4,4 -Dichlorodiphenyl sulfone DCDPS

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... 

The 4,4 -dichlorodiphenyl sulfone (DCDPS) kindly supplied by the Union Carbide Corporation was recrystallized twice from toluene (m.p. = 145-148 C. Hydroquinone (Tennessee Eastman Company) was recrystallized twice from acetone under nitrogen (m.p. 172-174 C) and stored in a desiccator until used. The 4,4 -biphenol obtained from Buffalo Color Company was of polymer grade purity and was used as recieved. The NMP (Fisher certified grade solvent) was vacuum distilled before use. 

In 1965 A.G. Farnham and R.N. Johnson of Union Carbide (this business was acquired by Amoco Polymers in 1986 and is currently part of Solvay Advanced Polymers) announced the preparation of thermoplastic polysulfones, PSU [25]. Tlie first commercially available polysulfone was prepared by the nucleophilic aromatic displacement of the chlorides on 4,4 -dichlorodiphenyl sulfone, DCDPS, by the anhydrous di-sodium salt of BPA. The reaction is conducted in a dipolar aprotic solvent, such as dimethyl sulfoxide. This polysulfone, PSU, was commercialized in 1966 under the Udel trademark. This amorphous polymer exhibits a of 186°C. The structure of PSU is shown in Fig. 1.11. 

Meanwhile, most commercial polysulfones (PSU) and poly(ether sulfone)s (PES) are obtained from conversion of suitable aromatic dihalides with bisphenols by nucleophiUc displacement polycondensation (Fig. 19B). Generally, 4,4 -dichlorodiphenyl suUbne (DCDPS) is reacted with alkali salts of bisphenols [92,93]. The reaction is carried out in solution using hT-methyl-2-pyrrolidone (NMP), N,N-dimethyl acetamide (DMAc), or dimethyl sulfoxide (DMSO) as the solvent. Occasionally, the more reactive, but also more expensive, 4,4 -difluorodiphenyl sulfone might be used for experimental purposes. Usually, the electronegativity of the sulfone Unkage is sufficient to increase the reactivity of the aromatic chloride in DCDPS (Fig. 19). 

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