PTC IS THE PHASE TRANSFER CATALYSIS HERE TYPES OF PTC ARE DISCUSSED , THEORIES OF CATALYSIS AND MECHANISM OF PTC, ADVANTAGES OF PTC, APPLICATION OF PTC

1. PHASE TRANSFER CATALYSIS

2. CONTENTS
 Introduction
 Mechanism of PTC reaction
 Theories of PTC
 Types of phase transfer catalyst
 Advantages of phase transfer reaction
 Application of phase transfer catalysis
 References
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3. Introduction
o Catalysis :-Catalysis is the process of increasing the rate of a chemical
reaction by adding a substance known as a catalyst.
o Definition :- Phase transfer catalysis (PTC) refers to reaction between two
substances located in different immiscible phases in the presence of catalyst.
o Heterogenous catalysis.
o It facillate the migration of a reactant from one phase into another phase
where reaction occurs.
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4. Following three factors plays important role in the successful use of
phase transfer catalyst reaction :-
i. Influence of solvent :-Solvent should be aprotic and immiscible with
water to avoid strong interaction with ion pairs.
ii. Influence of cation :- The large number of carbon atom around the
central N atom in the PTC.
iii. Salt effect:- Addition of sodium hydroxide and potassium carbonate
increases the extraction coefficient many times and thus increases the
rate of reaction.
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5. Theories of catalysis
1) Intermediate Compound formation theory (Homogenous catalyst reaction )
2) Adsorption theory ( Heterogenous catalyst reaction )
1) 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.
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6. 2) 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.
( i) 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.
ii ) Formation of intermediate complex:
The reactant molecule adjacent one another join to
form an intermediate complex ( A-B ). The intermediate complex is unstable.
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7. ( iii ) 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.
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( iv ) Release of product:
The product particles are released from the surface.

8. Mechanism of PTC Reaction
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9. Types of phase transfer catalyst
o Quaternary ‘Onium’ salts such as ammonium, phosphonium ,
antimonium and tertiary sulphonium salts.
Some of the PTC’s normally used are:-
1) Aliquat 336 : N+CH3(C8H17)3 Cl
Methyl trioctylammonium chloride
2) Benzyl trimethylammonium chloride or bromide (TMBA)
N+(CH3)3 CH2 C6H5 X-
3) Benzyl triethylammonium chloride
N+(C2H5)3 CH2 C6H5 X-
4) Cetyl trimethylammonium chloride or bromide (CTMAB)
N+ (CH3)3 (CH2)15 CH3 X- 19-12-2019
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10. Types of phase transfer catalysed reactions
Phase transfer reactions
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Liquid-Liquid phase
transfer reaction
Solid-Liquid phase
transfer reaction
Solid-gas phase
transfer reaction
Triphase catalyst
• Insolubilized ammonium
and phosphonium salts
• Insolubilized crown
ethers and cryptands
• Insolubilized cosolvents

11. Advantages of PTC
1. Do not require vigorous conditions and the reaction are fast.
2. Do not require expensive aprotic solvents.
3. Do not require high temperature ; the reaction usually occur at low temperature.
4. There is no need for anhydrous conditions since water is used as one of the
phases.
5. With the help of PTC , the anion is available in organic solvent and so its
nucleophilicity increases.
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12. Applications of phase transfer Catalysis
1) Nitriles From Alkyl Halides :-
R-X + NaCN RCN + NaX
2) Benzoyl Cyanides from Benzoyl Chloride:-
PTC
Organic Aqueous
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O
Cl
+ Na N N
O
+ Na Cl
Bu4 N +X-
Benzoyl
cyanide
Benzoyl
chlolride
Sodium
cyanide
Nitrile

13. 3) Aryl Ethers/Thioethers :-
4) Benzoin Condensation :-
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ArOH + RX ArOR
NaOH
Phenol Aryl ether
Benzaldehyde

14. 4) Esterification :-Carboxylic acids can be esterified with alkyl halides in the
presence of triethylamine.
RCO2Na + RX RCO2R + Na X
5)In the field of Pharmaceuticals like Synthesis of various drugs like dicyclomine,
phenoperidine ,oxaladine ,ritaline ,etc.
6) Williamson Ether Synthesis :-
C8H17OH + C4H9Cl C8H17OC4H9 + C8H17OC8H17
PTC
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Alcohol Alkyl halide
Ether By-product
Carboxylic
acid as sod.
salt
Alkyl
halide
Ester

15. THANK YOU……..!!!!!
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