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Base‐catalyzed isomerization of phenylpropenes
Author(s) -
Hassan M.,
Nour A. R. O. Abdel,
Satti A. M.,
Kirollos K. S.
Publication year - 1982
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550140403
Subject(s) - chemistry , isomerization , sodium ethoxide , kinetics , catalysis , medicinal chemistry , base (topology) , ethanol , reaction rate constant , stereochemistry , organic chemistry , mathematical analysis , physics , mathematics , quantum mechanics
The prototropic rearrangement of 3‐phenyl‐1‐propenes to the corresponding 1‐phenyl‐1‐propenes was investigated in basic media utilizing 0.1 M sodium ethoxide in absolute ethanol at 81°C. It was found that the effect of substituents on the rate of such isomerizations follows the order: p ‐NO 2 > o ‐Cl > m ‐Cl ≥ m ‐F > p ‐Br > o ‐CH 3 > m ‐CH 3 > m ‐CH(CH 3 ) 2 > p ‐CH(CH 3 ) 2 ≥ p ‐C(CH 3 ) 3 > o ‐OCH 3 . This is consistent with first‐order kinetics and “BS E 1 ” mechanism. Quantitative treatment in terms of Hammett's equation showed a straight line, with a slope ( p value) of +2.25. An increase in the strength of the base was also found to cause an increase in the rate of isomerization.