stéréospécifique

Traductions

• anglais

  Date : 1983

  Définition

  This term and its synonym stereoregular were introduced into polymer chemistry in the 1940s to designate three-dimensional organic structures whose molecules have an ordered (crystalline) orientation rather than the random (amorphous or static) form of most natural high polymers. This regularity of molecular arrangement results either from the nature of the monomer or from the use of unique polymerization catalysts.

  Note :

  The original work on developing such catalysis was done by Hermann Staudinger (1881-1965), a German chemist, Nobel Prize 1953, Karl Ziegler (b. 1898), a German chemist, Nobel Prize 1963, and Guilio Natta, an Italian chemist, Nobel Prize 1963. They found complexing or coordination catalysts, such as lithium or aluminum alkyl plus titanium dichloride, to be capable of so controlling the three-yeast, as well as in animals and man. Among the best-known are ergosterol, a precursor of vitamin D₂, and cholesterol, an important factor in metabolism.

  Terme :

  1. stereospecific