The rapid expansion of shale gas in the USA has led to a significant increase in the availability of feed-stock gases.1 Of significant commercial interest is therefore the conversion of light a-olefins, accessed via direct isolation, dehydrogenation or Shultz-Flory oligomerisation, into value-added products such as lubricants and high performance fuels. Trimerisation is an efficient synthetic route to these higher molecular weight products.Selective trimerisation of linear a-olefins can be achieved with the use of N-substituted 1,3,5-triazacyclohexane chromium complexes.2 The novel set of catalysts described in this presentation demonstrate activities an order of magnitude greater than the only known alternative system.3 The catalysts also greatly improve on preliminary results published by the group due to enhanced solubility, stability and activity. It is proposed that the catalytic cycle proceeds through the metallacyclic mechanism predicted for similar selective trimerisation systems.4 This is strongly supported by characterisation of the trimer isomers using NMR spectroscopy. Isotopic labelling with 13C enabled identification of the regioisomers via observation of carbon-carbon coupling. All isomers found were compatible with the proposed mechanism and as such support this catalytic cycle. Accurate calculation of isomer ratios also allowed insight into the favoured chromacyclic intermediates and elimination pathways.1. S��t et al., Oil Shale, 2012, 29 , 248-267.2. K�hn et al., Angew. Chem., 2000, 39 , 4337-4339.3. Sattler et al., Organometallics, 2013, 32 , 6899-6902.4. McGuinness, Chem. Rev., 2011, 111  , 2321-2341.

Selective trimerisation of a-olefins

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.