Abstract: Tartaric acid and its derivatives are commonly adopted as chiral resolving agents for the separation of racemic compounds. However, existing separation experiments tend to be complex with the not easily observed phenomena. This study presents an improved experiment in which aniline is reacted with racemic tartaric acid to form ammonium salts. By optimizing reaction conditions, including separation reagents, crystallization solvents, and temperature, visible L-type and D-type tartaric acid aniline ammonium salt crystals are obtained. These crystals are then subjected to alkaline hydrolysis and the following acidification to yield D-(−)-tartaric acid and L-(+)-tartaric acid. The separated crystals are further characterized and confirmed via various techniques, such as circular dichroism (CD), polarimetry, and nuclear magnetic resonance (NMR) spectroscopy. This improved experiment emphasizes the macroscopic manifestation of the microscopic chiral nature, making it easier for students to understand and grasp the concept of chirality (molecular structure).

Key words: Racemic tartaric acid, Aniline, Ammonium tartate, Crystallization, Chiral resolution