XOTES
1601
librium constant at 21 O was determined in thislaboratory from near-infrared measurements and found to be 59 f 5. The effect of ring substitution in phenol on the equilibrium constant was also investigated. Only limited data, primarily dealing with substituted pyridines,' have appeared in the literature concerning this reaction. A correlation of the hydrogen-bonding equilibrium constants with the Hammett substituent parameters was obtained. Apparently this effect has not been studied or has not appeared in the literature prior to this investigation. 0.001
0.01
0.I
I
IO
D OR 0 ,SEC-' Figure 5 . A comparison of qc with 11' as well as of [qa ( G ' / w ) ] with q . or 1q*1 for polymer A. at 160'.
+
explained by none of the current linear theories cited above: the constant c appearing in the theory of Williams, et al., varies with D or w , and ~ ' ( w is ) not the same as r c ( D ) in contrast to the prediction of thie theory by Strella. Very recently, Yamamoto'* has presented a new phenomenological theory for nonNewtonian flow on the basis of the three-dimensional nonlinear model and compared theoretical curveis for r,(D) with that for ~ ' ( w ) . His result also shows that the constant (* increases with increasing D or w, in general. Therefore, we are inclined to ascribe the above lack of agreement of our observations with the linear theories to an essential difference between the steady-flow and dynamic behavior: the latter is linear while the former is nonlinear.
--
(18) M. Yamamoto, paper presented at the 12th Annual Symposium on Rheology, Tokyo, Japan, September, 1963 (to be published).
Pyridine Interactions with Phenol1 and
Experimental The phenols and pyridine were purified by recrystallization and/or distillation in vacuo prior to use. The carbon tetrachloride was Matheson Coleman and Bell Spectroquality grade and used with no further treatment, All measurements were performed with a Beckman DK I1 ratio recording spectrophotometer a t 21 f 1'. Matched silica cells 5 cm. in length were used. All solutions were measured with an equivalent concentration of pyridine in the reference cell. Absorbance measurements a t 1.4 p were utilized in the evaluation of the equilibrium constants. This overtone of the fundamental hydroxyl group vibration was selected since no interfering absorption was encountered a t this wave length. The molar absorptivities of the pure phenols were determined under conditions where Table I : Equilibrium Constant Values a t 21", l./mole" PMePhenolb Methylb Methylb thoxyb Q-
65.6 59.2 61.7 54.6 56.0 54.1 52.8
Substituted Phenols by Jerome Rubin, Bernard Z. Senkoviski, Gilbert S. Panson Chemistry Department, Rutgers University, Newark, New Jersey (Received January 7, 1964)
Several investigations have appeared in the literature describing hydrogen bonding of Phenol in the Presence of pyridine. 'ITa1ues reported for the Constant at 20' obtained under different experimental 64,3and 88.4 The equiconditions were 42,' 55 f
59 i 5
112-
Q-t-
Butyl*
PIodoC
mChloro'
PChlorob
47.8 48.5 34.8 148 192 145 48.1 46.2 45.1 38.7 151 182 142 46.0 44.2 43.4 41.8 152 166 124 42.7 42.6 39.4 146 183 123 40.6 40.2 41.8 39.5 40.0 176 128 140 41.2 41.6 38.7 140 167 116 40.1 40.0 40.5 39.4 38.2 129 160 116 40.3 42.5 41.1 40.4 38.9 128 112 40.0 41.3 39.5 39.2 38.8 47.0 42.0 42 & 2 43 i 3 42 2 39 & 2 142 f 8 175 i 9 126 & 10
*
a The phenol concentrations in all solutions was 0.025 M . All solutions studied, except p-iodo- and m-chlorophenol, contained pyridine at concentrations from 0.01 to 0.10 M . ' I n t h e case of p-iodo- and m-chlorophenol, the pyridine concentration varied from 0.020 to 0.040 M .
(1) A. Halleux, B ~ L aOc. L . chim. ~ e l g e s6, 8 , 381 ( 1 9 5 9 ) . (2) N. Fuson, et al., J . Chem. Phys., 5 5 , 454 (1958).
(3) G. Aksnes and T. Gramstad, Acta Chem. Scand., 14, 1485 ( 1 9 6 0 ) . (4) A. K. Chandra and 9. Banerjee, J . P h y s . Chem., 66, 952 ( 1 9 6 2 ) .
Volume 68, Number 6 June, 1964
NOTES
1602
2.2
.
2.0
-
d
-d
+
‘ 1.8
+
*
1.6 ,
I
.
-0.6
.
.
.
I
-0.2
-0.4
0
. . . . . 0.2
0.4
0.6
0.
Figure 1 . Log K us. Hammett’s n-values. Points are: ( 1 ) m-chloro, (2) p-iodo, (3) p-chloro, (4) phenol, (5) m-methyl, ( 6 ) p-methoxy, ( 7 ) p-t-butyl, (8) p-methyl.
2.4
1
+
(5) L. P. Hammett, “Physical Organic Chemistry,” McGraw-Hill Book Co., Ine., New York, N. Y. (6) R. W. Taft, Jr., J . P h y s . Chem., 64, 1805 (1960). (7) R. L. Denyer, et al., J . Chem. Soc., 3889 (1955).
2.2’
k
Discussion and Results Although a good correlation was obtained using Haminett’s a-parameters, as is evident from Fig. 1, slightly better agreement results when Taft’s aO-values were used in the plot. The calculations of the slope [ p ] were obtained by least-squares treatment of the data. The equation of the line calculated using Hammett’s a-values was y = 1 . 1 4 ~ 1.26. Taft’s (rO-values were plotted and the equation of the line calculated was y = 1.29% 1.13. Denyer, et al,.,’ had made a limited study of the equilibrium constants of phenol, p-chlorophenol, and m- and p-methylphenol with trimethylamine by partition between vapor phase and solution. These authors were primarily interested in the determination of hydrogen bonding and heats of formation. Their data were evaluated in this laboratory and the equation of the line using ao-values was found to be y = 1.202 1.34. The p-value obtained from these data is 1.20 which is in good agreement with the value of 1.29 found in our study of pyridine and substituted phenols. An extensive investigation is currently in progress to evaluate the interaction of substituted pyridines with additional substituted phenols.
2.0-
0 “ .
&
Nuclear Magnetic Resonance Coupling
1.8‘
Constants in Maleic and Itaconic Acids 1.6.
1.4
and Their Anhydrides
. I
-0.6
.
.
-0.4
.
.
-0.2
.
0
. . . . . 0.2
0.4
60.
Figure 2 . Log K us. Tafts’ o”-values. Points w e : (1) m-chloro, ( 2 ) p-iodo, (3) p-chloro, (4)phenol, ( 5 ) m-methyl, (6) p-methoxy, ( 7 ) p-t-butyl, (8) p-methyl.
self-bonding did not occur. The decrease in absorbance at 1.4 p was used to calculate the concentration of the frce phenol; the bonded-phenol concentration was obtained by difference. These data were utilized in evaluating the equilibrium constants. The results are given in Table I. The average values obtained were plotted against the Haminett and Taft ao6-paranieters in the usual manner and are presented in Fig. 1and 2, respectively. The Journal of Phusical Chemistry
by H. &Hutton’ I. and T. Schaefer Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada (Received January 16, 196.4)
We wish to report some nuclear magnetic spin-spin coupling constants for maleic and itaconic acids and their anhydrides. They are given in Table I. In Table I the protons of itaconic acid and anhydride are labeled to indicate the type of proton iuagnetic resonance spectra they give rise to, i.e., ,4RXs or ABXz spectra.* The proton coupling constants for maleic -~
( I ) Canadian Industries Limited Fellow, 1962-1963. (2) J. A. Pople, W. G . Sohneider, and H . J. Bernstein. “High Resolution lluclesr Magnetic Itesonance,” McGraw-Hill Book GO.,New York, N . Y., 1959, Chapter 6.
