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RIZWANUL HAQUE AND WAHIDU. MALIK
AFel grows with a power of n greater than unity) and the hydrophobic parameters reported here (- A F ~ , grows at less than the first POTVerOf Calculations using only these terms in the Partition functions give maxima between 50 and 100 monomers per micelle. DISCUSSION E. D. GODDARD (Lever Brothers Company).-It has yet to be established whether the main contribution to the positive A S values is due to the hydrocarbon chains or to the water molecules. Very likely it is a combined effect. These high values are in keeping with theories of micelle formation recently advanced; regarding the AH values, however, I would think it somewhat hazardous to extrapolate from a butane or propane chain to a dodecane chain. It would be very useful indeed if the experiments could be repeated to include higher chain length hydrocarbons. A. Wrs”Ia.-If it is agreed that the micellar interior is not very different from a hydrocarbon liquid, in which alkanes would form nearly ideal solutions, then the large positive A S of transfer represents some interaction between the alkane and the solvent. I t is the difficulty of conceiving either (a) exceptional van der Waals interactions between HzO and CH, or CH3 groups or ( b ) eignificant restriction of the translational, vibrational, and rotational motions of the short alkanes (beyond the effect of a condensed
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phase) which has led current theorists of water structure (e.g., ref. 20 and 23) to attribute the greatest part of the entropy of transfer of alkanes to some sort of redistribution in the number of structural bonded and unbonded water molecules. I nould expect that such considerations still hold, in large measure, for longer alkyl chains. A linear extrapolation of the Cs-Cr data for AH to Cl9 would indeed be rash, even if the data were firmly established; as I indicated in the text, this sets an upper limit, with the true A H ~ s a x s very likely less negative. Moreover, as I remarked, the pentane data, after a good many more experiments, are still tentative, and given to too many significant figuresin Table 11: it is not excluded that AHTRAKS for pentane is closer to zero. It is not yet clear whether the uncertainty arises from some variability in residual radioactive impurity or from a real effect of pentane on the micelles, even a t the low pressures used. I have just concluded a eeries of H3 butane experiments a t 25’ between 0.1 and 1.0 atm.; the observed increase in the ratio of Henry’s law coefficients Sx/Ss of about 5% cannot arise from the type of impurity encountered with pentane, and may represent an effect of high levels of butane binding on micellar size which should be easily accessible to light-scattering measurements. Such a system, which is more flexible than studies of detergents of increasing chain length, may illuminate some problems of niicellar structure and afford ~ micelle formation. another F a y of estimating Ape, and A F E of
A SPECTROPHOTOMETRIC STUDY OF THE INTERACTION OF SURFACE-ACTIVE AGEXTS WITH DYES1& BY RIZWANUL H A Q U EAND ’ ~ WAHIDU. MALIK Department o j Chemzstry, Alagarh Muslzm Vnlzverszty, Alagarh, Indza Receked ,March 8, 1963 The interaction of the anionic surface-active agents sulfonated phenyl-, tolyl-, and xylylstearic acids with rosaniline hydrochloride and the cationic agents like dodecyl pyridinium bromide and isothiourea dodecyl ether hydrobromide with congo red, methyl orange, and alizarin sulfonic acid was studied spectrophotometrically. A definite change in the absorption maxima of a dye in the presence of one of these surface-active agents was observed. ,This change in maximum was interpreted in terms of compound formation. The effect of pH and critical miaelle concentration also was Atiidied.
Introduction agents. Later, other ~ o r k e r s ~ 5used - ~ ~this method for the determination of the c.m.c. value. The other The interaction of surface-active agents with subof the interaction are the existence of “metaaspects stances such as proteins,2-5 polymers,6 nucleic acid,’ c h r ~ m a c y ” ~and ~.~~ dye-detergent ~ o m p l e x i n g ~ ~ - * ~ hydrophobic S O ~ S , ~ Jmetal ions, lo and organic dyesll which have not been fully studied and need further has been studied by a number of workers to establish work t o understand the phenomenon, especially the their properties and extend their various uses. Among mechanism of dye-detergent interaction. I n conthese the interaction of dyes and surface-act’ive agents tinuation of our earlier work on the properties of surpresent some interesting features worth considering. face-active agentsZ4v29it was thought worthwhile to Hartleyl‘ noticed that the color of the dye changes investigate the abore aspects of the problem. The with the addition of surface-active agents, and he present conimunicatioii deals with the new interactions utilized this fact, in determining the c o i i c e n t r a t i ~ n l ~ ~ ~ ~ (i) anionic soaps like sulfonated phenyl-, tolyl-, and and critical micelle ~oncentratioiil~ of surface-active xylylstearic acid with rosaniline hydrochloride and (ii) (1) (a) Presented before the 37th National Colloid Symposium of the cationic soaps like dodecyl pyridinium bromide and isoAmerican Chemical Society held at, Ottawa, June 24-26, 1963; (b) Departthiourea dodecyl ether hydrobromide with congo red, ment of Chemistry, University of British Columbia, Vancouver 8, B. C.. Canada. (2) F. W. Putnam, “Advances in Protein Chemistry.” Vol. I V , Academic Press, Inc., New York, N. Y., 1948, p. 80. (3) E. G. Cockbain, Trans. Faraday Sac., 49, 104 (1953). (4) B. S. Harrap and J. H. Schulman, Discussions Faraday Sac., 13, 177 (1953). ( 5 ) K. Aoki and J, Hori, J . A m . Chem. Soc., 81,1885 (1959). (6) (a) S . Saito, J. Colloid Sci., 16, 283 (1960); (b) Kolloid-Z., 168, 128 (1960). (7) D. Guerritore and L. Bellelli, Nature, 184, 21, 1638(1950). (8) R. H. Ottewill and -4.Watanabe, Kolloid-Z., 170, 38, 132 (1960). (9) E . Rlatijevi6 and R. H. Ottewill, J . Colloid Sci., 13, 242 (1958). (10) J. H. Schulman, Australian J. Chem., 18, 236 (1960). (11) G. 9. Hartley, Trans. Faraday Soc., 30, 44 (1934). (12) G. 6 . Hartley and D. F. Runnicles, Proc. R o y . Sac. (London), A168, 420 (1938). (13) G. S.Hartley and C. S.Samis, Trans. Faraday Soc., 34, 1288 (1938). (14) G . S. Hartley, J . Chem. Soc., 1968 (1938).
(15) M. L. Corrin and W. D. Harkins, J . A m . Chem. Soc., 69,679 (1947). (16) I. hf. Kolthoff and W. Stricks, J. Phys. Colloid Chem., 62, 915
(1948).
(17) L. Arkin and C. R. Singletcrry, J . Am. Chem. Soc., 70, 3965 (1948). (18) P. Mukerjee and K. J. Mysele, ibid., 7 7 , 2937 (1955). (19) L. Lison, Arch. Biol., 46, 599 (1935). ( 2 0 ) W. C. Holmes, Stain. Technol., 1, 116 (1926). (21) C F. Hiskey and T. A. Downey, J. P h w . Chem., 6 8 , 835 (1954). (22) JI. Hayashi, Bull. Chem. 5oc. Japan, 84, 119 (1961). (23) T. Kondo and K. Meguro, ~ V i p p o nKagaki Zasshi, 77, 1240 (1956). (24) W. U. Malik and R. Haque, Anal. Chem., 82, 1628 (1960). (25) W. U. Malik and R. Haque, Z . anal. Chem., 180,425 (1960). (26) W. U. Malik and R. Haque, Naturwiss., 49,346 (1962). (27) TI‘. E. Malik and R. Haque, Z. anal. Chem., 189, 179 (1962). (28) TV. U. Malik and R. Haque, Nature, 194, 863 (1962). (29) R. Haque and W. U. Maiik, J. PoEarog. Soc., 8 , 36 (19d2).
