CATALYST

CATALYST

Defined as substance that affects the rate of a reaction but emerges from the process unchanged

Catalyst changes a reaction rate by promoting a different molecular path (or mechanism) for the reaction

CATALYSIS

The occurrence, study and use of catalyst and catalytic processes

The development and use of catalyst is a major part of the constant search for new ways of increasing product yield and selectivity from chemical reactions

Oil rigs

Power station

Industrial gas companies

Also known as sintering which referred to the loss of catalytic activity due to the loss of active surface area resulting from the prolonged exposure to high gas – phase temperature

Fouling or coking

This mechanism is common to reactions involving hydrocarbons

Poisoning

This mechanism occurs when the poisoning molecules become irreversibly chemisorbed to active sites, thereby reducing the number of sites available for the main reaction

Porous

A Catalyst that has a large area resulting from porous

Example:Raney nickel used in the hydrogenation of vegetable and animals oils

Molecular sieve

A catalyst that admit molecules but prevent large ones from entering

Example:The production of xylene from toluene and methane

Monolithic

A catalyst that can be either porous or on- porous

Example:The platinum gauze reactor used in the ammonia oxidation portion of nitric acid manufacture

Supported

A catalyst consist of minute particles of an active material dispersed over a less active substance

Example:The packed- bed catalytic converted automobile

Unsupported

Distinguish from supported catalyst

Example:The platinum gauze for ammonia oxidation

High surface area

A typical sillica

The area of catalyst is provided by inner porous structure

A large interfacial area

Heterogenuos catalytic

Homogenuos catalytic