INDUSTRIAL AND ENGINEERING CHEMISTRY
788
I. VALUES O F JOULE-THOMSON COEFFICIEXT AND ISOBARIC HEATCAPACITY FOR SUPERHEATED STEAM
T.4BLE
Pressure, Lb./Sq. Inch Abs. 0 200 400 600 800
a b c
600’ F., pa
CpEb
700’ F., Cp.wC
fi
CPE
CpM
0.13485 0,13830 0,13898 0.13791 0.13553 0.13203
0.47733 0.47733 O.lOlS9 0.48569 0.48669 0.52047 0.52500 0.10328 0.51219 0.51494 0.57791 0.56921 0.10365 0.53959 0.54406 0.65345 0.63805 0.10337 0.58197 0.57555 0.75345 0,75330 0.10259 0.62703 0.62670 0.88786 0.88264 0.10140 0.68080 0.67793 1000 800’ F. 90O0 F. 0 0.08006 0.49431 0.49431 0.06460 0.50314 0.50314 200 0.08044 0.51201 0.51359 0.06458 0.51600 0.51665 0.08050 0.53201 0.52883 0.06445 0.52988 0.53055 400 600 0.08029 0.55444 0.55100 0.06420 0.54500 0.54459 800 0.07987 0.57951 0.58154 0.06385 0.56119 0.56355 1000 0.07926 0.60753 0.60364 0.06342 0.57860 0.67781 1000’ F. 0.05328 0.51213 0.51213 0 0.05317 0.52144 0.52083 200 0.06301 0.53129 0.53386 400 0.05280 0.54168 0.54398 600 0.05255 0.55262 0.55715 800 0.05226 0.56411 0.56687 1000 From equation of state in F’./pound/sq. inch. From equation of state in B.t.u./pound-O F. From analytic method in B.t.u./pound-O F.
Vol. 45, No. 4
able, the lowest temperature encountered in this illustration, for example, was 428 O F. Table I shows the Joule-Thonisoii coefficients and c, values obtained from the equation of state and also the c, values calculated by this analytical method. Figure 1 is a plot of isobaricheat capacity as a function of temperature with pressure as the parameter. Solid lines indicate values of c p calculated from the equation of state and dotted lines are those obtained by the method described above. The effect of number of constants in the power series of l / p on the result is self-evident in the figure The average error of the final c p values is well within 1%. I t is believed that the error could be held down to within 0.5% if more constants in the power series &-ereused. The outcome of this illustration indicates that the analytical method described is reliable and accurate. The only limitation is t h a t the region under consideration must not include the inversion curve on which p is zero, since both W and I do not exist therc. More work must be done, so t h a t this limitation might be removed t o give a more general solution. ACKNOWLEDGRIENT
~
ary condition. I n this illustration the errors involved in the power series of l/p a t different pressures were all well within 0.5%. For pressures of 400 and 600 pounds per square inch absolute, four constants were used in the power series; while for pressures of 200, 800, and 1000 pounds per square inch absolute five constants were used. The purpose of doing so was t o check the effect of the number of constants involved in the power series on the final result. As i t was pointed out before that the p data extended to low temperatures a t zero pressure are desir-
The writer wishes t o thank R. -4.Budenholzer of the Mechanical Engineering Department, Illinois Institute of Technology, for his invaluable suggestions in the preparation of this paper. LITERATURE CITED
(1) Gordon, -4.R., J. Chem. Phys. 2 , 65 (1934). ( 2 ) Keenan, J. H., and Keyes, F. G., “Thermodynamic Properties of
Steam,” New York, John Wiley & Sons, 1936. (3) Keyes, F. G., Smith, L. B., and Gerry, H. T., Mech. Eng., 56, 87 (1934). RECEIVED for review June 18, 1962.
ACCEPTED November 21, 1952.
Alkaline Permanganate Oxidation of Oil-Shale Kerogen W. E. ROBINSON, H. H. HEADY, AND A. B. HUBBARD Petroleum and Oil-Shale Experiment Station, Bureau of Mines, Laramie, Wyo.
A
LKALINE permanganate oxidation as a means of studying chemical structure has been used for many years. Bone et al. (I) developed a technique of controlled permanganate oxidation and used it in studies of coal constitution. Various other investigators (7) employed the method to show t h a t coal contains a highly condensed benzenoid structure, as large quantities of benzenoid acids are produced upon oxidation. Bone et al. (2) showed t h a t oxidation of lignin and materials ranging from peat t o anthracite produced increasing amounts of benzenoid acids. Lignin produced 12 to 16% benzenoid acids, while the peat-to-anthracite series produced 10 t o 46% benzenoid acids. I n this report a condensed structure refers t o a carbocyclic or heterocyclic structure, which consists of two or more fused rings. A benzenoid structure refers to a structure which contains one or more benzene rings. I n recent years, similar techniques have been used in studies concerned with the constitution of foreign oil-shale kerogens. Down and Himus ( 4 ) used the method t o advantage in their study of kerogens of various deposits. They found that the constitution of some kerogens resembles, broadly, the constitution of coal in t h a t there was definite evidence of a benzenoid structure. Other kerogens (notably that of Estonian algal limestone) differed from coal in constitution, in that there was
little evidence of a benzenoid stiucture. They a190 concluded that some kerogens contained two types of material. One type was oxidized comparatively easily by alkaline permanganate, and the other was highly resistant to attack. Gdov and Volga shales were oxidized by Lanin and Pronina (6) in a similar manner, and they concluded that Gdov shale was sapropelic in origin because it did not yield benzenoid acids upon complete oxidation, and that Volga shale should be regarded as sapropelic-humic in origin. The latter yielded a small amount of benzenoid acids by oxidation. Daneg and Giedroyc ( 3 ) oxidized various shales and also concluded that oil-shale kerogens from different sources varied in oxidation behavior. I n the study described by this report, the nature of the products obtained by exhaustive oxidation of Colorado oil shale n-as investigated. It was found, by analyses of the oxidation products, that 96 to 99% of the organic carbon in the kerogen \vas converted t o water-soluble products, which consisted of carbon dioxide, oxalic acid, steam-volatile acids, and 1% or less of nonvolatile nonoxalic acids. The structure of the kerogen appears t o be essentially nonbenzenoid, as less than 1% of the organic carbon was oxidized to nonvolatile nonoxalic acids, and benzene carboxylic acids were not identified in the oxidation products.
April 1953
INDUSTRIAL AND ENGINEERING CHEMISTRY
All cyclic structure present exists in a form that is easily oxidized by alkaline permanganate to carbon dioxide and oxalic acid. The constitution of the kerogen accordingly differs from the organic material present in typical humic (coaly) deposits. OIL-SHALE SAMPLES
The oil shale used in this study was obtained from the Mahogany ledge (Green River formation) in the Bureau of Mines OilShale mine near Rifle, Colo. Analysis of the sample is shown in Table I. A complete description of the raw shale and the method of concentration is given in areport by Hubbard et al. (5).
TABLE I. COMPOSITION OF COLORADO OIL SHALE AND ITS CONCENTRATE
Ash
(Weight per cent) Kerogen Composition Assay Kero- Oil gen Yield C H N S 0'
C:H Ratio
Raw shale 5 6 . 6 a 4 3 . 4 b 28 1 76.34 10.15 2 . 5 8 1.34 9.5OC 7 . 5 3 Kerogen concentrate 2 8 . 4 7 1 . 6 = 4 7 . 5 7 6 . 2 1 10.04 2 . 5 4 1 . 4 1 9.80 7.59 " By difference Sum of organic carbon, hydrogen, nitrogen, sulfur, and oxygen. Average oxygen content of Colorado oil-shale kerogen. See report by Stanfield et nl. (I)). ~
~
~
~~~
789
alkaline potassium permanganate are shown in Figure 1. Colorado oil shale had a rapid initial oxidation rate, as approximately 70% of the permanganate was reduced in 10 hours. The kerogen concentrate had a slightly higher oxidation rate than the raw shale. This is believed to be due t o removal of carbonates from the concentrate, which resulted in exposure of more kerogen surface t o the oxidizing solution. BULKOXIDATION.A large quantity of oil shale was oxidized for 100 hours t o determine whether any benzenoid acids were obtained as the result of oxidizing Colorado oil shale. Raw shale equivalent to 100 grams of organic carbon was oxidized i n 6000 ml. of 1.6% potassium hydroxide solution by excess potassium permanganate, which was added in batches of 100 rams. The mixture was maintained a t 85' t o 90' C. for 100 %ours. At completion of the oxidation run, the watersoluble products were separated from the hydrated manganese dioxide and residue by filtration. The filtrate was made acid with hydrochloric acid, and the volume was reduced. The organic acids were separated from the inorganic salts by two methods: electrodialysis and liquid-liquid extraction. The electrodialysis method yielded oxalic acids, and small amounts of silicic acid and material of high molecular weight similar to fraction I I a (see section on step-oxidation below). X-ray diffraction analysis of these products confirmed the chemical analysis, showing t h a t no benzene carboxylic acids migrated to the anode compartment of the dialysis cell. Ether extraction of the water-soluble acids by liquid-liquid extraction yielded oxalic acid and a similar high-molecular-weight product. As this material of high molecular weight could not be induced t o crystallize, it was assumed that no benzene carboxylic acids were present in this product. These two materials were undoubtedly the same as the 1% nonvolatile nonoxalic acids obtained from the carbon-balance oxidation of 100 hours' duration, and it contained no benzene carboxylic acids. STEP OXIDATION,As complete oxidation of Colorado oil shale did not yield benzenoid acids, recovery of intermediate oxidation products was attempted by step-oxidation procedures. It was hoped that identifiable fragments might be obtained in this manner. However, water-insoluble acids of apparent high molecular weight were formed, These oxidation products are referred t o in this paper as "regenerated humic acids." Undoubtedly, these products differ in constitution from regenerated humic acids obtained from most coals and certain other carbonaceous materials, but use of the term does classify this complicated mixture as to source and method of preparation, A litera-
CARBON-BALANCE OXIDATION.Finely ground (- 100-mesh) samples of raw oil shale or kerogen concentrate, which contained 1 gram of organic carbon, were oxidized by a method and in an apparatus similar t o that described by Down and Himus (4). Analysis of the oxidation products consisted of determining the distribution of the original organic carbon of the shale in (1) the evolved gases and the water-soluble gases, (2) the steam-volatile acids, (3) oxalic acid, (4) the nonvolatile nonoxalic acids, and (5) the unoxidized organic carbon. Benzenoid acids, if produced, would have appeared as nonvolatile nonoxalic acids. The results of the carbon-balance tests and results obtained by other investigators on various shales (Table 11) show that Colorado oil shale produced only 1 % of nonvolatile nonoxalic acids by 100 hours of continuous oxidation and w&s almost completely oxidized during this period. Treatment for an additional 100 hours did not oxidize further this 1% of nonvolatile nonoxalic acids. These facts show that this kerogen is similar to some other foreign oil-shale kerogens. Down and Himus (1) ... found that Estonian algal limestone TABLE 11. DISTRIBUTION OF ORGANIC CARBON IN OXIDATION PRODUCTS OF OIGSHALEKEROGENS (kukkersite) produced 3.8% of % ' of Total Organic Carbon nonvolatile nonoxalic acids, UnoxiOxidabut obtained little evidence of ' VolaNonvolatile, dized tion tile Oxalic nonoxalic organic Period KMnO4: C benzenoid acids. Likewise, Con acids acid acids carbon Hour; Ratio Lanin and Pronina (6) were unable t o isolate benzenoid acids in the 0.570 nonvolatile nonoxalic acids obtained by 41 1 18 2 (No)& 39 50 9 complete oxidation of Gdov oil Cdov (Estonia) 9 8 . 0 2 . 2 3 . 8 0 . 5 (No)a 0 . 0 600 20 shale. Colorado oil-shale keroEstonian alg Ifirnestone (Estonia) 60.6 8.1 28.6 3.8(NO)' 285 ., 71 115 19.3 gen may be similar in composiArnherst (BurTa) 40.9 2.9 27.2 4.0 132 22.1 Volga (Russia) 88.1 3.9 5.2 4 . 1 (kkS)a 0.0 500 14.6 tion t o that in kukkersite and Gdov oil shale, as it produced, 48.5 100 ... 6.6 35.3 0.2 0.6 18.4 57 31.0 49.8 8.3 upon complete oxidation, only 43.4 190 10 11.7 3.6 30.4 51.4 13.1 Yes)= 125 9.3 10.7 21.0 4.5 1Yo nonvolatile nonoxalic acids 38.9 120 12.7 13.7 [Yes)" 14.9 28.1 6.1 and contained no benzenoid 7.1 125 17.4 1 4 . 6 ... 31.6 42.7 4.0 34.2 1 7 . 2 (Yes)a 145 13.2 13.2 5.1 30.7 acids. However, most other Indicates if benaenoid acids were identified. oil shales produce some benzeThis run was not of sufficient duration for complete oxidation. Reported by Lanin and Pronina (6). noid acids. Reported by Down and Hirnus (4). The oxidation rates of varie Reported by Dancy and Giedroyc (3). ous shales by a 3% solution of
790
INDUSTRIAL AND E N G I N E E R I N G CHEMISTRY
Vol. 45, No. 4 total organic carbon compared to '77.4% after I 1 hours' oxidation time. This indicates that conversion of this kerogen t o regenerated humic acid and other soluble products requires only a very mild oxidation.
At the completion of the step oxidation, the filtrates lrom each step were combined a n d made acid Kith hydrochloric acid. The precipitated water-insoluble acids were removed by filtration and dried a t 50" to 60" C. over anhydrous calcium chloride for 2 to 3 d a j s a t reduced pressure. They were then extracted with ether followed by ethyl alcohol, giving two fractions of pr e c i p it.a t e d r e g e nerated humic acids. Oxidation Rates of Colorado and Foreign Oil Shales Figure 1. T h e acid f i l t r a t e from the precipitation of t h e r e g e n e r a t e d humic acids mas evaporated t o dryness and dried a t 105' C. ture survey reveals that the term is used rather loosely for various for 2 to 3 hours a t reduced pressure. A black viscous liquid alkali-soluble products prepared by laboratory treatment of separated out as the volume was reduced. This dried residue carbonaceous materials with oxidizing agents and mineral acids. was extracted with ether, followed by ethyl alcohol, thus giving two more fractions. Kerogen concentrate, equivalent to 100 grams of carbon, n a a All four fractions were purified by electrodialysie in a threedispersed in 6000 ml. of. 1.6% potassium hydroxide solution. compartment cell. The high-molecular-weight products did One hundred grams of solid potassium permanganate were added not pass through the mpmbranee but remained in the middle to the hot solution, and the temperature was maintained a t 85' compartment. Water-soluble low-molecular-weight acids (such to 90' C. until the permanganate was completely reduced. The as benzene carboxylic acids) would migrate through the memsolution x a s filtered, and the unoxidiaed kerogen was returned branes to the anode compartment. The purified regenerated to the flask to be further oxidized. This procedure was repeated humic acid fractions viere removed from the cell and dried a t 50" until the kerogen was completely oxidized. to 60" C. for 2 to 3 days a t reduced pressures over anhydrous The filtrate from each step was concentrated to a known calcium chloride. volump, and a portion was taken for carbon-distribution a n a l y k Data from a typical oxidation (Table 111) show that 7i.4yOof KO identifiable acids, other than oxalic, were collected in the the original carbon in the kerogen was converted t o regenerated anode compartment after purification of the various fraction-. humic acids. However, a small amount of water-soluble noncrystalline material remained in the middle compartment, and a small amount of similar material migrated to the anode compaitment. O F ORGANIC CARBON I N OXID-4TION TABLE 111. DISTRIBUTION The four regenerated humic acid fractions \yere very different PRODUCTS PREPARED B Y STEPOXIDATIOS OF COLORADO OIL SHALE in physical appearance, Fraction Ia, the ether-soluble fraction precipitated by hydrochloric acid, 1%-asa light brown, waxy semisolid. This entire fraction represented only 3.8% of the total carbon, so that the fraction was not indicative of the major portion of the kerogen, The major portion of the regenerated humic acid was fraction Ib. or the ether-insoluble alcohol-soluble 7.2 15.5 5 0.5 3.3 1 0.3 4.2 5.6 1.6 0.3 0.6 3.4 4.0 0.2 0.4 3.6 1.8 4.2 0.8 4.2 1.8 0.2 7.5 3.7 2.1 0.1 0.4 4.5 0.2 0.4 13.3 1.9 6 4.8 0.3 5.1 7 1.7 0.1 2 . 2 0 . 2 0 . 3 0 . 0 8 _ - - - _ _3 . 0 Total 17.3 1.6 3.7 40.4 37 0 Time required t o reduce KMnOa in each step. 2 3
:
27.0 37.0 48.2 62.0 82.3 94.3 100.0
5 10 10 25 70 235 3 3
TABLEILr. PREPARED
C O M P O S I T I O N O F R E G E N E R A T E D HuivfIc A C I D S BY P E R K 4 N G A N A T E OXID.4TION OF OIL-SHALE
KEROGESS
660
C :I3 Ratio ______ C
The time required for the first four steps was brief; after 30 minutes of oxidation time, 48.0% of the total organic carbon was converted to soluble products. Of this carbon oxidized, 74.0% was oxidized to regenerated humic acid, representing a conversion of 35.5%. After approximately 2 hours of oxidation time (first six steps) 82.3% of the total organic carbon was converted to soluble products. At this point in the oxidation, conversion of kerogen to regenerated humic acids accounted for 64.5% of the
Colorado FractionIa FractionIb FractionIIa FractionIIb
Per Cent H N S
0"
Regenerated hrimic acids
Kerogen
17.89 20.59 33.97 28.38
6.81 7.37 7.30 8.97
7.59 7.59 7.59 7.59
Kimmeridgeb 63.79 6.16 0.86 3 . 6 1 25.58 Ermelob 65.00 3.17 1 . 3 4 0.69 29.80 64.00 2 . 3 8 1 . 6 3 1 . 0 9 3 0 . 9 0 St. Hilaire* a Determined by difference. Reported by Dancy and Giedroyc (3).
10.35 20.50 26.90
9.56 11.14 10.85
70.56 10.32 0 . 7 2 0 . 5 1 67.54 9 17 1 . 8 6 0.84 57.44 7.87 0 37 0 . 3 5 60.81 6 . 7 8 2 . 1 2 1 . 9 1
April 1953
’
. . .
INDUSTRIAL AND ENGINEERING CHEMISTRY
fraction from the precipitated acids. This fraction was a lustrous, light brown, resinous-appearing solid. It represented 36.6% of the total carbon, Fraction IIa, the ether-soluble acids from the hydrochloric acid filtrate, was a light brown, viscous liquid. The alcohol-soluble fraction I I b was a dark brown to black, viscous liquid. This fraction represented 30.4y0 of the total carbon, while fraction I I a represented only 6.6%. Ultimate analyses of the four fractions are given in Table IV. Knowledge of the oxiOXIDATION OF KNOWNCOMPOUNDS. dation behavior of specific-type compounds under conditions of this study would aid in correlating structure and oxidation behavior. Accordingly, various materials, whose structures may be similar to those in kerogen, were oxidized by the carbon-balance technique. The results shown in Table V indicate that monocyclic terpenes and noncondensed cyclic ketones (saturated) produce from 0 t o 3% of nonvolatile nonoxalic acids. This is comparable to the amount of nonvolatile nonoxalic acids obtained from the oxidation of Colorado oil-shale kerogen. However, polycyclic terpene, cyclic alcohols (saturated), cycloalkenes, and natural products produced a n average of 6 t o 3oY0 of nonvolatile nonoxalic acids.
TABLEv. DISTRIBUTION O F ORGANIC CARBON I N OXID.4TION PRODUCTS OF VARIOUS MATERIALS % of Total Organic Carbon Volatile Oxalic acid 1 37 1 19
’
‘O2 &Limonene 32 Terpinol hydrate 63 4-Cyclohexyl61 0 7 cyclohexanol Cyclohexene 44 3 0 9 1 3 0 Cyclohexanone 64 5 22 C yclohexanol C clopentanone 87 2 8 ietic acidb 87 4 2 Ursolic acid 55 7 13 0 Cholesterol 69 1 Natural products Gum copalb 83 2 0 Turpentine (crude) 66 2 0 Wormseed oilb 65 5 0 Balsam (tolu) 68 1 0 a Determined by difference. 13~02used t o destroy excess KMnOa.
Nonvolatile, Unoxi- Oxidanondized tion KMnOd: oxalic organic Time C acids Ratio 0 30 20 20 28 20 3 14 17 24 2 6 3 7 22 8
15 29 4 3 0 0 3 22
24 45 45 54 96 60 80 50
18 18 31 32 29 19 11 17
I5 12 11 30
0 20 19 1
67 62 47 57
15 26 26 11
*
An extensive study was made by Randall et al. (8) on the oxidation behavior of approximately seventy known compounds using the carbon-balance technique. It was found that carbohydrates, aliphatic acids, and noncondensed aromatic ethers and aldehydes produced less than 1% of nonvolatile nonoxalic acids. The following type compounds produced from 52 to 88% nonvolatile nonoxalic acids (mostly benzenoid acids) : (1) aromatic hydrocarbons; (2) condensed aromatic hydrocarbons; (3) aromatic compounds containing a -CO group; (4) condensed aromatic compounds with a -CO group; (5) aromatic carboxylic acids; (6) condensed carboxylic acids; and (7) condensed oxygen heterocylic aromatic compounds. I n addition, Randall et al. showed that benzene, cyclohexane, diphenyl, chrysene, retene, rubicene, decacyclene, truxene, and trimethyl truxene were almost immune t o oxidation, while naphthalene, anthracene. phenanthrene, fluoranthene, indene, Decalin, and tricyclotrimethylene benzene were among the cyclic hydrocarbons t h a t were oxidized and produced high yields of benzenoid acids. It may be concluded t h a t those aromatic structures t h a t produce large yields of nonvolatile nonoxalic acid upon oxidation and those that are immune t o oxidation are not present in Colorado oilshale kerogen. The data obtained from oxidizing Colorado oil shale do not indicate a definite structure of the kerogen. They do, however, give information concerning its general constitution. Compari-
791
son of the data obtained from oxidizing Colorado oil shale (Table 11) with those of known substances shows structures that are not present t o any great extent in this kerogen. The amount of nonvolatile nonoxalic acids produced from Colorado oil shale was 1% or less. Yields from 50 t o 75% of nonvolatile nonoxalic acids (mostly benzenoid) were obtained upon oxidation of aromatic hydrocarbons, condensed aromatic hydrocarbons, and condensed oxygen heterocyclic aromatic compounds. This indicates that these structures are not present in Colorado oilshale kerogen. Further comparison of the amount of nonvolatile nonoxalic acids produced upon oxidation of this kerogen with that of known compounds indicates structures t h a t may be present. Based upon data obtained from this study and general conclusions made by Randall, the following type structures may be present: (1) noncondensed heterocyclic rings, (2) noncondensed -OH or -0CHa substituted benzene rings, (3) aliphatic chains, (4) noncondensed aromatic ethers and aldehydes, (5) noncondensed cyclic ketones (saturated), (6) monocyclic terpenes, and ( 7 ) carbohydrates. Organic nitrogen and sulfur are known to be present in Colorado oil-shale kerogen; however, structures containing these elements were not investigated in this study. CONCLUSIONS
~ h study b was made to obtain information concerning the chemical structure of Colorado oil-shale kerogen. The data show that this kerogen was oxidized almost completely to nonbenzenoid water-soluble products b y a boiling solution of alkaline permanganate. The oxidation products consisted of carbon dioxide, oxalic acid, and small amounts of steam-volatile acids and nonvolatile nonoxalic acids. Based on the oxidation behavior of known compounds, indications are t h a t this kerogen is essentially nonbenzenoid and does not have a condensed benzenoid structure. These data also indicate t h a t Colorado oil-shale kerogen may be similar t o the organic material in Estonian algal limestone and Gdov oil shales, as they produce small amounts of nonvolatile nonoxalic acids upon complete oxidation and do not yield benzenoid acids. Intermediate high-molecular-weight acids were produced by oxidizing the kerogen by stepoxidation procedures. Approximately 80% of the kerogen can be converted to regenerated humic acids by this technique. These soluble mineral-free fractions will be of value for further constitutional studies. ACKNOWLEDGMENT
This work was done under a cooperative agreement between the Bureau of Mines, United States Department of the Interior, and the University of Wyoming as part of the Bureau of Mines Synthetic Liquid Fuels Program. LITERATURE CITED
(1) Bone, W. A., Horton, L., and Ward, S. G., Proc. Roy. Soc.
( L o n d o n ) , 127A, 480-510 (1930). (2) Bone, W. A., Parsons, L. G. B., Sapiro, R. H., and Grocock, C . M., Ibid., 148A, 492-522 (1935). (3) Dancy, T. E., and Giedroyc, V., J. Inst. Petroleum, 36, 607-23 (1950). (4) Down, A. L., and Himus, G. W., Ibid.,27, 419-45 (1941). ( 5 ) Hubbard, A. B., Smith, H. N., Heady, H. H., and Robinson, W. E., U. S. Bur. Mines, Rept. Invest. 4872 (1952). (6) Lanin, V. A., and Pronina, M. V.,’Bull. Aead. Sci. U.R.S.S., Classe sci. tech., 1944, 745-51. (7) Lowery, H. H., “Chemistry of Coal Utilization,” Vol. 1, pp. 363-75, New York, John Wiley & Sons, 1945. (8) Randall, R. B., Benger, M., and Grocock, C. M., Proc. Roy. Soc. ( L o n d o n ) , 165A, 432-52 (1938). (9) Stanfield, K. E., Frost, I. C., McAuley, W. S., and Smith, H. N., U. S. Bur. Mines, R e p t . Invest. 4872 (1952). RECEIVED for review June 7, 1952. ACCEPTED December 8, 1952. Presented before the Division of Gas and Fuel Chemistry, AMERICAN CHEMIOAL SOCIETY,a t State College, Pa., May 1962.
