Real-time analysis of methylalumoxane formation
| dc.contributor.author | Joshi, Anuj | |
| dc.contributor.author | Zijlstra, Harmen S. | |
| dc.contributor.author | Liles, Elena | |
| dc.contributor.author | Concepcion, Carina | |
| dc.contributor.author | Linnolahti, Mikko | |
| dc.contributor.author | McIndoe, J. Scott | |
| dc.date.accessioned | 2020-11-12T23:49:14Z | |
| dc.date.available | 2020-11-12T23:49:14Z | |
| dc.date.copyright | 2020 | en_US |
| dc.date.issued | 2020 | |
| dc.description.abstract | Methylalumoxane (MAO), a perennially useful activator for olefin polymerization precatalysts, is famously intractable to structural elucidation, consisting as it does of a complex mixture of oligomers generated from hydrolysis of pyrophoric trimethylaluminum (TMA). Electrospray ionization mass spectrometry (ESI-MS) is capable of studying those oligomers that become charged during the activation process. We have exploited that ability to probe the synthesis of MAO in real time, starting less than a minute after the mixing of H2O and TMA and tracking the first half hour of reactivity. We find that the process does not involve an incremental build-up of oligomers; instead, oligomerization to species containing 12–15 aluminum atoms happens within a minute, with slower aggregation to higher molecular weight ions. The principal activated product of the benchtop synthesis is the same as that observed in industrial samples, namely [(MeAlO)16(Me3Al)6Me]−, and we have computationally located a new sheet structure for this ion 94 kJ mol−1 lower in Gibbs free energy than any previously calculated. | en_US |
| dc.description.reviewstatus | Reviewed | en_US |
| dc.description.scholarlevel | Faculty | en_US |
| dc.description.sponsorship | JSM thanks NSERC (Strategic Project Grant #478998-15) and Nova Chemicals' Centre for Applied Research for operational funding and CFI, BCKDF and the University of Victoria for infrastructural support. The computations were made possible by use of the Finnish Grid Infrastructure and Finnish Grid and Cloud Infrastructure resources (urn:nbn::research-infras-2016072533). | en_US |
| dc.identifier.citation | Joshi, A., Zijlstra, H. S., Liles, E., Concepcion, C., Linnolahti, M., & McIndoe, J. S. (2020). Real-time analysis of methylalumoxane formation. Chemical Science. https://doi.org/10.1039/d0sc05075j | en_US |
| dc.identifier.uri | https://doi.org/10.1039/d0sc05075j | |
| dc.identifier.uri | http://hdl.handle.net/1828/12346 | |
| dc.language.iso | en | en_US |
| dc.publisher | Chemical Science | en_US |
| dc.subject.department | Department of Chemistry | |
| dc.title | Real-time analysis of methylalumoxane formation | en_US |
| dc.type | Article | en_US |