Doctoral Dissertations

Date of Award

12-1999

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Chemistry

Major Professor

Spiro Alexandratos

Committee Members

Mark Dadmun, Ziling Xue, Paul Phillips

Abstract

A general synthesis for the formation of polymer bound phosphonate esters and phosphonamides has been devised and studied. Phosphonic acid resin was produced by an Arbusov reaction and subsequent hydrolysis of a vinylbenzyl chloride-divinylbenzene copolymer. The phosphonic acid resin was reacted with thionyl chloride to form a reactive intermediate, phosphoryl dichloride resin. The phosphoryl dichloride resin was reacted with various alcohols and amines to form the aforementioned resins. Reaction time, reaction ten^erature, reaction solvent, pre-reaction work-up, and post-reaction work-up were all studied. A mechanism has been proposed to help explain the trends accompanying the reaction variables. The mechanism states that the weak base solvent, pyridine, can attack the functionality forming a salt with the phosphoryl moiety. If the salt formation is favorable, the amount of functionalization is reaction time and temperature dependent. If the salt formation is unfavorable, there is no dependence on the reaction time or the reaction temperature. The resins were analyzed for uptake of various divalent transition metals in a pH 2 nitrate solution with a large excess of competing sodium ions. Generally, the phosphonamides were an improvement for the metals studied upon comparison to phosphonic acid resin, the control. The phosphonate esters were, at best, as good as the phosphonic acid resin, but were usually much worse in removing the metals studied.

Combining long alkyl and short alkyl chain ligands to form a dual mechanism bifunctional polymer (DMBP) gives rise to a new type of anion exchange resin where one works as an access ligand and the second works as a recognition ligand. Working with scientists at Oak Ridge National Laboratory (ORNL), the newly found polymers were analyzed for the uptake of the pertechnetate anion from groundwater samples. It was discovered that the ligand with the highest affinity for the TcO4- (but the slowest uptake time) is a quaternary ammonium ligand made from trihexylamine. The addition of a second quaternary ammonium ligand by amination with a smaller trialkylamine (triethylamine) to form a bifunctional quaternary ammonium exchange resin improved the uptake and kinetics of the resin made from amination with trihexylamine. The reaction procedure was stream-lined for use on an industrial scale.

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