New publication in Dalton Transaction about lactide polymerisation online
The success in the development of new catalysts for the industrial polymerisation of lactide continues. Based on the TMGasme ligand framework, the Herres-Pawlis group has optimised the ligand. By varying different substituents on the aromatic skeleton, the influence on the catalysis activity in the ring-opening polymerisation of lactide was tested. The substitution of a dimethylamine group in para-position to the guanidine increased the polymerisation rate sixfold compared to the unsubstituted ligand. In addition, molecular weights of over 70,000 g/mol are obtained, so that industrial application is also possible here. The studies were performed with industrially used lactide and the rate of the polymerization was monitored by in situ Raman spectroscopy.
All four catalysts presented proved to be robust against the impurities in the monomer, but showed different activities due to the respective electronic influence of the substituent. This paper comes closer to the search for a suitable substitute for the currently industrially used and toxic catalyst tin octanoate. And this despite the fact that only a minor change was made to the ligand.
The article Tuning a robust system: N,O zinc guanidine catalysts for the ROP of lactide is available on the webpage of the publisher.