2. Purpose of Experiment
Objective
Investigate an efficient organometallic catalyst for
converting methane to methanol following the CH
activation pathway.
Activate the C-H bond of methane in order to
facilitate the binding of OH and formation of
methanol.
14. Background
Molecular Orbitals5
Ψ= Molecular Wave Function
Φ= Molecular Orbitals
To find Ψ, you must find Φ and its coefficients in
known functions.
The more flexible (and better) the wave function, the
lower the energy.
Orbital Approximation: Treating each electron
separately. Calculates one-electron wave functions.
16. Background
• Transition States4:
-Cannot be observed experimentally
-State in which some bonds are being broken
as others are being formed.
-Requires input of energy.
-Transition state theory:
• None of the reactants
have more energy than
necessary to reach the
transition state.
17. Uses
Predict many properties of molecules such as
transition states, molecular structures, molecular
orbitals, as well as reactions and reaction energies.1
Used to determine which reactions would be most
useful to do experimentally.
Draws structures of molecules.1
18. Advantages
Time efficient: runs reactions in hours or days that
would take months in the lab.
Does not waste materials.
Can be used in collaboration with experimental
chemistry to determine the best way to reach a goal
or product.
19. Types
Electronic Structure Theory:
Electronic Structure Methods: use the Schrodinger
equation: Hψ=Eψ
Semi-empirical methods: Use data from experimental
data.
Ab initio methods: Based solely on quantum mechanics.
Density Functional Methods: Includes effects of
electron correlations by using electron density
20. Types
Molecular Mechanics:
Uses laws of classical physics
Different types defined by their force fields.
Force field:
How the potential energy of a molecule depends on the
molecules around it
A series of atom types
Parameter sets that define force constants.
Based on the interactions of the nuclei.
21. Hartree- Fock
Theoretical Model- Electronic Structure Method5.
Utilizes basis sets to estimate a solution to the
Schrödinger Equation5.
Well defined and yield unique properties5:
Both Size consistent and variational
Applicable to molecules of 50-100 atoms.
Gives information and numerous chemical observables
such as equilibrium geometry and reaction energies.
22. Web MO
An interface to computational chemistry packages,
such as Gaussian.2
Key features:2
Runs online.
Access to a wide variety of computational chemistry
packages.
Simple and easy to use.
Access to input and output files.
Amine (3)
Iridium Eta 2
Product
24. Avogadro
Cross-Platform Molecule Editor.3
Provides a format to save and view molecular
structures.3
Provides a simple way to
edit structures.3
Compatible with Web MO.3
Quick and simple to use.3
Amine (3) Iridium Eta 2 Product
26. References
1. Foresman, James B., and AEleen Frisch. Exploring Chemistry
with Electronic Structure Methods. 2nd ed. Pittsburgh, PA:
Gaussian, 1996. Print.
2. "WebMO Enterprise." WebMO Enterprise. WebMO, 2000. Web.
24 May 2013. http://www.webmo.net/enterprise/index.html
3. "Avogadro." Avogadro. Trans. Ali Shahzad and Michael Banck.
GNU FDL, 17 May 2007. Web. 24 May 2013.
4. Engel, Thomas, and Warren J. Hehre. Quantum Chemistry &
Spectroscopy. New York: Prentice Hall, 2010. Print.
5. Grant, Guy H., and W. G. Richards. Computational Chemistry.
Oxford [England: Oxford UP, 1995. Print.
Editor's Notes
C-H activation is more efficient as methane is abundant in the atmosphere while oxygen needs to be a certain percentage for life to exist in the world.
Clean energy: less CO2/kgJ, high octane number, high density fuel.
Can be reproduced Can be put into a container without much ado.
Fisher: Methane + Syngas from coal (still using unclean and non-renewable energy) = methanol Reductive: To produce hydrogen, electrolysis is carried out. This is too expensive to be practical.
All these processes need high temperature. The lab processes produce low yields and selectivity.
Selectivity – producing one product vs. the other.
Safely transporting fuel, in contrast to the natural gas which is prone to explosions.
Providing electricity by direct conversion with DMFC (Direct Oxidation Liquid-fed Methanol fuel cell)
Providing fuel and propellants through the conversion of methanol into components of synthetic fuel, i.e. propylene and ethylene or dimethyl ether, a substituent for diesel.
DMFV car!
Good catalyst reduces temperature hence cost.
It also increases yield as it lowers activation energy hence more reactant molecules can convert to product molecules. It reduces the need for unclean syn-gas in Fisher process.
