Ludwig Claisen (1851-1930)

German chemist, born in Cologne. He studied at Bonn and Göttingen and obtained his doctorate in Bonn in 1875 under August Kekulé. He worked in Bonn, Manchester and Munich, was professor at Aachen (1890-1897) and Kiel (1897-1904) and honorary professor in Berlin (1904-1907). He then continued his research in his private laboratory in Godesberg, near Bonn, where he died in 1930.

His name is linked to several fundamental reactions of carbonyl compounds: the Claisen condensation of esters, the Claisen-Schmidt condensation between aromatic aldehydes and ketones, and the Claisen rearrangement of allyl phenyl ethers (1912). He also studied keto-enol tautomerism and designed the two-necked Claisen flask used in vacuum distillations.