ANALYTICAL CHEMISTRY
906 SUMMARY
T h e relationship between chamber volume and solvent volume has been investigated. A new term, critical volume, has been introduced which defines the volume of solvent necessary t o saturate a specific chamber under a given set of experimental coriditions. T h e R , values of amino acids and presumably of other water-soluble compounds (preliminary work with car boh\ drates gave results similar t o those reported here) vary with a given solvent system according t o the volume of the chamber, the volume of developing solvent, and the volatility of the organic solvent. ( I n preliminary work only slight variations in the R; values of amino acids were observed \Then a less volatile org:tnic solvent-i.e., phenol-water-was used.) These variations a l e not eliminated by pre-equilibration. It is felt t h a t the most repi oducible chromatograms can be obtained when small chambers are used because the amount of solvent generally eweeds the critical volume of the chamber. I n v i e x of this evidence,
the difficulty in reproducing R i values from one laboratory t o another might be greatly mitigated if authors report chamber and solvent volumes as part of the description of evperimental coiiditions. LITERATURE CITED (1) Block, R. J., Le Strange, R., Zweig, G., “Paper Chromatography, A Laboratory 11anuai.” Academic Press, Ken- York, 1957. ( 2 ) Casaidy, H. G., AYAL.CHEY.24, 1415 (1952).
(3) Clayton, R. A , , Strong, F. AI., Ibid., 26, 1362 (1954). (4) Kowkabany. G. S.. Cassidy, H . G., Ibid., 22, 817 ( 1 9 5 0 ) . (5) Landua, A. J., Fuerst. R., dwapara, J., Ibid., 23, 162 ( 1 9 5 1 ) . (6) hIcFarren, E. F., Ibid., 23, 168 (1951). (7) Rockland, L. B., Underwood, J. C., Ibid.. 26, 1557 (1954). (8) Strain, H. H., Ibid., 23, 25 ( 1 9 5 1 ) . (9) Underwood, J. C., Rockland, L. B.. Ibid., 26, lS53 ( 1 9 5 1 ) . RECEIVED for review September 27, 1935. Accepted March 8, 1956. Dirision of Biological Chemistry, 1’27th AIeeting, hCS. Cincinnati, Ohio, lRIarch 1955.
Radiotracer Studies of Analytical Methods for Styrenated Oil Acids and Esters E. G. BOBALEK, J. R. BRADFORD’, FRED LEUTNERQ,and ROBERT AKIYAMA o f Technology, Cleveland 6, Ohio
Case Institute
TIost analytical niethods for sty renated paint vehicles fail to separate neutral po1)styrene and the oil-acidst>rene copolymer. Armitage and Kut’s method for such fractionation, which depends on differential solubilit? of the copolymer’s calcium soaps and neutral polyst! rene in wet ethjl acetate, was investigated using I adiotracer techniques in polymers prepared from stj rene tagged on the alpha-carbon with carbon-lt. This procedure does not alwajs work. Apparently no method yet exists for determining polymeric species without supplementary anal) sis of the separated fractions. Fractionation data suggest that exten&\c copolymerization of styrene and fatty acids can occur, but that its extent taries with conditions of resin synthesis.
S
T l X E S E drying oil reaction products have been used com-
mercially in paint vehicles for more than 10 years, but the precise chemical nature of these “copolymer oils” is yet unknown. Process conditions of manufacture greatly alter their paint formulation properties, and exact reproducibility of polymerization recipes is a serious problem. Studies of these factors have been hindered by the lack of precise analytical methods for fractionating and estimating the amount of homopolymer and copolymer in tlie product oils. I-arious fractionation schemes have been proposed. Kappelnieier’s ( 4 ) extensive studies led him t o conclude t h a t very little of the drying oil acid escapes reaction with styrene, and probably very little neutral polystyrene is formed-i.e., polystJ-rene unreact’ed with fatty acid. On the other hand, Armitage and K u t ( 1 ) and others ( 6 ) claim to have found a fractionation technique, which, a t least for the reaction product of p-eleostearic acid and styrene, s h o w the presence of considerable quantities of nearly neutral polystyrene. If the latter claim is correct, the .lrmitage-Kut fractionation procedure might be a useful supplement to the Iiappelmeier method of analysis of stgrenated oils and alkyds. This would be trueif neutral polystyrene and the acid copolymer can always he separated in commercial polymers, and if the Armitage-I:. Radioassay-styrene in D, graiiis 11.2 gr:inis of glycerol and 180 4.5 11 45 40 46 53 43 5; styrene i n D 18 grains of phthalic anhydride. 2.2 2.2 0 38 2 0 2 0 3.0 2.0 0 59 3loles styrene per mole acid in E T h e temperature was raised t o Etliyl acetate solubles in residue 210" to 250" C. while a very 242 193 64.3h 18.1 22.1 146h 183'i 1:. D retained in EtO.lc, Fraction IT, grams 48 G slight positive flow of carbon 18.8 34.2 54 3 27.1 :32 3 88.G 72.0 77.5 I) retained in Fraction IJ-, "; dioxide was maintained 140 109 74 4 12 :i 2 8 184 1913 C;. KadioassaL--styrene in F 11 0 102 88 .. 5 8 19.3 .,. through the mixtiire. T h e re37.6 2:i 58 56 >90 Gi 12 >90 >90 action W:LR then contiiiiied a t 3.7 ;j 4
