Date of Award

6-1989

Document Type

Union College Only

Degree Name

Bachelor of Science

Department

Chemistry

Language

English

Abstract

The objective of this study is to compare the kinetic and thermodynamic properties of bisulfite additions to trans-cinnamaldehyde and two trans-cinnamaldehyde derivatives in order to examine substituent effects on these properties. The equilibrium constants at pH 4.63 and at 25C of two para substituted derivatives were determined using a spectrophotometric technique. The equilibrium constants were determined to be 299M-1 and 1340M-1 for 4-dimethylaminocinnamaldehyde and 4-nitrocinnamaldehyde respectively. Equilibrium constants were also determined at various temperatures, and changes in enthalpy and entropy were calculated to be: -39KJ/mol and -84J/molK for 4-dimethylaminocinnamaldehyde and -18KJ/mol and KJ/molK for 4-nitrocinnamaldehyde. The forward rate constants were also determined at pH 4.63 and 24.8C, by following absorbance of the aldehyde upon dilution of bisulfite with respect to time, until equilibrium is reached. The rate constants for 4-dimethylaminocinnamaldehyde and 4-nitrocinnamaldehyde were 4.0M-1s-1 and 42M-1s-1 respectively. By calculation, the reverse rate constants were 1.3s-1 and 3.1s-1 for 4-dimethylaminocinnamaldehyde and 4-nitrocinnamaldehyde respectively.

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