A new class of catalyst
31 Mar 2003
The Dow Chemical Company and Symyx Technologies have discovered a new class of single-site catalysts for olefin polymerisation through the application of a fully integrated high-throughput screening methodology.
The discovery of the new amide-ether based hafnium catalyst class validates the use of the technique as a time-saving research tool, and has broad implications for Dow's ability to greatly accelerate the discovery and commercialisation of next generation catalysts for olefin polymerisation.
The research results will be published in the April 9, 2003, issue of the Journal of the American Chemical Society (JACS), Vol. 125; Issue 14.
Conventional methods of polyolefin catalyst research involve an expensive, time-consuming 'trial and error' process with unpredictable and often disappointing results. Using the fully integrated high throughput primary and secondary screening methodology, however, Dow and Symyx researchers are now able to analyse large quantities of metal-ligand combinations, identify the most promising catalytically active systems, and reject those that are inactive, all in a matter of hours. As a result, a much broader range of catalysts candidates and conditions can be evaluated, allowing time and resources to be directed toward maximising the potential of the most promising ones.
Dow and Symyx have collaborated in the field of high-throughput discovery of polyolefin catalysts since January 1999. Dow is actively developing several catalysts discovered by Symyx under that collaboration.
'Any researcher involved in the synthesis of a new catalyst knows how slow the process can be, taking anywhere from five to ten years from idea to commercialisation,' said James C. Stevens, senior scientist, polyolefins and elastomers at Dow, and co-author of the JACS article. 'This new screening methodology can open the door to the development of a whole class of new materials at a faster pace than we've ever known before.'
In the case of the new amide-ether based hafnium catalyst, it took only a few hours for the primary screening to analyse 384 metal-ligand combinations and identify 10 interesting 1-octene polymerisation catalysts. Larger scale secondary screening experiments performed on a focused 96-member library led to the development of a new high temperature LLDPE (linear low-density polyethylene) catalyst class based upon a non-metallocene ligand. Large-scale batch reactor experiments further validated the performance features of the new catalyst and the high-throughput screening approach.
'Single-site, non-metallocene catalysis is a developing area and one that holds great promise for polyolefins research and development,' Stevens noted. 'Now that we have the ability to analyse these catalysts at the rate of about one thousand a day, new polyolefin catalysts can be discovered and optimised at unprecedented rates.'
