Alkenes combine with carbon monoxide and hydrogen in presence of octacarbonyldicobalt as catalyst un — Hydrogen Chemistry Question

💡 Solution & Explanation

# Hydroformylation Reaction **The reaction being described is the Hydroformylation (or Oxo Process):** $$\text{Alkene} + CO + H_2 \xrightarrow{[\text{Co}_2(\text{CO})_8], \text{high T, P}} \text{Aldehyde}$$ **Step-by-step mechanism:** 1. **Reactants involved:** An alkene reacts with $CO$ and $H_2$ under high temperature and pressure 2. **Catalyst role:** $Co_2(CO)_8$ (octacarbonyldicobalt) provides the reaction center by: - Dissociating to form active cobalt complexes - Coordinating with $CO$ and $H_2$ 3. **Insertion steps:** - The alkene inserts into the Co-H bond - Carbon monoxide inserts into the resulting Co-alkyl bond - Hydrogen attacks the acyl intermediate 4. **Product formed:** An **aldehyde** ($R-CHO$) is produced **Why answer A (aldehyde) is correct:** - The addition of one $CO$ and one $H$ across the C=C bond gives an aldehyde - This is a characteristic feature of the oxo process/hydroformylation - The cobalt catalyst specifically facilitates this CO insertion mechanism **Other options would be wrong because:** - Ketones form when internal alkenes are used or with different conditions - Carboxylic acids require oxidation (additional step) - Alcohols require reduction (additional step)