ANALYTICAL CHEMISTRY
2000 -.
b = 3.775 f 0.005 A. 13.98 f 0.02 A. @ = 115.14' =k 0.07"
a = 18.28 f 0.02 A.
Table 11. X-Ray Diffraction Data on Tungsten Oxides d , A.
4.78 3.45 2.828 2.446 2.436 2.428 2.418 2.393 2.181 2.150 1.847 1.827 1.731 1.724 1.709 1.698
I/II hk 1 WO2 0 . 1 5 001 1.00 i i ~ , i i i 0 . 2 0 201 0 . 4 5 020 0 . 5 5 20_0 0 . 2 0 202 0 . 8 0 111 0.50 002 0 . 1 5 121,210 0.10 012 0.20 22i 0.20 ZO! 0 . 4 0 311 0 . 6 5 220 0.48 022 0 . 5 0 113 WlSO49
12.9 8.3 6.65 6.1 5 .22 5.22 4.59 4.54 4.43 4.37 3.78 3.73 3.63 3.48 3.44
0.35 0.15 0.05 0.10 0.10 0.15 0 0.10 0.20 0.10 1.00 0.50 0.55 0.05 0.55
001 101,200 lOJ,ZOO 202 2Op 301 102 103 402 402.301 308 010 103 502,011 302 111,210
d , A.
4.28 3.89 3.77 3.70 3.64 2.821 2 729 2 707 2 640 2 620 2 211
1/11 h k 1 w2ooss 0 . 2 0 105 0 . 5 5 302 1 . 0 0 010 0 . 5 5 303 0.60 106 0 . 1 5 115 0 80 201,403 0 45 311 0 50 313 0 60 116 0 70 218,413
3.835 3.76 3.64 3.41 3.34 3.11 3.075 2.684 2.661 2.617 2.528 2,509 2.172 2.149
W03 1.00 001 0 . 9 5 020 1 . 0 0 200 0 . 0 5 011 0.50 120 0.50 111 0.50 111 0 . 7 5 024 0 . 6 0 201 0 . 9 0 204.220 0 . 3 5 121 0.40 121 0.50 221 0.60 221
c
=
for W2aOss(18). [The formula TT-200ss is preferred to WIOOZS structural reasons. Cf. (12).] \VO*.go heated a t 1050" C. for several days. Dark blue, very thin crystal needles. Dimensions of the monoclinic unit cell:
a c
= =
12.05 =!c 0.01 A. b = 3.767 f 0.005 -2. 23.59 f 0.02 A. p = 94.72 f 0.05'
WO,. According to Braekken (5)the symmetry of tungsten trioxide is triclinic but very nearly orthorhombic. Goniometric measurements by Wyart and Foex (16) also showed triclinic symmetry. Recent x-ray investigations on single crystals, carried out a t this institute by Andersson ( I ) , have confirmed the pseudoorthorhombic arrangement of the tungsten atoms. Powder photographs of preparations of various origin differed in the sharpness of the reflections. However, they never showed the multiplet structure of the lines required by triclinic symmetry, but were in full agreement with the quadratic form of a monoclinic structure (1, 1 0 ) with the unit cell dimensions: a = 7.285 f 0.003 A. b = 7.517 f 0.003opI. c = 3.835 f 0.002 -4. /3 = 90.90' f 0.03 ACKNOWLEDGMENT
The authors wish to thank G. Hagg for his kind interest in the investigation and for the facilities put a t their disposal. This study forms a part of a research program on oxides and oxide systems supported by the Swedish Satural Science Research Council. LITERATURE CITED
3.05 3.02 2.958 2.937 2,910 2.871 2.800 2.759 2.743 2.654 2.620 2.522
0.10 0.15 0.15 0.15 0.40 0.05 0.15 0.15 0.36 0.55 0.50 0.50
(1) Andersson, G., Acta C h e m . S c a n d . (to be published). ( 2 ) Andersson, G., and MagnBli, A., Ibid., 4, 793 (1950). (3) Braekken, H., 2. Krist., 78, 484 (1931). (4) Glemser, O., and Luta, G., 2. anorg. Chem.. 263, 2 (1950). (5) Glemser, O., and Sauer, H., Ibid., 252, 144 (1943). (6) Hagg, G., Rev.Sci. I n s t r u m e n t s , 18, 371 (1947). (7) Hagg, G., and RIagnBli, A, A r k i r K e m i , Mtneral. Geol., A19,
SO!
504 602 402 50J,113,41 412,311 305 600 405 11s 512 513,llZ
KO,2 (1944). (8) MagnBli, A , , Acta C h e m . S c a n d . , 2, 501 (1948). (9) I b i d . , p 861. (10) Ibid.. 3.88 (1949). RfrtgnBii,A.~,A r k i a K e m i , 1,223 (1949). (12) Ibid., 1, 513 (1950). (13) RTagnBli, A , , Arkio K e m i , M i n e r a l . Geol., A24, S o . 2 (1946). (14) MagnBli, A,, S o o a Acta Regiae Soc. Sci. Upsaliensis, [4] 14,
ill)
4.
a = 5.650 f 0.005 A. b = 4.892 f 0.005 c = 5.550 f 0.005 A. p = 120.42" f 0.07
(11). WO9.72 heated a t 1000" C. for 40 hours. Small, reddish-violet crystal needles. Dimensions of thermonoclinic unit cell: W1804g
KO.8 (1950). (15) \l*ooster, N., 2. K r i s t . , 80, 504 (1931). (16) X y a r t , J., and Foex, A t , , C o m p t . rend., 232, 2459 (1951). RECEIVED for review > l a y 29, 1962. Accepted September 6, 1952
Ethylenediamine A:Carbonate-Free Alkali f o r Carbon Dioxide Absorption ROBERT W. SWICK, DONALD L. BUCHANAN, AND AKIRA NAKAO Division of Biological and Medical Research, Argonne National Laboratory, Chicago, 111. OMPLETE recovery of purified carbon dioxide from "wet" oxidations, acidified carbonates, and other reactions has been obtained in a vacuum apparatus by the use of a proper sequence of cold traps and heated reaction tubes ( 1 ) . However, in many reactions which yield carbon dioxide, gaseous impurities are evolved which, like carbon dioxide, do not condense in a dry ice trap but only a t t h e temperature of liquid nitrogen. Most of these impurities are best removed by trapping the gas mixture in alkali and subjecting the alkaline carbonate to a vacuum before acidifying t o release the carbon dioxide. Despite careful preparation and handling, solutions of alkali usually contain measurable quantities of carbonate. A simple and effective method of eliminating the undesired
blank is to select an alkali that can be separated from its carbonate by distillation. Some amines such as ethanolamine and diethanolamine, which are used industrially for carbon dioxide scrubbing (3),are not sufficiently alkaline t o prevent the release of some carbon dioxide during distillation. Furthermore, these compounds have relatively low volatility. Ethylenediamine. a more alkaline and more volatile compound, can be readily separated from its carbonate by vacuum distillation. Figure 1 shows the partial pressure of carbon dioxide (32' C.) vihich equilibrates with a 20% solution of the base a t various stages of neutralization. The least carbonate contamination will result when small quantities of ethylenediamine are distilled from a sizable volume of the commercially available compound.
2001
V O L U M E 2 4 , NO. 1 2 , D E C E M B E R 1 9 5 2
w
a a v) v)
2
10
0 "
0
0.5 I .o MOLES GO2 PER MOLE ETHYLENEDIAMINE
Figure 1.
Ecruilibrium Partial Pressure of
C a h o n Dioxide i n 20% Ethylenediamine in
Water a t 32" C. Only one of the two equivalent amino groups can be re!ied on to bind carbonate firmly, as would be anticipated from the pHneutralization curve ( 2 ) . Ethylenediamine (95 to lOOa/,) and water arc distilled from reservoirs on the vacuum manifold and frozen into a vessel fitted with a stopcock. After the impure carbon dioxide is also frozen into this vessel (with liquid nitrogen), the stopcock is closcd and the mixture \v.armetl to room temperature. Evacuation then
removes neutral and alkaline gases. Subsequent acidification with sulfuric acid, followed by heating, releases carbon dioxide quantitatively. l i t h an excess of water, hydrogen chloride, present as a contaminant, is not evolved in measurable quantities, but sulfur dioxide, a weaker acid, is not retained upon acidification. Other acid gases probably behave as these doretention depending on their acid strength. T h e measured blank of vacuum distilled ethylenediamine was 0.001% of its carbon dioxide binding capacity. To test completeness of recovery, 5 purified carbon dioxide samples were measured manometrically and then absorbed in a tenfold excess of a 1 t o 4 ethylenediamine-ivater mixture. After evacuation the samples were acidified >yith a t ~ o f o l dexcess of 50% sulfuric acid, heated t o about 80" C., and the evolved carbon dioxide collected and again measured. The mean recovery was 99.8 & O.Z'% (standard error). When the solutions were unheated or first heated and allowed t o cool before collecting the carbon dioxide, the recovery vias Ion., usually by 2 to 4%. It is suggested t h a t ethylenediamine, which is so easily freed of carbonate, might find wide usefulness as an absorbing agent in chemical and radioactive analyses requiring the collection of carbon dioxide. LITERATURE CITED
(1) Buchanan, D. L., and Sakao, A., J . Am. Chem. Soc., 74, 2389
(1952). ( 2 ) Carbide and Carbon Chemicals Corp., Iiew York, S . P., "Or-
ganic Nitrogen Compounds," July 31, 1946. (3) Gregory, L. B., and Scharmann, W. G., Ind. Eng. Chem., 29, 514 (1937). RECEIVED f o r re\.ie\V Jiily 3, 19.52.
Accepted September 15, 10.52.
Quantitative Determination of Methylol Phenols by Paper Chromatography J. H. FREEllZN, Westinghouse Research Laboratories, East Pittsburgh, P a .
HE use of paper chromatography t o achieve a successful Tseparation and identification of each of the several possible mono- arid polymethylol phenols present in a phenol-formaldehyde reaction riiivture was described in a preceding paper ( 5 ) . Further application of this method as a quantitative tool is highly desirable. P'ist attempts to use paper chromatography for quantitative determinations have employed measurement of total or maximum density of the spot ( 7 , O), radioactivity ( 8 , I O ) ; or elution of individual spots follo\\-ed by colorimetric, spectrometric, or chemical determination of the eluate. Optical methods vere considered unsatisfactory for use in detcrmination of the methylol phenols because of the uneven background color produced by the diazonium indicator used and because of further changes in both spot and background color with time. Elution methods were not attempted because the indicator rcaction is irreversible and, in some cases, individual compounds wew not sufficiently separatpd to permit blind sectioning of uncolored areas of the strip. For use as a routine analytical tool it \vas also desirable that a technique be developed vhich would be rapid and would not require any special apparatus or training. Fisher and his colleagues (4)have shown that there is a linear relationship between the size (or density) of the spot of a substance found on a paper chromatogram and the logarithm of the amount initially applied to the strip. This relationship has been shoivn to hold for amino acids ( 1 , 4)and for sugars ( 9 ) and is presumably true for any compound-indicator combination yielding a clearly discernible spot. Brimley ( 2 ) advanced a theoretical explanation for this based on diffusion analogies. The originators of t h r method have pointed out the further need for consideration of the concepts of partition distribution theory (3).
Determination of spot areas by means of a planimeter as originally described by Fisher et a!. (4),was found to work satisfactorily with chromatograms of the methylol phenols if all conditions are adequately controlled. Holvever, the repeated tracing of spot outlines with the instrument is tedious. Equal or perhaps slightly better accuracy may be achieved and the process considerably expedited by simply cutting out the spots with scissors and weighing them individually on the analytical balance. The m i g h t of the paper comprising the spot may serve as a measure of spot area but it is also more directly related to concentration than is the corresponding area itself. T h e n spot w i g h t is plottcd against the Iogmithm of the eoncentration of component Tvhich produced it, a straight line results. Cnknomi concentrations may then be directly obtained from the determined Tveight of their corresponding spots. -4comparison of areas and weights of sevcral pairs of spots representing duplicate concentrations of substance run on the same paper strip is given in Table I. The per cent variation in weight is seldom found to be greater, and frequently is less than the variation in areas of spots representing equal concentrations of a substance. This is to be exppcted since determination of spot n-eight instead of area mill tend to compensate for errors clue to variation in density or thickness of the paper. Both factors must be presumed constant in methods involving direct measurement of surface area as an indication of concentration. JVhen paper chromatography is used for quantitative determinations by such procedures, it is essential that standard samples of known concentration be run in parallel, on the same sheet of paper as the unknovn, for each compound to be analyzed. The curve for logarithm concentration,versus spot weight for each compound must be established anew for each chromato-
