This document discusses various homogeneous catalytic oxidation reactions using dioxygen. It describes the Wacker process for ethylene oxidation to acetaldehyde using a palladium catalyst. Terephthalic acid production from p-xylene is discussed as another example of a homogeneous oxidation using cobalt initiators. The document also covers epoxidation reactions, including the SMPO process for styrene production and the Jacobsen asymmetric epoxidation using metal complexes.

1. Oxidation Reactions by
Homogeneous Catalysis
TO
Madam
SANA
BY Rukhsar

2. Catalysis
Homogeneous
Catalysis
Bio Catalysis
Heterogeneou
s Catalysis
Photo-Catalys
is
Electro-Catal
ysis

3. OKCatalysis research at the IFOK
•First Institute for Catalysis Research in Europe; founded 1952.
•2003: ca. 90 Employees (18 permanent scientists, >20 postdocs,
13 Ph.D. students).
•Background and main expertise is homogeneous catalysis,
based on transition metal complexes
•Transfer of excellent basic research to industrial applications

4. ❖ OXIDATION WITH DIOXYGEN
Oxidation with dioxygen is an important reaction as it is
cheapest and most abundant source of oxygen atoms in
petrochemical feedstocks and manufacturing of chemicals.
Large-scale chemicals made via oxidative routes include
ethylene oxide, styrene, acetic acid, phenol, maleic
anhydride, adipic acid, phthalic acid, and acetaldehyde.
Acetic acid is made via combustion of butane using cumene
(iPrC6H5), Maleic anhydride is made via oxidation of butane or
benzene with the use of a heterogeneous vanadyl pyrophosphate
catalyst. Adipic acid (HO2C(CH2)4CO2H), one of the
components of nylon-6,6, is the product of benzene radical
catalysed air-oxidation with cobalt initiators.
Refinement of olefins by Green Catalysis.

5. ETHYLENE OXIDATION TO ACETALDEHYDE:
WACKER PROCESS
Acetaldehyde – of commercial importance
- oxidation to acetic acid
- dehydration to acetic anhydride
Today, Wacker process is used producing 4 million
tons of acetaldehyde from ethylene.

6. Net Reaction:
CH2=CH2 + PdCl2 + H2O → CH3C(=O)H + Pd(0) + 2HCl
Pd(0) + 2 CuCl2 → PdCl2 + 2CuCl
2CuCl + 2HCl + 1/2O2 → 2CuCl2 + H2O
_________________________________________________
CH2=CH2 + 1/2O2 → CH3C(=O)H ΔHo = -243 kJ/mole
First organopalladium reaction applied on
industrial scale.
! First rendered commercial in 1960.
! At one point was responsible for the
production of over 2 billion pounds per
year of acetaldehyde!

7. ❖ Synthetic Applications
The Wacker oxidation has been used extensively in
organic synthesis, the reaction is aerobic and
operationally simple.
The Wacker oxidation was employed in the course of
synthesis of the macrolide elaiolide a useful antibiotic to
treat infections caused by gram positive ad gram negative
bacteria .

8. THE WACKER PROCESS

10. ❖ Terephthalic acid
The production of terephthalic acid (1,4-benzenedicarboxylic acid) is one of the
examples of a homogeneous, radical-catalysed oxidation with the use of dioxygen and
cobalt salt initiators.
Terephthalic acid is used for the production of polyesters with largest synthetic fibre.
Terephthalic acid is produced from p-xylene by catalytic oxidation with oxygen. The
reaction is carried out in acetic acid and the catalyst used is cobalt (or manganese)
acetate and bromide.

11. Glycolysis
It is the initial stage of glucose metabolism, takes place in the cytosol
and does not involve molecular O2. It produces a small amount of ATP
and the three-carbon compound pyruvate.
In aerobic cells pyruvate formed, pyruvate is formed .
In absence of oxygen, Lactate is formed.

12. EPOXIDATION
Ethene and Propene oxide Epoxidation of alkenes is a powerful reaction for the introduction of
oxygen in hydrocarbons.
Catalytic epoxidation of alkenes
▪ Catalytic oxidation of olefins is beneficial to the chemical process because it can provide more
chemical production for the chemical plant.
▪ Oxygen can be used for the epoxidation of ethene over a silver catalyst, but for all other alkenes
further oxidation occurs when the source of oxygen is dioxygen. The mechanism involves the
electrophilic attack of monooxygen on the π-electrons of ethane. Ethene oxide is converted mainly
to ethylene glycol for use in antifreeze liquids and polyesters.
▪ Higher alkenes, even propene, must be oxidised to their epoxides with the use of hydroperoxides.

13. ❖ SMPO Process
Ethylbenzene is oxidised to its hydroperoxide which is used for the epoxidation of propene
which results phenetylalcohol is dehydrated to give styrene (the major source of styrene
industrially is the direct dehydrogenation of ethylbenzene it is called the SMPO process,
Styrene Monomer, Propylene Oxide process.
The catalyst is immobilised complex of titanium (Shell) or molybdenum is used.
SMPO Process

14. ❖ The Jacobsen asymmetric epoxidation
Metal complexes of porphyrins, salens (tetradentate, dianionic ligands
bis(salicylidene)ethylenediamines ), phthalocyanins used as oxidation and epoxidation
catalysts with either dioxygen or oxygen donors as the oxidant. As oxygen donors used
hydrogen peroxide, hydroperoxoides, iodosobenzene (PhIO), NaOCl (bleach), peracids,
pyridine-N-oxides generates a high-valent metal-oxo complex, and electrophilic oxo atom is
transferred to the hydrocarbon substrate. Although the Sharpless catalyst was extremely
useful and efficient for allylic alcohols, epoxidation of simple alkenes both using catalysts
based on chiral manganese salen complexes.

15. The Jacobsen asymmetric
epoxidation

16. ❖ Epoxidation of alkenes through oxygen
activation over a bifunctional CuO/Al2O3
catalyst†
The epoxidation of alkenes as trans-methylstyrene was carried out
over a CuO/Al2O3 catalyst using cumene as an oxygen carrier, gave
the corresponding epoxide in 95% yield after 3 h.
Epoxides are synthetic intermediates used in the production of
epoxide resins, plasticizers, cosmetics, pharmaceuticals
In the Sumitomo process3 cumene (CUM) is used to produce cumyl
hydroperoxide (CHP) by reaction with oxygen and then, in a second
reaction step, CHP reacts with propene to give propylene oxide (PO)
and cumyl alcohol as the co-product.

17. One-pot epoxidation of trans-stilbene to give trans-stilbene oxide, in the presence of in
situ formed CHP generated by reaction between cumene and O2 over bifunctional
CuO/Al2O3.