I S D U S T R I A L A N D ENGINEERING CHEMISTRY
February, 1931
The holding of eggs for incubation in a sealed glass jar has been recommended and may be of advantage because the pH of the white may be kept down to about 8.0-8.2. Summary and Conclusions (1) The pH of the white of untreated eggs rises very rapidly after the eggs are laid, owing to the escape of carbon dioxide. The pH increases more rapidly the higher the temperature. (2) After long periods of storage, particularly a t the higher temperatures, the pH of the white begins to decrease. (3) The pH of the yolk increases much more slowly than does the pH of the white. (4) The pH of the yolk and white were found to change very little on dilution. ( 5 ) Attention was called to the desirability of the study of the control of the pH of the white during the first few days of incubation.
199
Literature Cited (1) Aggazzotti, A,, Arch. ilal. b i d , 69, 305-21 (1913). (2) Aggazzotti, A , , Arch. Entwicklungsnzech. Organ., 40, 65-97 (1914). (3) Bailey, C. H., J . A m . Chem. Soc., 42, 45-8 (1920). (4) Baird, I. C., a n d Prentice, J. H., Annlyvsl. 66, 20-3 (1930). ( 5 ) Burke, E . , Mont. Agr. Expt. Sta., Bull. 178 (1925). (6) Dryden. J., Utah Agr. Expt. Sta., Bull. 92 (1905). (7) Dryden, J., Ibid., 102 (1907). (8) Edmond, H. D., Conn. Agr. Expt. Sta. (Storrs), Annual Report. 1907, pp. 157-62. (9) Graham, W. R., a n d Thom, C. C., Ont. Dept. Agr., Bull. 163 (1908). (10) Gueylord, F., and Portier, M. P., Compt. rend., 153, 1962-3 (1925). (11) Healy, D. T., a n d Peter, A. M., A m . J . Physiol., 74, 363 (1925). (12) Lamson, G. H., and Edmond, H. D., Conn. Agr. E x p t . Sta. (Storrs), Bull. 76, 219-58 (1914). (13) Romanoff, A. L. and A. J., Bid. Bull., Marine B i d . Lab.. 67, 300-6 (1929). (14) Scholl, H., Arch. Hyg., 17, 535-51 (1893). (15) Schweizer, C., Mitt. Lebensm. Hyg., SO, 203-9 (1929). (16) Schweizer, C., I b i d . , pp. 312-3. (17) Sharp, P. F., Science [ N . S.], 69, 278-80 (1929). (18) Tice, W. G., N. J. State Board of Health, 35th Report, 275-95 (1911). (19) Wladimiroff, G. E., Biochem. Z.,177, 280-07 (1926).
Studies in the Development of Dakota Lignite V-Extraction and Study of the Benzene-Soluble Portion of Dakota Lignite',' E. E. Harris,3 C. F. Belcher, and A. W. Gauger' DAK DEPARTMENT OF CHEMISTRY, UNIVERSITYOF NOXTHDAKOTA,G R A N DFORKS, ?i
NE of the characteristic properties which distinguishes N o r t h Dakota lignite not only from other ranks of coal, but from other lignites or ''brown coal" as well, is the low tar yield given upon destructive distillation. I n connection with an investigation of the possibility of making a coherent coke from this lignite it became advisable to study the tarry substances present in the original material.
0
Previous Work on Coal Extraction
Lignite from the Velva deposit in North Dakota has been extracted by the method of Bone and a study made of the benzene-soluble portion. For comparison purposes extractions by the Fischer method are also reported, Benzene used under pressure, as in the apparatus described, has a considerable solvent action on Velva lignite, and extracts at least up to 4.3 per cent of the dry, ashless coal substance. At least that portion of the extract obtained up to a pressure of 17 atmospheres has a composition closely analogous to the montan wax from German brown coal. It was resolvable into waxy alcohols and acids (some of which are present in the coal as esters), resins, and compounds of unknown composition. It seems probable that any phenols occurring in the portion of the extract obtained at pressures higher than 17 atmospheres are the result of some breakdown or thermal decomposition of the Estevan. Assuming that Bone (5) did not have decomposition of his lignite during the extraction, then Velva lignite differs from the Estevan in that the acidic portion of the benzene extract consists of aliphatic acids instead of phenols.
According to Francis and Wheeler (26) coals can differ from each other in respect to both the proportions and the properties of the constituents, but there is some evidence that the chemical compositions of the free hydrocarbons, resinous compounds, and organized plant entities (spore exines and cuticular tissues) do not vary greatly whether those constituents form part of a lignite, a bituminous coal, or a semi-anthracite. The composition of the ulmin compounds (resulting from the decay of vegetable tissues) does vary
1 Received August 12, 1930. Presented before t h e Division of Gas a n d Fuel Chemistry a t t h e 80th Meeting of t h e American Chemical Society, Cincinnati, Ohio, September S t o 12, 1930. 2 This material was presented b y C. F. Belcher in partial fulfilment of t h e requirements for t h e degree of master of science, University of Piorth Dakota 8 Associate professor of organic chemistry, University of N o r t h Dakota. 4 Director, Division of Mines a n d Mining Experiments, University of h-orth Dakota.
widely, a c c o r d i n g to the coals from which they are obtained. Extraction with solvents has found extensive application as a means of determining the composition of coals and their origin. The substances extractable from a bituminous coal by organic solvents normally c o n t a i n the remains of oils, fats, and waxes of the original coalforming plants, in addition to resins and their degradation p r o d u c t s . This extract is often erroneously classed as the resinous portion. Bedson ( 2 ) first suggested pyridine as a solvent for resolving the coal conglomerate, Clark and Wheeler (9) resolved bituminous coal into alpha, beta, and gamma compounds: alpha insoluble in pyridine, beta soluble in pyridine but insoluble in chloroform or benzene, and gamma soluble in chloroform and pyridine. Pearson (21) also supports pyridine as a mechanical solvent for the colloidal mass of coal. Cockram and Wheeler ( I O ) used a similar procedure. They also resolved the gamma constituents further into gamma'' 'I, 1'1, IV fractions by means of light petroleum ether and acetone, respectively. Gamma' consists mainly of saturated and unsaturated hydrocarbons; gamma" mainly of resins and resin degradation products; gamma"' and gamma" of resin-like substances, soluble and insoluble in acetone but similar in character. Bone (4) used a pyridine-amyl alcohol mixture for extracting and isolating the resins in bituminous coal.
200
ILVDUSTRIALA N D ENGINEERING CHEMISTRY
Pyridine extracts a larger percentage of the coal substance than other solvents, but i t is quite probable that it has other effects than mere solvent action. Fischer and Gluud were the first to apply benzene pressure extraction to coal as a means of increasing the yield of extract. I n work on brown coal (from Fabrik Webau der Riebeckschen Montan Werke A,-G.) Fischer obtained a 11 per cent yield with a Soxhlet extractor a t atmospheric pressure, whereas another sample of the same coal when extracted successively four times with benzene under pressure yielded 25 per cent of extract. The first extract represented essentially the montan wax of commerce. Montan wax, according to Schneider and Tropsch (.24), consists of a mixture of carboceric and montanic acids both free and esterified with tetracosanol and ceryl and myricyl alcohols. When heated to about 200” C. the wax begins to deDc o m p o s e , yielding solid and liquid hydrocarbons. Schneider and Tropsch also found that benzene-pressure e x t r a c t i o n gave an importantly higher yield of montan wax. The e x t r a c t i o n s made by Fischer and Gluud (15) were carried out in a steel bomb capable of withstanding a pressure of 200 atmospheres. Each charge of coal (1 to 2 kg.) was broken to the size of hazel nuts and extracted with 3 to 3.5 liters of benzene, heat being applied to the bomb externally by means of a powerful triple burner surrounded by a sheet of iron. The temperature was g r a d u a l l y raised to 275” C. corresponding to a pressure of about 55 atmospheres, and m a i n t a i n e d Figure 1-Pressure Extractor a t such degree for an hour, after which the heat was cut off and the bomb allowed to cool slowly. Each sample of coal was repeatedly extracted in this manner, usually four to five times. The resulting benzene solution, which had a strong greenish fluorescence in reflected light and a dark port-wine color when viewed in thin layers by transmitted light, was distilled on the water bath and the residual extract weighed. Fischer (13)extracted bituminous coal with benzene under pressure a t 250” C. and obtained an extract which he divided into two main components by means of petroleum etlierone soluble, termed “oily bitumen,” and the other a solid brown, insoluble substance, termed “solid bitumen.” Fischer ascribes the coking quality of a coal to the oily bitumen, which consists apparently only of hydrocarbons. (In mineralogy the term “bitumen” includes all natural substances which contain notable proportions of hydrocarbons.) Fischer, Broche, and Strauch (14) have suggested that with increasing geological age of the coals the ratio of free hydrocarbons to resins increases while the decomposition temperature of the resins is raised. Bone, Pearson, and Quarendon (6) have improved upon the Fischer apparatus by constructing a bomb which operates on the Soxhlet principle. A comparison of yields by the two methods by Bone on a strongly coking Durham coal gave a total extract of 12.4 per cent with the Fischer type of bomb and 15.6 per cent with the Soxhlet type bomb. The benzene extract from bituminous coals was resolved
Vol. 23, No. 2
into four fractions by means of light petroleum and ethyl alcohol: fraction I a yellow-brown, non-nitrogenous portion soluble in light petroleum; fraction 11, a nitrogenous, redbrown solid of low softening point, soluble in a mixture of 4 parts of light petroleum and 1 part benzene; fraction 111, a non-nitrogenous resinous portion soluble in ethyl alcohol; and fraction IV, a group of nitrogenous bodies of humic type, insoluble in ethyl alcohol. Monvell brown coal (Australia) when extracted by this method yielded about 15 per cent of extract. Owing to the different nature of this extract, another method of resolution was employed which separated it into acidic, saponifiable, and neutral portions. By treating the benzene solution with 5 per cent aqueous solution of potassium hydroxide in the cold, the solution was divided into acidic and non-acidic portions. The non-acidic benzene-soluble portion was also refluxed with alcoholic potash and a small amount of esters saponified. Bone (6) classes these portions from Morwell brown coal as (a) non-acidic and unsaponifiable resene-like portion, (b) resene ester portion, and (c) aliphatic or alicyclic portion. Later Bone, Horton, and Tei (6) in the resolution of Monvell brown coal and Estevan lignite (Saskatchewan, Canada) extracts, obtained by the Soxhlet type benzene pressure apparatus, state that between 50 and 60 per cent of the extract was phenolic in character (and resolvable into phenol, para-cresol, and catechol) and about 40 per cent was neutral oils. This work of resolution, in so far as it refers to Morwell brown coal, seems to contradict Bone’s previous analysis, for in the earlier paper the content of polyhydroxy phenols from the Morwell coal was reported as almost negligible (6, p. 624). Preparation of Lignite Samples In the work a t North Dakota lignite was used from the Velva deposit (near Minot, N. Dak.), which the authors believe should be comparable to the Estevan lignite since it is apparently of the same geological age. The lignite samples were ground and screened and the 2 0 4 0 mesh portion was air-dried for 24 hours and then ovendried for 1 hour a t 105” C. They were then sealed in mason jars until ready for use. Moisture and ash determinations were made upon opening for use. Extraction APPaRaTus-The apparatus (Figure l),which is essentially the same as that used by Bone ( 5 ) , consists of a chromevanadium steel container, A , 60.96 cm. inside depth and 7.62 em. inside diameter, of about 3 liters capacity, the lower half containing the solvent, and is heated electrically by a coil of nichrome wire wound on an alundum cylinder, B, of 7 inches (17.8 em.) diameter. The cup, C, is equipped with a Soxhlet siphon tube and has a screened false bottom about an inch above the actual bottom. This cuplike bottom is screwed on and can be detached to remove accumulations of powdered coal which may tend to clog the siphon tube. This cup is attached to a head, H , which is held in place by a threaded collar, E , the joint being made tight by a lead gasket. To the head H in turn are attached the pressure gage, F , and one end of the closed steel condenser, D; the other end of the condenser attaches to an opening in the side of the cylinder, The vapor of the hot solvent ascends the condenser tube from this opening, is condensed in passing downward through the coil, and the resultant liquid falls upon the coal in the siphoning cup, C. The heating unit can be adjusted to give varying pressures up to 750 pounds per square inch (about 50 atmospheres). PRocEDURE-The siphoning cup was charged with 200-250 grams of the dried and sized lignite, about 1 liter of pure,
ISDUSTRIAL .4,1'0 ESGI,$TEERISG CHEMISTRY
February, 1931
dry benzene was added and the apparatus evacuated (attachment being made at the valve 8) and then filled with nitrogen a t atmospheric pressure. The extraction m-as allowed to proceed in successive stages over periods of 5 to 8 days a t pressures of 10 to 44 atmospheres (corresponding to temperatures of about 180" to 280" C.). At the end of each stage the solution therein was removed and replaced by fresh solvent. Most of the extract was obtained during the first stage. The extractions were continued until the amounts of the resulting extracts were negligible. By closing the opening on the side of the container and replacing the Soxhlet type head with a head to which was attached a copper gauze container having a capacity of about 1200 grams of coal, the apparatus was readily transformed into the type of extractor employed by Fischer and Gluud (15). Extractions were made by the Fischer method a t an average pressure of 10 atmospheres and were continued until 100 grams of the solvent-free extract had been accumulated for resolution. DATA-The results of the extraction by the two methods are given in Tables I and 11. Table I-Extraction of Dakota L i g n i t e b y Fischer M e t h o d WT, OF DRY, No. OF WT. OF ASHLESS EXTRAC- SOLVENT-FREE SAMPLE COAL TIONS EXTRACT PRESSURE Grams Grams Atm. 14,a A 791.5 2 3 4 682.8
n
la
2 3 4
778.5
1 2 3 4
681.6
1 2 3
13.26 3.53 1.54 0.97 -1 (2.8%) Av. 10 14.81 5.21 1.75 0.95 22.72 ( 2 . 9 % ) A V . 10c 9.92 1.44 0.65 12.01(1.8%) X V . 1oc came off with the first extract probablv
small amount of water due to insufficient drying. b Low pressure due to a slight leak in the head. C N o water or excess gas pressure was noted. a A
Table 11-Extraction NO. OF SAMPLE
EXTRACTXOSS TIME
of D a k o t a L i g n i t e b y B o n e M e t h o d WT. OF DRY WT. OF ASHLESS S O L V E N T - F R E E PRESSURE
cO.4L
Lbs. 125-150 123-150
Atm. 8.3-10.0 8.3-10.0
Grams 189.2
-4
14 2"
Days 6 7
A
lb 26 3b
7 6 7
125-150 100-125 150-175
8.3-10.0 6.7- 8.2 10.0-11.,
190.9
1
S
6
250-275 250-275
16.7-18.3 16.7-18.3
194.3
0
.1
EXTR.4CT
Grams 4.40
e
4 . 8 4 (2.55%) Siphonplugged 3.08 0 2 3.78 (1.98%) 6.53 0.21
6 . 7 4 13.47%)
a
Small amount of gas but no water oherved. gas or water noted. Considerable gas and small amount of water.
b No C
Though the fourth and fifth extractions of sample B by the Bone method showed no excess gas pressure or water, the third, fourth, and fifth extractions had a characteristic odor of phenols and responded to the qualitative tests of Liebermann and Hoffman ( 1 ) . The fifth extract was golden brown and from the trend of yields it seems probable that the yield of extract would have been greater if the extraction had been carried further.
201
Treatment of Benzene Extract The benzene extract, which had a greenish fluorescence when viewed by reflected light and a golden brown color by transmitted light, was freed from the solvent by distillation over a water bath under diminished pressure toward the last. The residual extract was dried in the atmosphere for several hours and then weighed. The extract was then redissolved in benzene and treated with an aqueous solution of potassium hydroxide (5 per cent) according to the method of Bone (6) on Morwell brown coal and Estevan lignite. A light brown precipitate was formed immediately, some of which settled in the aqueous layer but much of which remained suspended and finally formed a layer between the aqueous portion and the benzene. The benzene containing the soluble substances was drawn off from the top, but owing to the formation of an emulsion even after several weeks only a little more than half of the benzene solution had been recovered. By treatment of the mixture with additional benzene more of the benzene-soluble substances were recovered. Undoubtedly, however, some benzene-soluble substances still remained, but in order to remove the solvent remaining in emulsion the mixture was steamdistilled. After this removal of the benzene the deep brown to black alkaline solution remained. The benzene-soluble portion was refluxed for 8 to 10 hours three times with alcoholic potassium hydroxide (2 per cent) to saponify any esters present; after each period of refluxing it was washed with water to remove the alkali-soluble portion. d small amount of brownish substance was thus removed and added to the aqueous alkali-soluble portion. The benzenesoluble portion was then placed on the water bath and the solvent removed, whereupon the residue when cool set to a deep reddish brown solid of resinous odor. The extract was thus roughly divided into 50 to 55 per cent alkali-soluble and 45 to 50 per cent benzene-soluble portions. Treatment of Alkali-Soluble Portion I n the belief that the alkali-soluble portion must consist of phenols, as had been reported by Bone (5) in the extract from Estevan lignite, qualitative tests were applied but were negative. When the alkaline solution was acidified with hydrochloric acid a light brown, gelatinous precipitate appeared, which when washed and dried in the atmosphere gave a light brown powder. This powder was found to melt from 80" to 85" C. and on cooling solidified to a hard, brittle cake. Since it was found to be acidic, it was suspected that it might be the socalled montanic acid or wax which Lemkowitsch '19) states melts a t 80-86" C., his sample having been obtained from Thuringian (German) lignite. Fischer (15) and Schneider and Tropsch ( 2 $ ) have obtained montan wax from Rhenish brown coal by benzene extraction under pressure, and from this they isolated carboceric and montanic acids, along with tetracosanol, ceryl. and myricyl alcohols Fractionation of Acidic hlixture with Ether and Acetone The brown cake was removed from the liquid and dried, first on the steam bath and then in air. It was then placed in a Soxhlet and exhaustively extracted successively with ether and acetone, according to the method of Pschorr and Pfxff ( 2 ? ) . YIELD FROM
Ether extract Acetone extract Residue
19 3 GRAMSSUBSTASCE Grams 70 53.7 10 36 4 12 21.3 4 82 25.0
Y I E L D FROM
11.0 GRAMSSUBST.4NCB Grams % 6 96 63 2 1 51 13 7 2 53 23.1
The ether extract was a viscous, chocolate-brown mass when warm and a hard, brittle cake when cool. The solvent was re-
202
INDUSTRIAL AND ENGINEERING CHEMISTRY
moved by drying strongly on the mater bath. The acetone extract was of similar color, viscous when warm, but setting to a crumbly cake when cool. The residue was light brown to gray and readily crumbled to a powder when touched, Saponification of Fractions
The fractions were next separately saponified by refluxing for a period of 5 to 6 hours on the water bath with a mixture of three-fourths alcohol and one-fourth benzene and one-fifth their weight of solid potassium hydroxide. Calcium chloride, double the weight of the potassium hydroxide, was then added and the mixture refluxed 2 hours longer. This converts the potassium salts of the acids to the calcium salts which are insoluble in acetone. Part of the solvent was then evaporated on the water bath and the thick, flowing mass poured into hot water. That which adhered to the flask upon cooling was scraped loose and added to that in the hot water. The dark brown mass finally collected as a cake on the surface of the water when cool. It was removed and dried strongly on the steam bath, after which it was placed in a Soxhlet and exhaustively extracted with acetone to remove the alcohols and unsaponifiable material. From 17.32 grams of the ether fraction 2.64 grams of alcohols and unsaponifiable compounds were extracted; 5.63 grams of the acetone fraction yielded only 0.68 gram of alcohols and unsaponifiable compounds; 7.36 grams of the residue yielded 1.14 grams of alcohols and unsaponifiable compounds. It appears that the ether and acetone extractions merely concentrated the unsaponifiable portion. Treatment of Alcohols and Unsaponifiable Compounds
The crude mixture of alcohols and unsaponifiable compounds was acetylated by warming on the water bath under a reflux condenser with four times its weight of acetic anhydride for 2 hours. The mixture was then poured into water and warmed a half-hour on the water bath with stirring to remove the excess of acetic acid. After cooling, the cake was separated from the water and without drying was put into a large amount of alcohol. This dissolved the acetate but left most of the resinous substances undissolved. The alcoholic solution was decanted off and boiled with animal charcoal to decolorize, and then filtered through a hot filter. As the alcoholic solution cooled the acetate separated out in tiny nee'dle-like crystals of silky luster. The acetate mixture from the residue after this treatment gave after two recrystallizations almost snow-white crystals, but the acetate mixture from the ether and acetone fractions required numerous recrystallizations from alcohol before a pure product was obtained. The mother liquor was difficult to remove and had to be evaporated off on the water bath. The acetate melted to a nearly colorless oil and hardened to a white wax. From the ether fraction and the residue fraction were obtained acetate mixtures melting a t 62-63' C. The acetate from the acetone fraction melted a t 61-62kC. Fractionation of Acetate Mixture
The acetate mixture was dissolved in about ten times its volume of alcohol-ether (I :1) mixture and evaporated on the water bath in stages. Each time, before further evaporation, it was allowed to cool and the crystallized portion separated by use of a suction filter. Two fractions melting a t 58-60" C. and 64-68" C. were obtained as well as a mixture melting a t 62-63" C. Upon further recrystallization the two fractions gave melting points of 59" and 65" C. These correspond to the acetates of tetracosanol (C24H500,m. p. 59" C.) and ceryl alcohol (Cz&s40,m.p. 65" C.). Upon saponification of the acetates with alcoholic potassium hydroxide and reacetylation of the resulting alcohol, the acetate
Vol. 23, No. 2
which formerly melted a t 65" C. gave a melting point of 66" C. This was saponified and gave an alcohol melting a t 80-81" C. Upon saponification the acetate melting a t 65" C. gave an alcohol melting a t 80-81" C. Reacetylation of this gave an acetate melting a t 66" C. The acetate with melting point of 59" C. gave an alcohol which must have been a mixture, as the melting point was not sharp, ranging from 80" to 83" C. Recrystallizations did not change the melting point. Determination of Saponification Number and Molecular Weight of Acetate
The determination was made according to the method of Benedikt and Ulzer (5)and gave the following results: ACETATEOF MELTING POINT66' C. Weight of acetate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.09723 N KOH u s e d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Saponification number, . . . . . . . . . . . . . . . . . . . . . . . . . . . Calculated saponification number of ceryl acetate, , . . , If acetate had one acetyl group its molecular weight would be . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ceryl acetate (mol. wt. calcd.). . . . . . . . . . . . . . . . . . . . . . . . Molecular weight of acetate in camphor, a b o u t . . . . . . . . . .
0.1132 gram 2 . 6 9 cc. 129 132.3 433 424 400
The amount of the acetate of melting point 59" C. was too small to permit a satisfactory determination of the saponification number and molecular weight. Preparation of Montanic Acids after Removal of Alcohols and Unsaponifiable Compounds
The substance remaining in the extraction thimble after the removal of the unsaponifiable portion and alcohols, which consists of the calcium salts of the acids and unknown substances insoluble in ether and alcohol, was decomposed by refluxing 4 to 5 hours with strong aqueous hydrochloric acid. Above the aqueous layer was added a layer of benzene which took up the organic acids as they were freed, thus leaving the hydrochloric acid free to work upon the undecomposed calcium salts. After refluxing, the benzene layer was separated and evaporated on the water bath. The residue was added to water; the organic acids formed a hard, dark brown cake. The cake was separated from the aqueous portion and dried on the water bath. The organic acids were next esterified by refluxing 4 to 5 hours with absolute alcohol and anhydrous hydrochloric acid. On cooling a dark brown layer was formed at the bottom. This was removed, leaving the alcohol solution of the ester a light brown. When the hot alcoholic ester mixture was poured into water, the ester was precipitated in light brown flocs, whereas the darker brown portion previously noticed in the bottom of the flask hardened into a stringy, pitchlike mass. The mixture was then filtered off from the water and the ester taken up in hot alcohol, which left most of the pitchlike substance undissolved. The ester solution was treated with animal charcoal and passed through a hot filter. After several crystallizations the acid ester crystallized from either alcohol or acetic acid as microscopically fine needles which aggregated in bushlike clusters and were nearly snowwhite. The melting points of the crude ester mixture from the three fractions were from 68" to 70" C. The acid ester was saponified by heating about an hour on the water bath with alcoholic potassium hydroxide and then decomposing the potassium salt of the acid with hydrochloric acid, which gave the free acid. This was separated by suction and washed with cold water. The free acid was taken up in hot alcohol, from which it again crystallized in fine needles. The crystals melted to a nearly colorless oil, which upon cooling set to a very pale yellow wax, A thin layer of the wax viewed by transmitted light appeared white. The acid melted from 80-82" C.
February. 1931
ISDUSTRIAL A S D ESGISEERING CHEMISTRY
Determination of Molecular Weight of Acid The molecular weight of the acid was determined by saponification of the acid ester in a manner similar to that applied to the acetate. From the potassium hydroxide used the molecular weight of the acid was calculated. ACID-ESTER, M. P. 68' TO 7 0 ° C. \Veight of acid-ester used.. ........................... 0.09634 ,V KOH used.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Molecular weight of ester calcd. for one COOH group.. . . Molecular weight of a c i d . . ........................... Weight of acid-ester u s e d . , ........................... 0.09634 A' K O H used.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Molecular weight of acid calcd. for one COOH group. , , ,
0,1664 gram 3 . 8 3 cc. 451 423 0.2804 gram 5 50 cc. 444
The molecular weights of montanic acid according to the formulas are CmHsgOz= 438 and C28Hj602 = 424. The approximate resolution of the alkali-soluble portion based on the total weight of the benzene extract indicates: Alcohols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Residues, unknown compounds, . . . . . . . . . . . . .
Further Treatment of Benzene-Soluble Portion
As it was suspected that the benzene-soluble portion might contain some of the waxy alcohols found in the unsaponifiable part of the KOH-soluble portion, it was acetylated by refluxing for 2 hours with excess acetic anhydride. Upon pouring the warm mixture into water to remove the acetic acid, a reddish brown cake was formed. By treating this with hot alcohol the acetate was taken up leaving the neutral or socalled resinous portion nearly undissolved. The acetate obtained represented approximately half of the benzenesoluble portion. The alcoholic solution of the acetate was decanted from the resinous residue, boiled with animal charcoal to decolorize, and filtered through a hot filter. The acetate crystallized from the alcohol in pale yellow microscopic needles and melted between 62" and 64" C. Further recrystallization gave a nearly white product. The mixture was then fractionally crystallized from an alcohol-ether (1:1) mixture and gave fractions melting a t 58-59' C. and 65-67' C. as well as a mixture melting over the whole range. The fraction melting a t 58-59" C. was small. Saponification of the two acetate fractions with alcoholic potassium hydroxide gave the alcohols melting a t 80-83 " C. and 80-81 " C., respectively. These acetate fractions are apparently the same as those recovered from the acidic portion of the extract. Here again the acetate melting a t 58-59' C. fails to give an alcohol of sharp melting point. Obviously, other methods than fractional crystallization must be employed to effect a sharp separation of the acetates and subsequently the alcohols. Approximate Resolution of Benzene Extract The resolution of the benzene extract from T'elva lignite has shown the following apparent composition : 0
Alcohol5 4cids Neutral resinous compounds Residues, unknown compounds
i:} 62 23
15 138 100
Pschorr and Pfaff (E')gave the following resolution of the montan wax obtained from German brown coal: c
Free montanic acid, a t least Montanic esters Compounds of unknown composition
ki ] 70
30 100
Comparison of the grouped alcohols and acids of the Velva lignite extract with the grouped montanic acid and the mon-
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tanic esters indicate that the lignite extract has a composition similar to montan wax. Discussion of Results Inasmuch as the Velva lignite examined is very probably of the same age as the Estevan lignite examined by W.A. Bone and co-workers, one would expect that the resolution of the benzene extract from the two lignites would be similar. Bone ( 5 ) , however, found the acidic portion of the Estevan lignite extract to consist almost entirely of phenols, whereas the authors obtained positive qualitative tests for phenols only in the portion of the Velva lignite extract obtained a t pressures above 17 atmospheres. Since some gas and water were found after extraction a t higher pressures, it is apparent that some breakdown of the lignite must have occurred. One must conclude that the phenols found in the extract from Estevan lignite are the result of thermal decomposition or that the extract obtained from Velva lignite is of almost entirely different character. This work indicates that the Velva lignite extract is similar to the montan wax from German brown coal. Various investigators have resolved the so-called montan wax into waxy alcohols and acids. Pschorr and Pfaff (22) were able to isolate three waxy alcohols, tetracosanol, CNHmO of m. p. 83 " C., as well as montanic acid, to which tthey ascribe the formula C28&,02 and a melting point of 83.5" C. They separated the alcohols from the acid by first converting the acid to the calcium salt and then extracting the alcohols with ether and acetone, They then acetylated the alcohols and separated the acetates by fractional crystallization from an alcohol-ether (1:1) mixture. The alcohols were obtained by saponification with alcoholic potassium hydroxide. These alcohols were also found by Schneider and Tropsch (24). Even more work has been done on the acidic portion of the montan wax. As early as 1852 Bruckner (8) isolated from German brown coal an acid melting a t 82" C. which he called "geoceric acid" and gave the formula C26Hs602. Hell (17) obtained the acid from refined montan wax. He determined the melting point of 83-84' C. and not higher than 84.5" C. and his calculations led to the formula C29H~O2.The term "montanic acid'' was first applied to the acid occurring in the montan wax by von Boyen ( 7 ) . Eisenreich (12) found an acid of melting point 82.5" C. and confirmed the formula C29Hs802. Some later investigators gave the formula C"rHj602. Ryan and Dillion (23) extracted a yellowish wax from Irish peat and from it obtained an acid melting a t 83" C. and determined this formula. Easterfield and Taylor (11 ) obtained from montan wax an acid melting a t 82.5" C. and corresponding to the formula C28Hs602. hIeyer and Brod (%@, investigating montanic acid, arrived a t the same formula and the melting point 83-84" C. Tropsch and Kreutzer (25)) however, show that the acid obtained from montan wax is not a single compound but a mixture of acids. By esterifying the acid with ethyl alcohol and sulfuric acid, separating the ethyl ester from the impurities, and distilling the ester in a vacuum, numerous fractions were obtained which were ultimately resolved into three acids-montanic acid, Cz9Hsg02,m. p. 86.5" C.; carboceric acid, C27Hs402, m.p. 84" C., and an unnamed acid, C2sHm02! m. p. 78" C. A more recent investigation of montan wax by Holde, Bleyberg, and T'ohrer (18) indicates that there are several acids present other than those mentioned. They separated numerous fractions by very careful highvacuum distillation, and found that montanic acid after being freed from the other acids has a melting point of 89" C.(uncor.) and is identical with normal octocosanic acid, CzaH56O~.
