title: Dehydration polycondensation of dicarboxylic acids and diols using sublimating strong brønsted acids.
abstract: We investigated catalytic activities of strong brønsted acids for dehydration polycondensations of dicarboxylic acids and diols, which were carried out at low temperature (<100 °C) under reduced pressure (0.3-3 mmHg). Strong Brønsted acids, bis(perfluoroalkanesulfonyl)imide and perfluoroalkanesulfonic acid, showed higher activity than p-toluenesulfonic acid or rare-earth catalysts at 60 °C. In particular, bis(nonafluorobutanesulfonyl)imide (Nf(2)NH) showed the highest activity to synthesize not only aliphatic polyester (M(n) > 19000) but also aromatic polyester (M(n) > 7000). The used Nf(2)NH was sublimated from the reaction flask during polycondensation, and the sublimate, Nf(2)NH, was extra pure so that we can reuse the catalyst without loss of the activity in the dehydration polycondensations.
authors.affiliation: Department of Frontier Materials, Graduate School of Engineering,  Nagoya Institute of Technology , Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan.
authors.forename: Takaya
authors.initials: T
authors.lastname: Moyori
authors.forename: Tang
authors.initials: T
authors.lastname: Tang
authors.forename: Akinori
authors.initials: A
authors.lastname: Takasu
mesh_terms: D000143:Acids / Q000737:chemistry*; D000438:Alcohols / Q000737:chemistry*; D003681:Dehydration; D003998:Dicarboxylic Acids / Q000737:chemistry*; D015394:Molecular Structure; D011091:Polyesters / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000143:Acids; D000438:Alcohols; D003998:Dicarboxylic Acids; D011091:Polyesters