Abstract: The invention discloses a method for the preparation of 1-methyl-3-(trifluoromethyl)-1H-pyrazol-5-ol with high selectivity with respect to the content of the isomer 1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-ol.

Abstract: Method for enantioseparation of a chiral system with compound formation comprising a pair of enantiomers. The method comprises the steps of: placing the chiral system to be processed, which is optically enriched by a target enantiomer, in the 3-phase region of the ternary phase diagram of chiral compound forming systems to achieve the establishment of the solid/liquid phase equilibria; phase-separating the liquid and solid phase formed by the placing step; shifting the eutectic composition of the remaining liquid towards a lower eutectic composition (xE) until the overall composition is located in the 2-phase region of the ternary phase diagram of chiral compound forming systems; and performing crystallization in the 2-phase region of the ternary phase diagram for obtaining the target enantiomer in the solid phase. In some cases the shifting step can be skipped.

Abstract: The invention concerns a method for separating a racemic compound-forming chiral substance by a cyclic crystallization process which is conducted in at least one first crystallization unit (10) and in at least one second crystallization unit (18), wherein in a first process cycle an enantiomer is crystallized in the first crystallization unit (10) and a racemic compound is crystallized in the second crystallization unit (18), wherein in a second process cycle the enantiomer is crystallized in the second crystallization unit (18) and the racemic compound is crystallized in the first crystallization unit (10), wherein during each process cycle in at least one process sub-step (B?C, F?G) a mother liquor (12) being contained in the first crystallization unit (10) is mutually exchanged with a mother liquor (20) being contained in the second crystallization unit (18). An auto-seeding process sub-step is applied at the beginning of a process cycle.

Abstract: The invention concerns a method for separating a racemic compound-forming chiral substance by a cyclic crystallization process which is conducted in at least one first crystallization unit (10) and in at least one second crystallization unit (18), wherein in a first process cycle an enantiomer is crystallized in the first crystallization unit (10) and a racemic compound is crystallized in the second crystallization unit (18), wherein in a second process cycle the enantiomer is crystallized in the second crystallization unit (18) and the racemic compound is crystallized in the first crystallization unit (10), wherein during each process cycle in at least one process sub-step (B?C, F?G) a mother liquor (12) being contained in the first crystallization unit (10) is mutually exchanged with a mother liquor (20) being contained in the second crystallization unit (18). An auto-seeding process sub-step is applied at the beginning of a process cycle.

Abstract: The invention concerns a method for separating a racemic compound-forming chiral substance by a cyclic crystallization process which is conducted in at least one first crystallization unit (10) and in at least one second crystallization unit (18), wherein in a first process cycle an enantiomer is crystallized in the first crystallization unit (10) and a racemic compound is crystallized in the second crystallization unit (18), wherein in a second process cycle the enantiomer is crystallized in the second crystallization unit (18) and the racemic compound is crystallized in the first crystallization unit (10), wherein during each process cycle in at least one process sub-step (B?C, F?G) a mother liquor (12) being contained in the first crystallization unit (10) is mutually exchanged with a mother liquor (20) being contained in the second crystallization unit (18). An auto-seeding process sub-step is applied at the beginning of a process cycle.

Abstract: Method for enantioseparation of a chiral system with compound formation comprising a pair of enantiomers. The method comprises the steps of: placing the chiral system to be processed, which is optically enriched by a target enantiomer, in the 3-phase region of the ternary phase diagram of chiral compound forming systems to achieve the establishment of the solid/liquid phase equilibria; phase-separating the liquid and solid phase formed by the placing step; shifting the eutectic composition of the remaining liquid towards a lower eutectic composition (xE) until the overall composition is located in the 2-phase region of the ternary phase diagram of chiral compound forming systems; and performing crystallisation in the 2-phase region of the ternary phase diagram for obtaining the target enantiomer in the solid phase. In some cases the shifting step can be skipped.

Abstract: Methods for racemate separation for compound-forming substances. In this method, at least one fraction which is enriched with an enantiomer is produced in one method step. Finally, a preferred crystallization is carried out on the fraction.

Abstract: Methods for racemate separation for compound-forming substances. In this method, at least one fraction which is enriched with an enantiomer is produced in one method step. Finally, a preferred crystallization is carried out on the fraction.