1. Siliceous Mesocellular Foam (MCF) for Green Chemistry
Jaehong Lim, Su Seong Lee and Jackie Y. Ying
Institute of Bioengineering and Nanotechnology, Singapore
12th Annual Green Chemistry and Engineering Conference   June 25, 2008 Washington, DC

2. IBN, Biopolis, Singapore
The Nanos
Chromos
Centros
Matrix
Genome
Proteos
Nanos
Helios

3. Heterogenization of Catalysts
Shortcomings of Homogeneous Catalysts
High cost
Low stability
Difficulties in reuse
Toxic residues in product
Benefits of Heterogenization
Cost-effective
Good stability
Easy purification
Reduced toxicity in product
Recycling use of expensive material
Feasible for scale-up
Potential application as a continuous flow process

4. Spherical Mesocellular Foam (MCF)
Conventional MCF
- Effective for catalysis and separation
- Easy to prepare
Robust
Uniform particle size
Large pores
Large surface area
- Potential scale-up
Spherical MCF
Particle size: ~5 mm
Pore size: ~25 nm
Window size: ~15 nm
Wall width: ~5 nm
Pore volume: cm3/g
BET surface area: m2/g

5. Design of Immobilized Catalysts
Support
Mesocellular Foam
Inert
Robust
Well dispersed in solvents
Synthesizable
Catalyst
Organometallic
Organo-
Stable
Active
Reusable
Linker
Hydrocarbon
Triazole, etc.
Inert
Flexible
Synthesizable

6. Fabrication of Immobilized Catalysts
<1eq.
HMDS O H
TMS T M S OH O H OH
MCF
Procedure
1 – Precapping
2 – Grafting
3 – Postcapping
4 – Incorporation
Ligand O H L T M S
TMS OH
Catalyst
Well dispersed! C T M S
TMS
excess
HMDS L T M S
TMS

7. Ring-Closing Metathesis+
Catalyst = Mo, Ru, etc.
X = C, O, N, etc.
Ring size = 5 ~ >15
BILN 2061
Anti-HCV agent
Boehringer Ingelheim

8. Synthesis of Catalysts
2nd gen.
Grubbs Cat.
CuCl, 50°C
DCM
Catalyst n
Ligand
(mmol/g)
Ruthenium
Ru / Lig
PC-1
0.44
0.17
0.42
PC-2
0.24
0.13
0.57
BC-1 1
0.22
0.18
0.91
BC-2
0.36
0.21
0.64

9. Catalytic Activity PC-1 PC-2 Conversion (%) HG-II BC-1 Homog. BC-2
Homogeneous
Time (hr)

10. Recyclability Conversion (%) Run # BC-1, DCM PC-1, DCM PC-1, Toluene
BC-2, Toluene
Run #

11. Substrates 100-94% up to 7 runs: 25°C, DCM 88% - run 1 75% - run 2
80°C, Toluene
100-94% up to 7 runs
25°C, DCM

12. Enhanced Recyclability
SH-oct
0.15 mmol/g
Conversion (%)
SH-oct
SH-tms
SH-tms
0.21 mmol/g
Run #

13. Leaching Study Recyclability ICP-MS Temp. pre-BC-1 Ru residue [ppm]
Run 1
Run 3
Run 5
25°C - 35 30 20
5 mol% 23 18 15
50°C 13 9 7 10
Conversion (%)
25°C, 1 hr / run
50°C, 0.5 hr / run
25°C, 5 mol% pre-BC-1, 2 hr / run
50°C, 5 mol% pre-BC-1, 1 hr / run
Run #

14. RCM Catalysts via “Click” Chemistry
1 mol% CuI
DIPEA, THF
Room Temp
2nd-gen Grubbs Cat.
CuCl, DCM, 50oC
Catalyst
Linker
Ligand
(mmol/g)
Ruthenium
RCM-Pr
n-Propyl
0.19
0.16
RCM-Bn
Benzyl
RCM-Pn
n-Pentyl
0.15
0.14

15. Activity & Recyclability
5 mol% catalyst;
DCM; RT; C = 0.05M
RCM-Pr
RCM-Bn
RCM-Pn
Linker-Carb
Linker-Alkyl
Run #
Conversion (%)
Conversion (%)
RCM-Pr
RCM-Bn
RCM-Pn
Linker-Carb
Linker-Alkyl
Time (hr)

16. More Catalysis Cyclopropanation Organocatalysts “Click” MCF
L-Tyr-OMe.HCl
L-Phe-OMe.HCl

17. Magnetic Micro-catalyst for RCM
Synthesis
Fe2O3
SiO2
Fe2O3
SiO2
Fe2O3
SiO2
Easy recycle
Images
10nm
200nm

18. Acknowledgments Prof. Jackie Y. Ying and Ms. Noreena AbuBakar
Dr. Su Seong Lee
Ms. Siti Nurhanna Riduan
IBN, BMRC and A*STAR, Singapore