Hrdroformylation
- 1. ORGANOMETTALIC CHEMISTRY HYDROFORMYLATION D. Sudha III B.Sc. Chemistry St John’s College
- 2. HYDROFORMYLATION (Addition of –H and –CHO group to carbon-carbon double bond i.e. alkenes or olefins.) discovered by Otto Roelen in 1938 accidently during the investigation of origin of oxygenated products occurring in cobalt catalyzed Fischer-Tropsch reactions. also known as Oxo Process Homogeneous catalysis Industrial Method used for the production of aldehydes which is easily converted to secondary products such as alcohols, amines etc. -H and –CHO group
- 3. Hydroformylation The reaction of an alkene with carbon monoxide and hydrogen, catalyzed by cobalt or rhodium salts to form an aldehyde is known as Hydroformylation. CO Pressure increases , Formation of linear product increases . CO Pressure decreases, Formation of Branched Product increases. Normal is more stable than iso Main product (Anti markovnikov)
- 4. HYDROFORMYLATION USING COBALT CATALYST Mechanism - Heck and Breslow (1960-1961) CATALYST HCo(CO)4 formed by the hydrogenation of Co2(CO)8 Cobalt tetracarbonyl hydride Dicobalt octacarbonyl
- 5. Mechanism: 1. Hydrogenation of to form . 2. CO Ligand Dissociation to form an active catalyst . 3. Addition of Alkene. 4. Migration of Hydrogen followed by addition of CO to form the alkyl complex . 5. Migration of alkyl group to form an acyl complex . 6. Oxidative addition of hydrogen to acyl complex to form the 18 e- species . . 7. Reductive Elimination from this compound form Aldehyde and regenerates the starting material i.e. Catalyst .