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
656
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
was found t o be a very distinct one, not only as a reagent but also as a solvent. A residual oil asphalt, which we will designate as “asphalt B,”with a penetration of 1 2 ’ ( 1 0 0 g., 5 sec., 2 5 ” C.), containing 9 9 . 6 per cent pure bitumen, was found, qualitatively, t o be soluble in sulfur monochloride a t room temperature t o t h e extent of leaving no sticky residue on filtration of the solution. Several liquid bitumens were found t o be similarly soluble. Moreover, on treating a solution of “asphalt B” in carbon disulfide with a solution of sulfur monochloride in carbon disulfide, t h e writer found, by testing with filter paper moistened with ammonia, a n d comparison with a blank test on a solution containing no bitumen, t h a t hydrochloric acid gas was evolved, slowly, b u t in considerable amount. This was t h e only external evidence of a chemical reaction. More pronounced, however, were t h e effects, when a t a r product used for paving purposes, which we will designate as “ t a r binder B,” was so treated. I n addition t o a much larger evolution of hydrochloric acid gas t h a n in t h e case of t h e asphalt, a marked change took place, in t h e course of 1 5 minutes, in t h e character of t h e solution; i. e., much of t h e material in solution was removed, as evidenced by t h e precipitation of a black, friable powder, insoluble in carbon disulfide, a n d b y a color change, from black a n d opaque, to deep red a n d , t r a n s p a r e n t . It is interesting t o note t h a t when sulfur monochloride was added, full strength, t o “tar binder B,” in t h e proportion by volume of one t o two, a violent reaction ensued. Vigorous ebullition a n d frothing took place, a n d a degree of heat was developed, much t h e same as when strong sulfuric acid a n d water were mixed in t h e same proportion (one t o two). This effect is t o be contrasted with t h e externally quiet, solvent action of strong sulfur monochloride (undiluted with carbon disulfide) on “asphalt B.” Indeed, one of t h e most noticeable effects of t h e strong sulfur monochloride on “tar binder B” was t o increase its viscosity t o such a n extent t h a t , in t h e course of I O minutes, t h e originally liquid material became changed t o a hard, brittle mass. “ T a r binder B” yielded t h e following fractions on distillation: PERCENTAGES : First oils t Second oils to 1 Heavy oils to 2 Heavy oils to 3 Pitch. ....................................
B y Volume
By Weight 0.6 0.9 1.9
25.4 12.9
52.3
58.2
I n order t o prove t h a t t h e evolution of hydrochloric acid gas in t h e cases cited was not due t o t h e presence of water in t h e substances themselves, or in t h e reagents, as well as t o s t u d y t h e action of t h e sulfur monochloride, a n apparatus was devised t o measure accurately t h e ratio of t h e amount of hydrochloric acid gas evolved t o t h e amount of bituminous substance acted upon by t h e sulfur monochloride. T h e method employed in conjunction with t h e apparatus, which is seen in diagrammatic form in Fig. I, consisted in dissolving t h e bitumen in carbon disulfide, then adding t h e sulfur chloride reagent in a closed tube, aerating this solution with d r y air, a n d
Vol. 9, No. 7
sucking t h e dry air, mixed with hydrochloric acid gas a n d a certain quantity of sulfur monochloride vapor, f i r s t , through a Pennsylvania Railroad tube (R’), containing carbon bisulfide, in order t o dissolve and remove t h e vapor of sulfur monochloride, second through water,’
F/G. I (& Size)
MI... .
.
t o absorb t h e hydrochloric acid gas. This was t h e n determined b y titrating a n aliquot portion of t h e water with N / 2 o sodium hydroxide, using methyl orange as indicator. Before entering t h e reacting solution, t h e air was saturated with carbon bisulfide vapor in a second Pennsylvania Railroad t u b e ( R , Fig. I) t o prevent evaporation of carbon bisulfide from t h e reacting solution. The air used for aerating t h e reacting solution (by means of aspiration) was dried and freed from carbon dioxide by passing through two drying towers, 1 5 inches high, filled with fused calcium chloride, t h e n through a soda lime tube, four gas-washing bottles containing strong sulfuric acid (sp. gr. I . 84), a n d finally, through a drying tower 1 2 inches high containing alternately placed layers of glass wool a n d phosphoric anhydride. T h e Pennsylvania Railroad tubes ( R a n d R’, Fig. I ) and t h e reaction t u b e A were heated t o 1 3 0 ’ C. a n d cooled in a vacuum desiccator over strong sulfuric acid (sp. gr. I . 84) before use. T h e sulfur monochloride reagent finally adopted was made by dissolving jo g. of Kahlbaum’s “Schwefelchloriir” in 470 g. of carbon disulfide, which h a d been previously dried by shaking with a n d standing over anhydrous sodium sulfate a n d phosphoric anhydride, respectively. This solution was kept in a glass-stoppered bottle in a desiccator^ over concentrated sulfuric acid in which 2 0 per cent b y weight of phosphoric anhydride was dissolved. All t h e carbon disulfide used was dehydrated and pre1 It is not possible to use NaOH solution as absorbent, since carbon bisulfide is carried over into the absorbing solution, and would react with t h e latter, as the writer found.
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
July, 1917
I
served in the same manner. The asphalt, in order t o remove traces of water, was kept for ten minutes with stirring, a t ,130’ C., cooled and preserved in a desiccator containing t h e drying agent mentioned (HzS04 P206). The “tar binder B” used was dehydrated by keeping a t 1 1 0 ’ C., with stirring, for 5 minutes, then cooled and preserved as in t h e case of t h e asphalt.
It is t o be emphasized t h a t t h e action of t h e sulfur monochloride on the substances examined was found t o be distinctly a time reaction. Indeed, in t h e case of t h e hydrocarbon oils t o be mentioned, bubbles of hydrochloric acid gas were seen coming of? and shown t o be such, even after t h e lapse of 16 hours. The action in t h e case of t h e asphalts a n d t a r examined was much more rapid, but nevertheless, time-consuming, especially as regards the asphalt. Blank determinations on t h e apparatus, using a solution of sulfur monochloride without a n y bitumen, checked closely, and in t h e standard length of t i m e employed for reaction and aeration (4 hours), and with t h e standarcl rate of passage of gas (one bubble per second through t h e Pennsylvania Railroad tubes), there was imparted t o t h e water used as absorbent of t h e hydrochloric acid gas, an average acidity equivalent t o only 0.043 mg. of hydrogen === 0 . 8 4 cc. of 0.0504 N sodium hydroxide. The pipette P (Fig. I), used for adding t h e sulfur monochloride reagent, passed into t h e reaction tube A through a cork stopper, made gas-tight by soaking in paraffin. ’This pipette was heated t o drive off adsorbed moisture, immediately before use. T h e results are expressed in what t h e writer proposes t o call a “hydrogen number,” namely I O O x milligrams of hydrogen removed from organic combination and evolved as hydrochloric acid gas by the oxidizing action of sulfur monochloride, on one gram of t h e substance examined. Expressed in terms of sodium hydroxide solution, we have t h e following formula for t h e “hydrogen number,” viz.: cc. N a~O_H _Solution _ ~ _ _X _ ~N - x weight of sample ~
100,
where iV = normality of t h e sodium hydroxide, preferably N / 2 o or N / 5 o . T h e writer used from 0 . 2 t o - 0 . 5 g. of bituminous or t a r r y matter. and I O cc. of .,the sulfur monochloride reagent described above. The sample was first dissolved in I j cc. of carbon bisulfide and t h e sulfur monochloride then added. The method gave results concordant t o I per cent. The following hydrogen numbers were determined.
. . . ... . . ..... . .. ... . . .
”Oil asphalt B”. . . . 76.5, 75 (penetration = 12O) 126, 127 (penetration = 14O) Berrnudez asphalt (refined) . . . . . 184, 185 “Tar Binder B”.
The mechanism of the reaction betaween sulfur monochloride and t h e substances examined remains t o be elucidated by further work, which t h e writer hopes t o carry o n . At this time, however, it appears not unlikely t h a t t h e reaction takes place between unsaturated hydrocarbons and t h e sulfur :hloride, perhaps in one of the following ways:
r---i
I C = I2 I
r---i
C-H
1
+
657
C I 4
+ 2HC1 + 2 s
L---J
I
- C-S n C-8
C-H C I S L---J
I I r - - -Cl-S--S-Cl i C-H r---i
C-H CI&S-C1 L---J
1
+ZHCI
1
I
r---i
J
L---
I/I 1
HJ
r---i
H-C L---J
I
c-s-s-c
=
1
C--sS-C
I
f 4HC1
I
Whereas the first reaction produces further unsaturation in t h e already unsaturated hydrocarbon, t h e second reaction gives rise t o ring formation. T h e third reaction expresses a combined ring formation a n d polymerization phenomenon, a n d is of the general t y p e ascribed by various writers, notably Lange,’ t o express t h e reaction between sulfur chloride and phenols, as well as aromatic amines. I n t h e case of $-chlorophenol, Richter has shown2 t h a t sulfur monochloride acts as follows:
e)-+ c1
=
C1
+
) - : (
OH
HO-
OH
+ 4HC1
HO
This reaction a n d Equation ( 3 ) , above, are of t h e same general type, so far as condensation is concerned. It is known3 t h a t t h e natural asphalts from t h e Trinidad and Bermudez deposits contain a larger percentage of unsaturated hydrocarbons than the residuals prepared from Mexican, California and Texas oils. If t h e sulfur chloride reaction, as described by t h e writer, be due t o unsaturated hydrocarbons, then t h e large difference between t h e “hydrogen numbers” of “oil asphalt B” and refined Bermudez asphalt, noted above, is accounted for. It should be stated t h a t t h e acid gas evolved as described was shown t o be hydrochloric acid by the test with ammonia, as well as by precipitating silver chloride from t h e solution of t h e gas in water. No hydrogen sulfide or other sulfur-containing gases were detected in any of the reactions. Whether t h e sulfur monochloride also adds itself, as such, t o unsaturated hydrocarbons, contained in bitumens, remains t o be determined, possibly by means of an analytical method, which the writer has worked out, and which consists in pipetting out a portion of t h e reacting solution, determining t h e excess sulfur monochloride in this aliquot portion by shaking with water, and comparing first, with a blank, and then with t h e corresponding “hydrogen number” determined in t h e manner previously described. “Die Schwefelfarbstoffe,” Leipzig, (1912), 27-28 Richter, Bey.. 49 (1916), 1024-5; reported in C. A , , 11 (1917). 1100. 8-Richardson, THISJOURNAL, 8 (1916), 319. 1 Lange,
2
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
6j S ACTION
OF
SULFUR
MONOCHLORIDE
ON
G A S ENGINE
THE
PwsrcAL
OILS
I n testing several gas engine oils with sulfur monochloride, the procedure was adopted of adding I cc. of sulfur monochloride t o 5 cc. of t h e oil in a testtube, mixing thoroughly, allowing t o stand in the cold for 15 minutes, and then comparing the results with those obtained on an oil of known refinement. Several gas engine oils foundon the market were tested and i t was found t h a t t h e specially refined oils showed b u t a slight wine-colored tinge, whereas those not so carefully selected and refined changed t o a deep wine color in some cases, and almost black in others. I n t h e latter cases, t h e evolution of small bubbles of hydrochloric acid gas was clearly visible after half a n hour, and these were shown t o be such by testing with ammonia and comparing with a blank test. T h a t is t o say, t h e reaction in t h e case of the oils was found t o be evidently identical, as t o t h e evolution of hydrochloric acid gas, with the reaction in t h e case of t h e bituminous and t a r r y matter. It was also found t h a t the more rapid the development of color in the case of t h e oils, the more vigorous t h e evolution of hydrochloric acid gas. Finally, if t h e gas engine oils were arranged in order, beginning with those t h a t showed least color change in t h e same time interval, a n d proceeding t o those t h a t developed the darkest color, it was found t h a t this order was the same as t h a t in which t h e oils were placed b y Gill’s gumming test1 beginning with those showing least gum formation a n d proceeding t o those showing t h e most gum, or tar. Since hydrogen is removed from t h e hydrocarbon molecule b y t h e action of t h e sulfur monochloride and, since, as is well known, t h e removal of hydrogen (as water vapor or steam by t h e agencies of heat and atmospheric oxygen) constitutes a large p a r t of t h e process of carbonization of lubricating oils. i t would seem t h a t sulfur monochloride might be used t o measure t h e relative “sensitiveness” of the hydrogen in hydrocarbon oils, t h a t is t o say, as a measure of t h e relative stabilities of those oils. The matter is being further studied, in order t o show, if possible, whether the action of sulfur chloride on bituminous matter, t a r r y substances and paraffin oils, is due, as appears very likely, t o the presence of unsaturated hydrocarbons. SUMMARY
I-It
has been shown t h a t sulfur chloride acts on bituminous matter, t a r r y substances and hydrocarbon oils, giving hydrochloric acid gas as one product of the reaction. 11-Sulfur monochloride, undiluted, is propose& as a reagent for testing the comparative stabilities of transparent lubricating oils. 111-Sulfur monochloride in carbon disulfide is proposed as a reagent for investigating t h e nature of bitumens and hydrocarbon oils. MASSACHUSETTS INSTITUTEOF TECHNOLOGY, BOSTON ~~
1
Gill, “Handbook of Oil Analysis.” 7th Ed., p. 43.
1701. 9, No. 7
TESTING OF PAPER AS AFFECTED BY HUMIDITY By Ross CAMPBELL Received April 23, 1917
-4s a result of reading t h e article on the “Influence of Humidity on t h e Physical Constants of Paper” by Kress a n d Silverstein, in THIS J O U R N A L , g (I917), 2 7 7 , it was decided t o contribute t h e d a t a on t h e same subject which was collected in this laboratory by E. J. Goldstein during t h e summer of 1916. APPARATUS
Unfortunately, we were not blessed with the excellent equipment described in the above-mentioned article. We had no method of temperature control and were forced t o control t h e humidity by regulating a Comins Sectional Humidifier head b y hand. The humidity was determined by means of a recording wet and dry bulb thermometer and a sling psychrometer. Even with this very crude control, it was found t h a t t h e relative humidity did not vary more t h a n two or three points, a t most, nor the temperature more t h a n I O . The tensile strengths of the specimens were determined by means of a hand-operated Schopper tensile-strength test machine. The test strips were 180 mm. long. Resistances t o folding were determined by means of a motor-driven Schopper folding machine. Times of penetration were determined by floating the samples on a n ink bath. PROCEDURE
About 8.00 A . M . t h e test room was closed and t h e humidifier started. The sheets of paper t o be tested had been Rung in t h e test room t h e night previous. It was found t h a t t h e humidity could be brought t o t h e desired point by 1.00P . M . and t h a t , owing t o t h e gradual increase of t h e humidity, t h e weight of t h e sheets t o be tested was constant a t about t h e same time. The testing was then begun. All t h e tests of a given kind, on a given sample were, of course, run on t h e same day. OBJECT OF TESTS
The object of t h e tests which form the subject of this article was t o determine how closely i t would be necessary t o control the humidity in order t o have physical tests comparable from day t o day. I n addition it was desired t o see whether the different grades, as fines, bonds, etc., varied in t h e same way. PAPERS TESTED
The papers tested were t h e company‘s regular commercial output. They varied, as is shown in the table, from high-grade, loft-dried bond and ledger, t o a relatively low-grade, machine-dried, fine. Samule A B C
D E
F G H
&L
KIND Bond Ledger Bond Bond Fine Bond Envelope Bond Blueprint Bond Blueprint
FOLIOWT. FURNISH (PERCENTAGES)THICKNESS in Lbs. per Rag Soda Sulfite In. 500 sheets 25 Few i5 0.00384 20 .. 15 0.00385 20 85 .. 10 0.00360 20 90 50 0,00320 20 so .. Trace 25 i5 0.00362 24 5 80 0,00338 20 15 Few 25 i5 0.00410 28 10 75 0.00405 20 15 50 0.00406 16 50 90 .. IO 0.00492 19 50 0,00509 24 50
..
..
