June, 1927
INDUSTRIAL AND ENGIAVEERIAITGCHEMISTRY
that the bomb-washing and sodium peroxide fusion methods check those of the standard Eschka method sufficiently close to permit them to be used as alternate standard methods. Laboratory 2 for some reason or other obtained considerable differences between the Eschka and sodium peroxide methods, but the other laboratories had no difficulty in obtaining good checks between these two methods. From the tables it will be noted that some of the laboratories had considerable trouble with coals L and N , especially with coal L. As a whole, the sodium peroxide results on these two coals are more consistent than the Eschka or bomb-washing results. These two coals were unusual in that L contained about 17 per cent of sulfur and N about 11 per cent. Such high-sulfur coals are rare and apparently require special treatment. The laboratories that determined sulfur in these two coals by the sodium peroxide method were instructed to add 0.3 gram of benzoic
733
acid in making up the charge, as is done for anthracite and coke. Laboratory 1 found that coal L would not ignite without the addition of benzoic acid. This is explained by the large ash content of the coal-about 44 per cent. Laboratory 1 found that coal N gave the same results with or without the addition of benzoic acid. Acknowledgments
The sulfur determinations were made by or under the direction of Max Hecht, chief chemist, Duquesne Light Company; J. F. Kohout, director of laboratories, Commercial Testing and Engineering Company; C. A. Lunn, chief chemist, Consolidated Gas Company of Kew York; S. W. Parr and J. ill. Lindgren, University of Illinois; N. F. Prince, acting laboratory director, Rochester Gas and Electric Corporation; and H. M. Cooper, associate chemist, and W. L. Parker, junior chemist, U. S. Bureau of Mines.
Action of Sulfur Monochloride on Petroleum Hydrocarbons' By E u g e n e L o r a n d DIVISION OF I N D U S T R I A L
I
RBSI~ARCII, PENNSYLVANIA
S T A T E COLLEGE, STATE COLLEGE, P A .
oils reacted violently; higher kerosene fractions were atwhich could be removed without distillation, a sur- tacked a little less vigorously; various motor gasolines prisingly energetic reaction was observed between changed color when mixed with sulfur monochloride and after sulfur monochloride and the different fractions. Heat standing a dark sediment settled out. Moderate heating development, change of color of the solution, effervescence, started a more energetic reaction. and the escape of hydrogen chloride mark the reaction. The reaction can be carried further by heating after the The higher boiling the fraction, the more violently it reacts first energetic action is over, as the following experiment when mixed with sulfur monochloride. JTill shnw: I t is peculiar that the Thirty-five grams of sulfur monochloride were allowed to literature of organic chemflow gradually from a sepaistry, especially that of the The a c t i o n of s u l f u r m o n o c h l o r i d e on petroleum ratory funnel into a n Erlenaliphatic h y d r o car b ons , h y d r o c a r b o n s has b e e n investigated on both s i n g l e meyer flask containing 100 c o n t a i n s very little about grams of a petroleum frach y d r o c a r b o n s a n d p e t r o l e u m f r a c t i o n s , a n d f o u n d to b e tion boiling between 225" and this reaction. The action a general reaction of u n s a t u r a t e d hydrocarbons. It 250" C. When the reaction of sulfur monochloride on consists probably of chlorination and s u b s e q u e n t conb e c a m e less vigorous, the e t h y l e n e as used in the d e n s a t i o n or polymerization. mass was heated for several manufacture of mustard gas, hours on a water bath with T w o methods are suggested f o r t e s t i n g the degree of refluxing. The oil became and a similar reaction with u n s a t u r a t i o n of h y d r o c a r b o n s a n d p e t r o l e u m p r o d u c t s tarry, and after cooling monoamylene described b y on the b a s i s of this reaction. c 1 i n i c s u 1f u r crystallized. Guthrie* are apparently the The liquid was freed from the only exceptions. unchanged sulfur monochloride by distillation. On acMeigs3 described the acof foaming, the further fr; ionation of the reaction uroduct tion of sulfur monochloride on certain substances which he count was made a t anabsolute pressure of about 50 mm. of mercury. designated as "asphalt €3," "tar binder B," and "gas engine The first drop came over a t about 120" C., and the temperature oils." He attributed the reaction to the presence of bitumi- rose t o as high as 175" C. toward the end of the distillation. nous substances, and tried to develop a testing method for About 75 per cent of oil was recovered. A considerable amount of carbonized product remained in the flask. Seventy-five them, based on the use of sulfur monochloride. In careful cubic centimeters of the distillate were fractionated under experiments he excluded the presence of moisture and de- normal pressure. The first drop came over at 210" C. and termined the rate of hydrochloric acid evolution during the 7 cc. distilled below 225" C. The volume of the 225-250' C. reaction. However, the present experiments showed that the fraction was 49 cc. The end point was 278" C. higher fractions (above 300' C.) and crude oils react more The results indicate that the distillate contains not only violently than water alone. Thus the reaction, especially the the hydrocarbons unaffected by sulfur monochloride but evolution of hydrogen chloride, is not due to the presence also polymerized and condensed or chlorinated compounds of moisture. or their cracked products. In the present work the reaction was found much more Tests on Single Hydrocarbons general than Meigs supposed. Different kinds of lubricating A detailed study of this reaction was made on single Received January 24, 1927. hydrocarbons. The first step was t o determine what types * J Chcm Sor (London), l a , 112 (1860). of hydrocarbons do react with sulfur monochloride. Nor3 THISJ O U R N A L , 9, 6 5 5 (1917) S SEARCHING for a solvent for petroleurn fractions
1
734
I-IDUSTRIAL AND ENGINEERING CHEMISTRY
mal pentane, normal hexane, decane (diisoamyl), and commercial amylene were available. I n all cases the procedure was the same: Thirty t o fifty grams of the hydrocarbon were mixed cold with about half as much sulfur monochloride and then refluxed on a water bath for 5 t o 8 hours. The saturated hydrocarbons apparently did not react when cold, nor did heating start a reaction except in the case of diisoamyl, the color of which was changed. However, more thorough examination showed t h a t there was some reaction in all cases. The unchanged sulfur monochloride was hydrolyzed by dilute sodium hydroxide, and the oil was washed until neutral. The sulfur was filtered off and the reaction products were tested for chlorine and sulfur. Both reactions were positive. As sulfur crystallized on longer standing, the liquid was distilled and tested again. The chlorine reactions remained positive, but the sulfur test was negative.
Since these saturated hydrocarbons were not chemically pure, the same experiments were repeated after treating them with fuming sulfuric acid in order to eliminate the unsaturated hydrocarbons. No difference was found in the behavior of the treated hydrocarbons with sulfur monochloride. The behavior of commercial amylene was entirely different. There was no reaction a t ordinary temperature, but after heating slightly violent evolution of heat and change of color took place. The reaction product became brownish black and tarry. Chlorination could be proved easily, but no test for sulfur could be carried out on account of its solubility in the reaction product. Further, it was not possible to separate the two by solvents because of their similar solubility. Chemical agents such as hot sodium hydroxide would also react with any combined sulfur present. Distillation, even under vacuum, caused cracking and carbonization. Tests on Petroleum F r a c t i o n s
These facts indicate an outstanding difference between saturated and unsaturated hydrocarbons as regards their behavior with sulfur monochloride. It seemed advisable to check the above results on petroleum fractions which were freed from their unsaturated constituents by a treatment with fuming sulfuric acid. The following results were obtained : COMMERCIAL GASOLINE-The same procedure was carried out with various samples as in the case of the single hydrocarbons. The sulfur monochloride did not seem t o react either cold or hot. However, before distillation, both chlorine and sulfur reactions were positive. The distillation was smooth and gave about the same fractions as the untreated gasoline; but at the end the undistilled portion turned brown and the temperature rose suddenly. The distillate was colorless and contained no sulfur, b u t gave a distinct chlorine reaction. Sublimed sulfur could be seen in the flask. LIGHT KEROSENEFRACTION (distilling between 200 O and 225' C.)-The sulfur chloride treatment was carried out between 100" and 150" C. Apparently no change occurred. However, the distillation of the product freed from sulfur chloride gave fractions t h a t were somewhat different from those of t h e original sample. About 13 per cent went over below 200" C. and about 12 per cent above 225" C. The distillate was colorless until the temperature reached 230" C From this point the temperature rise was rapid and the distillate became yellow. The fraction below 230" C. was found to contain chlorine but no sulfur. The yellow distillate contained both, but the sulfur may have been carried over mechanically with the distillate HIGHER BOILING FRACTIONS-The higher boiling fractions gave similar results. Diisoamyl was found to occupy a position between the saturated and the unsaturated hydrocarbons. At ordinary temperatures there was no sign of reaction, but a continued heating at 100" C. and higher with an equal volume of sulfur chloride Hydrogen chloride escaped resulted in a marked reaction slowly, and after 6 hours of heating the color of the mixture became dark brown. After cooling, monoclinic sulfur crystallized. The same amount of sulfur chloride as before was added and i h e mixture heated for 6 hours more. Hydrogen chloride de-
T'ol. 19, S o . 6
veloped and the liquid turned black. A tarry substance separated similar to that in the case of amylene. The sulfur crystallized in rhombic form. N a t u r e of Reaction
This incomplete analysis of the action of sulfur monochloride shows an outstanding difference between the behavior of saturated and unsaturated hydrocarbons. The sulfur monochloride is a general reagent for the unsaturated chain. It reacts even with such low-boiling members as amylene. The slow and moderate action on saturated straight chains is essentially different. It is probably a mere chlorination of the following type: -C-
C-
= HC1
/',~/ \
+ Ss + --C---C/\
HC1
/\
H H
s-s The paraffin hydrocarbons with side chains give the same type of reaction when moderately heated, but the reaction rate is higher. By continued heating to a higher temperature, probably two neighboring carbon atoms lose a molecule of HC1 and form a double bond: R H H
\i
c-c-
\/. I
c-c-
---t
R'L
H
R '
R
R C1 H
H
\ ----f
R
c=c-
/
Furthermore, the resulting compound, like other unsaturated hydrocarbons, undergoes polymerization and condensation. The nature of these latter reactions could not be established, but Meigs' ideas about sulfur compounds and their condensation and polymerization do not seem very probable. The fact that a considerable amount of sulfur crystallizes from the reaction product shows that here also the action of sulfur monochloride probably consists in chlorination and the subsequent formation of a double or triple bond. The condensation probably occurs between two molecules, with elimination of hydrogen chloride. Meigs himself points out the possibility of triple-bond formation, and this reaction seems very probable: -C=CI I --_IHI I H ' /Clj -_-/Clj
-1s-s
--f
-C=C-
+ 2 HClf
S1
I
This reaction might immediately produce the triple bond, or a t lower temperature chlorination might occur, with subsequent removal of hydrogen chloride: -C=C-+-C=C--
I
'
C1 H
Guthriez describes an addition compound of sulfur monochloride and "amylene" analogous to mustard gas. It would be conceivable that whenever sulfur monochloride acts on unsaturated hydrocarbons a similar product is primarily formed which decomposes by heating. However, the unsaturated hydrocarbons, with the increase of the carbon atoms, react more and more violently, and thus the formation of such a primary addition product is improbable. Tests f o r Degree of U n s a t u r a t i o n
Meigs developed a method for determining the hydrogen chloride as one product of the reaction and proposed to use it as a comparative test for bituminous substances. Since the reaction has been shown to be more general, it could serve as a basis of a test for unsaturated hydrocarbons.
June, 1927
I S D C S T R I A L S S D E-VGISEERISG CHEMISTRY
This test might be worked out along two different lines, one being a modification of Meigs’ method. METHOD I-Meigs stated that the action of sulfur monochloride is a “time reaction,” since the evolution of hydrogen chloride continued for many hours without stopping. The above observations show that in a mixture of saturated and unsaturated hydrocarbons the latter react vigorously and cause the major part of the reaction. The saturated compounds or, better, the saturated chains react slowly and are responsible for the “time reaction.” Therefore the test should be carried out in such a way that after the main reaction and a subsequent heating for a definite short period the absorption of the hydrogen chloride is stopped. h solvent is necessary for higher fractions or crude oils, since they react too violently if mixed direct with sulfur monochloride. Meigs used carbon disulfide for this purpose, but carbon tetrachloride, or another chlorine derivative with a higher boiling point, seems to be preferable, irrespective of the fact that carbon disulfide reacts with sulfur monochloride. This is unquestionably true for the liquid which has the function of absorbing the sulfur chloride vapors which would hydrolyze in water and increase the amount of absorbed hydrogen sulfide. Meigs was obliged to use water as absorbent for the hydrogen chloride since the carbon disulfide vapors would react with the alkali. By the substitution of a chlorine derivative for the carbon disulfide, sodium hydroxide could be used without fear. This is one method which was tried in a few cases. It turned out to be practicable and gave comparative results. A more thorough study is necessary to decide its value in comparison with other methods. METHOD11--4 fexv experiments were carried out in another direction for the purpose of dereloping a testing method. The petroleum fractions were dissolved in carbon tetrachloride and mixed with about half as much sulfur
735
chloride. The mixture was refluxed on a water bath for 2 hours. About an equal amount of water was added to the reaction mixture to hydrolyze it and this mixture was then slo~vlyneutralized by sodium hydroxide. The whole mass was washed with carbon tetrachloride in a separatory funnel. After removing the alkali layer the content of the funnel was mashed with water until neutral. The carbon tetrachloride was driven off and the residue distilled a t an absolute pressure of 30 mm. of mercury. The lowering of the boiling point was taken into account in determining the end point of the distillation. This corresponded to the higher limit of the original range of the fraction. Both distillate and residue were weighed. Either the amount of the residue or that of the distillate subtracted from the original quantity of the petroleum sample could be used as a comparative basis for the degree of unsaturation. This is a second method which seems to be especially useful for testing lower fractions, since there is a considerable difference between the boiling range of the unchanged part of the fraction and that of the polymerized or condensed products. Further Investigations Planned The writer plans to continue the preceding investigations in various directions : (1) More thorough study of the condensation or polymerization products obtained by the action of sulfur monochloride on unsaturated hydrocarbons with regard to their possible sulfur content. (2) Study of the behavior of higher saturated, pure hydrocarbons with sulfur monochloride, with special reference to tertiary carbon atoms. (3) Experiments with unsaturated hydrocarbons from other series than olefins. (4) Testing the two suggested methods for the determination of the degree of unsaturation on various petroleum products and checking the results with other methods.
Effectiveness of Laboratory Rectifying Columns‘ By M. J. Marshall and B. P. Sutherland DEPARTMENT OF CHEMISTRY,UNIVERSITYOF BRITISHCOLUMBIA, VANCOUVER, B. C.
H E ordinary uiifilled Values have been obtained for the effectiveness of purpose of verifying distillal a b o r a t o r y column a lagged Hempel column with reflux, with a view to tion equations, no numerical separat,es almost endetermining the relation between this quantity and values are available for the relative effectiveness of the tirely by partial condensation, reflux ratio. A t the same time, similar data have been while a filled column of the obtained for the same column unlagged and without ordinary laboratory column Hempel type separates by parreflux. These two sets of data have been compared on a and the lagged column protial condensation a t the top common basis to obtain values for the relative effecvided wjth reflux. and in addition rectification tiveness of the two arrangements. Theory for a short distance from the bottom. Now it is generally considered that partial condensaLewis5 has derived an equation giring the change in cointion is neibher so effective nor so efficient as rectification. position of a volatile mixture from plate to plate in a rectifying Experimental evidence of the superior efficiency of rectifica- column as follows: tion over partial condensation has been obtained by Leslie.2 P x, + 1 = Fn - (xc - y n ) (1) It is evident, therefore, that the effectiveness of the ordinary laboratory column can be vastly improved by lagging where s, + I = mol fraction of the more volatile component in the liquid on the n l t h plate the sides and providing reflux, as in commercial columns. = mol fraction of more volatile component in the yn Laboratory columns of this t,ype have been devised by Leslie3 vapor over the nth plate and Peters.4 = mol fraction of the more volatile component in so the distillate Although a number of investigators have obtained values P = mols of distillate per unit time for the effectiveness of small packed columns, largely for t,he
T
+
Received September 27, 1926. 120, Chemical Catalog Co., 1923. a I b i d . , p. 555. THIS JOURNAL, 18, 69 11926).
0
=
1’
=
1
* “Motor Fuels,” p.
6
overflow in mols per unit time from one plate to the other mols of vapor per unit time passing up the column
THISJOURNAL, 14, 492 (1922).
