Published: October 20, 2020
Abstract: Cannabinoids like Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabigerol (CBG) are considered the main active components in Cannabis sativa L. and are obtained through the decarboxylation of their acid analogues (THCA, CBDA, and CBGA), which are the forms naturally present in the plant. The kinetics of this reaction were studied for hemp plant material in an oven at different temperatures (80–160 °C) and reaction times (5–120 min). The effect of oxygen and the amount of plant material on the reaction rate was also studied. The reactions follow first-order kinetics, with THCA showing the fastest decarboxylation rate. In all cases, a significant loss of neutral cannabinoids was observed at elevated temperatures and reaction times, although this can be minimized in the absence of oxygen. Two different kinetic models were used to fit the experimental data and to predict the optimum decarboxylation conditions to maximize THC or CBD concentration.