Ziegler, Karl (1898–1973)

German organic chemist. He shared the Nobel Prize for Chemistry in 1963 with Giulio Natta of Italy for work on the chemistry and technology of large polymers. He combined simple molecules of the gas ethylene (ethene) into the long-chain plastic polyethene (polyethylene).

Ziegler and Natta discovered in 1953 a family of stereo-specific catalysts capable of introducing an exact and regular structure to various polymers. This discovery formed the basis of nearly all later developments in synthetic plastics, fibres, rubbers, and films derived from such olefins as ethylene (ethene) and butadiene (but-1,2:3,4-diene).

Ziegler was born near Kassel and studied at Marburg. From 1943 he was director of the Kaiser Wilhelm (later Max Planck) Institute for Coal Research in Mülheim.

In 1933, Ziegler discovered a method of making compounds that contain large rings of carbon atoms. Later he carried out research on the organic compounds of aluminium. Using electrochemical techniques, he prepared various other metal alkyls from the aluminium ones, including tetraethyl lead, which was used as an additive to petrol.

In 1953 Ziegler found that organometallic compounds mixed with certain heavy metals polymerize ethylene at atmospheric pressure to produce a linear polymer of high molecular weight (relative molecular mass) and with valuable properties, such as high melting point.