Thermodynamic Study on Tautomerism of Salicylidene 3, 4 dimethyl aniline Via Coupling with Diazotized Sulfanilic Acid Salt

Abstract

A new spectrophotometric method has been developed for the determination
of trace amounts of Salicylidene 3, 4 dimethyl aniline (I) via coupling with
sulfanilic acid sodium salt at pH =7.2 . The method is simple, precise and selective
for the determination of enol contents of in a range 1.65 to 3.47 ppm.
The study is extended to study a tautomerism reaction of type enol
keto in molecule (I), beside the thermodynamic study of such reaction in solution
state. The results show the enol content in molecule (I), is predominant as evident
from the positive value of average G function of value 1.552kJ. mol-1. Moreover,
other calculated H and S parametrs have an avarage negative values of about
9.016 kJ. mol-1 and 33.765 J. mol-1. K-1 respectively, these support the tautomerism
reaction.