PROBLEM 12.11 - Organic Chemistry

Question

Question: a) Draw the structure of a compound of molecular formula  C₆H₁₀  that reacts with H₂ in the presence of Pd-C but does not react with H₂ in the presence of Lindlar catalyst. (b) Draw the structure of a compound of molecular formula C₆H₁₀  that reacts with H₂  when either catalyst is present

Step-by-Step Solution

Answer

Answer

 Compound with the molecular formula  C₆H₁₀  

Catalyst for reduction of alkynes and alkenes

The hydrogen on the Pd-C catalyst and the Lindlar catalyst give a reduction reaction, but the difference is in the obtained product.

The hydrogen on the Pd-C catalyst reduces alkynes$\left(\mathrm{C}\equiv \mathrm{C}\right)$ and $\left(\mathrm{C}=\mathrm{C}\right)$alkenes to alkanes$\left(\mathrm{C}-\mathrm{C}\right)$  .

The Lindlar catalyst reduces only alkynes$\left(\mathrm{C}\equiv \mathrm{C}\right)$  to cis alkenes $\left(\mathrm{C}=\mathrm{C}\right)$ .

Reduction of the compound in the presence of both the catalysts

Both the double bond and triple bond get reduced in the presence of the hydrogen Pd-C catalyst.

 Reaction in the presence of hydrogen Pd-C catalyst

Only the triple bond is reduced to cis-alkene in the presence of the Lindlar catalyst.

Reaction in the presence of Lindlar catalyst