1078
XNTONINO
FAVA, P. B.
SOGO AND
rate constant a t the last point sigIiificuitly lower than a t the first point. Mechanism.-Previous studies of base-catalyzed hydrolysis of esters and aniidesj9 ammonolysis of esters2,10and ester exchange" have indicated t h a t in the case of acyl-oxygen fission all can probably be included in one mechanistic scheme. The OI8 studies of Bender (see ref. loa) show t h a t this iiiust involve, for ester hydrolysis a t least, an addition of base to the carbonyl group giving ail ionic intermediate. For the hydrolysis of amides the 0 l 8 exchange evidence is permissive and the lack of salt effectIodis in accord with that interpretation. The data recorded here permit the inclusion of amide alcoholysis in the same group. I n support of this conclusion the following evidence may be cited. The rate is first order in anilide and first order in base and more rapid when the more basici2 catalyst ethoxide ion replaces methoxide. Jaff6I3 using the data accumulated by Verkade and his co-workers14has shown that a Hammett plot of the rate w m s a-constants for various substituents is linear with p = +1.723. This p-value is in good agreement with t h a t for hydroxyl ion catalyzed hydrolysis of ethyl benzoates (+2.37)15 and t h a t for methoxide ion catalyzed ester exchange of menthyl benzoates (+3.530) . I 1 Also using the data of \'erkadeI4 and assuming a temperature of 65' for his work, it is p s (9) For discussion and references see (a) J . Iiine, "Physical Organic Chemistry," McGraw-Hill Book C o . , I n c . , K e a York, N U.,19.56, p p 266-268, 29.5-298; also (b) .4. Bruylants, r l a l . , Bull. SOC. diiw. Beiges, 60, 191 (1951); 63, 140 (1954'; ( c ) K. Laidler and I. Neloche, THISJ O U R N A L , 73, 1712 (1951); (d) J. Packer, .4 Thompson and J. T'aughn, J . Chenr. .Tor., 2601 (1053); (e) C. Dunton a n d 0 . Spatchcr, i b i d . , 1079 (19.50). (10) F. H. TTetzel, J . G. Miller a n d A. Ia\-, THISJOCRNIT., 75, 1 l,?O (1953), a n d earlier papers. (11) R. T a f t . J r . , If. K e w m a n and F. I I . Verhnek, ( b i d . , 72, 4311 (1950) (12) J . Hine a n d 11. Hine, ibid., 74, 5200 (1952). (13) H . Jaffe, C/wm. Reus., 63, 191 (1953). (14) P. E. Verkade, et al., R e v . irau. chi?%, 71, 545, 1245 (1952): 70, 127 (1951); 69, 1393 (1950); 68, 88 (1949); 67, 411 (1948). ( I $ ) E. T o m m i l a a n d C X . Hinshelwood, .I. Chew S o c . , 1801 (1938).
[CONTRIBUL'ItlN
FROM I'IIJS I ) E P A R I X I ? \
I_
Vol. 79
MELVIN C-4LVIK
sible t u approximate (Table 111) eiiergies and elltropies of activation for this reaction. The results TAB1.G I11 ESTIMATED ENERGIES ASD EXTICOPIES OF ACTIVATIONF U K XETIIANOLYSIS OF 0- ASD ~TITROACETANILIDES
j-h-o?
0-\*02
1.34 x 10-4 RO Xlo--' 23 . 8 2.3
1.10 x 10 - ?
kZ(30 ")
19
kp(65 ")'&
x1or* lij. 7
k,, kcal. /rriolc
-12.4 A.S*(303'), cal.ideg.-niole D a t a from 1-erkade, et aZ.14
agree reasonably with values for other reactions i n the series as is illustrated by Table IT'. i l c r r v A r ~ o xESERGIES ASD ENTROPIES E .
