3,3 -Disulfonate-4,4 -dichlorodiphenylsulfone

At VirginiaTech, 3,3 -disulfonate, 4,4 -dichlorodiphenylsulfone co-monomers with varying degrees of sulfonation were prepared from commercially available monomers. Nuclear magnetic resonance (NMR) spectroscopy was conducted on selected polymeric films to investigate the level of sulfonation. The NMR results showed that the sulfonation levels could be quantified very accurately. The water uptake of bi-phenol sulfone (BPSH) films increased with an increase in the degree of sulfonation. The membrane samples drawn from BPSH40 with 20, 30 and 40 K molecular... 

The structures of the PEMs were confirmed by Fourier transform infrared (FTIR), H-, and NMR spectroscopy. A typical example from Wang et al. [21] is as follows. Aromatic poly(arylene ether sulfone)s (BPSH-XXs) containing up to two peudant sulfonate groups per one repeat unit were prepared by the potassium carbonate-mediated direct aromatic nucleophilic substitutiou polycondensation of disodium 3,3 -disulfonate-4,4 -dichlorodiphenylsulfone (SDCDPS), 4,4 -dichlorodiphenylsulfone (DCDPS), and 4,4 -biphenol as shown in Scheme 4.5. 

A slightly different synthetic procedure consists of an aromatic nucleophilic substitution involving a sulfonated precursor. In this respect, McGrath and coworkers [25,76] reported the synthesis of bis[4-(3-aminophenoxy) phenyl]sulfone-3,3 -disulfonic acid (43°/o overall yield) by directly reacting sulfonated dichlorodiphenylsulfone with 3-aminophenol (Fig. 7). 

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