Ordered Mesoporous Materials - UGent · Collaboration on acid catalysis (transesterification...
Transcript of Ordered Mesoporous Materials - UGent · Collaboration on acid catalysis (transesterification...
Ordered porous materials in liquid phase catalytic reactionsTowards zero leaching supports
Pascal Van Der Voort
Ghent UniversityCenter for Ordered Materials, Organometallics & Catalysis
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Multi-scale modeling and design of chemical reactions and reactors
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Evolving fromPerformance
analysisTo
Kinetics Based Design...
Methusalem – formal and informal
• Formal: 1 PhD student (+ benchfee)▫ Working on catalytic activity of MOFs
• Informal▫ Collaboration on acid catalysis (transesterification
reactions, modelling)▫ Use of infrastructure (GC-GC/MS, ammonia ads)▫ Preparing joint research projects (JT @ FWO;
possibly @IWT)▫ Copromotorships in PhDs & mastertheses
(starting 2010)
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COMOC – Center for Ordered Materials, Organometallics and Catalysis• Development of ordered porous materials▫ Synthesis and characterization▫ Applications in versatile fields
Low k-materials;Thin films
Adsorbents for heavy metals
Packing materialsfor HPLC
Zero leaching catalysts in liquid phase reactions
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Spray drying mesoporous particles
6Packing materials for HPLC
Spray drying is robust
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Varying spray dryerBuchi B290, two-fluid
nebulizerGEA Niro A/S Mobil Minor, rotary
nozzle
Packing materials for HPLC
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Results - Morphology700 eq 1400 eq 2800 eq 5600 eq 8400 eq
H2O concentration is the main factor
Spray drying is robust
Packing materials for HPLC
HPLC evaluation
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Results – Stability vs Packing and evaluation
Packing conditions:30 minutes at 900 bar
Measurement after 170chromatographic runs
Packing materials for HPLC
HPLC evaluation
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Results – Chromatographic performanceA, B: Analysis of a mixture containing uracil (1), 1-phenyl-1-ethanone (2), 1-
phenyl-1-butanone (3), 1-phenyl-1-pentanone (4), 1-phenyl-1-hexanone
(5), 1-phenyl-1-heptanone (6), 1-phenyl-1-octanone (7), 1-phenyl-1-
decanone (8) and 1-phenyl-1-dodecanone (9) (50 µg/mL each); C: Analysis of a mixture of uracil (1, 50
µg/mL), benzene (2, 80 µg/mL), naphthalene (3, 50 µg/mL), antracene
(4, 300 µg/mL), fluoranthene (5, 50 µg/mL), benzo[k]fluoranthene (6, 300
µg/mL); D: Analysis of a mixture containing uracil (1), methyl-4-hydroxybenzoate (2), ethyl-4-
hydroxybenzoate (3), propyl-4-hydroxybenzoate (4) and butyl-4-
hydroxybenzoate (5) (50 µg/mL each). The flow rate was 0.2 ml/min in A and
0.3 mL/min in B,C and D.
Packing materials for HPLC
Action points
• Back pressure is not reduced to the expected level
• Shift attention to▫ CEC (Capilary Electro Chromatography) -
Excellent preliminary results by coating open tubular columns with mesoporous layer;
▫ Spraydrying of hybrid materials (PMOs)▫ Lab on a chip – Collaboration VUB – Work in
Progress.
11Packing materials for HPLC
In microelectronics industry:Low-k materials are used as insulators of interconnect wiring in computerchips
Low-k materials:Low relative dielectric constant compared to SiO2 (k<4)
Low k-materials;Thin films
•Frederik Goethals, Benjamin Meeus, An Verberckmoes, Pascal Van Der Voort and Isabel Van Driessche, “Hydrophobic high quality ring PMOs with an extremely high stability”, Journal of Materials Chemistry, 2010, 20 (9), 1709‐1716.
•Frederik Goethals, Carl Vercaemst, Veerle Cloet, Serge Hoste, Pascal Van Der Voort and Isabel Van Driessche, “Comparative study of ethylene and ethenylene‐bridged periodic mesoporousorganosilicas”, Microporous and Mesoporous Materials, 2010, 131 (13), 68‐74. DOI
New low-k materials:
• Low-k value (current value 2.3)
• Thin Films
• Porous
• Low polarisable
• Hydrophobic
•Mechanical stable
PMOs
Low k-materials;Thin films
PMO -- What is a PMO ?
Limited commercial availability;« home made » precursors
Calcination not possible,important step
Functional groups in ENTIRE WALL
Low k-materials;Thin films
Carl Vercaemst, Matthias Ide, Bart Allaert, NeleLedoux, Francis Verpoort and Pascal Van Der
Voort, “Ultra-fast hydrothermal synthesis of diastereoselective pure ethenylene-bridged
periodic mesoporous organosilica”, Chemical Communications, 2007, 2261-2263.
PrecursorsLow k-materials;Thin films
Formation of porous material = surfactant removal
SEM HRTEM
Low k-materials;Thin films
Influence of porogen loading on porosity
Low k-materials;Thin films
Precursor Porosity k
58 1.96
55 1.8
Low k-materials;Thin films
PMOs still have silanol groups -> high affinity to water=> Removal of silanol groups:
=> Grafting with HMDS: 2SiOH + (CH3)3SiNHSi(CH3)3 ->2SiOSi(CH3)3 + NH3
Glass PMOs Hydrophobized PMOs
33°55° 85°
Low k-materials;Thin films
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Porosity k(RMPMO) k(EPMO)32% 2.28 2.4545% 1.95 2.12
Top contact: silver dotsBottom: Si sputtered with Pl/Ti
Summary
Finding optimum between k value and Young Modulus is crucial:
⇒HMDS treated PMOs have a high young modulus and low-k value
Close collaboration with IMEC for further implementation
Porosity (v%)
Low k-materials;Thin films
Solid acidcatalysis
Mercury(II) ion adsorption
Adsorbents for heavy metals
PMOs as adsorbents and as catalysts
Els De Canck, Linsey Lapeire, Jeriffa De Clerq, Francis Verpoort and Pascal Van Der Voort, "A new
Ultra Stable Mesoporous Adsorbent for the Removal of Mercury", Langmuir, 2010, 26(12), 10076-10083, DOI:
10.1021/la100204d
Thiol containing PMOs ‐ Synthesis
Bromination with Br2 (g)
Substitution with Cl‐Mg‐(CH2)3‐SH
•Els De Canck, Linsey Lapeire, Jeriffa De Clerq, Francis Verpoort and Pascal Van Der Voort, "A new Ultra Stable MesoporousAdsorbent for the Removal of Mercury", Langmuir, 2010, DOI: 10.1021/la100204d
Adsorbents for heavy metals
0 0.5 10
200
400
600
V a /c
m3 (S
TP) g
-1
p / p0
Mercury(II) ion adsorption• Other mesoporous silica adsorbents▫ One‐pot‐synthesis with –(CH2)3‐SH functionalities
• Using this material as anadsorbent results into:▫ Complete loss of mesoporousstructure
=> Hydrolysis of Si‐O‐Si bond
Before Hg2+
Adsorption
After Hg2+
Adsorption
Adsorbents for heavy metals
Mercury(II) ion adsorption• Other mesoporous silica adsorbents▫ SBA‐15 functionalized with –(CH2)3‐SH (post‐synthesis)
• Using this material as anadsorbent results into:▫ Loss of thiol functionalities
=> Hydrolysis of Si‐O‐Si bond
% SH/gram
Loss of 90%
Adsorbents for heavy metals
Mercury(II) ion adsorption• Structural stability: XRD and nitrogen adsorption measurement• Chemical stability: No loss of thiol groups=> Stable C‐C bond
0 0.5 10
150
300
450
V a /c
m3 (S
TP) g
-1
p / p0
SH‐(CH2)3‐PMO
After Hg2+
Adsorption
PMO
SH‐(CH2)3‐PMO
After Hg2+
Adsorption
Adsorbents for heavy metals
Mercury(II) ion adsorption• Experiments show a1:1 ratio Hg2+/SH
10 ppm
100 ppm
Adsorbents for heavy metals
Sulfonic functionalizedperiodic mesoporous organosilicas
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Sulfonation
E-ePMO
E-ePMO
SO3H-E-ePMO
SO3H-E-ePMOAfter catalysis
After catalysis
Acidity 1.19 mmol H+/g
+ 400
+ 600
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SULFONATED PMO
Acidic (trans)esterification
Homogeneous versus heterogeneous catalyst
- Propanol and acetic acid- 90°C- 3 hours
=> Conversion of propanol ~ 93%
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SULFONATED PMO
I Pore size and pore structure engineering
Swellingagent
N2-Physisorption
Zero leaching catalysts in liquid phase reactions
ETHENE PMO
Carl Vercaemst, Bart Goderis, Petra E. de Jongh, Johannes D. Meeldijk, Francis Verpoort and Pascal Van Der Voort, Ethenylene-bridged periodic mesoporous organosilica foams with ultra-large mesopores, Chemical Communication, 2009, 4052-4054
II Controlling the pore channel length and pore connectivity
Zero leaching catalysts in liquid phase reactions
ETHENE PMO
•Carl Vercaemst, Heiner Friedrich, Petra de Jongh, Alexander Neimark, Bart Goderis, Francis Verpoort, Pascal Van Der Voort, Periodic mesoporous organosilicas consisting of 3D hexagonally ordered interconnected globular pores”, Journal of Physical Chemistry C, 2009, 113, 5556‐5562.
II Controlling the pore channel length and pore connectivity
Zero leaching catalysts in liquid phase reactions
ETHENE PMO
III Controlling the morphology
Ethanol Pentanol Butanol (medium)
Butanol (high)Butanol (low)Propanol
Zero leaching catalysts in liquid phase reactions
ETHENE PMO•Carl Vercaemst, Matthias Ide, Heiner Friedrich, Krijn P. de Jong, Francis Verpoort and Pascal Van Der Voort, “Isomeric periodic mesoporousorganosilicas with controllable properties”, Journal of Materials Chemistry, 2009, 19, 8839‐8845.
Action points• Leaching stability of sulfonated groups must improve;• Sulfonation mechanism of ethene functions not clear; • Other functionalities; great prospects by a recent silyl
ester method this Columbian PhD student comes to COMOC in September:
• @ LCT: Use different porosities, plugs, ... to study diffusion effects in a profound way (proven concept with nanoparticles VS-1 INSIDE SBA-15) & Recent interest in “nanoMOFs” New PhD project ? FWO project ?
• Study “added value” reaction to compete with acid resins. Introduce chirality, size exclusion.
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ETHENE PMO
Supports: inorganic & organic
Periodicmesoporousorganosilica
Metal organicframeworks
Porous carbon(starbons)Macroporous
metallic scaffolds Phenolic resins
Redox catalysts Acid catalysts
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SBA-15
Zero leaching catalysts in liquid phase reactions
Mesoporous titania on macroporoustitanium scaffolds
Macroporoustitanium Scaffold
Mesoporoustitanialayer
1) EISA processtitanium precursor
2) Calcination
37Zero leaching catalysts in liquid phase reactionsMESOPOROUS TITANIA
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Titanium scaffolds
3DFD
PU replica
Foaming technique
Zero leaching catalysts in liquid phase reactionsMESOPOROUS TITANIA
Synthesis optimization• Variation of synthesis conditions (solvent, Ti-precursor,
template …)• e.g. template variation:▫ CTAB : (C16H33)N(CH3)3Br▫ P123 : EO20PO70EO20
▫ F127 : EO97PO69EO297
Type Template SBET
(m²/g)Pore volume
(cc/g)Pore size
(nm)
A CTAB 185 0,26 2,41
C P123 232 0,50 3,55
D F127 168 0,35 4,05
0
50
100
150
200
250
300
350
0 0,2 0,4 0,6 0,8 1
Volume adsorbed nitrogen (cc/g)
Relative pressure (p/p0)
A C D
39Zero leaching catalysts in liquid phase reactionsMESOPOROUS TITANIA
Action points
• Catalysts do not work well in olefinic epoxidations, basically form peroxide adducts;
• Test catalysts in water phase total oxidation of phenol; they could be very suited for gas phase reactions as well. (@ LCT ?)
• Graft V-complexes on TiO2 surface, using the silyl ester method.
• Graft Ti-complexes on SiO2 surfaces.
40Zero leaching catalysts in liquid phase reactionsMESOPOROUS TITANIA
Metal Organic Frameworks (MOFs)
• Metal ions are linked by organic ligands
• 3 dimensional network
• Microporosity
• High metal content
• Rigid structure
• Ligand coordinationinfluences electronic properties
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MOF
MOFs Metal ions Linkers
Cu2+
V4+
Zn2+
Co2+
Ni2+
Ag+
Cd2+
Cr3+
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MOF
V-MOF : synthesis• Simple synthesis: VCl3/ terephthalic acid/ H2O
4 days, 200°C (autoclave)Calcination: 22h30 min, 300°C
• Formula: VIVO{O2C-C6H4-CO2}
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MOF
Catalytic performance (MIL-47)
Oxidans: TBHP in H2OSolvent: ChloroformTemperature: 50°C
VO(acac)2
MIL-47
VOx/SiO2
VAPO-5
ChloroformTBHP, 50°C
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MOF
•Karen Leus, Ilke Muylaert, Matthias Vandichel, Guy B Marin, Michel Waroquier, Veronique Van Speybroeck and Pascal Van Der Voort, “The remarkable catalytic activity of the Saturated Metal Organic Framework V‐MIL‐47 in the cyclohexene oxidation”, Chemical Communications, 2010, DOI:10.1039/C0CC01506G.
Reaction mechanismVO(acac)2 V-MOF (MIL-47)
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MOF
Regenerability : V-MOF
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MOF
Action points• V-MOF synthesis from vanadium(III)-oxo acetic
clusters; avoid decavanadates ! (bottom up)• V-ZIF(zeolitic imidazolate framework) synthesis• Chiral, enantioselective catalysis: oxidation of
sulfides to sulfoxides.
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N NT Tβ (T-Imidazole-T) ~147 ˚
Zero leaching catalysts in liquid phase reactions
MOF
Mesoporous resins
48P/F resins ALD depositions
•Ilke Muylaert, Marijke Borgers, Els Bruneel, Joseph Schaubroeck, Francis Verpoort and Pascal Van Der Voort, “Ultra stable ordered mesoporous phenol/formaldehyde polymers as a heterogeneous support for vanadium oxide”, Chemical Communications, 2008, 4475‐4477
Controlling the porosityA B C D
49P/F resins ALD depositions
Leaching behaviour
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• Comparison of leaching behaviour ofVOx/SiO vs VOx/Resin
• Stirring in water at 80°C
• Stirring in 2.5M H2SO4 at 80°C
• VOx/resins are currentlyunder investigation for theircatalytic activity
P/F resins ALD depositions
Supported TiO2/SBA-15: synthesis
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Atomic layer deposition:
- sequential exposure to avolatile metal precursorand a reactive gas
- self-limitingly
- controlled deposition
- uniform layers
P/F resins ALD depositions
Rotatable powder reactor
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Actions points
• Cheap, easy producable, highly stable bakelite resins as catalytic support
• But... Only low to moderate activity of supported TiOx and VOx layers !
• Controlled ALD of resin-V-O-Ti-O-V...• Alternative activation of the resins:▫ Sulfonation – catalytic tests in progress▫ Metal complexes ?▫ Noble metals ? Reduction reactions.
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General remarks• Some nice materials, generally appreciated and COMOC is starting
to become known as center of expertise in synthesis of “new” porous materials (COMOC is founded in 2007)
• Our materials also used in collaboration in ▫ Dentistry (University Hospital)▫ Pesticides (bio-engineers – adsorption and controlled release)
• Need to adapt processes to cost and advanced level of the materials themselves▫ High end reactions, selectivity, chirality▫ Sensors, catalysts▫ Stability can compensate for cost
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COMOC -- April 2010
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