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Reactions of molecules with two equivalent functional groups. 2. Acetylation of the isomers of bis(hydroxymethyl)benzene
Author(s) -
Constantinides Ioannis,
LourdesGuerra Maria,
Macomber Roger S.
Publication year - 1990
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.610031204
Subject(s) - chemistry , acetic anhydride , hydroxymethyl , benzene , pyridine , tetrahydrofuran , reaction rate constant , medicinal chemistry , alcohol , molecule , stereochemistry , organic chemistry , kinetics , solvent , catalysis , physics , quantum mechanics
The acetylation (with acetic anhydride–pyridine in tetrahydrofuran) of the ortho , meta and para isomers of bis(hydroxymethyl)benzene (1) was studied. Third‐order rate constants k 1 (formation of monoacetate 2 from 1) and k 2 (formation of diacetate 3 from 2) for all three isomers were determined, as were the rate constants for acetylation of benzyl alcohol and its ortho ‐ and para ‐ethyl derivatives under the same conditions. The compositions of the final product mixtures (comprising 1, 2 and 3) were ascertained as a function of the initial ratio of acetic anhydride to 1. Comparisons were made with predictions based on a previously published independent functional groups model, which assumes that k 2 / k 1 = 0·50. All three isomers gave product mixtures whose compositions were in generally good agreement with predictions based on the model. For the para and meta isomers the ratios k 2 / k 1 were determined experimentally to be 0·548 and 0·521, respectively. The k 2 / k 1 ratio for the ortho isomer was found to be 0·605, and its k 1 and k 2 values were lower than those for the para and meta isomers. Possible explanations for the anomalous behavior of the ortho isomer are discussed.