The present invention relates to a process for preparing optically pure (+)-(2S,3S)-2-(3-chlorophenyl)-3,5,5-trimethyl-2-morpholinol and pharmaceutically acceptable salts and solvates from a mixture of (+)-(2S,3S)-2-(3-chlorophenyl)-3,5,5-trimethyl-2-morpholinol and (-)-(2R,3R)-2-(3-chlorophenyl)-3,5,5-trimethyl-2-morpholinol. The process utilizes continuous chromatography, including techniques like Multi Column Chromatography (MCC), VARICOL, and Cyclojet.