New synthetic routes to poly(isothianaphthene). II. Mechanistic aspects of the reactions of phthalic anhydride and phthalide with phosphorus pentasulfide
✍ Scribed by Rob van Asselt; Dirk Vanderzande; Jan Gelan; Peter E. Froehling; Olav Aagaard
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 685 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0887-624X
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✦ Synopsis
The results of some mechanistic studies on the formation of poly(is0thianaphthene) from phthalic anhydride and phthalide by reaction with phosphorus pentasulfide (P,Sl0) are described. Based on the observed intermediates during the polymerization and their reactivity, it is proposed that both reactions occur by a sequence of substitution (thionation), isomerization, and polymerization reactions. P4Slo is the most efficient reagent for the conversion of phthalic anhydride and phthalide, and Lawesson's Reagent (a commonly used thionating reagent) gives less satisfactory results. It is suggested that P4S,, assists the rate-determining step. Oxygen-containing monomers do not polymerize in the absence of a thionating reagent under the conditions for the synthesis of PITN, thereby keeping the incorporation of oxygen into the polymeric backbone to a minimum. 0