Question

Catalyst used in dimerisation of acetylene to prepare chloroprene is
A . HgSO₄ + H₂SO₄
B . Cu₂Cl₂
C . Cu₂Cl₂ + NH₄Cl
D . Cu₂Cl₂ + NH₄OH

Answer 1

Hint: In this question we have to use the reaction of dimerisation of acetylene to prepare chloroprene to find out the catalyst used in this reaction. Dimerization is the process by which two molecules with comparable chemical make-up combine to produce a single polymer called a dimer.

Complete Step by Step Answer:
When acetylene reacts with hydrogen chloride to create 4-chloro-1, 2-butadiene, an allene derivative, it dimerizes to produce vinyl acetylene. In the presence of cuprous chloride(Cu₂Cl₂) and ammonium chloride(NH₄Cl), this derivative rearranges to produce 2-Chlorobuta-1, 3-diene.

There are two phases in the conventional synthesis of chloroprene. Acetylene is first dimerized to vinylacetylene in a reaction tower at 80 °C in an aqueous hydro-chloric acid solution of Cu₂Cl₂ and NH₄Cl.

Water evaporation regulates the significant evolution of heat. The conversion of C₂H₂ is around 18%. The major by-product is divinylacetylene, and the selectivity to vinylacetylene can reach 90%. In the second stage HCl is added to vinylacetylene, forming chloropropene.

The correct answer is option (C) Cu₂Cl₂ + NH₄Cl.

Additional Information: A catalyst is a substance that, without being consumed by the process, speeds up a chemical reaction or lowers the temperature or pressure required to initiate one. The addition of a catalyst to a reaction is known as catalysis. By lowering the activation energy, the energy barrier that must be cleared for a chemical reaction to take place, catalysts increase the efficiency of a reaction. There will be two steps in the conversion of acetylene to chloroprene. A triple bond and two carbon atoms are both present in the organic molecule acetylene. Four carbon atoms make up the chemical chloroprene, which also contains a chlorine atom in the second position. There are double bonds in the first and third positions.

Note: A triple bond and two carbon atoms are both present in the organic molecule acetylene. Four carbon atoms make up the chemical chloroprene, which also contains a chlorine atom in the second position. There will be two processes required to transform acetylene into chloroprene.