This document will give you information about catalysis and type of catalysis like homogenious and heterogenious catalysis and its various application .
7. Homogeneous Catalysis
The catalyst and reactants are in the same phase, usually liquid.
Heterogeneous catalysis
Catalyst and reactants are in different phases.
Enzymatic Catalysis
Catalyst is an enzyme (macromolecules made of amino acids).
8. When the reactants and the catalyst are in the same phase (i.e., liquid or gas), the process is said to be homogeneous catalysis.
For e.g-:
Advantages
Good contact with reactants .
Disadvantageswww.ncert.nic.in/NCERTS/l/lech105.pdf
Catalysis needs to be separated after reaction
Catalyst recovery may be difficult because the temperature for the distillation can destroy the catalyst
www.ncert.nic.in/NCERTS/l/lech105.pdf
9. The catalytic process in which the reactants and the catalyst are in different phases is known as heterogeneous catalysis.
For e.g-:
Advantages
There is little difficulty in separating and recycling the catalyst.
Disadvantages
There is a lower effective
concentration of catalyst
since the reaction occurs
only on the exposed active surface.(www.knockhardy.org.uk)
10. Adsorption Theory of HeterogeneousCatalysis
www.ncert.nic.in/NCERTS/l/lech105.pdf
11. Numerous reactions that occur in the bodies of animals and plants to maintain the life process are catalysedby enzymes. The enzymes are, thus, termed as biochemical catalysts and the phenomenon is known as biochemical catalysis.
Enzymes are complex nitrogenous organic compounds which are produced by living plants and animals. They are actually protein molecules of high molecular mass
12. (i) Most highly efficient: One molecule of an enzyme may transform
one million molecules of the reactant per minute.
(ii) Highly specific nature: Each enzyme is specific for a given reaction.
For example, the enzyme ureasecatalyses the hydrolysis of urea only.
(iii) Highly active under optimum temperature
(iv) Highly active under optimum pH
17. Catalysis impacts the environment by increasing the efficiency of industrial processes, but catalysis also plays a direct role in the environment
18. Green Chemistry is Catalysis
Pollution control(air and waste streams; stationary and mobile)
Clean oxidation/
halogenationprocesses using O2,H2O2(C2H4O, C3H6O)
Avoiding toxic chemicals in industry
( HF,COCl2etc.)
Fuel cells( H2 generation)
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20. Ozone gas depletion
There is catalytic role of chlorine free radicals in
the breakdown of ozone. These radicals are formed by the action
of ultraviolet radiation on chlorofluorocarbons (CFCs).
www.okiu.ac.jp
23. Fine chemicals
Many fine chemicals are prepared via catalysis; methods include those of heavy industry as well as more
specialized processes that would be prohibitively expensive on a large scale.
www.essentialchemicalindustry.org
25. shape-selective catalysis
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The reaction that depends upon the pore structure of the catalyst & the size of the reactant & product molecules is called shape-selective catalysis.
Zeolitesis used as catalysts in petrochemical industries for cracking of hydrocarbons and isomerisation.
An important zeolitecatalyst used in the petroleum industry is ZSM-5.
It converts alcohols directly into gasoline (petrol) by dehydrating them to give a mixture of hydrocarbons.
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26. Energy processing
Petroleum refining makes intensive use of catalysis for alkylation , catalytic cracking (breaking long-chain
hydrocarbons into smaller pieces) , naphtha reforming and steam reforming (conversion
of hydrocarbons into synthesis gas).
Fuel cells depend on catalysts for both the anodic and cathodic reactions.
Catalytic heaters generate flameless heat from a supply fuel
27. One of the most obvious applications of catalysis is the hydrogenation (reaction with hydrogen gas) of
fats using nickel catalyst to produce margarine .
Many other foodstuffs are prepared via bio catalysis
