Separation of selected flavor compound enantiomers by simulated moving bed chromatography : screening of 1-phenyl-1-propanol for antimicrobial activity

Author

Saad Khattabi

Date of Award

12-1999

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Food Science and Technology

Major Professor

Georges Guiochon

Committee Members

Sharon Melton, F. Ann Draughon, John Mount

Abstract

While the concept of simulated moving bed technology (SMB) has been known for almost forty years, its application to fine chemistry, and chiral separations in particular, did not really develop until recently. SMB is a continuous countercurrent chromatographic technique geared mainly toward production, limited to binary mixture separations. Such limitation becomes of no concern, when chiral separations are considered.

In the first phase of this study our objectives were to use SMB to separate enantiomers of selected flavor compounds under both linear and non-linear conditions. In the linear case, we confirmed that determining operating conditions for an SMB separation, is rather simple. The toughest hurdle seems to be obtaining columns with close characteristics. The importance of, periodically, testing SMB columns was experimentally proven. A lab-scale SMB, with eight column setting, was used to carry out enantiomer separations of three flavor compounds (benzoin, σ-octalactone and 1-phenyl-1-propanol), under linear conditions. The separation was successful, in all three cases, generating products with a purity higher than 97%, and nearing 100% in several instances.

To "upgrade" the separation to non-linear conditions (for 1-phenyl-1- propanol, or PP), adsorption isotherm parameters needed to be determined. A simple competitive Langmuir model was able to describe well both single component, and competitive behavior of PP on cellulose tribenzoate. The isotherm parameters were used, in the context of the "triangle theory", to determine the SMB operating parameters, under non-linear conditions. Such an SMB run (total feed concentration 5g/l) generated a successful separation, with a purity >98% for the raffinate, and >95% for the extract. A production rate of 11.6 g of feed / day / kg of stationary phase, was achieved.

In the second phase of this study our objective was to screen PP enantiomers and their racemic mixture, for antimicrobial activity. All three exhibited strong activity against both bacteria and fungi. However, no significant differences (P>0.05) were found among the effectiveness of the three products. Among the bacteria, Pseudomonas aeruginosa and Staphylococcus aureus were the least inhibited, and the most sensitive, respectively. Among the fungi, Rhodotorula glutinus was found to be the least sensitive.

Recommended Citation

Khattabi, Saad, "Separation of selected flavor compound enantiomers by simulated moving bed chromatography : screening of 1-phenyl-1-propanol for antimicrobial activity. " PhD diss., University of Tennessee, 1999.
https://trace.tennessee.edu/utk_graddiss/7474