INDUSTRIAL AND ENGINEERING CHEMISTRY
July, 1931
deficiency, but 25 mg. were adequate to avoid any evidence of vitamin A deficiency and to permit good growth. A1though 50-mg. amounts were also fed, the condition of the animal was not improved over that of 25 mg. Vitamin B
Data for vitamin B are summarized in Chart 111. For determining vitamin B, 28-day-old rats were used. The Sherman and Spohn basal diet, 107, was kept before them at all times, and the various vegetable adjuncts to supply vitamin B were fed separately. By again regarding the abscissa, or base line, for each product on Chart 111, as 30 grams, the weight of each animal a t the beginning of the feeding experiment may be observed. Since celery was low in vitamin B complex, experiments are also given in which the celery was supplemented with varying amounts of yeast. In the case of the canned turnip greens, a supplement of Jansen and Donath No. 31 preparation (9) was also given to supply the antineuritic factor. In vitamin B content turnip greens resemble spinach in their low content of the antineuritic or B1 fraction. Amounts up to 5 grams per rat per day were inadequate as a source of B complex. When B1 was supplied in the form of 60 mg. of the Jansen and Donath preparation daily, 3 grams were adequate to avoid any Bz (G) deficiency, but 5 grams resulted in better growth. Roscoe (7) recently reported data on the vitamin B complex of lettuce. As a source of the B1fraction, she reported that lettuce produced a gain of 53 grams in 5 weeks when fed
81 1
daily in 0.3-gram amounts (dry basis or 3.75 grams wet basis). As a source of the Bz (G) fraction, 0.6 grams (dry basis) were required to give a gain of 55 grams in 5 weeks. She does not state whether she made an actual moisture determination or used an average figure, presumably the latter since she gives the same proportion of dry matter in cabbage. According to Atwater and Bryant (1) 0.3 gram of dry material would be equivalent to 5.2 grams of fresh lettuce. The present writers purchased head lettuce daily and made no moisture determination. In view of this, their Bgram amounts of lettuce should correspond to about 0.3 gram of dry matter. The average growth increment from 5 grams of lettuce as a source of the vitamin B complex was 33 grams in 60 days for the inner leaves and 45 grams for the outer leaves. Celery proved to be a much lower source of vitamin B complex, 5 grams of celery hearts being inadequate to maintain life for 60 days, while the unbleached was somewhat better. Canned turnip greens contain the B1 fraction in relatively low concentration, but are more potent in the Bz (G) fraction. Literature Cited Atwater and Bryant, U.S. Dept. Agr., Bull. 18 (1906). Bezssonov, Compl. rend., 171, 92 (1921). Eddy and Kohman, IND. ENG.CmM., 16, 52 (1924). Eddy, Kohman, and Carlsson, Zbid., 17, 69 (1925). Holst and Frolich, 2. H y g . Infckfionskrankh., 71, 1 (1912). Kohman and Eddy, IND. ENG,CHBM., 18, 1261 (1924). Roscoe, Biochem. J . , 44, 1754 (1930). Scheunert, “Der Vitamingehalt der deutschen Nahrungsmittel.” Springer, 1930. (9) Williams, Waterman, and Gurin, J. Biol. Chcm., 87, 3 (1930).
(1) (2) (3) (4) (5) (6) (7) (8)
A Microscopical and X-Ray Study of Pennsylvania Anthracite’ Homer Griffield Turner2and Harold Victor Andersona LBH~GH UNIVERSITY, BBTHL.EEEY, PA.
A
LL coals are composed
Pennsylvania anthracite is composed of three constructure closely analogous largely of three constituents-anthraxylon, attritus, and fusain. to, if not identical with, gras t i t u e n t s , to which A knowledge of the constitution of coal as revealed phitic carbon. American students of coal under the microscope is necessary to a correct interAnthraxylon constitution have given the pretation of x-ray analyses. This is shown by the names “anthraxylon,” “atfact that the diffraction patterns of the constituents Anthraxylon embraces all tritus,” and “fusain.” The of anthracite show marked differences. those ingredients of coal which The anthraxylon particle is similar to graphitic have been derived from the proportions of these constitucarbon and gives a difkaction pattern resembling woodyportionsof plants, such ents in different coals are s u b j e c t to wide variations. cellulose, thus showing a de5nite arrangement of m tree t r u n k s , branches, colloidal micelles. twigs, r o o t s , e t c . These In one coal the anthraxylon may p r e d o m i n a t e ; in anThe attritus contains almost all the mineral matter woody constituents have been other coal the attritus may of anthracite, as shown by radiographs and sharp split and f r a c t u r e d by the predominate; the fusain is a Debye-Scherrer rings in the attritus diffraction pattern. processes of decay a n d minor constituent with relaweathering in the original tively no great variations in its proportions. swamp, and this causes them to appear as strips and lenses These three constituents of Pennsylvania anthracite have varying in thickness from mere films to bands that can be been identified through the microscope and radiographs, readily isolated by hand. These woody constituents are isolated, and analyzed by means of x-ray diffraction methods. visible to the naked eye in the form of the brightest lamiThe anthraxylon yields a true fiber pattern characteristic nae of the specimen. Under the microscope they show cell of a very finely divided material; the attritus pattern shows structure varying from almost perfect cells to those that an absence of the fiber structure and the presence of Debye- have been compressed to the vanishing point or effaced by Scherrer rings. The anthraxylon, furthermore, shows a maceration. 1 Received April 13, 1931. Presented before the Division of Gas and Fuel Chemistry at the 81st Meeting of the American Chemical Society, Indianapolis, Ind., March 30 to April 3, 1931. * Director of research for the Anthracite Institute: assistant professor of geology, Lehigh University. * Associate professor of chemistry, Lehigh University.
Attritus
The attritus of coal is made up of many kinds of plant tissues and fragments, although one or more plant constituents may at times predominate. In it we find the more
812
Fikure I -Lump Anthracite from Little Buck Vein Wllliim Penn Colliery, Weir Mnbanoy District Thir deeply flarne~elrhedsuilace shows ail upper dark urea 01 mthrnxyion and a lower light ~ i r e aof nftritu.. Somewhat enlarged.
iriodifications of these terms LE i i n i e i>ew made iri a receirt paper iiy Tliiessen (3). 14:iitircly new terms sitowing 110 rciation to the three chief coiatituents should he avoided. It inight be wcll to point out here that the Eiigliah use tlie terms “vitraiin,” “r:larian,” rtdiirain,” and “fiwnin” t o desigiinte tlic differciit bands that may tie prcsent in i,it,umiiious coal. Tlieir vitraiir consists of a i ~ t h s y ! m ; tire elarain is made up oi airtliraxylon m d transparent attritus; tlie diirairi, of aiitliraxylon arid opaque attritiis. Their use of the term “Eiisain” is synonymous with tlie Amcricari use. Recently Ttiiessen lms used the terms “lucid attrite” and “opaque attrite” to distinguish hetwecn the two kinds of attritus found in some coals. The German “Glanzkol~ie”is the equi\wbnt of the British vitrain plus clarain, and the American bright c(1a1. The German “Mattkohle” is the equivalent of the British dmain and the American splint coal. The German “Fascrkohle” is the eqiiivalent of fusain. They also use scveral niodifyiirg adjectives for tine distinctions. Preparation and Study of Samples Samples of I’ennsylrania anthracite coiitainirrg thick bands uf antliraxylon were cut into blocks by ilieans of a hacksaw
resistant plant constituents such as spore coverings, cuticles, arid resin substances, together with thin strips of anthraxyloir, carimiiiaed iragrnents of plant tissues, structureless dcgradatim mattcr, pith a i d hark cells, and otlier nrinor plant components. 111 tlip attritiis also is found most of the mineral matter of the coal. The attritus serr\’esas the matrix in which
and then polished, flame-etched, a i d studied under the rnetaliographic niicrcwope (4). The Same samples were next deeply flame-etched and plrotographed to show the gross structure at natural six. Blocks 1 em. thick and having the same orientation as those st,udied uriiier tlic inicroscope m r e prepared for radiographs. Sectioris 1 nrrn. thick were ground from tile 1-cri1. blocks for iurtiier radiographs. The ant,liraxylon aird attritus were isolated from ot,her portions of the samples by nieaiis of a h a c k s m and sui,jected to x-ray and chcrnical analyses. The few photographs showm with this paper lrave been selected as representative of the components anthraxylon, attritus, and fusairr ohserved in a large numl~crof specimens.
Radiographic Examination of Anthracite The property of r - r a y s to pcnetrate matter opaque to ordinrary light., plus the fact tliitt they are differentially absorbed Fisure W r h i e k Anfhraaylon Band I n Fieurs ?, Anrhrarylnn of Fieure 2 by mat,ter placed in their path, m a k e s Fisure I Shows Wood Fibers. Shallow ShowlnS Wood Cella Enlaaed throush’ Etched. x 7R. possitile the examination of the gross Deep Btchlne. s t r u c t u r e of various materials.. If a the anthraxylon is irnhedded, except, of courie, in those in- photographic film is placed in contact with a speeiinen of stances where the coal is largely composed of anthrasylon. cod, and a lieterogcneous beam of x-rays is allowed to pass through the F;peeimen, a shadowgraph is registered on the Fusain film, which clearly shows definit,~density variations in tlie The charred plant tissues in coal ase called fuviiin by practically all stiidents of coal morphology. This material is seen as thin coatings on the parting faces of Iaminatcd coal and also as large or small fragments in coal masses. It is usually derived from the woody parts of plait&, aIthiiugli carbonized tissues of many other kinds have been fom~il. As a rule it shows tlie NKSL perfect plant structure of all the coal constit,uents. Terminology
The terms “anthraxylon,” “attritus,” and “insaid’ are th? to use in the description of all high-rank coals that are opaque in thin sections. Tho constituents oS these coals can be properly identified under the microscope only by the forms which they exhibit in light reflected from a polished surface. Coals that are transparent in thin sections show color contrasts which justify and even warrant such only reliable an%
Figure 4-Radiograph
of Seetlon 1 cm. Thick Taken from Lump Shown in FiBure 1
July, 1931
WIKYI it lx~,ii:iiof x-rays, collimated by ii ~ i ~ t l i oslit l e syst,ciu, is allowed t,o peiiebrate a tliin slnh of anthracite, a numim uf dilTrartcil lieams result which are simoltanoiiusly registered on a Rat photograpliic film plnced at a kni,wn dist,anrc from
Figure 5 Redioweph of Sectton i mm I'hick Taken from Section Shown i n Figure 4
t,he srunplc and normal to tlie incidrnt Ithe crystnl grrrins of the inaterial art! extrciral mndom orimtat.ion, the difiraction pattern oihCniriod consists i,f uniform concentric rings of inaxiiiiiim iiiteiisity. If the particles are of colloidnl dimensions, tlie (liffractiiru rings are vcry brand and difiose. If the fine grnios linve any preSiLrred iwicritution, the pattern consist,s of rcla.tive1y broad, ,Muse intensity maxima lying on eonrcntric iialoes. In irlhining diffraction patterns of a,ntlrracite, the K, radiatims from molybdenum and copper target x-ray tubes were used. 'rlie specimens ex:uniinad were in tlie form of thin plates, ahwit I mm. in thickness, and the specimeii t o film rlistance was 5 a n . The time of exposure with molybdenum rays was (io hours and witli copper rays about 4 hours. Examination of tlie diffraction patterns of anthraxylon, attritus, and so-called bone structures of anthrarite reveals distinct constitutional difiermccs.
T h e mineral matter in the coal absorbs the x-rayb to a greater extent than docs the coal substance and an idea of tlie mineral distribution is thereby obtained wlthout the cu\tomary destruction of the specimen. Kemp ( I ) employs R section of c o d 1 cm. in thickness for radioaaphlc purposes It occurred to the authors, after employingsimilar tcchnic, that E radiograph of a much thinner section woiild reveal the mincral distribution witliriut any distortion. This led to the examination of sections about. 1 mm. thick. 'rhe radiographic technic eveiitually found most s u i t a b l e for this purpose was as follows: The general radiation was ohtained from a Coolidge tiingsten target x-ray tube operated at. 60 kilovolts and 10 milliamperes for the thick section and 40 kilovolts and 10 milliamperes for the thin seetim. The distance irom the focal point of the tube to the specimeri \vas 7G.2 cin. (30 inches) and the time of exposure was IS seconds for eacli specimen. It should be noted tliat the nntlirarylon in tile coal is comparat.ivcly transparent to x-rays, wliile the mineral mattrr is relatively ~~paqtte.A cumparison of the radiiigraplis of the specimens Figure 7 Anfhrarylon Figure 8-Anrhrarylon sliowa very clearly that there is no superposition CuK, Radiation M o K , Radiadon of the lavers or hands of iiiineriil imuuritirs in the tliin section (Figure 5 ) , as is tire ease with the thickersection The aot,hraxylnrr pattern obtained by the use of c q ~ p e r (Figure4). It isapparent tliat the thinner thecoalsection the I i , radiation (Figure 7 ) shows a very strong scattering at more reliable will be tlie estimatirrrr of tile mineral content. small anglcs to the incident x-ray beam up to 7 degrees 7 seconds. Applying tho fundamental Bragg law, nmA= 2d sin 8, this angle corresponds to a spacing of 12.22 A. This large scattering at small angles indicates a very fine particle in random orientation, suggestive of atoms joined togetlier in clusters. There are also three haloes present,; The first very strmg'ring gives a spacing measiiring6.53 4.; a second ring, fullyoasintense as tlie first, measuring 3.6 A. as compared with 3.4 A. of graphite; and a third ring, fainder than either of the other two rings, correspondiiig to a spacing of 2.16 A. (the 111 spacing of graphite is 2.05 With molybdenum x-rays (Figure 8) the prominent rings registered correspond to the smaller spacings-namely, 3.61, 2.13, and 1.20 A., respectively-all of which are comparable with t.he interplanar spacings of graphite. As is ixjted, the spacings obtaiiied for anthraxylon are very similar to those of graphite, with one exception, and that is the pacing. However, this close resemblance of spacings PMvre $-Typical Aftiifu8 from Lump ShowninFiBure 1. ShallowEfched. x 78 thraxylon and gca$$te have very mucli the L i d
I.).
Note thin strip of fuvain %cross Center of photograph. ,Small dots are mimpirpoics, l a i g e i white, c ~ i ~ u l idots l r are former resins: large white clipre is a mcgasporc: remainder is macerated xeeetation and mineral matter.
jc:
important to note $hat anthraxylon yields a true fiber pattern characteristic of a very finely divided
.
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INDUSTRIAL AND ENGl rNEERING CHEMISTRY
Vol. 23, No. 7
pattern is very similar to that of cellulose, the mumption can bemade that duringthe coaliication processes the anthr&uylon particles maintained their original orientation (Fignre 10). Ifowever, it should be mentioned that the authors have obtained diffraction pattern in which the anthraxylon is not fibered!(Figure ll),indicating the so-called brush-heap arrange-
Flgure P.--PossIble S f r ~ c f ~ r e of Anthraiylon Particle
material-that-isTto say, one in which the intensity maxiilia are broad and diffuse connected arcs of dflraction haloes, in sddition to the large scattering a t small angles. The 12.221. spacing, which is the extent of the corona, is considered to be the dimensions in the plane of the particle and represents the cross section of the anthraxylon particle (2).
The two very prominent rings showing connected intensity maxima, indicating a comparatively high degree of preferred orientation of tbe fiue particles in this direction, have spacings of 6.53 and 3.6 A. This la&-named spacing correspondsto the average distance between layers of carbon atoms within the
ment of the particles (Fignre 12). In this cme the cellulosic structure has probably been destroyed through maceration. Attrltus
The diffraction patterns of attritus (Figure 13) in general show an absence of the fiber structure which is so pronounced in anthraxylon. However, where the a t t r i t u s contains many thin layers of anthraxylon, the characteristic fiber pattern is obtained. The o u t s t a n d i n g distinction between attritus and anthraxvlon is the appearance in the attrit& pattern of sharp Debye-Scherrer rings, which are attributed to the con- F I 12-nruah-Heap ~ ~ ~ P*rticle taiued mineral matter. It should also be noted that mineral matter consista of much larger particles in random orientation. The principal spacings due to silica, corundum, iron oxides, and mica are recognized. The so-called bone (Figure 14) or very dull and dense material associated with attritns is distinctly similar to the structure obtained in slate in which there is a preponderance of
Ezt;g;;tzf
FIgure LO-Dltfntction Pattern of AuthraryIon
particle of anthraxylo;. The 6.53 A. spacing, which is fully &s intense BS the 3.6 A. reflection, resnlts from reflection of planes parallel to the planes responsible for the 3.6 1.spacing, and this is assumed to represent the average distance between a C layer in one particle to the corresponding C layer in the next particle. Assuming that the 3.6 1.spacing is a measure of the thickness of the anthraxylon particle and the spacing Corresponding to the small angle scattering, 12.22 1.as the average dimensions in the plane of the particle and that anthraxylon has a density of about 1.6, the number of carbon atoms in any particle will be E
(12.22)* X 3.6 X (10-8)z X 1.6 _.__ 12 X 1.64 X 1WU
- 44
The passible structure of the anthraxylon particle (Figure 9), then, is one in which the carbon atoms lie ou two parallel planes of unit dimension, 12.22 1.cross section, 3.6 A. thick, and containing a b o u t 48 c a r b o n atoms. Smcc the diffraction
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INDUSTRIAL AND ENGINEERING CHEMISTRY
July, 1931
silica of microscopic and sub-microscopic size, in addition to corundum, and small quantities of cyanite, mica, marcasite, and lime. Only a very little anthraxylon is found associated with the bone. T a b l e I-Analyses of S a m p l e s CONSTITUENT ANTHRAXYLON ATTRITUS FUSAIN
%
%
BONE
%
%
1.2 3.2 94.3 1.3
1.0 5.7 43.2 60.1
2.2 93.6 0.2 2.3 0.4 1,3
1.8 43.2 0.6 3.2 1.1 60.1
8,072 14.530
3,767 6.780
P R O X I M A T E ANALYSIS
Moisture Volatile matter Fixed carbon Ash
1.1 4.5 92.5 1.9
1.1
5.2 89.1 4.6
ULTIMATE ANALYSIS
Hydrogen Carbon Nitrogen Oxygen Sulfur
Ash
CALORIFIC VALUE
Calories B. t. u.
8,189 14.740
7,917 14.250
815
Chemical Analyses Many chemical analyses of anthraxylon, attritus, and fusain have been made. The analyses of samples taken from the Forge Split of the Mammoth vein, Nanticoke, Pa., have been selected as typical of these components (Table I). Acknowledgment The writers wish to express their indebtedness to H. F. Leibert, roentgenologist at St. Luke's Hospital, Bethlehem, Pa., for his kind assistance in obtaining radiographs. Literature Cited (1) Kemp, C. N., Trans. I n s t . Mining Eng., 77, 175 (1929). (2) Krishnamurti, P.,Indian J . Physics, 6, 473 (1930). (3) Thiessen, Reinhardt, Symposium on Research Needs of Illinois Coal Industry, Quarter Centennial Celebration of Illinois State Geological Survey, Urbana, Coaperative Mining Series, Bull. 33. (4) Turner, H.G.,Trans. A m . Inst. Mining E n t . , 71, 127 (1925).
Industrial and Chemical Research with X-Rays of High Intensity and with Soft X-Rays' George L. Clark and Kenneth E. Corrigan DEPARTMENT OF CHEMISTRY,UNIVERSITY OF ILLINOIS, URBANA. ILL.
Some recent developments in apparatus and technic which make possible wider applications of x-ray diffraction science in chemical and industrial research are presented in response to a request for a paper of general interest on this subject. Special consideration is given to a highintensity x-ray tube which has made possible diffraction photographs in as short a time as l / 2 0 second and also easy observation of patterns on a fluorescent screen. The value of such equipment in studying chemical or physical change, unstable compounds, specimens cooled in liquid air, etc., apart from the great saving of time for any investigation, is indicated. Another new development is the direct measurement of very large periodicities, such as the size of colloidal
micelles in cellulose, rubber, etc., heretofore determined indirectly from the breadths of diffraction maxima. For this purpose a combined vacuum x-ray tube and camera unit is described. With a magnesiym target and a characteristic wave length of nearly 10 A., diffroaction interferences for long spacings of the order of 200 A. and more in rubber and cellulose are resolved and measured. These measurements have especial importance in giving weight to the long-chain micellar structure of cellulose as opposed to the small-molecule theory, and serve as a method of test for the various theoretical equations deduced for the calculation of particle size from breadths of interference maxima.
HE applications of x-ray methods to industrial and chemical problems are now so numerous and familiar that the sciences of radiography or examination of materials for gross defects or inhomogeneities, and of diffraction or examination of the fine structure of materials, have become iirmly established as valuable and often necessary aids in research and control. I n a recent brief paper ( 2 ) it was possible to enumerate more than fifty different types of industrial problems, covering almost every conceivable product, which have been studied and usually solved by the method of x-ray diffraction: metals and alloys of every description from the ore to the practical behavior of the finished product, textiles, ceramics, rubber, lubricants, waxes, paints, varnishes, coatings, chemicals, pharmaceuticals, and many others. Diffraction science is in a sense a kind of supermicroscope which permits examination of structure far beyond the power of any microscope. Numerous examples might be cited to show how peculiarities in physical properties and practical behavior, the causes of which are not revealed by the microscope, receive rational explanation by this more searching examination. The microscope and the x-ray diffraction apparatus thus become complementary, and both are necessary equipment in the progressive research and control laboratory.
X-ray apparatus and technic have been passing rapidly through the stage of development and improvement within the past few years. The method has been expensive, not only on account of the initial cost of equipment, but also because of the time required for photographing a diffraction pattern-sometimes many days and always many hours. Part of the difficulty was alleviated by construction of multiple apparatus, such as the familiar and excellent General Electric unit with which twelve or more exposures can be made simultaneously from the same x-ray tube. This time factor, however, has precluded the use of the method for control or for exhaustive studies of uniformity. Furthermore, it has been impossible to use unstable compounds, and special apparatus of intricate design is necessary for keeping specimens a t very low and high temperatures for any considerable time. A very logical development, therefore, has been the designing of x-ray tubes which will produce beams of so much greater intensity that times of exposure can be materially reduced. In the study of the numerous natural and colloidal substances of great practical value, such as rubber, cellulose, protein, etc., great progress has been made. There is strong indirect evidence of much larger spacings or periodicities in these substances than usually appear. Direct measure ment would have an important bearing on theories of col-
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1
Received April 15, 1931.
