Mechanistic Insight in the Enzymatic Ring-Opening Polymerization of beta-Propiolactam

• Main Authors: Schwab, Leendert W., Baum, Iris, Fels, Gregor, Loos, Katja
• Other Authors: Cheng, HN, Gross, RA
• Format: Article in Journal/Newspaper
• Language: English
• Published: AMER CHEMICAL SOC 2010
• Subjects: ANTARCTICA LIPASE-B; CANDIDA-ANTARCTICA; EPSILON-CAPROLACTONE; ORGANIC-SOLVENTS; AMINO ACIDS; LACTAMS; SPECIFICITY; Antarc*; Antarctica
• Online Access: https://hdl.handle.net/11370/c33dd882-2f8a-4dc9-b5c3-f22ab9221730; https://research.rug.nl/en/publications/c33dd882-2f8a-4dc9-b5c3-f22ab9221730

Here we report the polymerization of beta-propiolactam to poly(beta-alanine) catalyzed by the immobilized Candida antarctica lipase B (N435). The polymer is characterized by (1)H-NMR spectroscopy and MALDI-ToF mass spectrometry. The best results were obtained with N435 (dried for 24 hours in vacua at 46 degrees C) in toluene at 55 degrees C for a period of 96 hours. Polymerization of beta-alanine was not feasible via the N435 catalyst, showing that the beta-propiolactam ring is needed for this reaction. This finding ruled out reaction mechanisms that resembled enzymatic polymerization of epsilon-caprolactone. Instead, a detailed eight-step mechanism was developed by computational simulation that provided an appropriate description of ring-opening polymerization of beta-propiolactam.