Raceminen

Raceminen, or racemate, is a chemical term for a mixture that contains equal amounts of the two enantiomers of a chiral molecule. Each enantiomer is a non-superimposable mirror image of the other, and while they share the same chemical formula and connectivity, they may have different three-dimensional shapes and biological activities. A racemic mixture is optically inactive because the clockwise and counterclockwise rotations cancel each other.

Raceminen can form through non-selective synthesis, racemization under certain conditions, or partial resolution where one enantiomer is removed but not completely. The term is used especially in pharmacology and natural product chemistry because enantiomers can differ in potency, metabolism, or safety.

Analytical and separation techniques include polarimetry, circular dichroism, and chiral chromatography or synthesis. In many cases, regulatory and commercial considerations favor enantiomerically pure products, produced by asymmetric synthesis or chiral resolution.

Examples: Many drugs have been marketed as racemates; thalidomide is a well-known case illustrating enantiomer-specific effects. Not all racemates behave identically; in some instances, one enantiomer is therapeutic while the other is inactive or toxic.

Raceminen remains a central concept in stereochemistry, influencing drug development, flavor and fragrance chemistry, and materials science where optical activity matters.