This document discusses catalysis, including the definition of a catalyst, types of catalysts (positive, negative, auto, induced), types of catalysis (homogeneous and heterogeneous), theories of catalysis (intermediate compound formulation and adsorption theories), examples of enzyme catalysis reactions, and advantages and disadvantages of catalysis. Catalysis is the process by which a catalyst alters the rate of a chemical reaction but remains unchanged at the end. There are four main types of catalysts and two types of catalysis defined in the document.

1. Presented by-
Jubair Sikdar
Roll no-04
M. Pharm 2nd semester
Department of Pharmaceutical Chemistry
NETES Institute of Pharmaceutical Sciences, Mirza
CATALYSIS

2. CONTENTS
 Introduction
 Types of Catalyst
 Types of Catalysis
 Theories of Catalysis
 Advantages and Disadvantages of Catalysis

3. CATALYSIS
INTRODUCTION
• The substances that alter the rate of a reaction but itself remains
chemically unchanged at the end of the reaction is called a Catalyst and
the process is called Catalysis.
• Example:
➢ Solids (NaOH, V2O5)
➢ Liquids (H2SO4)
Promoter: Substance that increase the catalytic activity.
Catalytic poison: Decrease or stop catalytic activity.

4. TYPES OF CATALYST
There are various types of catalyst but usually, there are four types which
are significant and important
a) Positive catalyst: The catalyst which activates the rate of reaction is
called a positive catalyst.
b) Negative catalyst: The catalyst which deactivates the rate of reaction is
called a negative catalyst.
c) Auto catalyst: When any product forms during any chemical- reaction
act like the catalyst for the same chemical reaction then it is called an
auto catalyst.
d) Induced catalyst: When the product of any chemical reaction acts like
the catalyst of any other chemical reaction then it is called induced
catalyst.

5. TYPES OF CATALYSIS
There are two types of catalysis:
1. Homogeneous catalysis: When the reactant and catalysts are in the
same physical state i.e., catalyst is in the same phase as the reactant is
called homogenous catalysis. Example
2H2O2(aq) 2H2O(g) +O2(g)
This reaction proceeds slowly, but can be catalyzed by I(aq) ion
2. Heterogeneous catalysis: A catalyst is process in which the catalyst
and the reactant are in different phases is called heterogeneous
catalysis. This process is also called Contact or surface catalysis.
N2(g) + O2(g) 2NO3(g)
This reaction catalyzed by Fe(s)

6. THEORIES OF CATALYSIS
1. Intermediate compound formulation theory.
2. Adsorption theory.
• Intermediate compound formulation theory:
• According to this theory one of the reactants combines with catalyst to
form intermediate product, which carries out the reaction,
E.g. A+C = AC AC+B =AB + C
A+B+C = AB + C
where A and B are reactants, C is the catalyst and AC is the intermediate
product.

7. Example:
2NO (Catalyst) + O2 2NO2 (Intermediate)
NO2 (Intermediate) + SO2 SO3 (Product) + NO
Adsorption Theory
• In general adsorption theory applies to heterogeneous catalytic
reactions. The catalyst functions by the adsorption of the reacting
molecules on its surface. The adsorption reaction undergoes four
types of steps.

8. • Adsorption of reactant molecule: The reactant molecules A and B strike
the surface of the catalyst. The reaction molecules held up by the partial
chemical bond.
• Formation of intermediate complex: The reactant molecule adjacent one
another join to form an intermediate complex (A-B).The intermediate
complex is unstable.
• Decomposition of intermediate complex: The intermediate complex
breaks to form the products C and D. The product molecules hold to the
catalyst surface by partial chemical bond.
• Release of product: The product particles are released from the surface.

9. Some example of enzyme catalysis reaction
(i). Inversion of cane sugar: The invertase enzyme converts cane sugar into
glucose and fructose.
C12H22O11(aq) +H2O(l) Invertase C6H12O6(aq) + C6H12O6(aq)
(ii). Conversion of glucose into ethyl alcohol: The zymase enzyme converts
glucose into ethyl alcohol and carbon dioxide.
C12H22O11(aq) Zymase 2C2H5OH(aq) + 2CO2(g)
(iii). Conversion of starch into maltose: The diastase enzyme converts
starch into maltose.
2(C6H11O5)n (aq) + nH2O Diastase nC12H22O11(aq)
Cane sugar Glucose Fructose
Glucose Ethyl alcohol
Starch Maltose

10. • Conversion of maltose into glucose. The maltase enzyme convertsmaltose
into glucose.
C12H22O11(aq) + H2O(l) Maltose C6H12O6(aq)
Glucose
Maltose

11. Advantages
• Catalyst speeds up the reaction, which saves money
• Catalyst allows the reaction to work at a much lower temperature. This
reduces the energy used up in a reaction.
• They save industries money.
• Reusability.

12. Disadvantages
• They are very expensive to buy.
• They often need to be removed from a product and cleaned.
• Different reactions use different catalysts, so, if you make more than
one product you need more than one catalyst
• Catalyst can be ruined by impurities, so they stop working.

13. Reference
1. Vishwakarma, S.K. (2021b) “Types of catalysis, heterogeneous and
homogenous catalysis,” ResearchGate [Preprint]. Available at:
https://doi.org/10.13140/RG.2.2.25613.46568.

14. OPEN TO DISCUSSION

15. THANK YOU