catalyddion aml-ochrog mewn hylyfoedd uwchradd martyn poliakoff [email protected]
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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)
Supercritical Catalysis
• Catalysis in scCO2:- Hydrogenation, Hydroformylation
• Supercritical Water• Biocatalysis
Miscibility of H2/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.
T > TcT < Tc
Liquid
H2
Higher Concentration of “Dissolved” H2 in scCO2
Other Hydrogenations successfullycarried out in scCO2 and scPropane
NR'
RR" C NR O
R
R'
R OH
Oximes, Imines
Schiff Bases Nitriles
Aldehydes and Ketones
EpoxidesAlcohols
O
HR
O
R'R
O
HR
O
R'R
Hydrogenation of IsophoroneO
Pd Deloxan®
100 bar, scCO240-170°C
+ H2
O
scCO2 - quantitative, no by-products
The product & by-products have similar boiling points
Conventional process requires an expensive downstream separation
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
Bi-phasic Catalysis: Cole-Hamilton
P. B. Webb, M. F. Sellin, et al. J. Am. Chem. Soc.,2003, 125, 15577
Green Chemistry 12 Principles- 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 it’s safe
PRODUCTIVELY
- 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 it’s safe
Hydrogenation of α-pinene
A. Serbanovic, V. Najdanovic-Visak,
A. Paiva, G. Brunner,
M. Nunes da Ponte
8th ISSF, Kyoto
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.
3. CO2-Protected Amine Formation in GExLs
X. Xie, C. L. Liotta & C. A. Eckert, Ind. Eng. Chem. Res., 2004, 43, 7907.
Hydrogenation of Isophorone
O
Pd Deloxan®
100 bar, scCO240-170°C
+ H2
O
Reaction has a high space-time yield
How is this influenced by the phase behaviour of the system?
Isophorone /CO2/H2 phase boundaries
O OH2
Two phase Operational
window
50
100
150
200
250
300
350
40 90 140Temp/°C
Pre
ssu
re/B
ar
5%
13%
17%
22%
Two phase Operational
window
M. SokolovaKe Jie
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
Commercial Route to Zoloft®
N
ClCl
HN
ClCl
15 psi, 25oCH2/EtOH
Pd / CaCO3
(4S -) sertraline imine
cis- (1S-, 4S-) sertraline
HCl/ EtOH
HN
ClCl
Sertraline hydrochloride
.HClHH
OH
Cl
Cl
(i) AlCl3+
O
ClCl
H(ii) Continuous Chromatography
(4S -) tetralone
MeNH2 / EtOH
HH
H
Batch Process
Continuous hydrogenation of rac-sertraline in scCO2/THF
• Investigate both chemoselectivity & diastereoselectivity
• Aims: (1) < 1.5 % dechlorination (2) > 92:8 de
N
ClCl
HN
ClCl
rac-sertraline imine (1S, 4S), cis
H
H
scCO2H2/ cat.
Co-solvent
HN
ClCl
(1R, 4R), cis
H
H
HN
ClCl
(1R, 4S), trans
H
H
HN
ClCl
(1S, 4R), trans
H
H+ ++
P. Clark
Hydrogenation of rac-sertraline imine in scCO2/THF
Catalyst de (%) from NMR
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)
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
Supercritical Catalysis
• Catalysis in scCO2
• Supercritical Water:- Selective Oxidation,
Formation of Caprolactam• Biocatalysis
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
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)
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)
0.7 Mton p.a. per plant
• TA insoluble in CH3COOH
• 18% of world production of CH3COOH lost in the process
Oxidation of p-XyleneCH3
CH3
COOH
COOH
190oC CH3COOH solvent
Mn2+/Co2+, CH3COO- /Br-
catalysts
Oxidation of p-Xylene / scH2O
p-Xyl
Products
MnBr2 catalyst in cold H2O
scH2O + O2
PA Hamley, et al. Green Chem. (2002) 4, 235; (2005) 7, 294
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
EXAFS & Molecular Dynamics Results with 0.4 m MnBr2
W. Partenheimer, Y. Chen, J. L. FultonJ. Am. Chem. Soc. 127, 14086, (2005)
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)
4000.0 3600 3200 2800 2400 2000 1800 1600 1400 1200.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.62
cm-1
A
FTIR of Water
25 µm pathlength
High T & P IR Cell; Yu. E. GorbatyChanges pathlength
Windows
Cell body
Driving Mechanism
500 oC1000 bar
Inlet
Hydrolysis of MeCN
4000.0 3600 3200 2800 24000.01
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.13
cm-1
A
CN
N-H
O-H
500bar300ºC
H2ON
O
NH2
O
OH
Raman Spectra of CH3CN in ncH2O
1000 1500 2000 2500
2268938866
Time
0
30 min
CN
Raman shift / cm -1
no added acid 300 °C, 300 bar
CH3COOH in water
CH3CONH2 in water
500 1000 1500 2000 2500 3000Raman shift / cm -1
16801140
2268938866
Time
0
30 min
CN
Raman Spectra of CH3CN in ncH2O
Caprolactam
• Industrial synthetic route
• Problem
5 kg (NH4)2SO4 are made per kg CPL
O O
HN
(NH2OH)2SO4Oleum
AmmoximationBeckmann
rearrangement
NHO
Alternative Synthesis
• Cheaper feedstock, • No cyclohexane oxidation • No ammonium sulphate Yan Chong
O
HN
N
N NH2N
H2O
H. Vogel et al. Chem. Eng. Technol. (1999) 22, 494
70% conv. ACN but only 45% yield CPL 400 oC, 4 min. residence time
Strategy• Study effects of T and p
• Concentration of feedstock
O
HN
NH2N
H2O
ACN CPL
Caprolactam Summary
• Single-step green process
NH2N
O
NH2
H2N O
HN
Hydrolysis, SCW Cyclization, SCW
6-Aminocapronitrile, ACN 6-Aminocaproic acid amide, ACACPL
>60% yield of CPL within <2 min No organic solvent No additional catalysts
C. Yan et al. WO2006078403
Supercritical Catalysis
• Catalysis in scCO2
• Supercritical Water • Multiphasic Biocatalysis
Helen Hobbs, Neil Thomas
Enzymes in Fluorous Biphase
Hexane+
substrate
PFMC + Enzyme
25 ºC
SubstrateHexane
+Product
PFMC +
Enzyme
0 ºC
Product
Enzyme +
substrate
40 ºC
EnzymeRecycle
PFMCPerfluoro-
MethylCyclohexane
Fluorinated Anionic Surfactant
CF CF2 O
CF3
CF
CF3
F CO2 NH4
n
Krytox NH4+ n ~ 14/2500
KDP NH4+ n ~ 7/1400
Soluble in Fluorous phase and scCO2
Native CRL: 10.1 nm
CRL-KDP: 6.5 nm CRL-Krytox: 10.1 nm
Diameter (nm)
Volu
me (
%)
0
5
10
15
20
0.1 1 10 100 1000 10000
CRL Size Distribution By Volume
Biocatalysis in Fluorous Biphase
Ph
HNAc
O
O
OH
Ph
HNAc
O
O
OH
APEE
n-propanol
APPE
ethanol
CMT-KDP (FBS)
Supercritical Catalysis
• Continuous Reactions: Key aspect of supercritical fluids
• New Developments: “Green” technologies are not in competition
• Partnership between Chemists & Chemical Engineers
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
P. ClarkE VenardouEG Verdugo
J Fraga DubreuilChong YanHR Hobbs
P. Fields, R. Wilson, M. GuylerINVISTA, Thomas Swan & Co, GSK, ICIEPRSC, Royal Society, EU Marie Curie
All our Students,Postdocs and Collaborators
P Licence NR Thomas PA Hamley
GSC-33rd International Conference on Green & Sustainable Chemistry
1-5 July 2007, Delft, The Netherlands