Date of Award

1986

Document Type

Thesis

Degree Name

Master of Science (M.S.)

Department

Graduate School

First Advisor

Michael J. Minch

First Committee Member

Silvio Rodriguez

Second Committee Member

Ravindra C. Vasavada

Abstract

Effects of aqueous surfactant solutions upon cis/trans isomerization reactions of various N-alkyl-merocyanine dyes (II) were studied. Dramatic rate enhancements were found for all dyes in CTAB and SDS solutions above the CMC. CTAB solutions showed the greatest effect with some dye isomerizations catalyzed in excess of 1000-fold. Increases in either CTAB concentration or dye isomerization rates. N-methyl through N-pentyl dye isomerization rates were measured as a function of CTAB concentration and the data treated according to the pseudophase model for micellar catalysis. KS values ranged from 198 to 2000 M-1 for N-methyl to N-pentyl dyes, respectively. Micellar rate constants also increased as dye hydrophobicity was increased. Thermodynamic activation parameters were determined for N-methyl through N-hexylmerocyanine dyes in CTAB solutions. Rate enhancements in CTAB (above the CMC) relative to those in purely aqueous solutions were shown to be due to a substantial lowering of ΔH, for the various dyes. Increased CTAB concentrations of N-methyl dye solutions gave reaction rate increases resulting from a lowering of ΔS. In 0.054 M CTAB, increases in reaction rates with increased N-alkyl chain length were due to large increases ΔS (from ca. 0 eu for N-methyl to 13 eu for N-hexyl). The data were discussed in terms of molecular interactions which can occur within the micellar solubilization sites.

Pages

133

Included in

Chemistry Commons

Share

COinS
 

Rights Statement

Rights Statement

No Known Copyright. URI: http://rightsstatements.org/vocab/NKC/1.0/
The organization that has made the Item available reasonably believes that the Item is not restricted by copyright or related rights, but a conclusive determination could not be made. Please refer to the organization that has made the Item available for more information. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use.