Development of a solvent screening methodology for cannabinoid recovery from a wax by-product via recrystallization

Wax by-products from commercial Cannabis processing, containing between 41 and 46% (w/w) cannabinoids, are currently underutilized due to lack of research done, and significant value can be added through recovery of the cannabinoids. The cannabinoids are aimed to be recovered via a novel solvent-assisted recrystallization technology, and this study provides a robust solvent screening methodology for recovery of the cannabinoids for this technology. Solvents were screened based on their relative polarity, boiling point temperature, and safety of use. Further criteria such as reactivity toward wax compounds were implemented through evaluation of the Kamlet-Taft parameters of potential solvents. Solubility predictions of the wax in different solvents were done using the Hansen solubility parameters (HSP). The methodology was tested on a set of 73 commonly used solvents identifying five suitable solvents, which were 1,2-dimethoxyethane, 3-pentanone, ethyl acetate, methyl acetate, and methyl tert-butyl ether. The identified solvents were tested for use in recrystallization and were found to be suitable, validating the use of the developed methodology. Graphical Abstract