Question

What is Rosenmund's reaction? What is the purpose of adding $Ba{SO}_4$ in this reaction?

Answer 1

Rosenmund reduction is the hydrogenation of an acyl chloride to an aldehyde, in presence of catalyst (Pd supported on barium sulphate). Barium sulphate partially poisons Pd metal and prevents over-reduction. Untreated Pd catalyst is too reactive.