Quaternization of Condensation Polymers

A survey of the reaction conditions required to quaternize chloromethylated condensation polymers in a homogeneous media revealed that mixed solvent systems would be required to handle poly(oxy-2,6-dimethyl-3-chloromethyl-1,4-phenylene), The reaction of triethylamine with chloromethylated polysulfone proceeded cleanly in pure DMSO, and a model compound was easy to synthesize. Therefore, we focused our initial attention on polysulfone derivatives. 

The perhydropyrazine (piperazine) heterocycle has been a favorite of the polymer chemist for the preparation of both addition and condensation polymers because of the desirable physical and chemical properties imparted by the ring. Piperazine-functional acrylate esters (140) readily polymerize under free radical conditions (74BRP1361878). Polymers obtained from these monomers, due to the presence of tertiary amino groups, exhibit enhanced dyeabilities and are susceptible to quaternization to form hydrophilic polymers or polyelectrolytes. 

The second order nature of quaternization reactions in our system was confirmed by rate studies on model compounds. Although benzyl chloride is usually selected as the model for chloro-methylated polymers , we chose to synthesize a difunctional model that would be sensitive to neighboring group effects. Condensation of 4-chlorophenyl phenyl sulfone with the disodlum salt of bis-phenol-A yielded an excellent model for the polysulfone segment, Quantitative chloromethylation of with a chloromethyl methyl ether/ methyl acetate mixture in the presence of stannic chloride afforded the corresponding bischloromethyl adduct,... 

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