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it is stable, and it is thus a valuable source for preparing pyrrole uncontaminated by any homologs, and for obtaining a-pyrrolecarboxylic acid. It is interesting to note that pyrocoll has not been obtained from any of the substances known to yield pyrroles other than gelatin, and now scrap leather. n
Pyrocoll
a-Pyrrolecarboxylic acid
Pyrrole
Weidel and C i a m i ~ i a n , 'in ~ their investigation of gelatin, obtained in addition to the "lower pyrroles" boiling between 125" and 190' C., also some "higher pyrroles'' boiling above 200' and up to 260" C. The same fractions were also found in the distillation products from scrap leather. These higher boiling oils give many of the characteristic reactions of pyrrole, and their behavior has strongly suggested to the author that they may contain polypyrroles such as dimethyldipyrrole, of which there can be a t least three isomeric modifications. These pyrrole oils distil over with some of the higher boiling hydrocarbon oils, but the two are not miscible and separate into two distinct layers upon standing, the hydrocarbons ' fr, forming the upper layer. It is d a c u l t to determine whether the saturated aliphatic hydrocarbons obtained as by-products from the distillation of leather scrap are the original oils used in currying and dressing the leather, or whether they are the decomposition prod16
Monofsh., 1, 294 (1880).
Vol. 17, No. 3
ucts from the fatty acids present. The latter view is suggested by the consistent formation of these oils from all kinds of leather scrap, by the presence in leather of fatty acids, and by the boiling points of two of the oils, about 272" and 306" C. Palmitic acid, CljH3iCOOH = COa C1SH32, b. P. 270' c . Stearic acid, C17HasCOOH = COa C17Hae, b. p. 303" c.
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The mineral or hydrocarbon oils that may be used to treat leathers might, of course, contain oils of these boiling points. Some hydrocarbon oils are also formed from the animal matter present in the leather, but these oils are lower boiling and are principally aromatic. The question of the formation of the hydrocarbon oils can be settled only by the carbonization of leather of known origin and history; this is obviously not possible with scrap leather. A satisfactory solution of this question is important, for if the fatty acids decompose into hydrocarbon oils, then fatty acid nitriles are not formed; and if this is correct, then a previous extraction of the fats and oils from the scrap is not necessary. The hydrocarbons are recoverable and are members of the upper boiling fractions of petroleum used as lubricants. Substances Obtained by This Process By this process there have been obtained from scrap leather the following industrially valuable substances: (1)ani(3) ammal charcoal, (2) chromic oxide-"chrome-green," monium chloride, (4)precipitated calcium carbonate, (5) sulfocyanide, (6) pyrocatechol, (7) pyrocoll, (8) pyrrole and homopyrroles, (9) higher pyrroles, (10) a. fuel gas, (11)hydrocarbon oils, and (12) fats and oils (solvent extracted).
A Turbine Oil Deposit' By A. G. Blakeley PHILADELPHIA 8r READING COAL& IRON Co., POTTSVILLE, PA.
OMETIME ago a sample representing a material or deposit taken out of the water-cooling compartment of a Ridgeway turbine was received in this laboratory. The turbine oil used had been of quite satisfactory quality, and no lubrication trouble had been experienced. Owing to the nature of the deposit, however, it was thought desirable to report the analysis. The material as received a t the laboratory consisted of brown powder and lumps, the lumps being easily crumpled to a brown powder. Chemical analysis showed the following results :
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Moisture or water.. Oil (soluble in petroleum ether or gasoline) . . . . . . . . . . . . . . . . . . . Matter insoluble in petroleum ether b u t soluble in ethyl ether.. Asphaltic matter.. Insoluble matter ..........................................
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.
Per cent 0.5 43,3 50.4 2.2 4.4
The moisture or water was determined by heating the material for an hour a t 105' C. The material melted on heating. The oil was determined by extracting the original material by means of petroleum ether or gasoline. The oil was probably turbine oil slightly darkened in color. The matter insoluble in petroleum ether but soluble in ethyl ether was a brittle, brown solid containing about 0.7 per cent 1 Presented before the Division of Petroleum Chemistry a t the 68th Meeting of the American Chemical Society, Ithaca, N. Y . , September 8 to 13. 1924.
ash. This ash contained iron oxide and copper oxide. It is probable that this brittle, brown solid consisted in part of metallic soaps. This ether-soluble portion of the turbine deposit had, no doubt, been formed by continued circulation and use of the oil, and by the formation of free fatty acids which gradually acted upon the metal with which the oil came in contact. The asphaltic matter was found by solution in chloroform. The extraction with chloroform was made on the material remaining insoluble after the extractions with petroleum ether and ethyl ether. The asphaltic matter was a black powder which did not melt a t 105" C. The insoluble matter reported in the analysis represents the matter not soluble in either petroleum ether, ethyl ether, or chloroform. The insoluble matter was mostly metallic iron, but contained some particles of wood and dirt. It is regretted that the sample obtained was too small in amount to permit a more detailed examination. This turbine deposit or material had, no doubt, been formed by the circulation and use of the turbine oil and by the collection of small amounts of dirt. Any oil in use is likely to show slight changes, and eventually some depositing out w i l l take place. The writer believes that the material was formed almost entirely from the turbine oil itself. The oil reported in the table of analysis was liquid in nature, but was held in solid form by admixture with the ethylether solubles consisting in part of metallic soap.
March. 1925
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