Rosenmund Reduction (RCOCl + H₂ → RCHO + HCl (Pd/BaSO₄ catalyst, poisoned with S/quinoline))
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RCOCl + H₂ → RCHO + HCl (Pd/BaSO₄ catalyst, poisoned with S/quinoline)
What each symbol means
| Symbol | What it stands for |
|---|---|
| RCOCl | Acyl chloride (acid chloride) |
| Pd/BaSO₄ | Palladium on barium sulfate — partially deactivated catalyst |
| S or quinoline | Catalyst poison — prevents over-reduction to alcohol |
When to use this
Poisoned Pd catalyst stops reduction at aldehyde stage. Cannot prepare HCHO this way (HCOCl is unstable). BaSO₄ support + sulfur/quinoline poison are essential.