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T H E JOL-R-YAL OF ISDL-STRI.4L -4-YD E-YGI-YEERISG C H E X I S T R Y
I n the acid test the results are all good, some of them very strikingly so; but there is a general irregularity in the figures. The same is true in regard to the atmospheric tests with a seeming tendency towards decreased corrosion with increased tungsten content. However, the general results are not especially worthy of attention and considering the fact that any markedly decreased corrosion is obtained only after high tungsten additions, these alloys do not offer special value from the corrosion standpoint, since with the high tungsten additions we are entering the tool steel range of alloys of high cost and extreme hardness and brittleness. C 0N CL U SI O N S
'
The'se tests covering several series of alloys of iron with other elements do not seem to point to any quantitative relations as between the acid and atmospheric corrosion. So far as the atmospheric tests are concerned, numerous alloys can be noted in which the corrosion is less than in the electrolytic iron. The copper series would seem to offer particular advantages in view of the beneficial results obtained with small copper additions and because of the consistently low values throughout the series. Again these benefits are obtainable without prohibitive cost for the addition agent. UNIVERSITY O F %71SCONSIS
MADISON
CHARACTERISTICS AND DIFFERENTIATION OF NATIVE BITUMENS AND THEIR RESIDUALS' B y CLIFFORD RICHARDSOS
The native bitumens occur in such varied forms and for any particular form, such as petroleum, are of such varied character that their accurate characterization and differentiation are much to be desired. I t is a notable fact that in each new field developed, a type of petroleum is found which differs in some respects, often important, from those which have been previously known. There are, a t least in the Western Hemisphere, no two fields which produce oils of identical character, although similarities exist. This fact is particularly emphasized b y the peculiar differences in the heavy petroleums from the California, Mexican and Trinidad fields. The oils from Mexico and Trinidad resemble none with which we have previously been acquainted and differ from one another as strikingly as from other similar heavy petroleums, such as that found in California, especially as regards the manner in which the sulfur, which is found in considerable amounts in both of them, is combined and the behavior, on this account, of the two oils on distillation. A study of the relation of these petroleums and their residual products to each other and t o other well-known forms of native bitumen is of interest. Some of the important considerations in characterizing the native bitumens are the determinations of the series of hydrocarbons of which they are composed, whether they consist of paraffine hydrocarbons, 1 Also published in the Engineering Record, 67, No. 14, 466 (April 26, 1913).
Vol.
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6
to any and to what extent, what proportion of the hydrocarbons are saturated-that is to say, not removed by strong sulfuric acid on treatment with that reagent; how much sulfur the bitumen contains and, in the case of petroleums, whether and to what extent it is removed by steam during distillation and what percentage of residual coke, ash-free, they yield on ignition in absence of air when the ignition is carried out by a conventional method. Of course, there are other physical and chemical properties which characterize the various forms of bitumen, but they are not of the same value for purposes of differentiation as those which have been mentioned To these may be added a study of the possibility of handling t h e particular bitumen industrially, so that uniform results may be obtained and the products always be, with due care, of uniform character. With the view to making a comparative study of the character of the various native bitumens which are available in the United States in 1913 and differentiating them on such a basis, the accompanying data (Tables I to VI) have been collected from previous publications of the writer and from recent analyses made in this laboratory under the direction of Mr. C. N.Forrest. With these data available, the various forms of native bitumen which have been examined can be characterized and differentiated and, in connection with their behavior under treatment by industrial processes and under service tests and in highway construction, their value for the latter purpose may be determined. FLUXES
The materials which have been denominated fluxes in the accompanying table are the residuals left after the removal by distillation of the more volatile fractions of various petroleums, until the product is of such a density that it contains little or nothing volatile on heating 5 0 grams for 5 hours at a temperature of 325' F. They consist of viscous oils of a character used for fluxing solid asphalts or for direct application to road surfaces as a carpet coat. Parafine Fluxes.-The residuals derived from the paraffine petroleums are characterized by containing hard paraffine scale, from 14.5 to 4 per cent, consisting to a predominating degree of saturated hydrocarbons, 85.6 to 74.1 per cent, and having a specific gravity, normally, of 0 . 9 2 t o 0.94. Those derived from the paraffine oils of Ohio and Pennsylvania, as long ago as 1898, and not available commercially to-day, consisted of over 80 per cent of saturated hydrocarbons. They yield but a small percentage of residua1 coke and, with the exception of the Ohio residuum of 1898, contain but little sulfur. I n this classification there is included a Russian residuum which, although it contains no paraffine scale, consists largely of saturated hydrocarbons, and a shale oil from France which, although the amount of saturated hydrocarbons that it contains is much smaller than is found in the paraffine petroleum residuals, is of a paraffine nature, as shown by t h e paraffine scale present.
June, 1913
T H E JOL-R-\-AL
O F I A V D U S T R I A L A?iD E.YGI*YEERISG C H E - V I S T R Y
iLlexica?z Fluxes,-There is one other flux-that produced from Mexican petroleum-which differs from those of either of the other classes. I t is differentiated from them completely b y marked characteristics, such as the fact that i t carries a high percentage of sulfur, yields a high residual coke, ash-free, contains 2 per cent or more of hard paraffine scale, while only 8 0 per cent of it is soluble in 88’ naphtha, as compared to over 90 per cent in the case of the other residuals. As far as the density and percentage of saturated hydrocarbons are concerned it might be regarded as a n asphaltic flux, but because of its other characteristics it must be
These residuums are of no value as binders for highway construction other than for fluxing the native asphalts and are unsuitable even for this purpose, with other solid bitumens not true asphalts, such as gilsonite and grahamite. The data in regard t o the paraffine fluxes are of value for comparative purposes. Seitii-Asphaltic F1ztxcs.-The semi-asphaltic fluxes are differentiated. primarily, b y a higher density than those derived from paraffine oils, 0 . 9 j to 0.97, They contain a much smaller amount of paraffine scale and approach very nearly in the amount of saturated TABLEI-ANALYSES
163
OF
RESIDUALFLUXES Per cent Per cent pure hit. pure hit. sol. in as sat. Paraffine Specific 88’ naph. hydrocarbons scale gravity
TESTS O . IDEKTIFICATION Dcriiid f u o m parafi?ie pefioleums 30,485 Russia, 1896.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Penna., 1989. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ohio, 1898. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _. />,272 Ohio. 1904. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69,731 IVestl-a., 1904, Ky. crude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Canadzr, 1905.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34,255 Corsicana, T e x . , 1906. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100,537 Lima, Ohio, 1907.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100,610 Whiting, Ind.. 1907.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100,446 Seodesha. Kan., 1907.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65,402 Shale oil, F r a n c e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
0 ,910 0 ,913 0 ,924 0 ,922 0 ,940 0 ,937 0 940 0 ,943 0 ,930 0 ,926 0 ,985
99.4 96.5 96.9 95.6 97.3 96.6 97.4 93 6
79.3 85 . 6 X I .9 78.3 85 . 0 78 .O 83.1 _/ 3- . 1 75.3 74.1 43.6
Dcuired from .Ilcxican peiuoleum 3 4 , 9 9 6 Mexican, 1911.. . . .
1.007
79.9
Dcrivcd f r o i n semi-asghaltic @eirolcu?izs 66,364 Beaumont, Tex., 1903 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.974 68,265 Beaumont, Tex.. 190.3.. . . . . . . . . . . . . . . . . . . . 69,330 Beaumont. Trx., 1904 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.95: 75,260 Beaumont, Tex., 1904.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0,952 81.159 Texas, 1905.,. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0,961 0.962 S4,762 Chaison, Tex., 1906.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dcriwd ,fro?n asphaltic pcirolcu?ns 68,489 California, KO. 2, 1903... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69,607 California, “G” grade, 1904. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39,143 Trinidad, 1912 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.002 1,006 1,004
Sulfur
0.0
..
14.5
0.6 2.6
8.5 9.6 10.3
Residual coke, ash-free
4 0
.. ..
8.1
4.0
6.4 7.9 8 9 4.4
0.44 0 50 0 61
tr.
1 8 3 0
43 2
2 .0
4.3
10 0
95.2 96.3 97.5 99.1 96 9 94 9
79.4 67.9 72 Y 72.3 80.6
I T 0 3
.. 0.74
3 5 2 s 3 0
92.4 92.3 86.9
47 .‘I 41.8 35.3
..
1 .0 1 0
2.1 4 6
2 8 1 CY
.. ..
0.0 0.0 0.0
6.0
..
6.0
2.6
7 .0
TABLEII--ANALYSES OF COXDENSER BLOWS OILS
TEST So. 71,647 71,436 114,578 112.167 127,455 122,860 125, l i 3 122,134
IDESTIFICATION Penetration Pittsburgh flux.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Hydroline “ B ” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Hydroline “ B ” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 25 Calif. Obispo, 1909.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Calif. Ohispo, 1909.. . . . . . . . . . . . . . . . . . . . . . . . 11 S . 0. Co. hinder No. 3 . . . . . . . . . . . . . . . . . . . . . . . . . 85 S. 0 . Co. hinder “ B ” . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 Gulf hinder.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
hydrocarbons which are present t o the paraffine residuals. They are sharply differentiated b y the fact t h a t they will satisfactorily dissolve and flux such solid bitumens as gilsonite and grahamite. Asphaltic Fluxes.-The asphaltic fluxes are differentiated from the previously mentioned classes by a still greater density, nearly that of water, b y the absence of hard paraffine scale and b y the fact t h a t the unsaturated hydrocarbons predominate. They yield a larger amount of residual coke, ash-free, on ignition than other fluxes. Those from California petroleum differ from that produced from Trinidad oil b y containing less sulfur. I t appears t h a t the three classes of fluxes are distinctly differentiated.
Ductility None None None 73/4 cm. 2‘/p cm. 31/2
29 6
cm. cm. cm.
Bit. sol. in CSz 97.6 99.9 99.8 99.6 99.6 98.8 99.8 99.4
Per cenl Per cent pure bit pure bit. sol. in as sat. Paraffine 88’ naph. hydrocarbons scale 66.1 55.5 3.7 1.0 67.9 64.2 71 .O 57.0 1.o 61.5 35 5 0 1 63.4 38 2 0.3 74.9 44.3 1 .o 76.1 51.7 3.1 70.1 48.4 0.2
Sulfur 4.75 0.56 0.41 1.22 1.23 0.77 0.68 0.71
Residual coke, ash-free 13.7 12.2 8.7
17 3 19.6 13 2 12.6 14.6
classed by itself, more especially on account of the hard paraffine scale which i t carries, which points to the presence of paraffine hydrocarbons, and because of the behavior of the crude oil in which it originates on distillation. CONDENSED O R B L O W S OILS
For some time there have been upon the market bitumens prepared from the residual fluxes by treatment with sulfur or air a t high temperatures. They are short or lacking in ductility and cheesy or nonadhesive. The data which are available in regard t o these materials show that the effect of such a treatment is t o produce a material which may be regarded a s dehydrogenated and condensed as far as its molec-
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T H E JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
ular structure is concerned. They all yield much residual coke, ash-free, and the effect of the process is t o reduce to a marked extent the percentage of saturated hydrocarbons of which they consist and the solubility of the substance in naphtha. Without regard t o the character of the petroleum in which they originate the resulting products resemble one another closely. In the table the Pittsburgh flux originated
Vol. 5 , NO. 6
than that of the fluxes, which are intermediate products in their preparation, except in the case of a solid residual of 1910,and in this case the oil in which i t originated was probably not of as asphaltic a nature ’ as t h a t of previous years. California Residual Pitches.-The California residual pitches are distinguished from those derived from Texas oil to a marked degree in t h a t the percentage
TABLE111-ANALYSIS OF TEXAS,CALIFORNIA AND TRINIDAD RESIDUALPITCHES
TEST No. IDENTIFICATION Texas residual bitches
Penetration
63,527 Texas, 1903......... 63,528 Texas, 1903. . . . . . . . 68,943 Texas, 1904................................. 99,904 Texas, 1907 102,529 Texas, 1910................................. Celifcmia residual $itches
.................................
Ductility Brittle
13(a) 20(0) 18
126,413 Kern River oil.. ............................. 126,414 Kern River oil.. . . . . . . . . . . . . . .......... 125.485 Los Angeles refinery 127,211 S . 0 . C o .................................... 127,212 S. 0. Co... .... Trinidad residual pitch
165 31 72 27
110 130 130 133 18
............................ F.in laboratory.. ...........
45 50
135 130
......... ..................
125,217 Industrial scale.. 127,377 R u n back a t 400’ (e) Bowen.
Bit. sol. in CSa
Per cent Per cent pure bit. pure bit. sol. in as sat. Paratline 88O naph. hydrocarbons scale
96.6 95.7 99.0 98.3 98.2
73.6 66.9 70.9 65.2 70.9
58.1 48.1 48.6 47.8 65.6
1 .o 1 .o 1.2 0.5 0.8
0.62 0.74 1.22 1.06
17.6 21.1
99.7 99.6 99.5 99 .O 98.9
76.8 81.9 84.0 89.0 65.3
26.3 30.0 31.1 32.1 30.7
tr. tr. 0.6 0.5 0.2
1 2 1.3 0.82 1.17 1.38
10.4 12.9 9.2 12.9
99.0 99.0
70.8 77.0
24.6 30.9
tr.
1.93 2.10
..
tr.
..
24.0 18.5 19.5
..
..
of saturated hydrocarbons present is much smaller than in the case of the Texas residual pitches and the amount of residual coke, ash-free, which they yield is also smaller. They are devoid of more than a trace of paraffine scale and carry less than 1.5 per cent of sulfur, in which respect they resemble the Texas pitches, Trinidad Residual Pitches.-Residual pitches prepared from Trinidad petroleum are differentiated from the California products b y the higher percentage of Sulfur, about 2 per cent, and by the smaller percentage
in Ohio paraffine petroleum, the hydroline “ B ” in Texas petroleum, the Obispo in California oil, and the S. 0. Co. binder in petroleum from the midcontinental field. The similarity of the effect of such treatment on all these oils is worthy of remark. The solid residual pitches, as used for highway construction, first originated in California petroleum, but were soon followed in the Eastern market by others derived from Beaumont, Tex., oil and later in petroleum from other Texas fields. The Texas residual
TABLEIV-ANALYSES OF MEXICAN RESIDUALPITCHES Per cent Per cent pure bit. pure bit. DUCBit. sol. sol. in as sat. Paraffine Penetration tility in C& 88 O naph. hydrocarbons scale IDENTIFICATION TEST No. 99.4 60.7 31.7 1.0 42 102,261 Ebano “E,” 1908.. 97.9 55.0 32.4 1.3 20 102,262 Ebano “ D X , “ 1908.. 97.8 55.6 31.5 1.3 ................. 12 102,263 Ebano “D,” 1908 95.8 47.4 32.2 1.9 5 ... 102,264 Ebano “B,” 1908.. .......................... 46 99.1 70.6 40.8 2.1 48 126,362 “Aztec” exhibit, 1912.. 130 99.5 69.3 39.0 1.7 31 126,381 Aztec shipt., 1912. ... 133 99.4 76.5 32.5 168 127,026 Montezuma 62 99.2 68.7 33.8 1.2 35 127,027 Montezuma 74 99.6 71.9 41.1 2.4 . . . . . . . . . . . . 36 127,600 S. 0. Co., March, 1913
.......................... ... . . . . . . . . . . . . . . . . . .......
Sulfur
Residual coke, ash-free
... ... ...
...................... ............................ ................................. .................................
......
Sulfur 5.90 6.33 6.08 6.89 4.91 5.08 5.81 6.16 5.36
Residual coke, ash-free 19.2 23.9 24.9 30.5 16.7 17.4 12.6 17.6 15.5
TABLE V-ANALYSES OF NATIVE ASPHALTS
TEST No. 63,260 36,721 44,412 67,753 66,923 22,220 13,541
IDENTIFICATION
Penetration
....
Trinidad Lake.. ..................................... Trinidad Land. ................................. Bermudez, 1900 ................................. Bermudez, 1903. Maracaibo. Cuba, Bejucal.. ......................... ................ L a Pateria, C d . .
.. .......................... ................................................... ..............................................
pitches are characterized by containing a small percentage of paraffine scale, less than 1.25 per cent of sulfur, and yielding, on ignition, a very high percentage of residual coke, ash-free. The amount of saturated hydrocarbons which they contain is very much smaller
7 0
22 26 20 0 0
Bit. sol. in CSa 56.5 54.1 95 .O 96.0 96.8 75.1 49.3
Per cent pure bit. sol. in 88” naph. 63.1 61.9 56.4 71.9 47.2 43.1 43.8
Per cent pure bit. as sat. hydrocarbons 24.4 21.8 24.4 23.4 25.3 17 .O 8.1
Sulfur 6.2 5 .o 4.0 4.7 5.7 8.3 6.2
Residual coke, ash-free 10.8 12.9 13.4 14.0 18.0 25 .O 14.9
of saturated hydrocarbons which they contain, lower in amount than is the case in the California residual pitches and approaching in the latter respect the solid native asphalts. Mexican Residual Pitches.-The Mexican residual
June, 1913
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
pitches are strikingly differentiated from those produced from other petroleums in t h a t they carry from 5 t o 6 per cent of sulfur, yield in the more solid forms a high percentage of residual coke, ash-free, and a t the same time contain from I t o z per cent or more of hard paraffine scale. The Mexican residual pitches, like the fluxes prepared from this oil, are unique as compared t o others. They are also characterized b y the difficulties encountered in their preparation. I n the manipulation of Mexican petroleum on a n industrial scale peculiarities are immediately observed by a n y one familiar with the distillation of other asphaltic oils which plainly differentiate i t from these, especially as represented b y California and Trinidad petroleums. Mexican petroleum may be regarded a s a hybrid which, while resembling the asphaltic oils in gravity and distillates, more closely resembles the paraffine oils in its chemical characteristics and affinities. The sulfur which it contains is held very closely in combination, and it chiefly passes over with the distillates
TEST NO.
expected. A copious agitation of steam is required during distillation in order to carry off both distillate oils and sulfur gases, and any interruption in the steam service will result in the reabsorption of sulfur gases by the residual and the production of “short” pitches. As a further exhibit of characteristics similar t o those of the paraffine oils, the Mexican petroleum has the disagreeable trait of concentrating paraffine during winter storage in the portion of its container near the bottom. Residuum of about 4ooa F. flash test produced from freshly stocked crude may be expected to contain about 1.5 per cent paraffine scale, as determined by the customary method of analysis, while t h a t produced from the ends of stock which has been exposed t o winter temperature has been found t o run as high as 3.5 per cent paraffine. Preliminary operations with the Mexican petroleum in the laboratory held forth considerable promise t h a t residuals of suitable consistency and desirable charac-
OTHERTHAN ASPHALTS TARLEVI-AXALYSES OF GLANCEPITCHES AND SOLIDNATIVEBITUMENS Per cent Per cent pure bit. pure bit. Bit. sol. sol. in as sat. Paraffine in CS2 88O naph. hydrocarbons scale IDENTIFICATION Penetratioi1
Glance pitch 14,145 Glance pitch, Egypt.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14,143 Manjak . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Solid ma1il.e bitumens other than asphalts 92,603 Gilsonite., . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68,940 Grahamite. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
99.7 99.2
23.6 27.3
6.5 6.7
0.0 0.0
8.5
...
15 . o 25.0
0 0
99.0 94.1
47.7 0.4
5.9 0.3
0.0 0.0
1.7 1.7
13.0 53.3
--SULFUR
Fuel distillate Per cent 0.65 2.31
Furthermore, the residual pitches produced from these two petroleums exhibit marked differences, as f a r a s the sulfur which they contain is concerned, which is illustrated b y the following data: PENETRA- SULFUR Per cent TION Trinidad residual pitch. . . . . . . . . . . . . . Mexican residual pitch.. . . . . . . . . . . . . .
50 50
Sulfur
Residual coke, ash-free
0 0
as combined sulfur rather than as a gas. The Trinidad petroleum, which carries as much sulfur in the crude as the Mexican, behaves very differently in this respect, and hydrogen sulfide is evolved very copiously on distillation. The significance of this characteristic, which also applies t o the California petroleum, is t h a t the distillates from these latter petroleums may be refined for burning and other purposes a t a much lower cost and are, therefore, of greater original v‘‘i1ue. A direct comparison of the Trinidad and Mexican petroleums in this respect may be illustrated by the sulfur content of the 2 0 ’ B. fuel distillates from the two oils, as follows: Crude Per cent Trinidad o i l . . . . . . . . . . . . . . . . . . . . 3 . 6 0 Mexican o i l . . ; , . . . . . . . . . . . . . . . . . . . 3 . 2 8
465
2.10 5.38
The affinity of the hydrocarbons of the Mexican petroleum for sulfur necessitates the exercise of such great care in the distillation of that oil, for the production of residuals, t h a t the uniformity of the product obtained on a commercial scale can scarcely be
teristics for use in the paving industry could be prepared from i t , but it appears t o be extremely difficult to obtain uniformity either in fluxing agent or asphaltic residual, and in the latter the consistency and cementitious qualities are uniquely transitory and change very materially under the methods of manipulation which are customary in the paving industry for the production of paving mixtures with heated sand or crushed stone. I t is of interest t o compare the residual pitches which have been discussed with the bitumen of the native asphalts. I n the latter it is found t h a t the sulfur is always a t a high figure, from 4 to 8 ; t h a t paraffine scale is absent, and t h a t the saturated hydrocarbons are reduced in amount to z j per cent or less. It is apparent t h a t the more asphaltic a material is the less saturated hydrocarbons it contains. I t may be held t h a t this is in part due merely to the harder consistency of the material, b u t Mexican residuals of the same consistency a s Trinidad refined asphalt contain 8 or g per cent more saturated hydrocarbons than are found in the standard asphalts, Trinidad and Bermudez. I n the glance pitches, very hard and brittle materials, the saturated hydrocarbons are reduced t o between 6 and 7 per cent, while in the solid native bitumens other than asphalts, such as gilsonite a n d grahamite, they are reduced in the former case t o 6 per cent and in the latter t o practically nothing. It will be seen, therefore, t h a t the assertion made a t the beginning of this paper is justified-that petro-
T H E J O L 7 R S A L OF I * Y D C S T R I A L AlVD EiYGIA’EERISG C H E M I S T R Y
466
leums and their products can be differentiated in the manner there described. This was suggested as long ago as 1898 in a paper published by the writer in the Joztrual of the .Cociety of Chemical Indatstry for January, 1898,where data in regard to the differences in the amount of saturated hydrocarbons in various forms of bitumen were given, and the statement made t h a t asphalts are distinguished b y the large amount of sulfur they contain, the softer asphalts containing much less than the harder ones, and t h a t it is to the presence of this material t h a t many of the characteristics of the native bitumens are due. The relation of sulfur t o the solid native bitumens has also been commented on by Holde in his book entitled “ Investigations on Mineral Oils and Fats, ” where he has stated: “ A bitumen would be called a native asphalt when it contains considerable amounts (2 t o I O per cent, usually over 4 per cent) of sulfur not removable b y steam, when the amount of the latter in the chloroform extract which is insoluble in benzol is a t least 7 . 5 per cent and the asphalt, separated according t o the method of Marcusson and Eickman, contains 1.4 t o 31 per cent of oil. with a t the most 0.6 per cent of paraffine.“ “ A bitumen would be called a petroleum residual pitch if i t contains a t most I.; per cent of sulfur, even in the chloroform extract prepared as previously described, and further 26 to j9 per cent of oil, in which the paraffine amounted to 3.3 to 16.6 per cent.” The conclusion of Holde might well have been drawn from the data given in the writer’s paper in 1898. With the knowledge which we now have in regard to the products obtained from Mexican oil and their preparation, his statements may, however, be modified and amplified a t the present time. The relation of saturated t o unsaturated hydrocarbons in the native bitumens was followed up b y the writer in his book, “ T h e Modern Asphalt Pavement.” I n the first edition in 1905 the statement was made: “ T h e saturated can be separated from the unsaturated hydrocarbons b y strong sulfuric acid, and this will be found t o be a very important means of differentiating the oils and the solid bitumens among themselves, by determining the relative proportions of these two classes of hydrocarbons which they contain.” The relative proportion of unsaturated and saturated hydrocarbons in various bitumens has also been considered very recently by Marcusson in “ Communications from the Royal Material Testing Laboratory near Berlin,” Volume 30, 1912,page 7 7 . This writer has also remarked upon the peculiar nature of the Mexican material, but as he has had no knowledge of its behavior on attempting t o handle i t on a n industrial scale or with the industrial products as they are marketed he has not been able t o draw some of the concIusions which the data available t o the writer have made possible. ~VOOLWOKTH BUILDING S E W YORK
Vol. 5 , KO. 6
DISTILLATION OF TAR B Y P. P. SHARPLES
METHODS AND VALUES I K SPECIFICATIONS
The wide adoption of refined t a r in road work has led t o much study of the material both from a manufacturer’s and a consumer’s standpoint. The manufacturer is interested in the manufacture of the best possible product from the raw materials available, while the consumer is interested both in getting the best material and in holding the manufacturer up to his highest level. Many different tests have been proposed to define refined tar, but the only essential points to be defined in order to secure uniformity are the specific gravity, viscosity or melting point, free carbon, and a distillation test. Of these tests, the specific gravity, viscosity or melting point, and free carbon have been very well understood through the discussion which has raged around them, and the tests themselves are comparatively simple, using simple apparatus. On the other hand, with the distillation test so many variations are possible, each of them having a direct and important bearing on the result, that the standardization of a method of testing has been fraught with great difficulty. Each laboratory which has attacked the problem has chosen a form of apparatus of its own, or even where the apparatus was the same, i t was used in such different ways that radically different results have been obtained with the same apparatus. I t is hardly t o be wondered t h a t the manufacturer who came in contact with all these different methods had difficulties of his own in a t tempting to fill even a specification based on the analysis of his own material. The sources of variation in the methods of distilling may be enumerated as follows: I . Shape of still. 2. Size of still. 3. Position of outlet. 4. Material of still and weight. 5 . Method of heating. 6. Method of protecting still and outlets from drafts. 7 . Size of charge. 8. Rate of distillation. 9. Position of thermometer. I O . Accuracy of thermometer. I I . Size and shape of thermometer. 1 2 . Cutting points on fractions. 13. Personal equation. 14. Method of reporting results (by volume or b y weight). It is not necessary to go into detail in regard to the causes of variation in the different cases enumerated, but that they are serious is shown by Tables I , 11, and 111. Table I shows results obtained by Messrs. Arthur R . Warnes and W. B. Southerton, of the Midland Junior Gas Association, February, I 9 I 2. 1 Paper presented at the Cleveland meeting of the American Associa. tion for the Advancement of Science, Dec. 30, 1912-Jan. 4, 1913.
