Refining Cannabidiol Crystallization: Exploring Influential Factors and Quality Control for High-Purity Crystal Production

This study aimed to standardize process conditions to enhance the quality and yield in the production of cannabidiol (CBD) crystals. Experiments varied the solvent:CBD distillate ratio, crystallization temperature, and stirring speed in a cooling crystallization system using n-heptane. Results highlighted the significant influence of crystallization temperature, indicating that a temperature of −10 °C increased yield by 10% and purity by 6% compared to 10 °C. Higher solvent:distillate ratios led to lower yields due to the increased mother liquor with significant CBD content. Stirring speed had no significant effect on the yield or purity. Washing with n-heptane and drying increased purity by 4.16% and 0.063%, respectively. The most advantageous conditions (0.5:1 ratio, −10 °C, 200 rpm) resulted in CBD crystals with a purity of 99.997%, a 71.98% yield, uniform morphology (68.27 μm), monoclinic crystal system, and white color. X-ray diffraction confirmed structural consistency, making them suitable for pharmaceutical applications. Standardizing conditions, including washing and drying procedures, is imperative for obtaining high-quality CBD crystals and ensuring adequate yield. This work enhances understanding of CBD crystal production variables and informs process improvements in the medicinal cannabis industry.