The invention relates to a process for the preparation of the crystallization mother liquor which is obtained in the resolution of 1- (4-chlorophenyl) ethylamine of the formula (I) with S - (-) - N-phenylcarbamate lactic acid of the formula (II) by the ethanolic Crystallization mother liquor, the ethanol is distilled off in a first step and in a second step the remaining residue is stirred with tert-butyl methyl ether or toluene and the crystalline salt of (R / S) -1- (4-chlorophenyl) ethylamine and ( S) - (-) - N-phenylcarbamate lactic acid can be used directly for racemate resolution. The mother liquor is predominantly in the (S) form of the amine, which can be racemized and returned to the resolution.
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