Delivery of a Fatty Acid Signal Via RTIL for Biofilm Dispersion

Keyes, Rachaud M. (2015) Delivery of a Fatty Acid Signal Via RTIL for Biofilm Dispersion. Undergraduate thesis, under the direction of Paul Scovazzo from Chemical Engineering, University of Mississippi.

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A number of proposed applications for ionic liquids involve ionic liquid/water interfaces, such as, chemical separations or drug delivery systems. Therefore, an understanding of the solubility and micellar behavior of ionic liquids in an aqueous environment is critical fundamental knowledge. The long term goal of our study was ionic liquids for delivery of biological active agents; therefore, we chose the anion, bis(trifluoromethanesulfonyl)imide (Tf2N) since it promotes water stability and forms water immiscible RTILs. The study then paired the Tf2N-anion with three different classes of cations. By adding apolar substituents (-CH2-) to the cation, the size of the molecule increases in each RTIL class, rendering the RTIL less soluble in the water phase. The three classes of RTILs examined were 1-Cn-3-methylimidazolum (Rmim), Cn-trimethylammonium (CTA), and branched ammonium (BAM), with the “Cn” representing an alkyl functional group (propyl, butyl, etc.). For industrial use, CTAs are attractive, since they can be synthesized from inexpensive ammonium surfactants. However, large CTAs (twelve carbon chain and higher) are solids at ambient conditions. In contrast, BAMs have larger compounds that remain in the liquid state at ambient conditions. Nevertheless, each class has potential as a delivery agent by meeting the aforementioned criterion – namely, water immiscible and water stable at ambient temperatures. We used Total Organic Carbon (TOC) analysis to determine the RTIL content in water that is in equilibrium with the tested RTILs. Surface tension measurements of the RTIL containing water determined if RTIL micelles existed in the RTIL saturated water. We used LFER (Linear Free Energy Relationship) semi-empirical models to correlate the RTIL water solubility to the molecular size and structure of the RTIL cation. Combining the LFER results with surface tension measurements and thermodynamic calculations of sub-cooled RTIL fugacities, allowed us to determine that micelle formation is not significant for the tested RTILs with molar volumes less than 350 cm3/mol. We tested a total of 15 different RTILs with the water solubilities ranging from 10-2 to 10-4 moles-RTIL/L-water. Based on the water solubilities, the proposed RTILs are [N(10)111][Tf2N], [N(10)Me2(iPr)][Tf2N], and [C(6)MIM][Tf2N] for delivery of the signal cis-2-decenoic acid for biofilm dispersion.

Item Type: Thesis (Undergraduate)
Creators: Keyes, Rachaud M.
Student's Degree Program(s): B.S. in Chemical Engineering
Thesis Advisor: Paul Scovazzo
Thesis Advisor's Department: Chemical Engineering
Institution: University of Mississippi
Subjects: T Technology > TP Chemical technology
Depositing User: Mr. Rachaud Keyes / RK Rachaud
Date Deposited: 12 May 2015 17:03
Last Modified: 12 May 2015 17:03

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