2. Oxidation
Definition
Gain of oxygen.
Removal of hydrogen.
Lose of electrons.
Functional group conversion from low oxidation state to higher oxidation
state . E.g. Fe+2 Fe+3+ e-
3. An oxidizing agent, or oxidant, is that oxidize the compounds
and is reduced itself in a chemical reaction. Oxidizing agent is
normally in one of its higher possible oxidation states because
it will gain electrons and be reduced.
Types of Reagents
Metal base oxidants
Oxidizing agents:
Definition
Non-metals base oxidants
4. Metal base oxidation
Chromium based oxidation
Manganese based oxidation
Titanium based oxidation
Ruthenium based oxidation
Osmium based oxidation
Lead based oxidation
Per acids Oxidation
Photo oxidation
Bio-oxidation
Non-metal base oxidation
5. Oxidation with Osmium tetroxide (OsO4).
• A highly toxic and volatile oxide of osmium used in industry as
an oxidizing agent. Its vapor can cause eye, skin, and lung
damage.
After oxidation the oxidation state of
OsO4 change from +8 to +6.
• It is a reagent, mostly used for the cis-hydroxylation of carbon-
carbon double bond.
• Hydroxylation is the process that introduces hydroxyl group in
organic compound.
Oxidation State +8
7. Step 1:
The pi- electrons in the alkene act as a
nucleophile forming a favorable 5 membered
ring as a cyclic osmate ester as an intermediate.
Step 2:
The hydroxide liberates the cis-diol and after
oxidation osmium changes oxidation State from
+8 to +6 this shows that OsO4 reduced.
Mechanism for the reaction of alkenes
8. Similarity between OsO4 and KMnO4
The mechanism dihydroxylation of alkenes by the both of them is same but one
advantage of OsO4 is that it is much more compatible with other functional
groups than KMnO4.
O3
