T H E J O U R i V A L O F I N D U S T R I A L A N D EWGI N E E RI NG C H E M I S T R Y
July, 1917
residues from fuel combustion, together with volatilized alkalies. 11-Such dust contains considerable amounts of potash present both in readily a n d slowly soluble form. 111-The readilv soluble potash usually occurs as sulfate, due t o a combination of this base with t h e sulfur of t h e fuel a n d where there is a deficiency of sulfur, partly as csrbonate. IT‘-The slowly soluble potash is probably of a silicious nature, largely formed b y t h e u n i o i of potash vapor with incandescent ash particles. V-This silicious potash becomes soluble on boiling with water for a fen- hours, a n d on treatment with cold water for longer periods. VI-The presenc’e of lime accelerates the solution. VII-Slowly soluble potash compounds are also formed b y t h e interaction of potash salts in solution with silicious material, this recombination besing greatly accelerated b y heat. VIII-The action of moist soil promotes t h e arailability of t h e slowly soluble potash. IX-In view of t h e gradual a n d continued solution of t h e potash in cement kiln dust, i t should be of particular value as fertilizer material. Acknowledgments are due t o Mr. R . C . Haff a n d associates, of t h e Security Cement & Lime Company, a n d t o Mr. H. T‘. Welch, of this laboratory, for assistance a n d suggestions. LABORATORIES
\vEST’ERX PRECIPITATION ANGELES, C A L I F O R N I 4
OF THE LOS
COM1’4’1Y
SOME RELATIONS OF THE EFFECT OF OVERHEATING TO CERTAIN PHYSICAL AND CHEMICAL PROPERTIES OF ASPHALTS’ B y 4 . W. HIXSONA K D HAROLDE . HAKDS
The use of carbon tetrachloride as a solvent in differentiating bitumens was first suggested b y Richardson a n d Forrest* in 1906. They found t h a t true asphaltic hydrocarbons were soluble t o t h e same extent in i t as in carbon bisulfide. I n residual pitches which were carelessly refined, they found t h a t t h e bitumen soluble in carbon tetrachloride was less t h a n in carbon bisulfide. T o t h e hydrocarbons soluble in carbon bisulfide b u t insoluble in carbon tetrachloride, Richardson later applied t h e term “ C a r b e n e ~ . ” ~It was suggested t h a t these were t h e result of weathering in t r u e asphalts. I n t h e case of residual pitches i t was thought t o be t h e result of overheating during t h e industrial processes used in production. Kirschbraun4 took up Richardson’s suggestion a n d performed a series of experiments on t h e effect of overheating on refined Bermudez asphalt a n d on fluxed Bermudez asphalt. He found t h a t carbenes were formed a t high temperatures ( 6 5 0 - 7 0 0 ’ F.) a n d suggested t h a t t h e y were t h e result of either cracking a t high temperature or concentration-probably both. . Presented at the 54th Meeting of the American Chcrnical Society, Kansas City, April 10 t o 14, 1917. 1 Richardson and Forrest, J . SOC.Chem. I n d . , ‘24, 31 1. 8 “The Modern Asphalt Pavement,” 1st Ed., pp. 118. l.!O. 4 Municipal Engineer, SS (1908), 349.
65 1
I n 1910 Mackenziel took up t h e subject in t h e endeavor t o determine t h e cause of certain discrepancies in t h e results of carbene determinations in t h e same samples made in t h e S e w I’ork Testing Laboratory a n d another laboratory on t h e Pacific Coast. He found t h a t in t h e same sample of bitumen there Tas a n increase of carbenes when t h e carbon tetrachloride, solution was allowed t o stand in the light. He therefore called those carbenes which were precipitated completely from a tetrachloride solution on standing in t h e dark for 1 2 hrs., “true carbenes.” T o those which were then precipitated on allowing the filtrate from this determination t o stand in t h e light he applied t h e name ‘ t pseudo-carbenes.” He concluded: “ T h a t light acting upon a solution of bitumen in tetrachloride causes t h e bitumen t o decompose, t h e tetrachloride giving hydrochloric acid, which in t u r n combines with unsaturated hydrocarbons and precipitates them. B u t only certain bitumens (namely, those which have been more or less overheated) can bring about this phenomenon.” Similar results and conclusions were t h e result of practically a simultaneous work by Alexander.? As far as can be ascertained, no systematic work has been published which has t o do with t h e effect of overheating, and t h e presence of carbenes caused by this overheating, upon t h e physical and chemical properties of asplialts. This investigation was therefore undertaken with t h e object of determining t o what extent a n asphalt could be heated a n d still retain those properties desirable for a durable pavement. If carbenes are a result of overheating, then what is their effect upon a n asphalt; is t h e effect due simply t o t h e heating or do they alter markedly t h e properties of asphalt by their presence? It was hoped to arrive at a conclusion as t o t h e value of t h e carbene specification for asphaltic materials t o be used in road construction. I t was noticed t h a t , using t h e same asphalt, Mackenzie was unable t o check t h e results obtained by Kirschbraun either concerning t h e carbene content. or certain other properties, e . g., bitumen soluble in carbon bisulfide. This is not t o be wondered a t since neither investigator gave details of t h e methods of analysis used. It is a well-known fact t h a t in asphalt analysis two investigators have difficulty in checking each other even when t h e same methods are used. The errors due t o technique are too well known t o be recounted here. Keedless t o say, i t is therefore inipossible for any later investigators t o check their results quantitatively. I n this work no effort was made t o check t h e results of either Mackenzie or Kirschbraun. PURIFICATION OF REAGENTS
In order t o be absolutely sure of t h e results it was thought necessary carefully t o purify t h e carbon bisulfide and t h e carbon tetrachloride t o be used. The bisulfide was first shaken with lime-water until no color was imparted t o it. This removed any inorganic sulfides which might be present as impuri1
THISJOURNAL,
* I b i d . , 2 (1910).
a ( L ~ I O124. ), 242.
652
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
ties. T o insure t h e complete removal of any hydrogen sulfide t h e bisulfide was placed in a distilling flask, covered with one inch of a water solution of lead acetate and distilled over a water bath. The distillate was then fractionated using a Glinsky 4-bulb distilling head. T h a t fraction with a boiling point of 46.3’ was saved. This was water-white with a pleasant ethereal odor and gave no residue when 2 0 cc. of it were allowed t o evaporate spontaneously on a watch glass. It was then dried over lime, placed in glass-stoppered, brown bottles, and kept in a cool, dark place. The carbon tetrachloride was freed from carbon bisulfide by adding a quantity of alcoholic potassium hydroxide solution. It was then heated t o 60’ C. for one-half hour and t h e potassium xanthate formed was precipitated by adding water. The liquid was repeatedly washed with water until free from alcohol and potassium hydroxide. It was then fractionated, using a Glinsky 4-bulb distilling head. Fractions with a boiling point of 76.6 t o 76.8’ C. were kept dried over calcium chloride and stored in the same manner as the bisulfide. I n using both solvents, t h e wash bottles were completely covered with black paper t o prevent any decomposition by light. M E T H O D S O F ANALYSIS DETERMINATION
OF
BITUMEN SOLUBLE
I N CARBON
BITUMEN)-The method proposed by the Committee on standard tests for road materials of t h e American Society for Testing Materials was tried. I n the case of Trinidad asphalt, where t h e mineral matter is high, t h e results were very unsatisfactory. Filtration proceeded very slowly and much of t h e fine mineral matter went through the filter. I t was also found difficult t o prepare two asbestos pads for the Gooch crucible which would retain t h e same amount of mineral matter. For this reason great difficulty was experienced in obtaining concordant results. When very dense pads were used it was still found difficult t o check t h e results. Moreover, when carbon tetrachloride was used as a solvent, it required several days for filtration, and in one case over a week. Obviously, this would not do, for, as Alexander a n d Mackenzie found, t h e longer t h e time taken t o filter a tetrachloride solution of bitumen, t h e greater t h e amount of bitumen insoluble, due probably t o t h e action of light. So the following method was used: One gram of t h e asphalt (if t h e mineral content be low, more can be taken) was weighed into a tared 2 0 0 cc. Erlenmeyer flask and treated with I O O cc. of carbon bisulfide. The flask was then loosely stoppered and was shaken from time t o timeuntil solution was complete. This usually required about 30 minutes. The solution. was then centrifuged a t high speed for 30 minutes. Two C. Schleicher and Schiill No. 589 Blue Ribbon filter papers, which had been previously extracted with carbon bisulfide, were then weighed and onto these the supernatant liquid was carefully decanted. A double filter was used t o insure t h e collection of even t h e finest mineral matter. T h e residue in t h e BISULFIDE
(TOTAL
Vol. 9, No. 7
bottom of t h e centrifuge flasks was then washed with bisulfide a n d utimately all was brought upon t h e filters. The residue was washed with bisulfide until t h e washings were colorless. Suction was applied when necessary. All flasks and t h e filters were then dried a t 100’ C. and weighed. The filter papers containing t h e residue were then ignited t o determine t h e amount of “organic matter insoluble” and ash. I n this manner the ratio of “organic matter insoluble” t o ash was found. If any insoluble matter remained in the flasks this ratio was applied t o it and t h e ash and “organic matter insoluble” thus found were added t o t h a t found on ignition of the filter papers. The reason for this is obvious when one considers t h a t t h e insoluble mineral matter in t h e flasks will have absorbed or adsorbed a certain amount of bituminous material. It was found t h a t t h e ash determined in t h e fixed carbon test was slightly greater (about 1.35 per cent in t h e case of Trinidad asphalt) t h a n t h a t obtained by filtration. The reason for this is unknown. Richardson’ is authority for t h e statement t h a t the solution containing this shows, under the ultra-microscope, t h e characteristic Brownian movement of colloids and t h a t i t is due t o colloidal clay and other mineral matter. But might not this difference be caused by a solution of slight amounts of mineral salts in the solvent? These salts might be salts of mineral acids or mineral salts of organic acids of high complexity. This might be expected, especially if the solvents were not completely waterfree-a condition hard t o secure. If t h e mineral is colloidal then it will probably have bitumen adsorbed on its surface. I n this work it was assumed t o be colloidal a n d therefore a correction was applied t o t h e mineral matter found on filtration. I n making this correction t h e same ratio between ash and “organic matter insoluble” was used as t h a t found on ignition of the filter residue. I n order t o determine if t h e long standing, as specified in t h e method of the American Society for Testing Materials, was of value before centrifuging, experiments were carried out in which t h e asphalt stood in contact with the solvent for different lengths of time. I n each case one gram of refined Trinidad asphalt was shaken with I O O cc. of carbon bisulfide. The results, given in Table I, showed t h a t long standing was not necessary when t h e centrifuge was used. TABLBI TIMEoa 30 mins. .. STANDING 58.02 Bitumen soluble in C & . , Mineral matter insoluble.. . 30.00 “Organic matter insoluble”. . 7 . 9 8 ( a ) Stood 24 hours, was decanted then stood 24 hours longer.
.... . .. .. ..
24 hrs. 48 hrs. 70 hrs. 48 h d o ) 57.41 58.65 59.77 58.00 30.04 33.48 33.31 32.66 7.19 9.11 8.69 8.69 and 100 cc. fresh solvent added;
The following points then led t o t h e adoption of the above method of separation: I-The time element was cut t o a minimum, it being possible t o complete filtration, even from a tetrachloride solution which formerly took several days, in a few hours. This is very important in making t h e carbene determination. 2-Results could be made t o check closely. 3-By t h e use of filter paper, instead of an asbestos 1
J . P h y s . Chem., 19, 245.
TH.E J O U R N A L O F I N D l J S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
July, 1917
padded Gooch crucible, i t was possible i o control more evenly t h e sLze of t h e openings a n d therefore t h e amount of mineral matter retained. B I T U U E N S O L U B L E I N C A R B O N TETRACHLORIDE-The same method was used as in determining t h e bitumen soluble in carbon bisulfide, using instead IOO cc. of carbon tetrachloride. CARBEKES--NO a t t e m p t was made t o determine t h e pseudo-carbenes described by Mackeiizie. T h e bitumen soluble in carbon bisulfide b u t insoluble in carbon tetrachloride, when t h e determinal ions were made as described above, was taken as t h e carbene value. F L O W TEST-This test was performed ac2ording t o t h e directions given b y Richardson.1 The test was made a t t h e melting points of t h e asphalts a n d t h e flow in millimeters during j minutes was taken. An electric oven was used. All other tests were performed accordiqg t o t h e directions given in T h e Office of Public Roads, Bulletilt 38, on “Methods for t h e Examination of Bituminous Road Materials.” I n making t h e melting-point test, t h e oil b a t h was heated at t h e rate of 5’ per minute. All Flenetration ---CRUDE
Temperature ofHeatine -
\ .... 163O
-....
163O ZOO0
99.26 99.26 None
... ... .. ,
TABLEII--TESTS TRINIDAD ASPHALT200°
235O
265O
300°
MAD&AT
black homogeneous substance which was quite soft a n d sticky. T h e oil asphalt was a dull black homogeneous substance which was also quite soft and sticky. However, i t could easily be cut with a knife.
Temperafure of heof/nq PROPERTIES A F T E R HEATING
I n t h e case of each asphalt there was a n increase in t h e melting point after heating t o zoo’ C., more marked possibly in t h e case of t h e brick filler (Fig. I). DIFFERENT TEMPERATURES
BRICK
OIL ASPHALTICCEMENT-
FILLER 235”
265O
300’
....
163’
200°
235’
265’
300’
97.27 97.52 -0.25
97.36 96.14 1.22
96.88 81.32 96.58 73.38 0.30 7 . 9 4
2.48 0.25
2.34 0.30
2.7616.94 0.36 1 . i Q
15.33 15.33
15.03 13.52
350°
I
Bitumen Soluble: 54.90 , 53.77 51.62 50.39 30.70 in CSt inCCt 52.78 53.63 52.27 53.13 27.64 2.12 0 . 1 4 -0.65 -2.74 3.06 Carbenes Matter Insoluble: Organic 9.45... 10.58 10.87 1 2 . 0 0 1 8 . 2 9 Mineral 35.65 35.65 37.21 37.61 51.01 Fixed Carbon: Determined 8 . 7 1 ... 10.70 8.73 8.45 18.98 8.71 10.70 8.30 8.02 13.26 Corrected Loss on Heating ... 1 . 0 4.95 5 . 2 1 30.11 M. P. ( ” C.), 113 129.5 133.0 130 5 Doesn’t flow 40 1.0 Penetration.. 40 5 4 . 0 4.0 4.0
...... .... .....
. . ...
....
_..
... . ..
...
...
13 49 13.49
...
78
........ ...
None 0.74
.,,,
65 7
98.48 98.48 None
97.80 85.50 12.30
98.18 97.93 0.24
... ...
0.78 0.74
0.17 0.89
0.17 1.13
0.78 1.42
1.55 0.27
...
15.96 15.96
16.93 14.07
18.46 12.09
26.18 13.64
14.38 14.38
... ...
0.23
...
1.0 121
. .. 34.51 16.85 128.3 136
47.88 159
....
0.40
53.0
21.5
... ... ...
. . 123.5 120 90 0 32 5 ... 50.5 tests were made under a load of IOO g. for j seconds at a temperature of 38’ C , except in t h e case of t h e oil cement, where t h e load was 50 g. T h e New York Testing Laboratory Penetrometer was used. MATERIALS USED
I-Crude Trinidad asphalt which h a d been finely powdered and air-dried before testing. 2-A brick filler which consisted of a natural asphalt fluxed with 7 0 per cent of asphaltic oil residuum. 3-.4n oil asphaltic cement of unknown origin. M E T H O D O F HEA’rING-About IOO g. of t h e asphalt were placed in a ’arge crucible-shaped porcelain dish a n d heated t o t h e desired temperature in a n air oven over a period of five hours. At t h e end of this time i t was poured out, allowed t o cool, a n d if h i r d enough was ground t o powder a n d sampled. Tests were made at t h e different temperatures as given in Table 11. The nature of t h e change on heating mtty perhaps be followed better by considering t h e change a t each temperature . O R I G I N A L PROPERTIES
T h e crude Trinidad asphalt when pulverized h a d a dry earthy appe,zrance. The brick filler was a jet“The Modern Aspbalt Pavement,” 1st Ed., p. 537.
98.94 98.70 97.21 97.51 1.73 1.19
.. . ... ...
Flow a t M. P. 10 5
1
6 53
16.3 Over 185
8.4
6.4
47.5
3.0
14.97 31.13 58.83 11.23 4.83 13.46
...
1.0 16.4
4 2 . 0 30.5 Over 185
27.5
24.5
25.0
81.6
13.5
8.0
8.0
1.0
133
...
... ... .. . ... 1.18
10.00 25.00 84.48 77.12 167.5 164.5 91.3
... ... ...
There was a decrease in t h e penetration (Fig. 11); greatest in t h e case of t h e brick filler and crude Trinid a d asphalt. The fluidity of these two asphalts also increased, t h a t of t h e Trinidad being greatest a t this temperature. The oil cement showed a marked decrease in fluidity. The fixed carbon (Fig. V)
Temperature of hwfiny
showed a slight increase, as was t o be expected. Of special interest is t h e decrease of carbene content (Fig. IV) in t h e Trinidad asphalt. A corresponding decrease was found in t h e oil cement; in fact, t h e bitumen was even more soluble in carbon tetrachloride t h a n i n carbon bisulfide!
654
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
Changes in t h e nature of t h e asphalts were quite noticeable after heating t o 2 3 5 ' C. The melting points continued t o rise in all cases. T h e asphalts became harder. T h e Trinidad became so hard t h a t i t was easily crushed a n d ground in a coffee mill. The brick filler broke with a conchoidal fracture when hit a quick, hard blow. The oil cement continued t o be fairly soft. The flow tests showed t h a t t h e Trinidad asphalt and oil cement became slightly more viscous, while t h e brick filler showed its max-
I
F
F
st
t! Temperafure of heatiny
imum fluidity a t this point, it being so fluid t h a t i t flowed off t h e end of t h e plate. While t h e oil cement a n d brick filler both showed a n increase in carbenes at this temperature, t h e decrease was still greater in t h e case of t h e Trinidad asphalt, which now became more soluble in carbon tetrachloride t h a n i n carbon bisulfide; there also appeared a decrease in t h e fixed carbon content! After heating t o 265' a break was noticed in all t h e curves depicting t h e various properties. I n t h e case of t h e Trinidad asphalt a n d oil cement, there was a lowering of t h e melting point, t h e fluidity, a n d t h e fixed carbon, while in all three there was a decrease in t h e carbenes. The Trinidad became more markedly soluble in carbon tetrachloride t h a n in carbon bisulfide! Upon heating t o 300' a very decided change took place. T h e Trinidad asphalt became so hard t h a t i t was easily- ground t o I O O mesh. After being ground -
Ecyeruhre
of heating
i t would not fuse together again, so i t was impossible in this manner t o make a cube for t h e melting-point determination. Fortunately, a large lump was at hand, which was then molded into shape a n d t h e test performed. However, t h e asphalt would not flow even after heating t o 300' C. T h e brick filler was ground in t h e mill a n d t h e oil cement became very soft, mealy a n d lost its stickiness. While t h e penetration of t h e other samples became suddenly less, t h e penetration of t h e oil cement became decidedly
Vol. 9, No. 7
greater. I t s melting point became lower a n d i t refused t o flow on t h e flow plate. I n each case a decided increase in fixed carbon a n d carbenes was noticed. Each asphalt seemed t o lose its fluidity. I n centrifuging t h e carbon bisulfide and carbon tetrachloride solutions of these samples a n interesting observation was made. I n t h e case of t h e former, all t h e insoluble matter went t o t h e bottom of t h e flasks. However, in t h e carbon tetrachloride solution there was a separation-there being a layer of shiny bituminous substance a t t h e top. If this t o p layer consisted of t h e carbenes i t indicates t h a t their density lies between t h a t of t h e bisulfide ( I . 2 7 0 ) a n d tetrachloride (1.604). This may afford a n effective means for their separation. I n reviewing t h e changes in properties, t h e question naturally arose as t o t h e cause of t h e Trinidad asphalt becoming more soluble in tetrachloride after heating t o 235' and 265') a n d why t h e carbene content of t h e other two became less at 265 ' t h a n a t 2 3 5 '. There seemed t o be a corresponding change in other properties during this range of temperature. Evidently there was a decided change in t h e nature of t h e hydrocarbons themselves. Just what this change is can a t
Temperature of heating
present only be surmised. The fixed carbon content may be of assistance in explaining this. If this is calculated back t o t h e basis of t h e weight before heating, it may offer a suggestion. If there is no change in t h e nature of t h e hydrocarbons, a n d t h e process is simply one of distillation, we should get a straight line curve when t h e values are plotted. Accordingly this vias done using t h e formula
and t h e values so obtained were plotted in Fig. VI. It is noticed t h a t in all cases there is a drop a t 2 3 5 to 265'. The brick filler and Trinidad curves then t u r n upward a t 3 0 0 ' . However, t h e oil-cement curve continued t o fall a t this temperature. Evidently then, there was some change in t h e nature of t h e hydrocarbons themselves a n d this may give a clue as t o t h e nature of t h e carbenes. Richardson' has found t h a t paraffin hydrocarbons of t h e series C,Hzn-2 yield no fixed carbon on ignition and t h a t t h e amount left increased as t h e propor2
"The Modern Asphalt Payement
"
1st
Ed, p. 118
July, 19 I 7
T H E J O U RIVA L O F I N D LTST RI .I L ,4 LVD E X G I - V E E R I N G C H E M I S T R Y
tions of carbon t o hydrogen increased. I n Grahamite, when t h e ratio is 8 t o I , there is as high as j 3 per cent of fixed carbon. If this is t r u e for asphaltic hydrocarbons. t h e general nature of t h e change: may be followed. By consulting Fig. VI i t is seen t h a t up t o 2 0 0 ’ t h e process was prcbably one of distillation of lighter hydrocarbons. This was confirmed by a n increase in melting points and decrease in t h e penetr.xtion. I n t h e case of t h e natural asphalts t h e hydroce.rbons left were more mobile when melted. I n t h e case of oil cement, when t h e hydrocarbons are chiefly of t h e paraffin series,’ they are less mobile when heated, due t o higher hydrocarbons. Upon heating t o 2 3 j O2 6 j ’ t h e curve would indicate t h a t t h e proportion of carbon t o hydrogen is less. .This may be due simply t o a distillation of low boiling point hydrocarbons rich in carbon. Those hydrocarbons left in case of natural asphalt, though very hard, show t h e maximum fluidity when heated t o their melting point. They are also more soluble in carbon tetrachloride t h a n in carbon bisulfide. J u s t what hydrocarbons are formed offers a n interesting field for research. Cpon heating to 3 0 0 ’ t h e natural asphalts show an upward t u r n in t h e curve, indicating that t h e proportion of carbon t o hydrogen has again increased. This may be due t o a cracking process in which either unsaturated hydro’carbons or those of t h e naphthene
65 5
Accordingly, a sample was heated t o 3 j o ’ C. for j hours. The fixed carbon ivas found t o increase as was expected. Evidently, then, t h e so-called carbenes may consist of either unsaturated hydrocarbons or saturated naphthenes, or both. Much further work is necessary, hon-ever. before their nature can be definitely established. Co~cLusIoXs I-The results of this work seem t o show t h a t carbenes are probably t h e result of t h e cracking of paraffin a n d asphaltic hydrocarbons into both naphthenes and unsaturated hydrocarbons. 11-hloderate heating may so change t h e nature of t h e hydrocarbons as t o render t h e m more soluble in carbon tetrachloride t h a n in carbon bisulfide. 111-Overheating causes marked changes in both natural and oil asphalts which render them unfit for paving purposes. Whether natural asphalt which has been heated over 2 3 j O C. is still suitable for durable pavements can be determined only by actual experience, but certainly a temperature limit is important. IV-It is believed t h a t t h e fixed carbon curve when corrected t o t h e original \\-eight of material before heating offers a means of tracing t h e changes in t h e molecular structure of t h e hydrocarbons when they are subjected t o t h e influence of heat. V-There is a close relation between the carbene value a n d t h e physical properties of asphaltic materials. Although t h e physical specifications may be so made t h a t a high carbene content will be excluded, i t would seem wise t o keep t h e carbene specification as a safeguard until further information on t h e subject can be obtained. INDUSTRIAL CHEMISTRY LABORATORY IOWACITY
STATE UNIVERSITY O F IOWA,
Emperature q@ heating
type are formed-either of which are stable a t high temperatures. Carbenes now p u t in a marked appearance. Mackenzie suggests t h a t t h e carbenes are unsaturated hydrocarbons, b u t might they not be both? T o determine whether a large amount of unsaturated compounds appeared, t h e iodine numbers were run upon t h e brick filler a n d Trinidad. T h e method used was t h a t of Hubl-Waller described b y Holde.2 The values are given in Table 111. I n neither case was there a marked increase due t o t h e presence of carbenes. TABLE111-IODINE NUMBERS Original Crude Trinidad.. . . . . . . . . . 20.14 Brick Filler . . . . . . . . . . . . . 15.11
.. . .
...
Heated to 300’ 22.16 19.26
I n t h e case of t h e oil cement a still further decrease Since in t h e fixed carbon was observed a t even 300’. oil residuums consist mainly of saturated paraffin hydrocarbons, i t would seem t h a t distillation of t h e lighter hydrocarbons proceeds even a t this temperature. If such is t h e case, further heat should crack t h e m into unsaturated hydrocarbons a n d naphthenes. 1
“The Modern Asphalt Pavement,” 1st Ed., p. 105.
a “Examination of Hydrocarbon Oils,” Holde, Mueller, p. 350.
OBSERVATIONS ON THE ACTION OF SULFUR MONOCHLORIDE ON BITUMINOUS AND TARRY SUBSTANCES AND HYDROCARBON OILS ’
By JOSEPH V. MEIGS Received March 22, 1917
It was t h e writer’s original intention t o work out a n analytical method for examining bituminous substances on t h e basis of t h e amount of hydrogen sulfide evolved per unit weight of bitumen on heating t h e latter with sulfur. This idea was soon abandoned, however, on account of t h e inconvenience a n d undesirability, for analytical purposes, of maintaining a uniform elevated temperature (approx. 13 j’ ‘2.). T o see whether sulfur and bitumen would react in solution, varying amounts of both were dissolved together in carbon disulfide, and allowed t o stand, b u t no sensible reaction was observed. On evaporating t h e carbon disulfide, black sulfur crystals were obtained, which, examined under t h e microscope in polarized light, had in some cases t h e appearance of a solid solution of bitumen in sulfur. T h e advantages of sulfur monochloride, as a form of sulfur more active, in t h e cold, t h a n t h e element, then presented themselves. The effect of this reagent (“Schwefelchlorur,” made by Kahlbaum) on bitumen
