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specific gravity of a gas and its gasoline content as determined by the charcoal method. It should be stated t h a t in none of the methods in use for the determination of the gasoline content of natural gas is all of t h e gasoline recovered in liquid form. The charcoal method probably gives larger yields than any other method commonly employed. The highest obtainable efficiency will no doubt depend t o a considerable extent on the nature of the gas being treated. SUMWARY
I-The use of charcoal in testing gas for gasoline has been investigated. This has involved a study of the conditions under which the gas should be treated and of the conditions under which the adsorbed gasoline should be recovered. 11-A portable testing outfit has been described and directions for its use have been prepared. THE EXTRACTION OF BITUMENS FROM MINERAL AGGREGATE‘ By M. R. Walczak and H.I. Rice CHICAGO LABORATORY, THEBARRETT COMPANY, CHICAGO, ILL Received March 6, 1920
I n investigations of the behavior of bituminous road materials there has been a long-felt need of some method by which a binder could be recovered for further examination from a bituminous aggregate without materially changing its character and particularly its consistency. it has been the usual practice to extract with solvents such as benzene or carbon disulfide either by digestion and decantation or in some form of. extractor of which the “Forrest Hot Extractor”2 and the “Reeve Centrifuge Extractor”3 are representative types. These methods are entirely satisfactory for the quantitative determination of bitumen content of an aggregate or for the recovery of an aggregate for purposes of further examination. The bitumen may be recovered by evaporation of the solvent, and several methods of manipulation have been suggested,a but by none of them can one be sure of obtaining the bitumen in the exact condition in which it existed before extraction, particularly if i t contained volatile matter which is removed with the solvent. Moreover, in the recovery of t a r bitumens by the above methods the free carbon is left with the aggregate and the characteristics of the bitumen are changed accordingly. With the above objections in mind, the authors have succeeded in developing a method and apparatus which appears t o oRer a large possibility of success, particularly in the recovery of fluid or semi-fluid t a r bitumen without any material change in character or consistency through the r e ~ o v e r yprocess. This method is based on the principle of specific gravity where the two substances, bitumen and minParticularly adapted to tar bitumens. Forrest, Proc. Am. Soc. Testing Materials, 13 (1913), 1069. 8 “Reeve Centrifugal Extractor: Methods for the Examination of Bituminous Road Material,” by Prevost Hubbard and Charles S. Reeve, W S. Dept. of Agriculture. Office and Public Roads, Bulletin 314 (1915). 4 “Testing of Bitumens for Paving Purposes,” by A. W. Dow. Proc. Am. ,506. Testing Mater%&, 1903, 360. “The Modern Asphalt Pavement,” by Clifford Richardson. 1
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era1 aggregate, each mutually insoluble in the other, the bitumen having a low specific gravity (approximately I . 2 a t 60’ F.) and the mineral matter a higher specific gravity (approximately 2.70), are separated by the use of a solution of a n (approximately) inert salt of a gravity intermediate between the other two substances, thereby floating the bitumen while allowing the mineral matter t o remain as a sediment. The materials used in this work were: the mineral aggregate, consisting of a mixture of standard limestone, passing a three-quarter inch screen; a standard torpedo sand, mixed in the proportion of three t o one; and aqueous sodium carbonate as the intermediate solution. This was considered the best adapted for the purpose because of its ready solubility, and because of its inertness t o the t a r bitumen in question, as its only probable action on the t a r mixture would be solvent action upon the tar-acid content. Tests were made t o determine this point by thoroughly shaking 7 j cc. of the sodium carbonate solution (sp. gr. I . 2 7 t o I. 2 8 a t 60’ F.) with 2 5 cc. of dry t a r acids a t 140’ F., allowing t o settle in a separatory funnel graduated t o 0 .I cc. and noting any increase or decrease in either the soda solution or the upper layer of t a r acids present. No variation of volume of either substance was noted, but after removal of the soda solution and its slight acidification with sulfuric acid the odor of tar acids was noted, but no layer or measurable quantity of acids was present. Actual operation of this method confirmed the view t h a t the solvent action could be neglected. The t a r bitumen used in the experiment varied from a fluid t a r t o a soft pitch readily indented with the finger. APPARATUS
An ordinary, twoliter, vertical copper still was fitted with a tightly fitting funnel-shaped lid or cover fastened t o the still body with six screws and a rubber gasket. A flanged glass tube about I . j in. in diameter was fastened t o the top of the funnel lid by means
Aug., 1920
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of a union pipe joint. The top of the glass tube was closed with a cork stopper fitted t o a water-cooled, glass, reflux condenser, an overflow tube, and a thermometer. The interior of the still was fitted with a wire gauze ( 2 0 mesh) false bottom placed one inch above the bottom of still, resting for support on a circular collar of zo-gage metal one inch thick and 3 in. in diameter. The reflux condenser returned any of the lighter constituents t o the tar bitumen present, while the overflow tube was used for the withdrawal of the bitumen when the extraction was completed. METHOD
Two thousand grams of bituminous concrete were placed in the still and the lid fastened well, and sufficient sodium carbonate solution (sp. gr. of 1 . 2 7 t o I . 28 a t 60’ F.) was added t o bring the surface of the liquid just visible within the glass neck. Heat was applied t o the bottom of still until the bitumen adhering t o the mineral matter was liquefied and rose in globules and accumulated as a layer in the upper portion of the glass tube. The heat was applied gradually and care was taken not t o raise the temperature any higher than necessary t o float the bitumen. After all the bitumen present had accumulated the reflux condenser was washed with I O cc. of soda solution t o wash down adhering oils, after which the upper end of the reflux condenser was securely stoppered and the plugged end of the overflow tube removed. Heat was then applied rapidly to the bottom of the still t o cause a rapid formation of a steam pocket below the false bottom, causing the liquid bitumen in the glass tube or neck t o be ejected through the overflow which had been opened. The material was collected direct in a large test tube held a t the overflow tube, and was then centrifuged for 15 min. in a Babcock milk tester. The upper layer of bituminous matter was decanted and its consistency determined by any convenient method. For very soft or fluid bitumens a float’ test was used, having the cold bath a t -5’ C. and warm bath a t 2 0 ’ C. For heavier bitumen having a determinable melting point a regular cube melting-point (water) method2 was used. If any difficulty is encountered in securing the floating of the bitumen, the addition of about I O O g. of solid sodium bicarbonate t o the sodium carbonate bath a t the start of test will greatly aid the separation, as some bitumens, particularly the older or more weathered samples, adhere very strongly t o the mineral aggregate. The sodium bicarbonate apparently overcomes this trouble by its solvent action upon the limestone when this aggregate is present, undermining the bitumen, and loosening it, when i t is carried t o the surface of the liquid by means of the carbon dioxide gas liberated from the sodium bicarbonate. The following factors of this method were determined for their effect upon the consistency of the bitumen under question: 1 “Methods of Analysis Used in Coal-Tar Industry. 11-Distilled Tars and Pitches,” by J. M. Weiss TBIS JOURNAL, 10 (1918), 817. Test
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1-Accuracy of method on duplicate extractions. 2-Influence of finely suspended mineral matter present in Separated bitumen upon its consistency. 3-Influence of suspended soda solution present in separated bitumen upon its consistency. 4-Quantity of mineral matter suspended in separated bitumen. 5-Does selective separation of bitumen occur, or has the first separated bitumen in a test the 3ame consistency as the last separated portion? 6-Application of method to the two extremes of consistency of bitumen, oiz., fluid tar and tar pitch, 7-1s the free carbon of the tar retained by the bitumen?
The tests shown in Tables I and I1 were made t o determine the effect of the above-mentioned factors upon the consistency of t h e recovered bitumen. All mixtures of bitumen and mineral aggregate were made by rotating in a 2-liter, stoppered, wide-mouth TABLE I-CONSISTENCYOR MATERIAL UNDER TEST Float Test Seconds a t 20’ C./-5‘ C. TEST
1st 2nd 3rd MATERIAL TestTestTest Original fluid-tar bitumen.. 30 30 30 Original solid-tar bitumen. Fluid-tar bitumen after 1st test.. ................. 38 37 37 Fluid-tar bitumen after 2nd extraetion test, 1st portion.. 42 42 40 Fluid-tar bitumen after 2 tion test, last portion., , 46 42 45
No. 1
2 3 4
5
.........
........... ...
I b i d . , Test D6.
Standard Water Bath M. P. F.
--
Aver- 1st 2nd age Test Test 30 107 107 37.3 41.3 44.3
. . . . . . . . . . . .
31.3 . . . . 7 Original fluid-tar bitumen (with addition of 2 per cent mineral matter 1.. 35 35 33 34.3 . . . . 8 Original fluid-tar bitumen (with 20th soda solution and mineral matter added and centrifuged). 35 34 35 34.6 . . . . 9 Solid-t raction test, 108 108 10 Solid-t raction test.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 108.5 11 Solid-tar bitumen after addition of mineral matter and soda solution 108.5 107.5 and centrifuging.. 1 2 per cent mineral matter consisting of powdered limestone passing a 200-mesh screen was used here, as this is approximately the quantity found in the extracted bitumen, which on analysis was found to consist almost entirely of limestone passing a ZOO-mesh screen, very likely present from the limestone dust produced during the mixing of the bitumen and mineral aggregate. 31
31
32
........... ..............
.......................
bottle t o prevent evaporation of the ligher constituents of the bitumen. All mixtures consisted of 1500 g. of limestone, 5 0 0 g. of torpedo sand, and 150 g. of t a r bitumen. The two bitumens used consisted of a coalt a r pitch1 having a (cube method) melting point of 107’ F. chosen as the upper extreme and a fluid t a r bitumen2 sample. T A B L11-INSOLUBLE ~
MATTERI N BENZENE, FRESCARBON AND AS= CONTENT OR MATERIALS UNDER TEST Approximate Total Free Carbon Analysis of Ash Insol. (Insol. Matter Matter in in Benzene Asha Sodium Sand, TEST Benzene’ minus Ash) Per Carbonate Etc. No. Per cent Per cent cent Per cent Per cent 1 16.61 16.43 0.18 Normal Coal Ash Tar 2 22.86 22.64 Q.22 Normal Coal Ash Tar 3 18.87 16.13 2.74 30 70 4 17.01 15.69 (Av. 16.40) 1.32 20 80 5 18.71 17.12 1.59 20 80 9 22.90 21.62 (Av. 22.39) 1.28 20 80 10 24.63 23.16 1.47 30 70 1 J. M. Weiss, Lac. cil., Test B7. 2 Test B9. DISCUSSION OF RESULTS
A comparison is here shown between the original material and the same under the influences of the various substances with which i t is liable to contamination during the application of the method. The influence of soda solution is found to be but slight, 1
2
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Barrett’s Standard Tarvia X (road binder).
a Barrett’s Standard Tarvia K P (for cold patching of roads).
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7 . 3 sec., while a sligl-ltly greater influence is shown by contamination ’ with 2 per cent of mineral matter. T h e combined effect of mineral matter and soda solution is found slightly higher than t h a t o€ the mineral matter alone, but not quite the sum of both. There seeins t o be some selective separation of bitumen as shown under Consistency Tests 4 and 5 , which, however, will be reduced some under the application of the method as i t is aimed t o extract all of the bitumen, not half; when the extraction is completed any bitumen adhering t o t h e mineral aggregate would b e but a small percentage. By taking an average of Tests 4 and 5 (consistency), 4 2 . 8 , and comparing i t with Test 3 a comparison is obtained of the accuracy of the test, which in this instance was 5 . 5 sec., which seems reasonably close when it is seen t h a t the float test itself under these conditions gives a variation of 4 sec. The “Insoluble in Benzene” tests clearly demonstrate t h a t the free carbon content of the bitumen is not altered to any appreciable extent by the application of the method. The centrifuge method for the removal of the soda solution was adopted because of its ease of application. With the regular method of dehydration1 there was a very great tendency t o foam, and a possible loss of lighter constituents.
siderable study. Berthelot and Gandechon,l Kailau,2 Thiele,3 and Lesure4 have demonstrated the effect of ultraviolet rays in causing polymerization or decomposition of chemical compounds. Ostromisslenski5 showed t h a t vinyl bromide can be polymerized b y ultraviolet light in a few hours t o cauprene bromide. Similarly, Pribram and Franke6 found t h a t freshly distilled formaldehyde being exposed t o ultraviolet rays for some time contains a substance identified as glycol-aldehyde. Studies by Buchta? show t h a t light prevents the germination of cells. He also finds t h a t yeast cells exposed t o ultraviolet light for I O sec. do‘not germinate and exposure for 3 min. kills t h e cell. Stiner and Abelin8 found hemolytic amboceptors, diluted I : 100, t o be destroyed in I O min. llrvnres Fungus
Oidiwm olbirnnr Ch. Robin Pororacrharomyies A rhjordii Anderson Pororacchoronyies Thomnsii Anderson Socchnromyier albur Sotchoramyces anrmolour Hansen Sorrharomycer of Binot Sncch+romycer of Curtis Saccharomyces cereniriae Hansen Sarrhoromyccr rlliproidrur Hansen Sacrharomycrr hominir Busse Saccharomyces morrinnus Schizorairhnromycer Pombe Linder Torula m o i i o ~ ( ~ Torula humiiola Daczewska lVillia brlgiia Linder Zygosarchnroinyeer bisporur Anderson
OF SURVIVAL OF EACH ORGANISM AFTER EXPOSURE TO U L T R A V I O L E T L I G H T
FIG. TI TIME
Likewise Hartoch, Schurmann and Stinerg found diphtheria toxin t o be weakened by exposure t o t h e rays. Agulhon’O and Chaulpeckyl* studied the action of ultraviolet rays on enzymes which were shown t o be rendered inactive. Amylase and invertin are exceedingly sensitive t o them, and albumin is coagulated by their action. Further, Chamberlain and Vedder12 find amebae egisting in water supplies, whether motile or encysted, very easily killed on comparatively short exposure t o the rays. Von Recklinghausen13 gives considerable data on the bactericidal activity of ultraviolet light together with its adaptability in the purification of water. Comfit. rend., 153 (1911), 383. Monatsh., 84, 1209. 8 2 angew. Chem., 22 (1909), 2472. 4 J . #harm. chimie, [71 1 (1910). 569. 5 Chem.-Ztg , 36 (1912), 415. 6 Monatsh., 3S, 415. 7 Centr. Bakt. Parasitenk., I I Abt., 41 (1914), 340. 8 2. Immunitllt , 20 (1914), 598. 9 I b i d . , 2 1 (1914), 643. 10 Ann. inst. Pasteur, 26 (1912), 38. 11 Zenlr. Biochem. B z o p h y s , 14 (1912), 927. l a Philippine J . Sci , 6B (1911), 383. 18 J . Frank. Inst., 1914, 681; J . A m . Water Works A s s o c , 1 (1914), 565 1 2
THE ACTION OF ULTRAVIOLET LJGHT ON THE YEASTLIKE FUNGI-I By Bertram Feuer and F. W. Tanner STATE WATRRSURVEY DIVISION,
U R B A N A , ILLINOIS
Received March 2G, 1920
The effect of light on both a variety of microbial organisms and chemical reactions has received conI
Test B3.
io
Champagne yeaat c ~ ~ p i o ( o ~ogregalus cm Anderson crypioiarrur globralur Anderson Cryptrcocrur Ludwigii C,ypcoiomur ueirucosur Anderson Endomycer albicanr Monile candida Bon Mycoderma iaclir .Mycoderma monosa Avderson .Mycoderma ruforn
CONCLUSIONS
While the above tests were not as elaborate as desired, they indicate t h a t the method would prove sufficiently accurate for the purpose €or which i t was designed. I t is more rapid than many other methods, a n d the tar bitumen is separated from its mineral aggregate in substantially its true state as existing in the mixture. The increase in consistency of the extracted bitumen is due largely to contamination and not t o loss of constituents which with proper care can be reduced t o a minimum; althdugh there does seem t o be some slight solvent action of the soda solution as evidenced by its change t o a reddish brown solution. Such satisfactory results were obtained by t h e application of this method t o t h e extraction of t a r bitumens, t h a t there is no doubt in the authors’ minds but t h a t i t would prove equally well adapted t o the extraction of asphaltic binders from their mineral aggregate, perhaps not exactly as used here, but with some slight modification of the solution, dependent upon the character of the asphaltic material. This, of course, would require some further work which was not undertaken a t this time.
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