The packing for use in resolution proposed for the liquid chromatography for particularly the opti-cal resolution of racemic compounds is prepared by reacting a silica gel carrier with a so-called silane treating agent to introduce a spacer part therein and chemically bonding it with a copper salt of a carboxylic or thiocarboxylic acid selected from the group consisting of optically active D- and L-2--acetizinecaroxylic acid, proline, hydroxyproline and allohydroxyproline. The steric bulkiness, the distance between the silica gel and the optically active group and the degree of hydrophobicity are specified so as to obtain an excellent resolving power.
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(2008/06/13)
Method of preparing 2-chloroethyldichlorosilanes
A method for the preparation of 2-chloroethyldichlorosilanes by the reaction of vinyldichlorosilanes with hydrogen chloride in the presence of ferric chloride or tantalum chloride is disclosed. In the presence of these anhydrous metal chlorides, this reaction can be performed in the temperature range between 30° and 90° C., without the formation to any appreciable extent of methyl or ethyl trichlorosilane or other cleavage products. The end products obtained can also be easily separated from the byproducts by vacuum distillation without the need to resort to additional measures. The vacuum distillation can also be performed in the presence of the metal chlorides.
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(2008/06/13)
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