Rosenmund还原反应（罗森孟还原法；罗斯曼得还原法）

酰氯在部分失活的钯催化剂（Pd/BaSO₄）作用下用氢气进行还原，得到相应的醛。

反应由德国化学家 Karl Wilhelm Rosenmund (1884-1965) 首先报道。

该反应是通氢气于悬浮有催化剂的酰氯溶液中来进行。是从羧酸合成醛的方法之一，一般应用于制备一元脂肪醛和一元芳香醛。反应的副产物有醇、烷烃、酸酐和酯。用三叔丁氧基氢化铝锂也可以将酰氯还原为醛。此外，芳香酰氯也可在钯络合物催化下用聚甲基氢硅氧烷（PMHS）还原为芳醛。 亦可用三丁基氢化锡来进行或在氢供体存在下用光照射来还原。

The Rosenmund reduction is a hydrogenation process in which an acyl chloride is selectively reduced to an aldehyde. The reaction was named after Karl Wilhelm Rosenmund who first reported it in 1918.

The reaction is catalysed by palladium on barium sulfate, which is sometimes called the Rosenmund catalyst. Barium sulfate has a low surface area which reduces the activity of the palladium, preventing over-reduction. However for certain reactive acyl chlorides the activity must be reduced further, by the addition of a poison. Originally this was thioquinanthrene although thiourea has also been used. Deactivation is required because the system must reduce the acyl chloride but not the subsequent aldehyde. If further reduction does take place it will create a primary alcohol which would then react with the remaining acyl chloride to form an ester.