Jeevankumar M presented a seminar on the pyrolysis of acetaldehyde under the guidance of Mr. Pruthviraj. Pyrolysis is the thermal degradation of compounds in the absence of oxygen above the boiling point of water. The pyrolysis of acetaldehyde occurs through a chain reaction, producing methyl radicals and hydrogen. The mechanism involves initiation, propagation, and termination steps. Applying steady-state approximations, the rate law for the pyrolysis of acetaldehyde was determined to be third order with respect to acetaldehyde concentration. Pyrolysis has applications in producing fuels from waste and in industrial processes like steelmaking and syngas production.

1. TUMKUR UNIVERSITY
TUMAKURU
Department Of Studies and Research In Organic chemistry
Seminar topic: “Pyrolysis of acetaldehyde”
Presenting by
JEEVANKUMAR M
I M.Sc. I Sem
Reg No-P11AZ22S104008
Under the Guidance
Mr. Pruthviraj .K
Faculty
Department of Studies and Research in Organic Chemistry
Tumkur University,Tumakuru
Submitted to
Dr. D. Suresh
The Coordinator
Department of Studies and Research in Organic Chemistry
Tumkur University, Tumakuru
2022-2023
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2. Contents
• Introduction
• Pyrolysis of acetaldehyde and it’s reaction
• Mechanism of reaction
• Applications of pyrolysis
• Conclusion
• References
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3. Introduction
• Pyrolysis is a chain reaction process in which the compound is converted into
smaller fragments in the absence of oxygen
• It is a word coined from Greek.
pyro:-”fire” , “heat”
lysis:-”separating”
•Pyrolysis is a chemical degradation process that occur at higher temperature.
i.e. above the boiling point of water and other solvents
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4. Pyrolysis of acetaldehyde
• It is the primary splitting of acetaldehyde molecule to form methyl radicals
and further decomposition leads to the formation of hydrogen.
• Acetaldehyde :
• The reaction of pyrolysis of acetaldehyde is
.
• The rate of reaction is
• d/dt[CH3]=K[CH3CHO]3/2
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5. Mechanism
• The mechanism of pyrolysis of acetaldehyde is
Step 1:Initiation
Step 2:Propagation
Step 3:Termination 5

6. The rate of formation of CH4 from acetaldehyde is given by
d/dt[CH4]=K2[CH3
•][CH3CHO]………….(5)
Applying the steady-state approximation to the CH3
•
i.e, rate of formation of methyl radicals=rate of disappearance of methyl
radicals
d/dt[CH3
•]=0=K1[CH3CHO]-K2[CH3
•][CH3CHO]+K3[CH3CO•]-K4[CH3
•]2
………..(6)
Now applying steady-state approximation to [CH3CO•]
d/dt[CH3CO•]=0=K2[CH3
•][CH3CHO]-
K3[CH3CO•]……………(7)
On equating the equations (6 )and (7), we get
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7. K1[CH3CHO ]- K4[CH3
•]2 = 0
K1[CH3CHO] = K4[CH3
•]
[CH3
•]2 = (K1/K4) [CH3CHO]
[CH3
•] = (K1/K4)1/2 [CH3CHO]1/2………..(8)
Substituting the equation(8)in (3)
d/dt [CH4] = K2(K1/K4)1/2 [CH3CHO]1/2 [CH3CHO]
=K2(K1/K4)1/2 [CH3CHO]1+1/2
d/dt [CH4] = K[CH3CHO]3/2. …………(9)
where K = K2(K1/K4)1/2
Equation (9) is required rate of reaction
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8. Conclusion
• Pyrolysis is a thermal degradation of materials in the absence of
oxygen.
• Pyrolysis is a chain reaction.
• The order of reaction of pyrolysis of aceataldehyde is 3/2.
• Learnt how to apply Steady state approximation rule to pyrolysis of
aceataldehyde.
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9. Applications of pyrolysis
• Pyrolysis is used to produce many kinds of carbon they can be as
fuels.
• Coke can be used as reagent in the manufacturing of Steelmaking .
•Pyrolysis is used in the production of syngas.
•Pyrolysis is used in the treatment of municipal solid waste and plastic
waste
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10. References
• A textbook of “advanced physical chemistry “ by Gurudweep Raj
Page no: 837-839
•A textbook of “physical chemistry “ by
Mandeep dalal
Page no: 348-349
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11. Thank you.
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