June, 1916
T H E J O R iV A L 0 F I N D C S T RI 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
ular weights of t h e acids obtained are fairly close t o the simple molecular weight as calculated from t h e combining numbers. With t h e possible exception noted, then, t h e method can be applied t o routine determinations without t h e necessity of laboriously plotting curves showing t h e concentration effect for each oil used. Owing t o t h e great solubility in stearic acid of t h e various oils likely t o be encountered, t h e method is widely applicable and, in fact, there will be but very few oils found t h a t cannot be dissolved completely in t h e quantities required for a determination. The method is simple a n d easy t o operate. No correction for loss of solvent b y evaporationtneed be applied. The solvent is non-hydroscopic and t h e precautions which must be taken with nitrobenzol and, t o some extent, with benzol, can therefore be omitted. Some difficulties with t h e method have, of course, developed during its investigation in this laboratory; these in general, however, admit of satisfactory solution. For example, t o obtain concordant results i t is necessary t o keep the bath in which the freezing point tube is immersed a t approximately 40' C. Variation of more t h a n one degree in t h e temperature of t h e bath will cause slight variation in t h e observed freezing point. If a n automatically regulated thermostat is available t h a t factor will cause no trouble. I t is necessary t o stir somewhat more vigorously t h a n when benzol is used, in order t o prevent undue supercooling. Under no circumstances are t h e observed freezing points sharper t h a n one one-hundredth of a degree. On this account t h e accuracy OP t h e method is not as great as t h e freezing point method in benzol but i t compares very favorably with any of t h e boiling point methods. The method as outlined clears up a number of difficulties which have been found with t h e determinations of molecular weights of oils a n d varnishes in the past a n d opens up the field for further investigations 04 this type. I t has been found in this laboratory, for example, t h a t determinations of molecular weights are of great importance in varnish control work and of even greater value in varnish analysis, for in many cases t h e treatment of a n oil or varnish will be more accurately represented by its molecular weight t h a n by any other of t h e common constants. For such application it is, of course, necessary t o have at hand methods for determining t h e .molecular weight of t h e various substances which make up the mixture of which t h e mean molecular weight has been determined by t h e methods indicated. The process of determining such individual molecular weights in substances as simple as oils a n d polymerized oils is comparatively easy a n d will be outlined in full in a subsequent paper on polymerized linseed oil. Much greater difficulties arise when the molecular weight of t h e oil portion of a rosinChina wood oil varnish needs to be determined, b u t considerable progress has been made in t h e development of satisfactory methods. This mill also be reported on later.
493
SUMMARY
The question of t h e determinations of molecular weights of oils, treated oils and varnishes has been outlined a n d t h e value of such investigations brought out. The most usual solvents used in molecular weight determinations have been investigated and their inadaptability t o t h e present problem pointed out. A method for determinations of molecular weights of these products by use of stearic acid as a solvent has been outlined and the conditions surrounding its use developed. Determinations by this method have been made on a large number of oil and varnish products. The applicability and value of such a method have been indicated. The writers wish t o acknowledge their indebtedness to Dr. W.R. Veazey, Case School of Applied Science, Cleveland, Ohio, for advice a n d suggestions. RESEARCH LABORATORIBS. THE 4 R C O CLEVELAXD. OHIO
COMPANY
GlLSONITE AND GRAHAMITE: THE RESULT OF THE METAMORPHISM OF PETROLEUM UNDER A PARTICULAR ENVIRONMENT By CLIFFORD RICHARDSON Received December 29, 1915
Gilsonite and grahamite are two forms of solid native bitumen which are not widely distributed in nature, gilsonite being t h e rarer, and are t h e result of metamorphism of petroleum under a particular environment. They are found in fissure veins which approach the vertical and afford conditions which are favorable for t h e metamorphosis of petroleum into those materials. This change has gone on, under a varying time factor, to a n extent t h a t has resulted in substances presenting various degrees of condensation, from one which floim slowly in t h e sun, as in the case of t h e softest gilsonite, t o one of t h e hardness of t h e brittlest grahamite, which does not melt even a t high temperatures. Between these extremes is t o be found materials of varying consistency, both in t h e gilsonite and grahamite series, showing that these bitumens are t h e products of metamorphism, t o a varying extent. under t h e environment t o which they have been subjected, of some more or less liquid bitumen. The indication of these changes or metamorphism is t o be explained in t h e gradual decrease, as the metamorphism goes on, of t h e hydrocarbons a n d their derivatives which are soluble in naphtha, from t h e amount present in the softest gilsonite to t h a t found in t h e hardest grahamite, with a corresponding increase in t h e residual coke which they yield on ignition. The following data €or typical gilsonites and grahamites demonstrate this very plainly. The gradual decrease from t h e softer t o the harder form in t h e percentage of bitumen soluble in naphtha and increase in t h e yield of residual coke is striking. At t h e same time there is a corresponding increase, as t h e metamorphism increases in degree, in the melting point a n d in t h e specific gravity. These results
491
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 CHEMISTRY
demonstrate very plainl5, t h e changes which go on in nature, under a certain environment, in particular types of petroleum. The environment is a governing condition. Under a different one true asphalt would be formed, such as is widely distributed in nature. The question arises as to what these conditions are, especially in view of the fact t h a t both forms of solid bitumen must be looked upon as originating in petroleum and are sharply differentiated from each other. The asphalts consist, to a very considerable extent, Flow
SOURCE RESIDUAL: Texas Residual Petroleum. . . . . . . . . . . . . . . . GILSONITES: 1 Utah (softest).. . . . . . 2 Utah. . . . . . . . . . . . . . 3 Utah, . . . . . . . . . . . . . 4 Utah.. . . . . . . . . . . . . 5 Utah (hardest), . , . CRAHAMITES: Cuba, Bahia . . . . . . . . . . . Trinidad.. . . . . . . . . . . . . West V a . . . . . . . . . . . . . . Colorado.. . . . . . . . . . . . . Oklahoma.. . . . . . . . . . . .
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* F.
285
Specific Gravity
Per cent Per cent Soluble in Residual Naphtha Coke
0.9524
88.0
6.5
1.011 i.037
55.5 46.9 47.2 46.1 24.5
10.0 12.3 12.8 13.9 16.7
38.8 14.8 9.4 0.8
40.0 40.0 36.8 47.4 51.4
260 345 Intumesces
1.037 1.057
Intumesces Intumesces Intumesces Intumesces Intumesces
1.157 1.156 1.130 1.160 1.184
0.4
of hydrocarbons not acted upon by sulfuric acid; i. e., of saturated hydrocarbons. Gilsonite, on t h e other hand, contains but a very small amount of such components. They may both have a common origin in petroleum but the environment t o which this has been subjected has been so dissimilar in each case as t o result in quite a different product. I n the case of the gilsonite, t h e bitumen in which it has originated has been confined in relatively narrow veins. I n t h a t of t h e asphalts it has been spread out horizontally and subjected t o quite different conditions, with a resulting product of entirely different character, t h e one consisting of more t h a n 20 per cent of saturated hydrocarbons and t h e gilsonites and grahamites containing b u t a relatively small amount, as appears from the following data: Specific Gravity Petroleum Flux (Texas), . . . . . . 0.956 Residual P i t c h . , , , . . , , , , , . . , . 1.089 Bermudez Asphalt, . , , , . , , , , , , 1.082 Gilsonite (Utah), . . . . . . . . . . . . 1.044 Grahamite (Okla.). , . , , , . , . , . . 1.171
Per cent Soluble in Kaphtha 97.5 65 . O 62.2 47.7 0.4
Per cent Saturated Hydrocarbons 72.8 03.1
2t.t 3.5 0.3
These differences in character may be accounted for by t h e fact t h a t gilsonjte and gral-lamite originate in veins which are vertical or nearly so while the asphalts occur under entirely different conditions. ,I material intermediate between an asphalt and gilsonite is found in s'hales of Tertiary age in t h e Central \'alley of California a t -lsphalto, in rertical fissures, which confirms t h e idea t h a t the character of a solid bitumen originating in petroleum i s dependent o n t h e enx-ironment t o which i t is exposed. I t i s of interest t o observe t h a t t h e veins of gilsonite a n d grahamite end rather abruptly a t certain depths and do not thin out gradually, and also that t h e material near the \-ein walls and also t h e surface consists of a harder form of bitumen t h a n t h e mass of t h e deposit. Grahamite is t h e result of metamorphic changes in gilsonite and gilsonite of similar changes in petroleum brought about by its environment. T h a t they are of considerable geological age as t o origin can be
Vol. 8 , NO. 6
seen from the fact. t h a t in one instance in t h e s t r a t a in which gilsonite occurs there is a fault extending a quarter of a mile without a n y disturbance of t h e enclosed bitumen, s h o r i n g t h a t t h e gilsonite must have been introduced into t h e vein before t h e displacement. WOOLWORTH BUILDING NEWY O R K CITY
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THE GALACTAN OF LARIX OCCIDENTALIS By A. W. SCHORGER A X O D. F. SMITH Received March 1, 1916
The western larch ( L a r i x occidentalis, Nuttall) is found in extensive stand in t h e Pacific Northwest. It is a magnificent ,tree sometimes reaching a height of 2 0 0 feet and a diameter of j t o 8 ft. I n t h e course of some experiments it was found t h a t a considerable portion of the wood was soluble in water. Further investigations led t o t h e in,eresting discovery t h a t the soluble matter consisted almost entirely of a galact a n (C6Hl~Os)n(specific rotation [a]2g0" 12.11 ") yielding only galactose on hydrolysis. The watersoluble content of t h e wood varied from 8 t o I ; per cent in the individual trees examined. -4 large number of galactans have been found in nature but only a few have been well characterized. Many of the galactans yield other sugars than galactose on hydrolysis so t h a t t h e terms galacto-mannan, galacto-araban, etc., are applied, depending upon t h e sugars obtained. The galactan from western larch has been called e-galactan. The &galactan isolated by Miintz' from the seeds of lucerne, by Maxwell2 from beans, a n d by Lindet3 from barley has the rotative uj 84.6' and is precipitated from aqueous sqlution with lead acetate: e-galactan has t h e rotation [a]:" 12.11 O and i t is not precipitated from aqueous solution with lead acetate. The @-galactan of Winter4 and Prinsen-Geerligs" has a yellow color and when dried is insoluble in water: e-galactan is white and is readily soluble in mater after drying. The y-galactan of Lippmane a n d others is oviginally insoluble in cold water and is precipitated Prom concentrated solutions by lead acetate: y-galactan differs also from €-galactan in having a very high rotation, [aID= + 2 3 8 ' . The 6-galactan of Payen' and Bauer* obtained from agar-agar and other sources is insoluble in cold mater and. when dissolved in joo parts of boiiing water a gelatinous mass is formed on cooling: €-galactan shows no inclination t o gelatinize. The unusual occurrence of e-galactan was of such interest as to warrant a careful examination of t h e literature with respect t o the occurrence in woods of carbohydrates yielding galactose. I t was found that Trimble9 had examined an e x c y e s c e n c e of Luvix occideiLtalis t h a t contained 19.4per cent of reducing sugar and
+
+ +
1 Compt. vend., 94, 453. * A m . Chem. J., 12, 26. 3 Bull. de l'nssoc. Chem.. 20, 1223 6 Deut. Zuckerind., 16, 538. 5 Chem.-Ztg., 21, Rep. 150. 6 Ber.. 20 (1887). 1001; Z , Ver, Zuckerind., 36, 259; 37, 468; 38, 1252. 1 Comfit. Tend., 49, 521. 8 J O U Y . prakt. Chem,, 30, 11, 283. 9 A W L , J . Pharm., 70 (1898), 152.
