NOTES
Jan., 1958
+
+
+
RI(1/R2 1/&) = (Rs %)/(Re Rd = n h z (9) By rearranging and making the substitutions, Lt = L - nl/R1and L ~ += , L~ = n2/R2,equation 10 is obtained Lt - Lt+, = nz/RT for mA > mB (lo) Had it been assumed that ?%B is greater than ?%A with the above derivation carried through in the same manner, equation 11would have resulted
119
same differences observed when comparing the spectrum of the red Potassium (Or sodium) salt of phenolphthalein with the spectrum of white phenolphthalein.s Specifically, several samples of the red material each showed a decrease in the relative intensity of the 1740 cm.-l band which in phenolphthalein is due t o the lactone structure3
Lt - Li+7 = -nl/R7 for mB > mA If either equation 10 or 11 is now equation 4 the following is obtained 1/R,= e-kt [ [A]o(m~- mB)(1 - e - k r ) / n z } for mA > mB
-
(12)
and 1/Rr = e+$( [ A ] o ( ~ B - V Z A )( ~e - k r ) / n l } for mB
0
> mA (13)
Thus, by plotting the natural logarithm of 1/R, vs. t for a reaction treated in this manner a straight line with a Of - k is Obtained. Data obtained in this manner, exhibiting the success of the method, are now being prepared for publication. This work was assisted by a research grant (REHI and a predoctoral fellowshiP (DMG) received from the National Science Foundation.
WHITE
Fig. 1.-Proposed
RED
reaction responsible for color change.
and which is absent in the potassium (or sodium) salt The red material produced by &ear did not sho&, however, infrared bands at 1572 cm,-l and a t 1154 cm.-l where the red salt of phenolphthalein shows infrared bands which do not appear in white phenolphthalein. 3 Examination of the visible spectrum of the sheared material, again using the potassium bromide pellet technique, showed no well-defined absorption maxima. The pellet examined contained a sample loading of 400 y-cm.-2 and PLASTIC DEFORMATION OF showed an optical density of 0.3 at 553 mp, the PHENOLPHTHALEIN AT 50,000 wave length of the absorption maximum reported ATMOSPHERES for the red form of phenolphthalein in a solution of pH 10LL4 Based upon the extinction coefficient of BY H. A. LARSENAND H. G. DRICKAMER Talalay, et ~ l . only , ~ about 4 y-cm.-2 of red phenolDepartment of Chemzstry a d Chemical Engineerang, Unzuerszty of phthalein would be required t o give an optical denIllznoaa, Urbana, Illznoas sity of 0.3 a t this wave length. No direct chemical Recezved August 19,1967 studies were attempted as the red material prowhite phenolphthalein has been found to duced by shear at high pressure became colorless turn red when plastically deformed in shear at pres- upon dissolving in ethanol methanol and sures from 20,000 to 50,000 atm. The experimental Evidently the color ,,hanke persists in the technique was the same as that reported in detail state only. in an earlier communication.2 I n essence the high lntermolecular hydrogen bonding must Play an pressure experiment involves first the compression of a thin layer of powder between flat pistons. The important Part in the crystalline structure of phesample is then deformed plastically in nolphthalein as shown by the broadness of the infrashear by forcing the pistons to rotate with respect red absorption band at 3430 cm.-l which is due to the oxygen-hydrogen vibration. It seems reasont o one another about the common axis. Based upon evidence cited below it is postulated able to suppose that the severe plastic deformation that a small percentage of white, crystalline phenol- of high Pressure shear has a strong effectupon these phthalein when disordered by plastic deformation a t hydrogen bonds as the relative orientation of the high pressure undergoes the chemical change shown molecules is changed. Once the crystal is disin Fig. 1 and that this change is responsible for the ordered by high pressure shear restoration of order red coloration observed. It will be noted that this will be Slow due to the restricted nature Of mOleCUchange is analogous to the change induced by the h' motion in the solid State. Solutions obtained reaction of sodium hydroxide with phenolphthalein; from the ordered white material and from the dishere, however, protons take the place of the sodium ordered red material should be the same, however, as they appear t o be. ions. The yellowish color of vitreous phenolphthalein The infrared spectrum of the material produced by one minute of shear at 50,000 atm. was com- which has been prepared by rapid cooling from a pared with the spectrum of the original white phe- melt has been ascribed to a slight decomposition.6 nolphthalein. This examination, which was made It may be that this color is also due t o solid state using potassium bromide pellets of the solid Sam- disorder induced by the quenching. ples, showed inconclusive evidence for some of the (1) This work was aupported in part by the A.E.C. (2) H. A. Larsen and H. G. Drickamer, THIEJOURNAL, 61, 1249 (1957).
(3) M. Daviea and R. L. Jones, J . Cfiena.Soo., 120 (1954). (4) P. Talalay, W. H. Fishman and C. Huggins, J . Biol. Chsm., 166,
757 (1946). (5) E. Rencker, Compt. rend., 208, 179 (1939).
