Martyn Poliakoff

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Catalyddion Aml-Ochrog mewn Hylyfoedd Uwchradd

• Martyn Poliakoff
• martyn.poliakoff_at_nottingham.ac.uk

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Supercritical Fluids

• Gases e.g. CO2, C2H4, H2O compressed until they
  are nearly as dense as liquids
• SCFs can dissolve solids solubility increases
  with density (applied pressure)

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Critical Points
Pc
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Supercritical Catalysis

• Catalysis in scCO2- Hydrogenation,
  Hydroformylation
• Supercritical Water
• Biocatalysis

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Miscibility of H2/scCO2
Higher Concentration of Dissolved H2 in scCO2
Howdle, S. M., Healy, M. A., Poliakoff, M. J.
Am. Chem. Soc. 1990 112, 4804. Jessop, Ph. G.,
Ikariya, T., Noyori, R. Nature 1994, 368, 231.
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Continuous Supercritical Hydrogenation
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Other Hydrogenations successfullycarried out in
scCO2 and scPropane
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scCO2 Chemical Plant opened July,2002

• continuous
• multipurpose
• 1000 ton p.a.

Thomas Swan Co
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Hydrogenation of Isophorone
The product by-products have similar boiling
points Conventional process requires an
expensive downstream separation
scCO2 - quantitative, no by-products
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scCO2 and Ionic Liquids
scCO2 very soluble in ILs ( 0.6 mole
fraction) ILs are insoluble in scCO2 L.A.
Blanchard, D. Hancu, E.J. Beckman and J.F.
Brennecke, Nature, 1999, 399, 28 scCO2 can
extract many organics from ILs L. A. Blanchard
and J. F. Brennecke, Ind. Eng. Chem. Res., 2001,
40, 287
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Bi-phasic Catalysis Cole-Hamilton
P. B. Webb, M. F. Sellin, et al. J. Am. Chem.
Soc.,2003, 125, 15577
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Green Chemistry 12 Principles
P R O D U C T I V E L Y
- Prevent wastes - Renewable materials - Omit
derivatization steps - Degradable chemical
products - Use safe synthetic methods -
Catalytic reagents - Temperature, Pressure
ambient - In-Process Monitoring - Very few
auxiliary substances - E-factor, maximize feed in
product - Low toxicity of chemical products - Yes
its safe
- Prevent wastes - Renewable materials - Omit
derivatization steps - Degradable chemical
products - Use safe synthetic methods -
Catalytic reagents - Temperature, Pressure
ambient - In-Process Monitoring - Very few
auxiliary substances - E-factor, maximize feed in
product - Low toxicity of chemical products - Yes
its safe
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Gas-Expanded Liquids
Increasing Pressure
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Hydrogenation of a-pinene A. Serbanovic, V.
Najdanovic-Visak, A. Paiva, G. Brunner, M.
Nunes da Ponte 8th ISSF, Kyoto
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Gas-Expanded liquids (GExLs)

• 1. Autoxidation by O2 in GExLs,
• DH Busch, B Subramaniam co-workers, Green
  Chem., 2004, 6, 387.
• 2. Enhanced Solubility of gases in GExLs,
• JF Brennecke coworkers, Ind. Eng. Chem. Res.,
  2006, 45, 5351.
• CO2-Protected Amine Formation in GExLs
• X. Xie, C. L. Liotta C. A. Eckert, Ind. Eng.
  Chem. Res., 2004, 43, 7907.

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Hydrogenation of Isophorone
Reaction has a high space-time yield How is this
influenced by the phase behaviour of the system?
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Isophorone /CO2/H2 phase boundaries
M. Sokolova Ke Jie
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CO2- expansion Hydrogenation

• Increases solubility of H2
• (B. Subramaniam, J. Brennecke)
• Increases diffusion ? faster transport across
  phase boundary (EJ Beckman)
• Reduces viscosity
• All of these accelerate reaction

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Hydrogenation of sertraline imine in CO2expanded
THF
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Commercial Route to Zoloft
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Continuous hydrogenation of rac-sertraline in
scCO2/THF

• Investigate both chemoselectivity
  diastereoselectivity
• Aims (1) lt 1.5 dechlorination
• (2) gt 928 de

P. Clark
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Hydrogenation of rac-sertraline imine in scCO2/THF
Catalyst de () from NMR de () from NMR
Catalyst cis- trans-
5 Pt/ C 56 44
2 Pd/ C 87 13
5 Pd/ CaCO3 97 3

• System pressure (125-175 bar) has little effect
  on selectivity

(Conditions 175 bar 3x excess H2 0.4 ml/ min
org flow 0.1 M soln in THF 0.5 g catalyst 1.0
ml/ min CO2 flow)
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Summary

• Switch from Batch to Continuous
• Dechlorination is reduced in scCO2 why?
• One of the first examples of diastereoselective
  hydrogenation in scCO2
• First example of hydrogenation of final stage
  pharmaceutical in scCO2

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Supercritical Catalysis

• Catalysis in scCO2
• Supercritical Water- Selective
  Oxidation, Formation of Caprolactam
• Biocatalysis

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Total Oxidation in scH2O

• Tc 374 oC pc 218 atm.
• At 300 oC, H2O is similar to acetone
• O2 is miscible with H2O above Tc
• Already in commercial use

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Johnson Matthey ChematurAquaCatProcess for
Catalyst Recoveryopened Oct 10th 2003
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Heterogeneous Catalyst Recovery
Before
After
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Partial oxidation in scH2O?
Nottingham P.A. Hamley, E.G. Verdugo, J.
Fraga-Dubreuil, C. Yan, E. Venardou, R. Auerbach,
R.J. Pulham,T. Ilkenhans, M.J. Clarke, J.M.
Webster, M. Thomas, A. Johal. INVISTA Performance
Technologies, UK W.B. Thomas, G.R. Aird, I.
Pearson, S.D. Housley, A.S. Coote, K. Whiston,
L.M. Dudd, J. Fraga-Dubreuil (ICI D.A. Graham, P.
Saxton)
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Oxidation of p-Xylene

• 0.7 Mton p.a. per plant
• TA insoluble in CH3COOH
• 18 of world production of CH3COOH lost in the
  process

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TA
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Oxidation of p-Xylene / scH2O
PA Hamley, et al. Green Chem. (2002) 4, 235
(2005) 7, 294
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Oxidation of p-Xylene in scH2O
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Selective Oxidation in scH2O

• If our results are scalable,
• total elimination of CH3COOH
• increased energy recovery compared to existing
  process
• significant reduction in cost of manufacturing TA

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EXAFS Molecular Dynamics Results with 0.4 m
MnBr2
W. Partenheimer, Y. Chen, J. L. Fulton J. Am.
Chem. Soc. 127, 14086, (2005)
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IR spectroscopy in scH2O
First achieved 1967 (Franck Roth)
Much work by T. B. Brill et al. J. Phys.
Chem. (1996) 100, 7455
Recent work by Y. Ikushima et al., Achema,
(2003)
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FTIR of Water
6.62
25 µm pathlength
6.0
5.5
5.0
4.5
4.0
A
3.5
3.0
2.5
2.0
1.5
1.0
0.5
3600
3200
2800
2400
2000
1800
1600
1400
1200.0
4000.0
cm-1
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High T P IR Cell Yu. E. Gorbaty
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Hydrolysis of MeCN
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Raman Spectroscopy
Eleni Venardou Appl. Spectrosc., (2003) 57
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Raman Spectra of CH3CN in ncH2O
no added acid 300 C, 300 bar
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Raman Spectra of CH3CN in ncH2O
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Hydrolysis of MeCN Effect of Concentration
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Caprolactam

• Industrial synthetic route
• Problem
• 5 kg (NH4)2SO4 are made per kg CPL

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Alternative Synthesis

• Cheaper feedstock,
• No cyclohexane oxidation
• No ammonium sulphate

Yan Chong
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Strategy
H. Vogel et al. Chem. Eng. Technol. (1999) 22,
494 70 conv. ACN but only 45 yield CPL 400
oC, 4 min. residence time

• Study effects of T and p
• Concentration of feedstock

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Caprolactam Summary

• Single-step green process

Hydrolysis, SCW
Cyclization, SCW
6-Aminocapronitrile, ACN
6-Aminocaproic acid amide, ACA
CPL

• gt60 yield of CPL within lt2 min
• No organic solvent
• No additional catalysts

C. Yan et al. WO2006078403
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Supercritical Catalysis

• Catalysis in scCO2
• Supercritical Water
• Multiphasic Biocatalysis
• Helen Hobbs, Neil Thomas

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Enzymes in Fluorous Biphase
PFMC Perfluoro- Methyl Cyclohexane
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How can one dissolve an enzyme in a fluorous
solvent (or even scCO2)?
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Hydrophobic Ion Pairing
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Fluorinated Anionic Surfactant
Krytox NH4 n 14/2500 KDP NH4 n 7/1400
Soluble in Fluorous phase and scCO2
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Cytochrome c inaqueous buffer
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Fluorous Phase added
Fluorous Krytox
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HIP extraction into theFluorous Phase
Butis the enzyme really dissolved?
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Dynamic Light Scattering Candida rugosa lipase
Expected Diameter 6.8 nm
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KDP surfactant mw1400 Expected length 1.4 nm
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Expected diameter 9.6 nm (CRL-KDP)
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Biocatalysis in Fluorous Biphase
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CMT-KDP Recycling (FBS)
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Dissolving Biomolecules

• Precipitation from aqueous buffer

Dissolve in scCO2
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Biological Molecules in scCO2
Cytochrome C
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Supercritical Catalysis

• Continuous Reactions
• Key aspect of supercritical fluids
• New Developments Green technologies are not in
  competition
• Partnership between Chemists Chemical Engineers

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DICE Driving Innovation in Chemistry Chemical
Engineering

• EPSRC initiative led by Nottingham to stimulate
  research at the interface of Chemistry/Chem.Eng
• 6 new faculty posts in Chem. Chem. Eng.
  including 3 joint posts
• Big opportunities for collaboration particularly
  with POC at Cardiff

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P Licence NR Thomas PA Hamley
All our Students, Postdocs and Collaborators
P. Fields, R. Wilson, M. Guyler
INVISTA, Thomas Swan Co, GSK, ICI EPRSC, Royal
Society, EU Marie Curie
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• Impact
• Factor
• 3.26
• www.rsc.org/
• Greenchem

martyn.poliakoff_at_ nottingham.ac.uk
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GSC-33rd International Conference on Green
Sustainable Chemistry
1-5 July 2007, Delft, The Netherlands
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GSC-33rd International Conference on Green
Sustainable Chemistry
Professor Graham Hutchings RSC Green Chemistry
Lecturer
1-5 July 2007, Delft, The Netherlands