Benefits of Heterogeneous Catalysts (3 P)

Surface area formula

IUPAC definition... size for:

1) Micropores

2) Mesopores

3) Macropores

Variable surface chemistry

2D Materials:

- Clays

Clays - neutral, no catalyst activity

--> Isomorphous substitution: inserts charge into system: more active catalyst

Clays:

- Effect of isomorphous substituion

Clays:

- Effect of isomorphous substituion 2

Catalyst activation

Pillaring cations

Layer collpase - problem especially w/ high charge density cations

Reactions of clays

Other layered materials

3D Catalysts

- Microporous systems

Catalytic sites within zeolites

Acidic Zeolites

Pore size and diffusion

Pore size and diffusion 2: (3 P)

Diffusion in porous materials depend on: (3 P)

5 stages involved in a liquid phase reaction using a porous solid catalyst

- NOTE: for gas phase reactions, thickness of hydrodynamic layer = 0, so 1) and 5) can be omitted

5 stages involved in a liquid phase reaction using a porous solid catalyst 2

- Optimizing performance:

Test for diffusion control

How is pore size measured (2 P):

How is pore size measured

- Porosimetry

Measuring acidity of zeolites

Shape selectivity - Key property of zeolites (eg H-ZSM5)

Reactant selectivity

Other uses of zeolites

Titanium silicates (TS-1): Oxidation catalyst

Titanium silicates (TS-1): Oxidation catalyst 2

Titanium silicates (TS-1) w/ 2 Ti: Oxidation catalyst

Mesoporous systems - Larger templates give unstable materials.

Solution...

Addition of Heteroatoms to MTS

ALMA industrial process

Catalyst =
\((VO)_2P_2O_7\)

What is meant by isomorphous substitution in context of porous solids