Aliphatic Polyesters by Bismuth Triflate-Catalyzed Polycondensations of Dicarboxylic Acids and Aliphatic Diols

• Published in: Macromolecules Vol. 41; no. 22; pp. 8491 - 8495
• Main Authors: Buzin, Pavel, Lahcini, Mohammed, Schwarz, Gert, Kricheldorf, Hans R
• Format: Journal Article
• Language: English
• Published: American Chemical Society 25-11-2008
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma8017662

Polycondensations of aliphatic dicarboxylic acids (ADAs) with 1,4-butane or 1,6-hexane diol were conducted in bulk at 80 or 100 °C. Temperature and monomer/catalyst ratio were varied. With bismuth triflate, Bi(OTf)3, as catalyst, number average molecular weights (M n’s, uncorrected SEC data) up to 30 000 Da were obtained. Analogous polycondensations were performed with the triflates of sodium, magnesium, aluminum, zinc, tin(II), scandium, and hafnium, but the highest M n values were achieved with Bi(OTf)3. Polycondensations and model experiments proved that most triflates catalyzed the formation of tetrahydrofuran from 1,4-butane diol above 100 °C. Therefore, polycondensations of 1,4-butane diol required temperatures ≤100 °C. Polycondensations of 1,4-butene diol or 1,4-butyne diol were unsuccessful, because of side reactions. All polycondensations involved rapid equilibrations, and the content of cyclic oligo- and polyesters increased with the conversion.