Action of Aqueous Alkali on a Bituminous Coal LEO KASEHAGEN
This paper reports the results of heating Edenborn (Pittsburgh seam) coal with sodium hydroxide solutions of various concentrations a t various temperatures.
Coal Research Laboratory, Carnegie Institute of Technology, Pittsburgh, Pa.
Alkali Treatments The alkali treatments were carried out in an electrically heated, 800-cc., chrome-vanadium steel pressure vessel fitted with a nickel liner and a nickel head. This reactor was found to work satisfactorily at pressures as high as 4300 pounds er square inch (302 kg. per sq. em.) at 400" C. Reaction times or20 to 30 hours, divided into three or more stages, were used. Each run was started with 50 grams of 16-20 mesh Edenborn coal and 200 cc. of alkali solution of the proper concentration. When the solution was too concentrated to be prepared at room temperature, the proper amounts of solid sodium hydroxide and water were added with the coal. Air was removed by flushing with nitrogen and partial evacuation. At the end of each stage the gaseous products were removed, the alkali solution was drawn off, and fresh solution was introduced through a liquid line without opening the reactor. At the end of the last stage the residue was removed from the reactor, washed with water by Soxhlet extraction, and dried. The neutral oils were collected by extracting the alkaline solution from each stage of the alkali treatments with benzene and allowing the benzene to evaporate in air at room temperature. Carbon dioxide was determined by acidifying an aliquot portion of the alkaline solution from each stage and determining the carbon dioxide evolved in the usual manner. This acidification also brought about the reci itation of the phenols and acids, which were then removezby fiytration. After removal of the carbon dioxide and phenols and acids from the acidified solution, small amounts of rather volatile liquids could be obtained by benzene or ether extraction of the solution, and a light red solid couId be obtained by acetone extraction of the salt obtained on evaporation of the solution. The two materials were not investigated further than a determination of their acidic nature. Together, they were always equivalent t o less than 5 per cent of the coal. The hydrogenation test applied to each of the residues consisted of heating a sFm le of the residue ground to pass 200 mesh for 24 hours at 400 (fin the presence of hydrogen at an initial pressure of 2000 pounds per square inch (141 kg. per sq. em.); the latter gave a working pressure around 3700 pounds per square inch (260 kg. per sq. cm.), which decreased gradually as the hydrogenation roceeded. No dispersion medium was used. A catalyst o f molybdenum trisulfide precipitated on the residues
On heating at elevated temperatures and pressures in the presence of aqueous alkali, a bituminous coal is converted into cokelike residues which have lower percentages of oxygen and of hydrogen than the coal itself. Results of the alkali treatments throw some light on the chemical constitution of coal. Neutral, viscous liquids and solid phenolic substances of high molecular weight are byproducts of the treatments. By the proper choice of conditions, residues which have hydrogen percentages as high as, but oxygen percentages much lower than, those of the coal can be formed. Hydrogenation of these residues forms products more hydrocarbon-like in nature than does a similar hydrogenation of the coal itself. Although the data presented do not appear to have immediate practical application, in the future there may be possible commercial use of residues produced by the alkali treatment of bituminous coal as raw materials for hydrogenation.
PREHYDROGENATION treatment for removing a part of the oxygen from a coal would be desirable from the standpoint of hydrogen economy because i t would decrease the hydrogen required for the formation of the waste product, water, during hydrogenation. Waterman and Doting (16) removed a part of the oxygen from a lignite by heating it with carbon monoxide under pressure. The success of Fry and eo-workers (8-11) in removing oxygen from various oxygenated compounds as carbon dioxide by alkali treatment suggested the possibility of removing oxygen from a coal along with sufficient carbon to form carbon dioxide b y subjecting the coal to the action of aqueous alkali under pressure. The formation of carbonates during the pressure-heating of bituminous coals in the presence of aqueous alkali, as reported by Fischer and associates (6, 7) and by Drees and Kowalski (4),indicated the possible success of this method for removing a part of the oxygen from a coal.
A
5 PER CENT OXYGEN
+
NITROGEN
10
+ SULFUR
FIQURE 1. COMPOSITIONS OF RESIDUES 600
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INDUSTRIAL AND ENGINEERING CHEMISTRY
from a water-alcohol solution was found t o give better results than admixing separately prepared molybdenum disulfide O r precipitating molybdenum trisulfide on the residues from water solution. The water-alcohol solution, in contrast to the water, wet the residues thoroughly, thus ensuring intimate dispersions of the molybdenum trisulfide throughout the residues. Using a catalyst prepared in this manner, it was found that agitation during hydrogenation TV&S unnecessary. The yield of benzene-soluble products was determined in ea& case, and these products further separated into petroleum-ether-solubleand petroleum-ether-insoluble fractions.
Coke Residue
601
material is a typical coking coal, and the product, a t 400', has practically the composition of an anthracite. Carbonization has quite different effect; cokes prepared from Edenborn coal a t temperatures from 500' to 1100' c. ( 5 ) fall on line CD, which leaves the coal band entirely. The compositions of the residues produced a t 350' C. using alkali solution concentrations ranging from normal to 100 per cent are shown by line EFG. Here, a t concentrations up to 60 per cent, the oxygen contents of the residues become lower and their hydrogen contents higher as the solution concentration is increased. Above 60 per cent this trend ceases, and a t 80 per cent the carbon content becomes rapidly lower and that of oxygen rapidly higher, so that the residue prepared with 100 per cent sodium hydroxide has nearly the same composition as the original coal. This residue and the one prepared a t 250" C. with 5 hi sodium hydroxide were the only ones which retained the granular form of the coal and did not resemble cokes. The residues made by the action of 60 and 80 per cent sodium hydroxide have almost the same hydrogen contents as the original coal but considerably lower oxygen contents, so that on the basis of composition alone and from the standpoint of hydrogen economy, they are much more suitable for hydrogenation than the original coal.
Tht: major product of the alkali pressure-heatings was always a solid, alkali-insoluble, carbonaceous residue greatly resembling a low-temperature coke, Although the lower limit of the plastic range of Edenborn coal is 393' C., this cokelike product was formed a t temperatures as low as 275". The appearance of the residue was such that it must have been in a semi-liquid state during the react,ion. Although it did not cake on carbonization a t 500' C., the ground residue could be again agglomerated by subjecting it to a second alkali treatment a t a temperature no higher than that a t which it was first produced. The residues were, in general, quite soft and friable; they became harder and their pore size became smaller with increasing temperature and/or alkali concentration. The compositions of the residues depended TABLEI. COMPOSITION OF RESIDUES (DRY,ASH-FREEBASIS) upon the conditions existing during the alkali Sol. in -Preparation0 (DifBentreatments; they are plotted on a ternary diagram Temp. Concn. C H N S ference) O + N + S Bene in Figure 1. Line AB shows the compositions of a c. % % % % % % % the residues obtained using 5 N aodium hydrox250 5 N 84.15 5.96 2.16 0.42 7.31 9.89 275 5 N 86.30 5.61 2.15 0.32 5.62 8.09 8:s ide solutions at temperatures from 250' to 300 5 N 87.15 5.53 1.66 0.34 5.32 7.32 13.1 325 5 N 88.95 5.27 2.12 0.15 3.51 5.78 14.2 400' C. As the temperatures of the alkali treat325 60% 88.11 5.66 2.26 0.26 3.71 6.23 26.8 ments were successively raised, the percentages of 350 1N 89.38 4.78 2.36 0.16 3.32 5.84 7.9 350 5 N 90.43 4.48 2.05 0.12 2.92 5.09 8.3 oxygen plus nitrogen plus sulfur in the residues 350 10N 90.39 4.78 0.98 0.21 3.64 4.83 15.8 350 15 N 90.66 5.04 1.94 0.10 2.26 4.30 21.5 became successively lower, so that the 400" 350 60y0 90.16 5.59 1.55 0.42 2.01 3.98 27.3 residue had an oxygen-nitrogen-sulfur content 350 89.26 5.48 1.64 0.73 2.89 5.26 23.1 350 lggg 85.85 5.44 1.72 0.78 6.21 8.71 8.3 only 37 per cent as large as that of the original 375 92.01 3.85 1.83 0.22 2.09 4.14 2.9 400 5N 92.93 3.62 1.82 0.13 1.50 3.45 2.4 coal. However, these residues were also lower in 400 60 92.04 4.36 1.68 0.58 1.34 3.60 12.3 hydrogen than the coal, particularly those formed Originalooap 84.99 5.68 1.66 0.65a 7.02 9.33 6.6-8.4 Orgrtnic sulfur only. at temperatures above 325 ' C., so that the loss of oxygen which would have made this process valuable as a prehydrogenation treatment was The compositions of the residues are shown in detail in partially nullified by a simultaneous loss of hydrogen. An Table I. It may be seen that in general the percentages of interesting feature of this plot of composition us. temperasulfur in the residues are considerably reduced from those ture of the treatment is that the curve maintains fairly uniof the original coal. The percentages of nitrogen, on the formly the same position in the coal band, bounded by the other hand, have an average higher than that of the coal dashed lines, as the original coal, The alkali treatment evi(1.92 as against 1.66 per cent for the coal), apparently indentiiy brings about an artificial coalification, for the starting dicating that n i t r o g e n c o n c e n t r a t e d to some extent in the residues. The total nitrogen recoveries averaged about 4 per cent higher than the total carbon recoveries and in some cases were over 100 per cent. This would indicate that the alkali treatment has the effect of making the nitrogen in the residues more available for the Kjeldahl method of analysis than that in the original coal. Samples of each of the residues were extracted for about 300 hours with benzene in Soxhlet extractors a t atmospheric pressure. The yields, extrapolated to infinite time according to the PESROLNM ETHER - U S I 20method of Asbury (1) are also given in Table I. They increase as the oxygen contents of the 10residues decrease but fall off quite markedly as the hydrogen contents become smaller. The -b residues already pointed out as being most %o 275 300 32s 550 375 400 suitable for hydrogenation on the basis of com1EMPWA'fWE position had the highest percentages of material FIQURE 2. PRODUCTS FROM HYDROGENATION OF RESIDUES PREPARED W I T H 5 N SODIUM HYDROXIDE soluble in benzene. '
'
602
INDUSTRIAL AND ENGINEERING CHEMISTRY
Hydrogenation of Residues Factors, other than their compositions, which affect the values of the residues as materials for hydrogenation are their hydrogenating characteristics as compared with those of the original coal. The time and temperature required for hydrogenating each, as well as the quantity and nature of the resulting products, are important. To investigate these characteristics, each of the residues, as well as the coal itself, was subjected to a uniform hydrogenation test. The yield of benzene-soluble products, designated BS, was determined in each case, and these products further separated into petroleum-ether-soluble and -insoluble fractions, designated PES and PEI, respectively. Figure 2 shows the yields of PES and BS obtained by hydrogenating the residues prepared with 5 N alkali as a function of the temperature of preparation of the residues. The general trend of the curve is a decrease in the total yield as the temperature is increased, as well as a change from a product 94 per cent soluble in petroleum ether to one, a t
TABLE11. COMPOSITIONS OF BENZENE-SOLUBLE PRODUCTW BY HYDROGENATINQ RESIDUES AND ORIQINAL COAL OBTAINED
--
Temp.
I
I
Residue-Alkali ooncn.
a b
+
0 +,N S (by Difference)
H
C
c.
0
I
VOL. 29, NO. 5
up almost entirely of unoxygenated compounds, while the PEI are definitely of an oxygenated nature. The relatively high oxygen percentages of certain of the BS are due to their high content of this oxygenated fraction.
%
%
250 5 N 89.70 275 5 N 89.76 3006 90.31 5 N 300 C 90.49 5 N 350 1N 90.11 350 89.91 5 N 350 10 N 90.36 350 89.96 350 90.19 350 89.66 Original coal 89.64 Dry, ash-free basis. Petroleum-ether-soluble fraction. Petroleum-ether-insoluble fraction.
%
9.87 9.69 9.55 6.54 8.48 8.06 9.24 9.74 10.04 10.32 9.39
0.43 0.55 0.14 2.97 1.41 2.03 0.40 0.30 -0.23
I
n.nz .. .-
0.97
I TABLE111. REFRACTIVE INDICESOF BENZENE SOLUBLES MADEBY HYDROQENATINQ A 350" C., 80 PER CENTRESIDUE B.P. O
232-254 254-276 276-295 295-314
FIQURE3. PRODUCTB FROM HYDROGENATION OF RESIDUES PREPARED AT 350' c.
B. P .
n
c.
1.4900 1.4966 1.5057 1.5123
314-327 327-344 344-395
B. P.
c. 1.5219 1.5303 1.5448
395-410 410-419 419-435
n
sa
1.5616 1.5710 1.6000
The BS made from the residues produced a t 350" C. with 60, 80, and 100 per cent alkali were of the most interest, not only because they were the most hydrocarbon-like in composition but because of their physical nature. They had kerosene-like odors and felt distinctly oily when rubbed on the fingers. No quantitative determinations of oiliness or viscosity were made on account of the lack of sufficient material. The BS from the 80 per cent alkali residue was the lightest in color and the most fluid. I n a distillation a t atmospheric pressure, 75 per cent of it was found to distill between 230" and 440' C . Refractive indices of fractions taken during this distillation are given in Table 111. These constants, together with the boiling ranges of the separate fractions, indicate that the distillate was composed of partially and completely saturated condensed ring compounds, a result similar to that obtained by Biggs ( 2 ) on hydrogenating other derivatives of Edenborn coal.
350" C., containing 46 per cent of material not soluble in this solvent. Above 350" the yield of BS falls off almost to zero; this sharp break may perhaps be explained by assuming a critical temperature above which polymerization reactions take place rapidly during the alkali treatment. Figure 3 shows the yields of the same products, obtained from the residues prepared a t 350", plotted against the concentrations of the solutions used during the alkali treatments. Here the product becomes more completely PES, and, with the exception of a dip a t the beginning of the curve, the total yield increases as the concentration of the solution is increased. When Edenborn coal was subiected to this same hvdrogenation test, the yields obtained were: PES, 55.0 per"cent; BS, 65.0 per cent. The 275' C. ( 5 N ) and 350 'C. (60 per cent) residues were the only ones giving yields of BS as high as that from the coal. I n the case of the PES, four residues gave higher yields than the coal-namely, the 5 N a t 275" C. and the 60, 80, and 100 per cent ones at 350". The PES were light red to black liquids which darkened on standing. Some were quite fluid, but others would flow only slowly. Where the PEI constituted a large percentage of the BS, the PES were very viscous. The fraction of the BS which was petroleum-ether-soluble and the fluidity of the PES are probably both measures of the extent of the hydrogenation. The PEI were light orange to black amorphous solids. They readily redissolved in cold benzene after being separated from the PES. FIQURIE 4. PRODUCTS FROM RUNSWITH 5 N SODIUM HYDROXIDE Analyses of the BS are given in Table 11. 1. Phenols and acids 2. Neutral oil The one case in which the separate fractions 3. Hydrocarbon gases 4. Carbon dioxide were analyzed shows that the PES are made 1
I
n >z
c.
MAY, 1937
INDUSTRIAL AND ENGINEERING CHEMISTRY
60 3
solvent could not be obtained. The production of this phenolic material is in keeping with the concept of the presence of oxygen in the coal Carbon substance in the form of ether linkages, as set Dioxide forth by Biggs (a),for it is easily conceivable that % the alkali treatments could bring about the con01 .. 8 version of ethers to phenols, either by direct split0 1.8 ting or by hydrolysis. 3.1 3.5 The neutral oils were black, viscous liquids 2 5 . 29 readily soluble in benzene. They were insoluble 6.7 in acids or alkalies. They contained roughly 5.5 only 40 per cent as much oxygen as the original 6.2 coal but 45 per cent more hydrogen. Their com31 .. 71 7.2 positions, together with their molecular weights 9 .. 18 in catechol and diphenyl, are given in Table 7 VI. I n v e s t i g a t i o n of their chemical nature was not carried further than a determination of their neutral character. The gas produced consisted of hydrogen and gaseous hydrocarbons. Of the latter, methane and ethane predominated, but homologs as high in the series as butane were identified by the micromethod of Sebastian and Howard (IS). Hydrogen was produced in part by the decomposition of water, for in every case more oxygen was recovered in the
TABLEIV. YIELDSOF PRODUCTS FROM ALKALI TREATMENTS Y E x p t l . ConditionsAlkali Temp. concn. Pressure Lb./sq. Kg./sq. c. in. 32 250 5N 450 800 56 275 5N 1300 91 300 5 N 123 325 5 N 1750 600 42 325 60% 176 350 1N 2600 350 5N 2550 179 350 10 N 2400 169 350 15N 1900 134 700 49 250 18 .. 375 5N 3600 253 400 5N 4300 302 400 60% 1350 95
liig
...
Residue
%
96.5 91.9 86.0 78.8 89.5 81.2 77.4 80.9 83.0 , 87.5 99 4 2 .. 74 74.0 78 21 .. 31
Phenols and Acids
Neutral Oil
%
0.5 4.8 9.4 12.5 0.9 11.0 6.9 1.3 0.8 1.2 0 .. 78 0 0.5 00 .. 72
%
*. .. .. ..
..
i:5 3.1 2.4
..
0:1 10.1 40 .. 79
Hydrocarbon Gases
%
... 0.2 0.4 0.8 21 . 02 2.2 2.3 0.7 0.8 6.4 9 .. 1 6 4
...
TABLEv. COMPOSITIONS OF PHENOLS AND ACIDS %
%
%
S
OC.
%
0 %
275 300 300b 325 350
77.59 77.52 79.22 80.04 80.98
5.35 5.53 5 .24 5.30 5.44
1.53 11 .. 35 20 1.53 1.55
0.92 21 01 .. 7 9 1.16 0.64
14.61 14.42 13.25 11.97 11.39
Temp.n
b C
C
H
N
Mol. Wt. in Catechol
242 zigc 218
Alkali solution 5 N . From petroIeu&-ether-insoluble portion of benzene extract. Equivalent weight by methylation, 226.
to
Other Products of Alkali Treatments (I
The yields of the various products resulting from the alkali treatments are given in Table IV. All yields are calculated i e on a carbon basis as percentage equivalents of the dry, ashfree coal. The greatest yields of residues occurred in two 4 groups of runs, those at the lower temperatures, where little reaction took place, and those in which alkali solution concentrations were 60 per cent or higher. Table IV also shows 2 the maximum pressures developed during the treatments. These pressures exceeded the vapor pressures of the alkali 0 solutions by amounts depending upon the quantities of gas A L K W CONCENlR4TION formed during the runs. FROM RUNSAT 350" C. FIQURE 5. PRODUCTS With the exception of the residues, the product yields are 1. Phenols and acids 2. Neutral oil also shown on Figure 4,which illustrates the effect of tem3. Hydrocarbon gases perature, and on Figure 5, which shows the effect of alkali 4. Carbon dioxide concentration. The curves labeled "phenols and acids" represent the production of a material which was 95 per cent products than originally existed in the coal. The total phenolic in nature. It was a light brown to black, amorphous oxygen recoveries are shown in Table VI1 and indicate that solid, having an oxygen content about 70 per cent higher than the decomposition of water increased with the temperature. the original coal. It was partially or completely insoluble The third column of Table VI1 shows the theoretical total in the ordinary solvents but was readily soluble in aqueous alkali from which the phenols could OF NEUTRAL OILS ON A DRY,ASH-FRE~ BASIS TABLEVI. COMPOSITION be precipitated in the usual way by saturating -Preparation-Mol. Wt. jn:the solution with carbon dioxide. The phenolic NorO+ CateDinature of this precipitate was confirmed by Temp. mality C H N S N N + S chol phenyl methylating with dimethyl sulfate according to c. % % % % % % 350 10 85.90 , 8 . 2 7 .. .. .. 6.83 .... the method of Waliaschko (15) and boiling the 350 15 86.05 8.67 5.28 . . .. . . .. methylated product with 5 N sodium hydroxide 376 5 87.78 8.08 1:Ol 0:35 2:iS 4.14 195 260 solution. No hydrolysis occurred, indicating defi400 5 88.27 8.29 .. .. .. 3.44 196 261 nitely that the material was phenolic and not IN PRODUCTS AS A RESULT TABLE VII. OXYGENAND HYDROGEN acidio. Analyses of the phenols and acids are given in Table OF THH DECOMPOSITION OF WATER V. They indicate roughly that, for each atom of phenolic Total 0 (as Theoretical Free H in Gas oxygen, another oxygen atom of undetermined nature was .qof 0 in Tptal H jaa 7 of (a! % ' of H in present. The low molecular weights obtained in catechol Temp." Original Coal) H In Original 8oal) Original coal) c. are not consistent with the physical properties of these bodies 275 119 103 4 since they could ngt be distilled in vacuo, and are examples of 300 142 107 7 155 109 11 325 the anomalous behavior of certain coal products and polymers 350 211 118 23 375 247 124 31 as described by Smith and Howard (14). The phenols and 400 280 129 52 acids are only partially soluble in diphenyl, so that the higher a Alkali solution, 5 N . molecular weights which might be expected when using this
2
'
.
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INDUSTRIAL AND ENGINEERING CHEMISTRY
604
hydrogen in the products, as calculated from the total oxygen recoveries, and is to be compared with the free hydrogen produced, shown in the fourth column. It is evident that free hydrogen is not only formed by the decomposition of water but is also split off from the coal, as was to be expected from the loss of hydrogen already mentioned in the discussion of the residues. The curves in Figure 4 show that, as the production of the phenols and acids falls from its maximum with increase in reaction temperature, the productions of neutral oil, hydrocarbon gases, and carbon dioxide increase, indicating that these three probably result in part from the decomposition of the phenols and acids. This is to be expected from the results obtained by Hofmann and associates (12) on pressureheating various pure phenols with aqueous alkali. These workers found the major products to be carbon dioxide, hydrogen, and gaseous hydrocarbons, but noted the formation of small amounts of a complex mixture of hydrocarbons and oxygenated compounds which may correspond to the neutral oil here obtained from coal. Above 375" C. the neutral oil is itself decomposed into carbon dioxide and gaseous hydrocarbons. Figure 5 also illustrates the decomposition of the phenols and acids into carbon dioxide, gaseous hydrocarbons, and neutral oil. The low yields a t alkali concentrations of 60 per cent and above for all the products shown constitute the cause of the high yields of residues already mentioned for these concentrations. From the yields of carbon dioxide, and the oxygen added to *he products by decomposition of water, it was evident that carbon dioxide was formed by two reactions, one in which both oxygen atoms per carbon dioxide molecule came from the the water and the other in which one oxygen atom came from the water and the other from the coal. The latter reaction has already been postulated by Fry and Butz (8) to explain the formation of carbon dioxide by the action of alkali on various aliphatic oxygenated compounds. When the rate of formation of carbon dioxide during the alkali treatments of coal is plotted on a logarithmic scale against the reaction time, the curve obtained shows two distinct parts, indicating two distinct reactions. By extrapolation and integration, the amounts of carbon dioxide produced by each reaction were calculated. These amounts, together with the shapes of the curves, and the oxygen balances mentioned above, showed that the reaction in which one oxygen atom comes from the coal and one from the water is the initially pre-. dominant one, but falls off rapidly and becomes negligible in the latter half of the run, compared to the reaction in which both oxygen atoms come from the water.
BETWEEN ALKALI TREATMENTS OF TABLEVIII. COMPARISON COALAND BENZENE EXTRACT"
Yields (Carbon Basis), % YCompn. of Residues 7Phenols O+rj+% and Carbon (by $if Residue acids dioxide C H ference)
-
Benzeneext. Coal a
83.5 86.0
12.6 9.4
1.1 1.8
88.57
5.81
7.62
87.15
5.53
7.32
Temperature, 300' C.; alkali concentration, 5 N .
The PEI fraction of the benzene pressure extract of Edenborn coal was also subjected to alkali treatment for comparison with the coal itself. The yields obtained and the compositions of the residues produced are shown in Table VIII. Those from the extract are sufficiently like the ones obtained from the whole coal to indicate that the natures of the two materials are quite similar, as has already been shown by Weiler by halogenation ( l 7 ) ,and by Biggs by comparing the
VOL. 29, NO. 5
products of hydrogenation of, and humic acids made from, the two materials (3).
Summary The action of aqueous alkali on Edenborn coal has been investigated at temperatures from 250' to 400' C . and a t sodium hydroxide concentrations from normal to 100 per cent. The major products were cokelike residues which could be produced at temperatures as low as 275' C. although the temperature of initial plasticity of Edenborn coal is 393'. Using 5 N sodium hydroxide, the oxygen and hydrogen contents of the residues became progressively lower as the temperatures of the treatments were increased; but when alkali concentrations of 60 to 80 per cent were used, the lowering of the oxygen content occurred with very little lowering of the hydrogen content, so that from the standpoint of hydrogen economy, residues so produced are more suitable for hydrogenation than the coal itself. Moreover, hydrogenation of these residues yielded a product which was more hydrocarbon-like in composition than the product from a similar hydrogenation of the coal, and which showed some oiliness. Other products consisted of a solid phenolic material of high molecular weight, a viscous liquid of neutral nature, carbon dioxide, free hydrogen, and gaseous hydrocarbons. The oxygen in the carbon dioxide and the free hydrogen came partly from the coal and partly from the decomposition of water. The nature of the products supports the theory that oxygen is present in the coal substance in the form of ether or heterocyclic linkages. Similar results on alkali treatment of the coal and the amorphous portion of the benzene extract indicate that the chemical natures of the two materials are similar.
Acknowledgment The author wishes to express his gratitude to T. B. Smith and F. C.Silbert for making the ultimate analyses, to J. M. Scott for making the gas analyses, to R. C. Smith for the cryoscopic work, and to B. S. Biggs for the preparation of the petroleum-ether-insoluble portion of the benzene extract.
Literature Cited Asbury, R. S., IND.EXQ.CHEW,26, 1301 (1934). Biggs, B. S., S. Am. Chem. Soc., 58,484(1936). Ibid., 58,1020 (1936). Drees, K., and Kowalski, G., Brennstof-Chem., 15,449(1934). Fieldner, A.C.,et al., Bur. Mines, Tech. Paper 525 (1932). Fischer, F., and Gluud, W., Ges. Abhandl. Kenntnis Kohle, 3,243 (1918). Fischer, F., and Schrader, H., Ibid., 5, 353 (1920). Fry, H. S.,and Butz, A. J., Rec. truv. chim., 52, 129 (1933). Fry, H. S.,and Otto, E., S. Am. Chem. Soc., 50, 1122, 1138 (1928). Fry, H. S., and Schulze, E. L., Ibid., 48, 958 (1926); 50, 1131 (1928). Fry, H.S., Schulze, E. L., and Weitkamp, W., Ibid., 46, 2268 (1924). Hofmann, F.,Boente, L., Steck, W., and Amende, J., Nuturwissenschaften, 20,403 (1932). Sebastian, J. J. S., and Howard, H. C . , IND.ENQ.CHEM., Anal. Ed., 6,172 (1934). Smith, R. C., and Howard, H. C., S.Am. Chem. SOC.,58, 740 (1936). Waliaschko, N., Arch. Pharm., 242,225 (1904). Waterman, H. I., and Doting, J. S., J.Inst. Petroleum Tech., 16, 600 (1930). Weiler, J. F., Fuel, 14, 190 (1935). RECRIVED October 9, 1936. Presented before the Division of Gas and Fuel Chemistry at the 92nd Meeting of the American Chemical Society, Pittsburgh, Pa., September 7 t o 11, 1936. Abstracted from a thesis submitted to the Carnegie Institute of Technology for partial fulfillment of the requirements f o r the degree of doctor of science, June, 1935.
