by Sahil Inamdar Sap ID 60011115017 Definition Pillaring is a commonly used procedure to transform a layered crystalline inorganic compound into a material with microporosity and mesoporosity ID: 494758
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Slide1
Pillaring of Clays and Colloids
by Sahil Inamdar
Sap ID: 60011115017Slide2
Definition:
Pillaring is a commonly used procedure to transform a layered crystalline inorganic compound into a material with
microporosity
and mesoporosity.Slide3
Important Points to discuss:
Layered Compound
Intercalation
PillaringPillaring AgentInterlayer RegionSlide4
Layered Compounds
:
It is a crystalline material wherein the atoms in the layers are cross-linked by chemical bonds.
The atoms of adjacent layers interact with each other with physical forces.A single layer is called a slab, sheet
or lamella.Slide5
Intercalation:
It is the insertion of a guest species in the interlayer regional of a layered solid with a preservation of the layered structure.
It is called as a intercalation compound.Slide6
Pillaring:
It is the process by which a layered compound is transformed into a thermally stable micro- and/or
mesoporous
material with retention of the layer structure. The material obtained is pillared compound or a pillared layered solid.Slide7
A pillared derivative is distinguished from an ordinary intercalate by virtue of
intercrystalline
porosity made possible by the lateral separation of the intercalated guest.Slide8
Pillaring Agent:
Any compound which can be intercalated between adjacent layers of a layered compound.
It maintains the spacing between the adjacent layers on removal of the solvent
It induces an experimentally observable pore structure between the layers.Slide9
Interlayer Region:
It is the space between the adjacent layers of a layered compound.
It is also called as “gallery”.Slide10Slide11
Characteristics:
The layers are propped apart vertically and do not collapse on removal of the solvent.
The minimum increase in basal spacing is the diameter of N
2
molecule: 0.315-0.353 nm.Slide12
The pillaring agent has molecular dimensions and is laterally spaced in the interlamellar space on a molecular length scale
.
The
interlamellar space is porous and at least accessible to molecules as large as N2; there is no upper limit to the size of the pores.Slide13
Criteria for a material to be called pillared:
Chemical and thermal stability.
The lamellae of the layered compound must be ordered so as to give an X-Ray Diffraction (XRD) pattern which allows the determination of the d
001 spacing.
Accessibility of the interlayer region by molecules as large as N
2
.Slide14
Advantages:
Pore sizes can be controlled.
Increased surface area.
Thermally and Chemically stable.Selective reactivity towards compounds.Slide15Slide16Slide17
Thank You!!Slide18