High-molecular-weight sulfonates

A noncovalent protection method was developed by Andrianov et al. to prepare directly sulfonated polyphosphazenes (Figure 7.20) [96]. The formation of unstable intermediates was prevented by protecting hydroxybenzenesulfonic acid with hydro-phobic dimethyldipalmitylammonium ions, which were not reactive against PDCP. The protective dimethyldipalmitylammonium groups can be easily removed by treatment with potassium hydroxide and hydrochloric acid sequentially. It was found that the conversion of sodium phenoxide into a hydrophobic ammonium salt did not lower its reactivity against PDCP. High-molecular-weight sulfonated polyphospha-zene homopolymers and copolymers were synthesized. However, no membrane was prepared from these polymers, and no characterization results were reported on ionic conductivity, water uptake, or methanol permeability. 

Kruczek B, Matsuura T. Development and characterization of homogeneous membranes made from high molecular weight sulfonated polyphenylene oxide. J. Membrane Sci. 1998 146 263-275. 

Kruczek, Boguslaw, Development and Characterization of Dense Membranes for Gas Separation Made from High Molecular Weight Sulfonated Poly (Phenylene Oxide). Effect of Casting Connditions on the Morphology and Performance of the Membranes, Ph.D. Thesis, University of Ottawa, Ottawa ON 1999. 

Kruczek B. and Matsuura T., Development and Characterization of Homogeneous Membranes from High Molecular Weight Sulfonated Polyphenylene Oxide, J. Membrane Sci., 1998,146, 263-275. 

Another type of soHd supetacid is based on perfluorinated resin sulfonic acid such as the acid form of Du Font s Nafion resin, a copolymer of a perfluorinated epoxide and vinylsulfonic acid or soHd, high molecular weight petfluotoalkanesulfonic acids such as petfluotodecanesulfonic acid, CF2(CF2)qS02H. Such sohd catalysts have been found efficient in many alkylations of aromatic hydrocarbons (225) and other Friedel-Crafts reactions (226). 

With as httie as 0.5% hydrolysis of the sulfone monomer, the polymerization stoichiometric balance is sufficientiy upset to prevent high molecular weight polymer from being achieved. The dependence of maximum attainable PSF molecular weight on water content during polymerization can be inferred from Figure 1. 

A significant proportion of lube sulfonates are based on high molecular weight synthetic alkylated aromatic feedstocks. Sulfonation of these... 

The SnAt reactions were first successfully used in the synthesis of high-molecular-weight poly(arylene etherjs by Johnson et al.4,5 This reaction represents a good example for poly(ether sulfonejs in general, either in laboratory -or industrial-scale preparations. In this procedure, the bisphenol A and sodium hydroxide with an exact mole ratio of 1 2 were dissolved into dimethyl sulfoxide (DMSO)-chlorobenzene. The bisphenol A was converted into disodium bisphenolate A, and water was removed by azeotropic distillation. After the formation of the anhydrous disodium bisphenolate A, an equal molar amount of 4,4,-dichlorodiphenyl sulfone (DCDPS) was added in chlorobenzene under anhydrous conditions and the temperature was increased to 160°C for over 1 h... 

Robeson and Matzner were the first to report the synthesis of the sulfonation of DCDPS.205 This work makes it possible to synthesize sulfonated poly(arylene ether sulfone) with well-controlled structures. Ueda et al. used this monomer (Scheme 6.27) as a comonomer of DCDPS to react with bisphenol A and high-molecular-weight bisphenol-A-based copolymers with up to 30 mol % sulfonation achieved.206 Biphenol-based copolymers with up to 100 mol % sulfonation were recently reported by Wang et al.207... 

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