CO 2 as a chemical feedstock School of Chemistry Professor Michael North

Synthesis of heterocycles from epoxides All are known reactions but often with harsh reaction conditions (e.g. 20 bar CO 2 pressure and >100 o C for cyclic carbonate synthesis) Could a bimetallic catalyst activate both substrates? Can we use only sustainable elements in the catalyst?

Sustainable catalysis Red/orange = rising threat from increased use; Red = serious threat in next 100 years; Orange = limited availability; Many elements are endangered.

A bimetallic aluminium(salen) catalyst M. North et al., Eur. J. Inorg. Chem. 2007, 3323–3326; Chem. Eur. J. 2010, 16, 6828–6843; Patent WO/2008/

Cyclic carbonate synthesis from terminal epoxides RYieldR R Ph62%Me77%CH 2 OCOMe50% PhCH 2 44%H76%CH 2 OCOPh58% Bu87%CH 2 OH36%CH 2 OPh55% C 8 H 17 64%CH 2 Cl60%CH 2 O t Bu50% M. North et al., Eur. J. Inorg. Chem. 2007, 3323–3326; Chem. Eur. J. 2010, 16, 6828–6843.

Supported catalysts

Results with supported catalysts SupportYield t Bu-silica69% t Bu-MCM-41 (silica)57% t Bu-Solgel (silica)52% t Bu-Aluminium pillared clay21% M. North et al. Patent WO/2009/109765; Chem. Commun. 2009, 2577–2579; Dalton Trans. 2011, 40, 3885–3902

Gas phase flow reactor M. North, et al. Chem. Eur. J. 2009, 11454–11457; Dalton Trans. 2011, 40, 3885–3902 Column dimensions: 3-15 cm x 1 cm.

Continuous flow results at 60 o C Catalyst / support Catalyst amount mL / minevaporation rate EO % CO 2 consumed TOF (h -1 ) CO 2 N2N2 t Bu-silica2.17 g mL/h972.6 t Bu-MCM g mL/h958.3 t Bu-solgel1.94 g mL/h975.2 t Bu-PS1.94 g mL/h632.6 H-silica2.17 g mL/h981.1 In each case, CO 2 is 21% of the gases passing into the reactor. Ethylene oxide (EO) flow rate ca 1.2 mL / min. Column length 15 cm M. North, et al. Chem. Eur. J. 2009, 11454–11457; Dalton Trans. 2011, 40, 3885–3902.

Continuous flow results with t Bu-silica catalyst at 100 o C 3cm reactor containing 0.65g catalyst. Catalyst reactivated with BnBr M. North, et al. Chem. Eur. J. 2009, 11454–11457; Dalton Trans. 2011, 40, 3885–3902

Doosan Power systems test facility Flue gas composition Flow rate 20 mL/min GasCoal T53 o C52 o C CO 2 5%15% O2O2 9%3% SO 2 26ppm291ppm CO189ppm40ppm NO x 33ppm443ppm M. North et al. Energy Environ. Sci., 2011, 4, 4163–4170. Used El Cerrejon coal (typical hard coal): 74%C; 0.5%S; 1.5%N; 5%H; 7% H 2 O

Real flue gas flow reactor results with ethylene oxide M. North, et al. Energy Environ. Sci., 2011, 4, 4163–4170. Catalyst reactivated

Synthesis of di- and trithiocarbonates M. North, et al. Synlett 2010, 623–627; J. Org. Chem. 2010, 75, 6201–6207. R1R1 R2R2 50 o C90 o C yieldA:BA:B A:BA:B CH 3 H9789:11945:95 CH 2 MeH5485:159047:53 (CH 2 ) 3 MeH5666:348743:57 (CH 2 ) 5 MeH6170:308139:61 CH 2 ClH7685:158436:64 CH 2 OPhH9797:38771:29 (CH 2 ) :427619:81 PhH620:100910:100

Stereochemistry Internal epoxides are substrates. Reaction involves inversion of epoxide stereochemistry. M. North, et al. J. Org. Chem. 2010, 75, 6201–6207.

Oxazolidinone synthesis 1CocatalystConv.A:BA:B 5 mol%-86%1.8:1 2.5 mol%-63%2:1 -Bu 4 NBr37%1: mol%Bu 4 NBr18%1:0 2.5 mol%Et 3 N38%1: mol%DMAP24%1:5 2.5 mol%Ph 3 PO29%3.1:1 2.5 mol%PyNO64%1:1.1 Best conditions eventually found to be 5 mol% 1 at 80 o C in toluene for 24 h with no cocatalyst. Gave 100% yield with A:B = 2.2:1

Other epoxides and isocyanates

Acknowledgements Dr. Riccardo Pasquale Dr. Jaisiel Melendez Dr. Pedro Villuendas Dr. Carl Young Professor Bill Clegg Dr. Ross Harrington EPSRC, TSB, SSE DoosanBabcock CarbonConnections Newcastle University