教你如何设计催化剂Kung

Preparing sites with predetermined spacing
Dufaud and Davis, JACS 125 (2019) 9403
What would one like to accomplish in total catalyst synthesis?
• Complete atomic control of active site • Ability to design and position ancillary groups • Shape of the cavity • Path to cavity
Raja and Thomas, J. Molec. Catal. 181 (2019) 3
CoAlPO-18 (Co/P=0.04) CoAlPO-18 (Co/P=0.1) CoAlPO-36 (Co/P=0.04) CoAlPO-34 (Co/P=0.1)
Hexane (
) Oxidation
R
P
R
P
Active
At rest
Figure 1 Molecular model of endoclucanase 12A and schematic model of the DMAAm-enzyme molecular switch. The red residues represent the catalytic glutamic acid side chains at the active site of EG 12A, the green residue is the Asn 55 position, the purple residue is the Ser 25 position, and the N-terminus is represented as the blue circle.
Reactant C6H14
1.5 MPa air, 373 K, 24 h, Selectivity %
Conv. 1-ol 1-ald 1-acid 1,6-acid 1,6-ol/al 2-ol/one
7.2% 4.5 3.3 53.5
36.1
9.3% 4 2.4 33 31.6 1.9
24.5
30
Conversion of epoxide (% )
25
20
15
10
5
0
0
500
1000
1500
Time (min)
Xue, Kung, Kozlov, Popp, and Kung, Catal. Today, 2019.
Generation of active site by building on a well-defined structure
O
Active site
O O
Al
O
Al
O Al O
HO OH
n
Al HO OH
-H2O
(HO)3Al (HO)3Al
O OH Al
O OH
HH OO
O
Al
O Al O
O
High temp -H2O
O
O Al O
O
Al
O Al O
Strategy: use amine (Lewis base) to preserve Lewis acidity. Can make
29Si NMR of (Si-O)n oligomer units
60 40 20
0 -20 -40 -60 -80 -100 -120
60 40 20 0 -20 -40 -60 -80 -100 -120
60 40 20
0 -20 -40 -60 -80 -100 -120
60 40 20
0
-20 -40 -60 -80 -100 -120
Towards Total Design of Heterogeneous Catalysts
Harold H. Kung Chemical Engineering Department
Northwestern University Evanston, IL 60208-3120
October 13, 2019
O +HN
77oC
OH
N
Conversion of cyclopentene oxide in reaction with piperidine catalyzed by various aluminas.
● PPD-Al2O3, ◊ SG-Al2O3-200, ○ SG-Al2O3-500-H2O-200, ▲ SG-Al2O3-500H2O, Δ PA-Al2O3-500-H2O-200 ■ PA-Al2O3-500-H2O, □ blank.
Control of surface coordinative unsaturation sites of aluminum oxide (Al2O3) by synthesis
• Active sites are surface exposed Al ions (Lewis acid sites).
5.2% 8.7 3.8 10.2
29
7.9% 7.3 6.2 29.4 19.7 3.9
30.9
J.M. Thomas, et al. Nature 398 (2019) 227; Angew. Chem. Int. Ed. 39 (2000) 2310.
001203c
Atom-by-Atom Synthesis of Metal-Oxygen Chain
Metal clusters derived from metal carbonyl complexes
BC Gates J. Molec. Catal. A Chem 163 (2000) 55 Os5C on MgO
Ir4 in zeolite
Size-selective cluster beam deposition of Aun clusters on MgO
What would one like to accomplish in total catalyst synthesis?
• Complete atomic control of active site (metal, oxide) • Ability to design and position ancillary groups • Shape of the cavity • Path to cavity
Heiz, Sanchez, Abbet, Schneider, Chem. Phys. 262 (2000) 189.
MS signal of C16O18O in TPD after exposure to 18O2 and then CO
Deposition of metal clusters using lithography Array of Pt on silica
A. Corma, U. Diaz, M.E. Domine, V. Fornés, Angew. Chem. Int. Ed. 39 (2000) 1499.
(h00)
Eliminated pore diffusion control, Little shape selectivity.
Molecular Imprinting
60 40 20
0 -20 -40 -60 -80 -100 -120
Chang, Kung, and Kung, Chem. Comm. submittted.
Metal-Oxygen Backbone of Designed Sequence and Structure
O
Si
M
Molecular templating:
Importance in controlling relative location of sites
• Two Co(III) ions in CoAlPO-18 at the desired distance apart in Co/P = 0.1 samples.
• CoAlPO-36 of larger pore structure and shape, produces much more 3-ol and 3-one.
Cat. 4 made from 2; control cat. 5 made from 1
K. Polborn and K. Severin, Chem. Commun. (2019) 2481-2482.
Molecular hinges to control accessibility of active sites
TsuyBiblioteka Baidushi Shimoboji, Edmund Larenas, Tim Fowler, Allan S. Hoffman,* and Patrick S. Stayton* Bioconjugate Chem., 14 (3), 517 -525, 2019
Figure 4 Characterization of ONPC enzyme activities for free DMAAmEG 12A conjugates in solution at as function of polymer size and conjugation site. The enzyme activities were measured for 100 nM conjugates using ONPC (8mM) as a substrate and normalized to the activity of N55C or S25C EG12A controls as 100% at each temperature. EG 12A-M10, 10 kDa DMAAm-EG12A conjugate; EG 12A-M6, 6 kDa DMAAm-EG 12A conjugate; EG 12A-M3, 3 kDa DMAAm-EG 12A conjugate; and EG 12A + M10, physical mixture of enzyme plus 10 kDa DMAAm.
A. Katz and M.E. Davis, Nature 403 (2000) 286.
• Introduce functional groups at specific locations in the cavity.
• Molecules diffuse through silica wall into and out of cavity.
Preparation of uniform sized metal particles using functional resins
Corain, Centomo, Ferrari Meyer-Zaika, Schmid, Gold2019, October 2019.
P-SO32- + Mn+(aq) → P-SO32-Mn+ P-SO32-Mn+ + NaBH4 → P-SO32-/Mo
Aaron S. Eppler, Günther Rupprechter, LászlóGuczi, and Gabor A. Somorjai, J. Phys. Chem. B 101 (2019) 9973.
Insufficient control of shape, exact size, and atom locations; current limit on smallest size achieved.
R
RO O OR
Al Al
RO
OR
O
NRH2
monomer
RO OR
2
Al
RO
NRH2
R
monomer
Final solid an active catalyst
HR2
HR2
NN
O
Al
O Al O
O
H2O
Amine protection is retained
Kozlov, Kung, Xue, and Kung, Angew. Chem. Int. Ed. 42(2019) 2415
Metal Crystallite Catalytic Active Phase
• Surface arrangement of atoms
• Composition • Nature of support • Location of crystallite on
support (defect sites) ✓ Structure sensitivity ✓ Electronic effect ✓ Ligand effect