Syntheses of Polyesters from Succinic Anhydride and Various Diols Catalyzed by Metal Triflates

Abstract

Succinic anhydride (SuAh) was polymerized with various α,ω‐alkanediols from 1,3‐propanediol up to 1,10‐decanediol. Most polycondensations were conducted in bulk at temperatures of 80 °C with bismuth triflate as catalyst and number average molecular weights ($\overline M _{\rm n} {\rm s}$, uncorrected SEC data) up to 35 000 Da were obtained. Polycondensations of SuAh with 1,6‐hexanediol were also catalyzed with aluminum, tin(II), scandium, lanthanium, samarium, and hafnium triflate. Whereas, poor results were achieved with La‐triflate, aluminum and tin(II) triflate yielded $\overline M _{\rm n} {\rm s}$ comparable to those obtained with Bi‐triflate. With exception of the basic lanthanum triflate, all other catalysts generated small amounts of ether groups. The MALDI‐TOF mass spectra proved that the molecular weights depended on the conversion and on the extent of cyclization. The polycondensations of 1,4‐butanediol at temperatures up to 120 °C were affected by the formation of tetrahydrofuran, and even with an excess of the diol $\overline M _{\rm n} {\rm s}$ <10 000 Da were not obtained. Yet, BiCl3 and Bi‐triflate catalyzed polycondensations in refluxing decalin gave satisfactory results ($\overline M _{\rm n} {\rm s}$ ≈ 30 000 Da, uncorrected SEC data).

Biotic and Abiotic Synthesis of Renewable Aliphatic Polyesters from Short Building Blocks Obtained from Biotechnology

“…In additiont ot ypical metal alkoxides, new strong Lewis acid catalysts have been recently developed based on rare-earth or transition metals,s uch as scandium (e.g.,s candium triflate (Sc(OTf) 3 ) , scandium perfluorooctanesulfonate (Sc(OPf) 3 ), or scandium(III) trifluoromethanesulfonimide (Sc(NTf 2 ) 3 ), neodymium (e.g.,N d(OTf) 3 ), thulium (e.g.,T m(OTf) 3 ), or yttrium (e.g., Y(OTf) 3 ). These catalysts have exhibited remarkable activities under mild conditions (mostly < 80 8C) for the synthesis of polyesters through the ROP of lactones (i.e., e-caprolactone, dvalerolactone, lactide), [143,144] ac ombinationo fR OP and polycondensation, [145,146] and step-growth polycondensation or transesterification. [124,147,148] As an example, the reaction between SA and 1,4-BDO catalyzed by Sc(OTf) 3 in bulk under vacuum at 180 8Cl eads to PBS up to 31 000 gmol À1 (Table 2).…”

“…[124] Even if this catalyst is highly active at low temperature, an increase of the reaction temperature permits polyester chains to be obtainedw ith higher molar mass. Similarly,K richeldorf et al reported the successful use of bismuth compounds for the synthesis of aliphatic polyesters from dimethyl ester, [149] succinic anhydrides, [146] or from the direct polycondensation of dicarboxylic acids. [149,150] M n values of up to 30 000 gmol À1 were obtained from the bulk polymerization at 80 8Cf or over 48 h. Compared with scandium, bismuth is particularlyi nteresting because it combinest wo advantages:lower toxicity and ah igher efficiency as an esterification catalyst.…”

Solution viscosity – molar mass relationships for poly(butylene succinate) and discussion on molar mass analysis

“…They are numbered PBS1 to PBS7 in the order of increasing molar mass. [18]. The number of scans was 256.…”

“…As reported in the literature, the synthesis of PBS may produce a non negligible amount of oligomers, especially cyclic species [18,19]. Most of the time, in scientific studies, PBS is purified to get rid of these species but commercial PBS clearly contains oligomers since dissolution/precipitation steps are not performed.…”

“…The above comment illustrates one of the reasons why the determination of molar mass by SEC with a refractive index or light scattering detector for polyesters is controversial in chloroform. Several authors have recently highlighted that polystyrene-calibrated SEC measurements in chloroform overestimate the real M n -by at least 50% in the range above 10 4 g·mol -1 for poly("-caprolactone), polylactide and related copolyesters [18][19][20][21][22][23][24]. For these reasons, researchers have used complementary techniques such as MALDI-TOF mass spectrometry [19,25].…”