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

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Presentation on theme: "CO 2 as a chemical feedstock School of Chemistry Professor Michael North."— Presentation transcript:

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

2 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?

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

4 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/

5 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.

6 Supported catalysts

7 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

8 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.

9 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.

10 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

11 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

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

13 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

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

15 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

16 Other epoxides and isocyanates

17 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


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