Question

1Please describe the difference between a heterogenous catalyst (like Ni on Carbon) and a homogeneous catalyst (like Wilkinson's catalyst) 2. Please provide a strategy to make cyclohexyl epoxide from cyclohexene. 3. Draw the intermediate for the addition of Cl2to cyclohexene. 4. Explain why one receives a racemic mixture from the following reaction. HBr CH3 +Enantiomer CH3

Answer 1

Heterogeneous Homogeneous Readily separated Readily recycled /regenerated Difficult to separate x Difficult to recover x Short service life x Long-lived Cheap Lower rates (diffusion limited) x Sensitive to poisons x Lower selectivity x High energy process x Poor mechanistic understanding x Expensive Very high rates Robust to poisons Highly selective Mild conditions Mechanisms often known