Racemic acid

Racemic acid

Racemic acid is an old name for an optically inactive or racemic form of tartaric acid. It is an equal mixture of two mirror-image isomers (enantiomers), optically active in opposing directions.

Its sodium-ammonium salt is unusual among racemic mixtures in that during crystallization it can separate out into two kinds of crystals, each composed of one isomer, and whose macroscopic shapes are mirror images of each other. Louis Pasteur was thus able to separate the two enantiomers by picking apart the crystals.

In a modern-time re-enactment of the Pasteur experiment Ref|Tobe it was established that the preparation of crystals was not very reproducible, the crystals deformed but that the crystals were large enough to inspect with the naked eye (microscope not required).

ee also

*Tartaric acid

References

# "The reexamination of Pasteur’s experiment in Japan" Yoshito Tobe Mendeleev Communications Electronic Version, Issue 3, 2003 [http://dx.doi.org/10.1070/MC2003v013n03ABEH001803 DOI article] [http://www.mendcomm.org/pages/goodies/mc0303/pdf/mc1803.pdf Free access version with experimental details]


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Look at other dictionaries:

  • racemic acid — n. [< RACEME: orig. found in grapes] a transparent, colorless, crystalline compound occurring in nature with d tartaric acid: it is an optically inactive isomer of tartaric acid …   English World dictionary

  • racemic acid — noun the optically inactive form of tartaric acid that is often found in grape juice • Hypernyms: ↑tartaric acid * * * noun : optically inactive tartaric acid that consists of equal parts of dextro and levo tartaric acids into which it can be… …   Useful english dictionary

  • racemic acid — vynuogių rūgštis statusas T sritis chemija apibrėžtis Vyno rūgščių racematas. atitikmenys: angl. racemic acid rus. виноградная кислота …   Chemijos terminų aiškinamasis žodynas

  • racemic acid — Chem. an isomeric modification of tartaric acid that is sometimes found in the juice of grapes in conjunction with the common dextrorotatory form and is optically inactive but can be separated into the two usual isomeric forms, dextrorotatory and …   Universalium

  • racemic acid — noun an equal mixture of the d and l forms of tartaric acid found in grape juice; the isomers can be separated via crystallization …   Wiktionary

  • racemic acid — /rəsimɪk ˈæsəd/ (say ruhseemik asuhd) noun an isomeric modification of tartaric acid, which is sometimes found in the juice of grapes in conjunction with the common dextrorotatory form, and which is optically inactive, but can be separated (or… …  

  • racemic — [rāsē′mik] adj. [< RACEME + IC: for sense see RACEMIC ACID] Chem. 1. consisting of an optically inactive, equimolecular mixture of the dextrorotatory and levorotatory forms of certain substances 2. designating or of a compound formed of such a …   English World dictionary

  • Racemic mixture — In chemistry, a racemic mixture, or racemate , is one that has equal amounts of left and right handed enantiomers of a chiral molecule. The first known racemic mixture was racemic acid , which Louis Pasteur found to be a mixture of the two… …   Wikipedia

  • racemic — adjective Etymology: racemic acid, a compound with such a structure obtained from grape juice, ultimately from Latin racemus Date: 1892 of, relating to, or constituting a compound or mixture that is composed of equal amounts of dextrorotatory and …   New Collegiate Dictionary

  • Racemic — Ra*ce mic (r[.a]*s[=e] m[i^]k), a. [Cf. F. rac[ e]mique. See {Raceme}.] (Chem.) Pertaining to, or designating, an acid found in many kinds of grapes. It is also obtained from tartaric acid, with which it is isomeric, and from sugar, gum, etc., by …   The Collaborative International Dictionary of English

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