Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
Institute of Organic and Macromolecular Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany.
Angew Chem Int Ed Engl. 2020 Nov 23;59(48):21778-21784. doi: 10.1002/anie.202008473. Epub 2020 Oct 22.
Polylactide and polycaprolactone are both biodegradable polymers produced through metal-catalyzed ring-opening polymerization. For a truly sustainable lifecycle of these polymers it is essential to replace the industrially used cytotoxic catalyst tin(II) bis(2-ethylhexanoate) [Sn(Oct) ] with non-toxic alternatives. Here, we report the fastest known robust catalyst in the polymerization of lactide and ϵ-caprolactone. This zinc guanidine catalyst can polymerize non-purified technical rac-lactide and ϵ-caprolactone in the melt at different [M]/[I] ratios with fast rate constants, high molar masses, and high yields in a short time, leading to colorless, transparent polymer. Moreover, we report that polylactide and polycaprolactone produced by zinc-guanidine complexes have favorably high crystallinities. In fact, the obtained polylactide shows a more robust degradation profile than its Sn(Oct) -catalysed equivalent due to a higher degree of crystallinity.
聚乳酸和聚己内酯都是通过金属催化开环聚合生产的可生物降解聚合物。为了使这些聚合物具有真正可持续的生命周期，必须用无毒替代品替代工业上使用的细胞毒性催化剂二（2-乙基己酸）锡（II）[Sn（Oct）]。在这里，我们报告了在丙交酯和ε-己内酯聚合中已知的最快的稳健催化剂。这种锌胍催化剂可以在熔体中聚合未经纯化的技术外消旋丙交酯和ε-己内酯，在不同的[M] / [I]比下具有快速的速率常数、高摩尔质量和在短时间内的高收率，得到无色透明的聚合物。此外，我们还报告了锌胍配合物制备的聚乳酸和聚己内酯具有有利的高结晶度。事实上，由于结晶度较高，所得到的聚乳酸的降解性能比其 Sn（Oct）催化的对应物更稳健。
