Catalysis is the key to optimized and efficient process engineering. Catalysis is the major problem for the chemical engineer while understanding the basic chemical reaction engineering. Catalysis is used in most of the industrial and biological processes, and the products of these processes include food, drugs, clothing, plastics, fuels or detergents.
To understand the phenomena of the catalysis, a chemical engineer must understand that what is catalyst? Catalyst is the substance, which changes the rate of the chemical reaction, with out being consumed in the reaction it self. But practically after the completion of the process, the catalyst transforms (not consumed), so mostly, the catalysts needed to be regenerated and can be used again.
These catalysts may be in any state of matter, i.e. liquid, gas or solids. There can be two types of a catalyst:
- positive catalysts : increases the rate of the reaction.
- negative catalysts : decreases the rate of the reaction. These are also called as inhibitors.
Catalysis is the phenomena of change in the rate of a chemical reaction in presence of a catalyst. There can be two types of the catalysis.
1) Homogeneous catalysis:
The catalysts are in the same phase as the reactants are. I.e. the homogeneous catalysts are co-dissolved substances in the solvent, with the reagents. The acid catalysis can be taken as an example of the homogeneous catalysis. In which the water, after self ionization forms protons (most penetrating homogeneous catalyst).
2) Heterogeneous catalysis:
The catalysts are in different phase, as that of the reactants. Most heterogeneous catalysts are solids (in a liquid or gaseous reaction mixture). But as the surface area of the catalyst (especially in solid catalyst case) has important effect on the rate of reaction. So the catalysts are generally crushed into the smaller particle size, as the smaller the particle size, the more will be the surface area of the catalyst.
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