Abstract: This invention is directed to synthetic co-crystals of anhydrous guanine and at least one additional material, wherein the co-crystals have a high refraction index and therefore, provide products with pearlescence or whiteness with high coverage. The invention is further directed to a process for the preparation of anhydrous guanine and of the co crystals.

Abstract: This invention is directed to synthetic co-crystals of anhydrous guanine and at least one additional material, wherein the co-crystals have a high refraction index and therefore, provide products with pearlescence or whiteness with high coverage. The invention is further directed to a process for the preparation of anhydrous guanine and of the co crystals.

Abstract: The invention relates to a process for the kinetic resolution of D,L-racemic mixtures of racemates crystallizing as conglomerates. Resolution is effected from supersaturated solutions of these which is carried out in the presence of a polymer bound inhibitor of crystallization of the one form, resulting in the preferred crystallization of the one form, and when the other form is desired - in the presence of such inhibitor for the other form. Amongst racemic mixtures amenable to this process are amino acids. The process can be carried out in a two-compartment device, where the compartments are separated by a membrane which is permeable to the constituents of the racemate, while it is impervious to the polymer-bound inhibitor for the crystallization of one of the racemic forms.

Abstract: A process for resolution of a mixture of D- and L- amino acids, selected from threonine (THR), asparagine (ASN), p-hydroxyphenylglycine p-toluene sulfonate (pHPGpTS) and glutamic acid hydrochloride (GLU), which crystallize in the form of a conglomerate, whereby the ratio of one desired enantiomorph to the other undesired enantiomorph of said amino acid is increased in the crystalline compound obtained, as compared to the ratio in the starting material, which process comprises forming a supersaturated solution of said mixture, adding another predetermined amino acid as additive, which has a molecular structure which resembles that of one of the enantiomers of said racemic mixture, said additive being a D-amino acid as an inhibitor of the growing D-amino acid when the L-amino acid is desired, or a L-amino acid when the D-amino acid is desired, and crystallizing part of the compound from said supersaturated solution. When GLU.

Abstract: A process for resolution of a mixture of D- and L- amino acids, selected from threonine (THR), asparagine (ASN), p-hydroxyphenylglycine p-toluene sulfonate (pHPGpTS) and glutamic acid hydrochloride (GLU), which crystallize in the form of a conglomerate, whereby the ratio of one desired enantiomorph to the other undesired enantiomorph of said amino acid is increased in the crystalline compound obtained, as compared to the ratio in the starting material, which process comprises forming a supersaturated solution of said mixture, adding another predetermined amino acid as additive, which has a molecular structure which resembles that of one of the enantiomers of said racemic mixture, said additive being a D-amino acid as an inhibitor of the growing D-amino acid when the L-amino acid is desired, or a L-amino acid when the D-amino acid is desired, and crystallizing part of the compound from said supersaturated solution. When GLU.