Page 359 - Advanced Organic Chemistry Part A - Structure and Mechanisms, 5th ed (2007) - Carey _ Sundberg

340 Table 3.27. Reaction Constants a

CHAPTER 3 Reaction
+
Structural Effects on ArCO 2 H ArCO 2 – + H , water 1.00
Stability and Reactivity
+
ArCO H ArCO 2 – + H , ethanol 1.57
2
+
ArCH 2 CO H ArCH 2 CO 2 – + H , water 0.56
2
+
2
2
ArCH 2 CH CO H ArCH 2 CH CO 2 – + H , water 0.24
2
–
+
ArOH ArO + H , water 2.26
+ +
ArNH 3 ArNH + H , water 3.19
2
ArCH NH 3 + ArCH 2 NH + H , water 1.05
+
2
2
–
C H + OH ArCO – + C H OH 2.61
ArCO 2 2 5 2 2 5
–
ArCH CO C H + OH ArCH 2 CO 2 – + C H OH 1.00
2 2 5
2
2 5
ArCH Cl + H O ArCH OH + HCl –1.31
2
2
2
) OH + HCl
ArC(CH 3 ) 2 Cl + H 2 O ArC(CH 3 2 –4.48
ArNH + PhCOCl ArNHCOPh + HCl –3.21
2
a. From R. P. Wells, Linear Free Energy Relationships, Academic Press, New York,
1968, pp. 12–13.
k
m−NO 2
= 49
k H
s
k = 98×10 −4 M −1 −1
m−NO 2
Example 3.4 Using data in Tables 3.26 and 3.27, calculate how much faster than
p-nitrobenzyl chloride p-bromobenzyl chloride will hydrolyze in water.
k p−Br k
log = −1 31 0 23 log p−NO 2 = −1 31 0 78
k H k H
logk −logk = 0 30 logk NO 2 −logk =−1 02
H
H
Br
logk +0 30 = logk logk NO 2 +1 02 = logk H
H
Br
logk +0 30 = logk NO 2 +1 02
Br
logk −logk NO 2 = 0 72
Br
k Br
log = 0 72
k
NO 2
k
Br
= 5 25
k
NO 2