Borsook, Henry and Huffman, Hugh M. and Liu, Yun-Pu (1933) The preparation of crystalline lactic acid. Journal of Biological Chemistry, 102 (2). pp. 449-460. ISSN 0021-9258 http://resolver.caltech.edu/CaltechAUTHORS:BORjbc33b
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On account of its importance in intermediary metabolism, lactic acid was among the first compounds chosen in our plan, which we have described in a previous communication (1), to augment the available data on the free energies of formation of substances significant in biological chemistry. It was necessary for this purpose to obtain pure crystalline lactic acid, free of water, anhydride, and lactide. The only description in the literature of the preparation of crystalline lactic acid is that of Krafft and Dÿes (2). Table I shows that the product obtained by their method contains relatively large quantities of anhydro impurities. The subject of the present communication is the description of a method which yields the active isomers of lactic acid in a crystalline state, free of water, anhydride, and lactide, supplemented by the description of two methods of separating the active forms from the commercial syrup (1). Lactic acid commercially available at present either is in the form of the U.S.P. syrup, which usually exhibits a low optical activity corresponding to the excess it happens to contain, which is variable, of one or the other optical isomer, or is the expensive zinc sarcolactate. The methods described below now make it possible to obtain easily and quickly and at low cost large quantities of both active isomers in a relatively high degree of purity.
|Additional Information:||© 1933 American Society of Biological Chemists. Received for publication, June 7, 1933. [Y.-P.L. was a] China Foundation Scholar.|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||01 Oct 2008 05:55|
|Last Modified:||26 Dec 2012 10:17|
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