Selective Organocatalytic Ring-Opening Polymerization:  A Versatile Route to Carbohydrate-Functionalized Poly(ε-caprolactones)

Abstract

Cationic catalysis using simple carboxylic acids to combine the ring-opening polymerization of ε-caprolactone and the regioselective acylation of carbohydrates has been investigated. l-Lactic acid catalyzed the acylation of methyl β-d-glucopyranoside and sucrose with ε-caprolactone in high yield by bulk polymerization at 120 °C. The main products were regioselectively acylated on the primary hydroxyl groups of the carbohydrate end groups. The overall conversion to methyl β-d-glucopyranoside-functionalized poly(ε-caprolactone) was more than 90%, M w 2000 and polydispersity index 1.5, with one major product methyl 6-O-poly(ε-caprolactone)-β-d-glucopyranoside, in agreement with the corresponding Candida antarctica lipase B-catalyzed acylation.

Improving the reproducibility of chemical reactions on the surface of cellulose nanocrystals: ROP of ε-caprolactone as a case study

“…In this work, we chose to use a benign organic acid, namely citric acid, while performing all reactions in bulk, in line with the green objectives of our group, to study the reproducibility of the surfaceinitiated ROP of e-caprolactone from the surface of cellulose nanowhiskers. Carboxylic acids (lactic acid Persson et al 2004;Casas et al 2004, tartaric acid Casas et al 2004Hafrén andCórdova 2005, hexanoic acid Persson et al 2004;Casas et al 2004, propanoic acid Rindlav-Westling andGatenholm 2003;Persson et al 2004;Casas et al 2004-hydroxyhexanoic acid Persson et al 2004, citric acid Casas et al 2004) as well as amino acids (Casas et al 2004) (glycine, proline, serine) have been used before to catalyse the ROP of e-caprolactone using monosaccharides ) (methyl b-D-glucopyranoside), disaccharides ) (sucrose), or trisaccharides ) (raffinose) as initiators and SI-ROP from cotton fibres has also been performed (Hafrén and Córdova 2005). Casas and co-workers proposed a monomer activated mechanism for this polymerisation (Casas et al 2004).…”

Nanofibrous Membranes Containing Reactive Groups: Electrospinning from Poly(acrylonitrile-co-maleic acid) for Lipase Immobilization

“…[6][7][8][9][10][11][12][13][14] As a biocatalyst, lipases have received increasing attention for biotransformation and polymer synthesis. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] However, practical applications prefer immobilized enzymes because they offer easy catalyst recycling, feasible continuous operations, and simple product purification. Furthermore, immobilizing enzymes onto various insoluble or solid supports is a useful tool to increase their thermal and operational stabilities.…”

Thiourea binding with carboxylic acid promoted cationic ring-opening polymerization

“…Strong Brønsted acid featured with fast reaction rate usually accompanied with drawbacks in poor control. Weak Brønsted acid such as tartaric, citric and L-Lactic acid [47][48][49] showed limited efficiency in bulk polymerization at high temperature (120 °C), solution polymerization was not feasible. Between the strong and weak ones, trifluoroacetic acid (TFA) as a Brønsted acid has been successful in ROPs of ε-caprolactone [46] and trimethylene carbonates [50], however, ε-CL polymerized in bulk condition at elevated temperatures; similarly, poly(trimethylene carbonates) (PTMC) was obtained as oligomers with poor molecular weight distributions [50], and TFA as Bronsted acid due to its pseudoliving character in ROP of TMC [51].…”