition of the 60' diluent-Le., by the aromaticnaphthene-paraffin ratio. As a matter of fact the test, as it is now carried out, is completely meaningless; and it will remain so until the composition of the 60" diluent is standardized or the aniline is replaced by a reagent of lower freezing point. This latter alternative would eliminate the use of a diluent and, hence, the need for standardizing it. The present paper presents a study of the application of furfural for the determination of miscibility solution temperatures of petroleum fractions. A critical study has been made of the influence of the composition of the 60" diluent on the results of the mixed aniline point test. Manle McCarty, and Gross (9) in 1933 studied the use of furfural {dr the solvent extraction of motor oils. They found it to have a high degree of selective solvent action on a wide variety of petroleum fractions, to be stable in closed systems, possessed of a high application temperature (149' C.), and nonpoisonous. Syono (12) determined the furfural miscibility temperatures of a gasoline of 53.8% aromatic hydrocarbon content a t various ratios of furfural to test oil. Trimble (13) recently has studied the solvent properties of furfural, chiefly with inorganic materials, although he tested a number of organic compounds including :I solvent naphtha. He suggested that furfural could be used to
INDUSTRIAL A N D ENGINEERING CHEMISTRY
108 Table
I. Variation of Furfural Point with Aromatic Content
Xylene Val. % 0 10 20 30 40 50 60 70 80 90
Xylene
Petroleum Solvent 1
Furfural
M1.
M1.
MI.
0 0.7 1.4 2.1 2.8 3.5 4.2 4.9 5.6 6.3
7.0 6.3 5.6 4.9 4.1 3.5 2.8 2.1 1.4 0.7
7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0
Furfural Point O
c.
110.8 102.3 93.0 83.6 73.4 62.0 48.9 32.5 13.3 -14.8
Vol. 16, No. 2
furfural point” and was so marked on the furfural supply bottle. Whenever tests were made on successive or separate days the “furfural point” of the petroleum solvent 1, retained as standard, was checked against the supply of furfural on each day that determinations were to be made, and corrections were made on all determinations for the day on the basis of the check test. When the furfural point of the reference petroleum solvent 1 varied by more than 0.5’ C. from its original furfural point, the supply of furfural was considered unsatisfactory and was not used again until it had been redistilled and restandardized. Present experience indicates that the furfural can be used over several weeks within the limits imposed. EXPERIMENTAL RESULTS
Table
II.
Effect on Furfural Point of Varying Volume Ratio of Furfural to Petroleum Solvent 1
Volume Ratio Furfural/ Petroleum Solvent 1 1:4 1:3 1:2 1:l 2:1 3:l 4:l
Furfural
Petroleum Solvent 1
M1.
M1.
2.8 3.5 4.5 7.0 9.0 10.5 11.2
11.2 10.5 9.0 7.0 4.5 3.5 2.8
Furfural Point O
c.
99.8 105.4 109.4 110.8 108.5 101.6 95.2
distinguish between aliphatic and aromatic hydrocarbons. Dunlop and Peters (6) studied the thermal stability of furfural and in confirmation of Manley et al. (9) found that this material possessed high tern erature stability. An extensive bibliographic survey of furfurayand its derivatives has been published (IO).
AROMATIC CONTENT. The variation of furfural point with aromatic content was determined on a series of synthetic mixtures comprising varying volumes of petroleum solvent 1 and xylene. The data obtained are summarized in Table I and Figure 2.
Table
IV. Furfural Points of Various Petroleum Fractions
Sample
Aniline Point0
Furfural Point
73.5 59.5 93.0 53.0 83.5 68.0 89.0
110.8 81.0 122.8 88.4 120.0 99.4 122.0
c.
Solvent Oil Solvent Naphtha Transformer Oil Heavy Marine Diesel Lubricating Oil
Gas Oil
Hydraulic Oil
c.
Aniline points were determined by Standard Inspection Laboratory, Standard Oil Development Co., Bayonne, N. J.
MATERIALS
FURFURAL.This reagent was secured from the Eastman Kodak Company and comprised the best grade. It was purified before use by the method of Adams and Vorhees ( 1 ) . PETROLEUM FRACTIONS. A set of petroleum fractions upon which “aniline points” are normally determined was obtained through the courtesy of the Standard Inspection Laboratory, Standard Oil Development Company, Bayonne, N. J. Before use, all the hydrocarbons were dried by contact with anhydrous calcium chloride followed by filtration.
Table
111. Effect on Furfural Point of Varying Volume Ratio of Furfural to Petroleum Solvent 1 Plus 40% Xylene
Volume Ratio Furfural/TePt Oil 1:4 1:3 1:2 1:l 2:l 3:l 4:l
Furfural
Oil Composition Petroleum solvent 1
Xylene
Furfural Point
M1.
MI.
M1.
c.
3.0 3.75 5.0 7.0 9.4 11.25 12.0
4.8 4.5 4.0 2.8 1.9 1.5 1.2
7.2 6.75 6.0 4.2 2.8 2.25 1.8
45.0 52.5 60.6 72.8 76.4 72.8 67.5
APPARATUS AND PROCEDURE
The apparatus and procedure are essentially those described by Williams and Dean (16) for the determination of aniline points. All test mixtures were prepared volumetrically by means of a buret. Furfural miscibility temperatures below about 30” C. are obtained with the same apparatus and procedure, except that cooling instead of heating is employed. The cooling medium comprises isopropyl alcohol and dry ice, the dry ice being added slowly to a point slightly below immiscibility. The bath is then allowed to warm spontaneously to the point of miscibility and the temperature recorded. All recorded furfural miscibility temperatures are the check results of three or more independent determinations which agreed to 0.2O c. METHOD
STANDARDIZATION OF FURFURAL.Within the first hour after
the distillation of the furfural by the method of Adams and Vorhees ( I ) , its tem rature of miscibility with petroleum solvent 1 was d e t e r m i n e r This value was designated as the “original
RELATIVEVOLUME RATIOOF FURFURAL TO OIL. The effect on the furfural miscibility temperatures of different relative volumes of furfural to test oil was determined from the standard petroleum solvent 1 and petroleum solvent 1 containing 40% by volume of xylene. The data obtained are summarized in Tables I1 and I11 and Figure 1. FURFURAL POINTS O F VARIOUS PETROLEUM FRACTIONS. Table IV summarizes the results obtained upon a series of petroleum fractions. These fractions represent typical products upon which aniline points are ordinarily determined. SUBSTITUTION OF FURFURAL FOR MIXED ANILINE POINT DETERMINATION. Table V summarizes the list of petroleum and aromatic materials used in the evaluation of the mixed aniline point determination. Distillation boiling ranges, approximate aromatic contents, and aniline and furfural points are presented for these materials where possible. Table VI summarizes the data obtained in determining the variation in mixed aniline point with composition of the “60’ diluents” which were prepared by various combinations of the petroleum solvents whose properties are presented in Table V. Table VI1 presents a comparison of the mixed aniline and furfural points of the aromatic petroleum naphthas studied in Table VI.
Table
V.
List of Petroleurn and Aromatic Materials Used in M i x e d Aniline Point Evaluation
Material
Distillation Range
c.
Petroleum Solvent 1 203.0-265.0 Petroleum Bolvent 2 155.0-210.0 PetroleumSolvent3 97.5-139.0 Petroleum Solvent 4 136.0-155.0 Petroleum Solvent 5 220.0-355.0 Petroleum Solvent 6 175.0-300.0 PetroleumSolvent 7 175.0-275.0 Petroleum Solvent8 138.5-181.5 Petroleum Solvent 9 186.0-216.0 PetroleumSolvent 10 98.0-134.0 Benzene, C.P. 80.1 Toluene, C.P. 109.0-111.0 0 Crystallization temperature.
Aromatics
voz. % 0
Aniline Point O
c.
69.0
81.8 58.3 -30.4
0 5 12 84.5 88.0 45.0 100 100
63.5 ... ... 13.4 ... ...
...
01.5
... 80.3
69.3
Furfural Point
c. 111.5 87.2 -4.1 -61.5 113.3 98.0 94.5 -42.0 -18.2 40.8
...
-60.70
.ANALYTICAL EDITION
February, 1944
109 ____-___
____.________
Table VI. Variation in M i x e d Aniline Point with Composition of 60" Diluent -50/50 Blend of Diluent with:--Petroleum Petroleum Petroleum Petroleum Petroleum solvent 10 solvent 3 solvent 9 solvent 8 solvent 4 Benzene Toluene Composition of 60' Diluent----3Iixed Mixed Mixed Mixed Mixed Mixed Mixed Aro- Aniline Aro- aniline Aro- aniline Aro- aniline Aro- aniline Aro- aniline Aro- aniline Aro- aniline Blend matic point matic point matic point matic point matic point matic point matic point matic point rd. % c. Vd. % O c. T ' d . % O c. VOL. % c. VOl. % c. I ' d . % ' c. T'd. 7'0 O c. V d . % ' c. I
7 -
Ililuent XO.
etroleum solvent 2 111
76.0% 24 0 7 6:7$ 93.3% 73.37, 26.79' 77.352 22.77 13.3% 86.7%
IV
v YI VI1
Petroleum Petroleum Petroleum Petroleum Petroleum Petroleum Petroleum Petroleum Petroleum Petroleum Petroleum Petroleum Petroleum Petroleum Petroleum Petroleum
%:V
VI11
IX
94.69 5.4% 96.09' 4.0%
X
solvent 1 solvent 4 solvent 5 solvent 2 solvent 5 solvent 3 solvent 5 solvent 4 solvent 6 solvent 2 solvent 7 solvent 2 solvent 7 solvent 3 solvent 7 solvent 4
60.1
,.
40.1
..
25.4
..
21.8
..
10.1
..
9.1
60.3
32.0
43.4
44.0
28.8
53.5
25.7
51.7 23.8
55.2 20.1
59.5
15.1
59.5
15.9
22
60.2
33.5
40.7
45.5
28.0
55.0
24.6
53.2
21.4
56.7
19.0
61.0
15.8
61.0
14.9
.,
60.3
,.
39.8
.,
25.7
..
21.9
..
17.8
..
14.2
..
10.0
..
8.5
18
60.0
31.5
42.2
43.5
27.2
53.0 25.0
51.2
21.2
54.7
18.9
59.0
16.1
59.0
14.9
21
59.9
33.0
-10.0
45.0
28.0
.X.5 25.2
52.7
22.4
56.2
18.2
60.5
17.4
60.5
14.3
..
60.0
..
39.6
..
25.2
,.
22.0
..
17.9
. ,
14.4
..
10.3
..
8.6
..
60.2
,.
39.9
,.
25.1
,.
22.5
..
18.4
..
15.2
..
11.2
..
9.6
15
60.2
30.0
40.9
42.1
27.4
51.5
22.9
49.8
19.2
53.3
16.2
57.5
12.9
57.5
11.1
15
60.4
30.0
39.6
42.1
26.2
51.5
23.2
49.8
19.6
53.3
16.6
57.5
13.6
57.5
11.4
Maximum variation in mixed aniline point,
O
C.
3.8
3.7
3.9
..
..
,. 19
17.6
6.2
14.7
5.9
7.1
7.4
DISCUSSION
The application of furfural for the determination uf miscibility solution temperatures of petroleum fractions appears to offer considerable promise over the solvents now generally employed. Furfural is nontoxic, stable under proper conditions of storage, and applicable to a wide range of petroleum fractions. The point of complete miscibility is easily and readily determinable even in darkly colored petroleum fractions. Aniline is completely miscible in petroleum fractions conhining approximately 505% or more of aromatic hydrocarbons.
Table VII. Comparison of M i x e d Aniline and Furfural Points of Aromatic Petroleum Naphthas Mixed Aniline Point Maximum Minimum
Material
c.
c.
28.8 20.1 23.8 25.7 43.4 17.4 15.9
25.1 14.2 17.6 21.8 40.0 10.0 8.5
a
Petroleum Solvent 3 Petroleum Solvent 4 Petroleum Solvent 8 Petroleum Solvent 9 Petroleum Solvent 10 Benzene , Toluene a Crystallization point.
Furfural Point
c.
-4.1 -61.3 -42.0 -18.2 40.8
...
-60.7a
~
I
1
1
I
I
I
I
Table VIII. Effect of Aromaticity
I
Xylene in Petroleum Solvent 1
5%
100
Furfural Point
c.
Aniline Point C'.
Difference
c.
V O
i
8z 2 a 3 2
90 80 70
60
3
L
50
40
1
1:s
I
I
I
I
1
I
I
1:4
1:3
112
lil
2:1
31
4!l
I
VOLUME RATIO, FURFURAL:OIL I20
lI
1l
li
VOLUME
O/o
l/
[l
l/
l/
1/
l
I
1I
XYLENE IN SYNTHETIC -MIXTURE
1
For these materials it is necessary to employ the so-called "mixed aniline point" determination. This determination becomes a relatively complex proceeding in comparison with the furfural miscibility determination, which can be carried out directly. The critical study which has been made of the influence of the composition of the 60" diluent on the results of the mixed aniline point has shown the extent of the variation which can occur when using an unstandardized diluent. I t is obvious that an unlimited number of 60" diluents can be prepared; all that is necessary is two hydrocarbon fractions, one having an aniline point above 60' and the other below. On the other hand, a direct miscibility solution temperature can be determined on these materials by the use of a lower freezing point solvent, such as furfural. The furfural miscibility temperature, as indicated by Figure 1, is dependent upon the relative volumes of furfural to test oil, In this respect its behavior is similar to that of aniline and other solvents (15). For practical determinations of miscibility the standard procedure of employing equal volumes of furfural to test oil is suitable. Variation in aromaticity for a given paraffinic and aromatic fraction will yield differences between furfural and aniline miscibility temperatures of fairly constant value as indicated in Table VIII.
INDUSTRIAL AND ENGINEERING CHEMISTRY
110
The average difference is 32.3. While it appears that for certain petroleum fractions this difference may vary over a much wider range: nevertheless, it is interesting to note that for the varied petroleum fractions studied in Table IV, the average difference between the furfural and aniline miscibility temperatures is 32.1. The large variations from the mean which are encountered are involved with the composition of the paraffinic fraction although work with pure hydrocarbons will have to be carried out in order to establish this point. Work is in progress in that direction and will be reported in a future paper. CONCLUSIONS
and criticism of the present work, and to thank the Standard Oil Company of New Jersey for permission to publish this work. LITERATURE CITED (1)
(2) (3) (4) (5)
Adams, R., and Vorhees, V., “Organic Syntheses”, Vol. I, p. 49, New York, John Wiley & Sons, 1921. A.S.T.M. Designation D611-41T. AubreB, M., Chimie et Industrie, Spec. No. 336 (Sept., 1926). Dietrich, K. R., Autotechnik, 16, 7 (1927). Dunlop, A. P., and Peters, F. N., Jr., IND.ENG.CHEM.,32, 1639
(1940). (6) Ellis, C., “Chemistry of Petroleum Derivatives”, Vol. I, p. 1136, 1934, Vol. 11, p. 1178, 1937, New York, Reinhold
Publishing Corp.
The aniline point method, though widely used, has the disadvantage of using a toxic reagent and limited applicability to low aromatic content petroleum fractions. A search of the literature and an experimental study have indicated that furfural offers considerable promise as a reagent for the determination of miscibility solution temperatures. It is nontoxic and is directly applicable to petroleum fractions of high aromatic content, making possible the elimination of the mixed aniline point determination. ACKNOWLEDGMENT
Opportunity is taken to thank the Standard Inspection Laboratory of the Standard Oil Development Company for comment
A
Vol. 16, No. 2
(7) Erskine, A. hf., IND. ENG.CHEM., 18, 694 (1926). (8) NcClurkin, T., J . I m t . Petroleum, 25, 382 (1939). (9) Manley, R. E., McCarty, B. Y., and Gross, H. H., OiZ Gas J . , 32, No. 23, 78 (1933). (10) Miner Laboratories, Chicago, Ill., “Furfural and Its Derivatives”, Bull. 2, revised June, 1928. (11) Sweeney, IT. J., and McArdle, E. H., ISD. ENG.CHEW,33, 787 (1941). (12) Syono, S., J . SOC.Chem. Ind., Japan, 41, Suppl. binding, 391 (1938). (13) Trimble, F., IND.ENG.CHEM.,33, 660 (1941). (14) Vellinger, E., and Herrenschmidt, J. D., Compt. Tend., 201, 780 (1935). (15) Vogel, H., Oe2 u. Kohle, 36, 547 (1940). (16) Williams, A. A., and Dean, E. W., IND.EM. CHIOM., rlriu,. ED , 14, 63 (1942).
Color Test for the Carbonyl Group FREDERICK R. DUKE N. 1.
Frick Chemical Laboratory, Princeton University, Princeton,
THE
carbonyl group is usually identzed by reaction with a hydrazine derivative, the appearance of the hydrazone precipitate constituting a positive test (2). This reaction is both sensitive and specific, but it lacks the simplicity and rapidity which are characteristic of a color test. Hydroxylamine hydrochloride reacts with carbonyl groups, forming the oxime and liberating hydrochloric acid. If a suitable acid-base indicator is added to the reaction mixture, the liberation of hydrochloric acid is accompanied by a color change; thus, t,he reaction serves as a color test for the carbonyl group. When combined with a specific test for the aldehyde group (1) the presence of ketones can be established in the absence of aldehydes.
EXPERIMENTAL
The test was applied to the following aldehydes and ketones: Aldehydes Formaldehyde Acetaldeh de Propionadeh de ButyraldehyL Chloral Benzaldehyde Salicylaldehyde Vanillin Citral Citronellal Furfural Acetal Cinnamaldehyde
Ketones Acetone Methyl ethyl ketone Aceto henone Cyclogexanone Biacetyl Pyruvic acid Ethyl acetoacetate Diacetone alcohol Pinacolone Mesityl oxide Benzophenone Benzil Benzoin Camphor
REAGENTS
REAGENTA. Prepare a solution containing 5 grams of hydroxylamine hydrochloride per liter of 95% alcohol. To 1 liter of this solution add 3 ml. of Bogen (Coleman and Bell, Norwood, Ohio) or Grammercy (Fischef Scientific Co., 711 Forbes St., Pittsburgh, Pa.) universal indicator. If necessary, add dropwise sufficient alcoholic sodium hydroxide to change the color to a bright orange (pH 3.7 to 3.9), taking care not to add too much base. The reagent, now ready for use, is stable for long periods of time. REAQENT B. Prepare a solution of the indicator by adding 3 ml. of the latter to 1 liter of 95% alcohol. PROCEDURE
Place 0.5 to 1 ml. of Reagent A in a s m d test tube, and add a drop, or a few crystals, of the compound to be tested. A change in color from orange to red is a positive test. If no pronounced color change occurs, heat the contents of the test tube to boiling and allow a few minutes for the reaction to take lace. If the compound is suspected of being slightly acidic or Ea&. add 4 or 5 drops to 0.5 ml. of Reagent B and brin to the color of Reagent A by adding dropwise dilute sodium%ydroxide or hydrochloric acid. Then carry out the test by adding this solution to Reagent A.
An immediate change in color wzts shown by all except the last four ketones; in these cases, heating was required. Sugars, quinones, and compounds such as the benzoyl benzoic acids fail to give a test. INTERFERENCES. No noncarbonyl compound was found which gave a positive test. Because of buffer action, excessive amounts of amines or acids obscure the test and must br srparated from the carbonyl compounds. SEKSITIVITY.A positive test is obtained with aldehydes when their concentration in the test solution is 0.01 M to 0.02 Af, the aldehydes of lower molecular weighf being most sensitive. The sensitivity to ketones varies greatly with the type and molecular weight, varying from 0.02 Jf for acetone to about 0.25 for benzophenone. LITERATURE CITED
(1)
Shriner and Fuson, “Identification of Organic Compounds”, 2nd ed., p. 62. New York, John Wiley & Sons, 1940.
(2) Ibid.. pp. 64-5.
