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Acid-base properties of the pure alumina and aluminas modified by addition of various ions were determined by IR spectroscopic and Benesi method. The quality and concentration of OH groups of alumina samples containing SO42-, F-, Cl-, Na+, Zn2+ and Mg2+ ions were determined by IR spectroscopy, Pyridine, benzonitrile and carbon monoxide were used to determine the concentration and strength of aprotic centres and deuteriochloroform was used to determine the concentration and strength of basic centres. The results allowed to evaluate changes in the above properties caused by changes in the concentration of ions in alumina. It was found that the total acidity of modified aluminas determined by Benesi method correlates well with the relative proportion of acidic OH groups in the total spectrum of OH groups.

The rotational diffusion coefficients for rodlike micelles of C14DAC and C14DAB are smaller than those of dodecyldimethylammonium chloride and poly(7-benzyl L-glutamate)s, depending on the long contour length.Schmidt and Stockmayer23 presented approximately an equationfor semiflexible polymer chains. If ( 23) is transcribed to semiflexible rodlike micelles, the contribution by the anisotropy of the translational diffusion, which is omitted in (8), can be described by -(/>" -D±)/3 = -(1 /4)Z>0[ 1 -0.5(¿C/2«)V4] (24)Numerical values can be calculated by using the contour length and persistence length of rodlike micelles and the translational diffusion coefficient listed in Table I. The -(Z)¡| -Z)±)/3 values are definitely small in comparison with the Da and (Lc* 2/ 12)0r values, as seen in Table I. This proves that the assumption of the negligible contribution by the anisotropy of the translational diffusion in ( 7) is reasonable.At high micelle concentrations above 2 X 10"2 g cm"3 4which belong to the semidilute or concentrated regime, mutual diffusion coefficients for 2.6 M NaCl solutions of C14DAC and 4.3 M NaBr solutions of C14DAB reached a constant value at high µ2. Constant values are listed in Table II, where the Z>(0) and Afl(°°) values are also included. The AZ)(=°) values are negative, and their (23) Schmidt, M.; Stockmayer, W. H. Macromolecules 1984, 17, 509. absolute values increase with an increase in micelle concentration, independent of the temperature.The AZ> d(°°) values in the semidilute and concentrated regimes change from ( 13) to (20), with increasing micelle concentration.At the high limit of micelle concentration, where the rotational diffusion and the perpendicular translational diffusion are restricted ADM/D(0) = D'¿?°)D\{c^v")/DW)D\{c-c"Q) -1 » -1 (25) from ( 1) and ( 19). The AD(=°)/Z)(0) values were calculated and included in Table II. They approach -1 as micelle concentrations are increased.It is stated that, in solutions of rodlike molecules at higher concentrations, the field correlation functions at nonzero scattering angles decay in a double-exponential fashion.24 It is due to the coupling of the restricted rotational diffusion to the translational diffusion, in which the perpendicular translational diffusion is precluded. Such non-single-exponential curves of the field correlation function at finite scattering angles were observed for aqueous sodium halide solutions of surfactants at the semidilute and concentrated regimes examined here. This observation must confirm that rodlike micelles in such surfactant solutions behave similar to the rodlike molecules at high concentrations.Acknowledgment. I am grateful to Drs. S. Fujime and T. Maeda for their valuable suggestions to apply their theory.

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