Enzyme-Catalyzed Synthesis of Aliphatic–Aromatic Oligoamides

Enzymatically catalyzed polycondensation of <i>p</i>-xylylenediamine and diethyl sebacate resulted in oligo­(<i>p</i>-xylylene sebacamide) with high melting temperatures (223–230 °C) and the enzymatic polycondensation of dimethyl terephthalate and 1,8-diaminooctane leads to oligo­(octamethylene terephthalamide) with two melting temperatures at 186 and 218 °C. No oligoamides, but products 1 and 2, were formed from the enzymatic reaction of dimethyl terephthalate and <i>p</i>-xylylenediamine. All reactions were catalyzed by CAL-B, icutinase, or CLEA cutinase. All reactions catalyzed by CAL-B show higher conversion than reactions catalyzed by icutinase or CLEA cutinase. The highest DP_max of 15 was achieved in a one-step and two-step synthesis of oligo­(<i>p</i>-xylylene sebacamide) catalyzed by CLEA cutinase

Lipase-Catalyzed Ring-Opening Copolymerization of ε‑Caprolactone and β‑Lactam

The enzymatic ring-opening copolymerization of ε-caprolactone (ε-CL) and β-lactam by using Candida antarctica lipase B (CAL-B) as catalyst was studied. Variation of the feed ratios of 25:75, 50:50, and 75:25 of ε-CL/β-lactam was performed. The products contain poly­(ε-CL-<i>co</i>-β-lactam) and the homopolymers of poly­(ε-CL) and poly­(β-lactam). The structure of the copolymers was determined by MALDI-ToF MS. Poly­(ε-CL-<i>co</i>-β-lactam) has an alternating and random structure consisting of alternating repeating units with oligo­(ε-CL) or oligo­(β-lactam). The highest fraction of the alternating copolymers resulted from the reaction with a feed ratio 50:50. The copolymer is a semicrystalline polymer with a <i>T</i>_m at 124 °C and <i>T</i>_gs at −15 and 50 °C. Interestingly, the copolymer also demonstrated cold crystallization at 29 and 74 °C, after quenching the sample from the melt in liquid nitrogen