Experimental Solubility of Cannabidiol (CBD) in Different Organic Solvents

Inthe present work, the solubility of cannabidiol (CBD) is reportedas a function of temperature (253.1-310.1 K) in four pure solvents: n-pentane, n-hexane, n-heptane, and iso-octane. Experimental data were obtained under alocal pressure of 74 kPa by an isothermal method using an in situfilter to sample only the homogeneous liquid phase. The samples wereanalyzed by gravimetry and gas chromatography coupled with a flameionization detector (GC-FID). A thermal analysis of the CBD by wayof differential scanning calorimetry (DSC) was also carried out inorder to determine its melting point and enthalpy of fusion. The solid-liquidequilibrium was theoretically studied using the Wilson equation, thenonrandom two-liquid (NRTL), and the UNIQUAC activity coefficientmodels in order to obtain a predictive model for CBD solubility. Itwas found that the melting point and the enthalpy of fusion for CBDwere 341.4 & PLUSMN; 0.4 K and 21 & PLUSMN; 3 kJ mol(-1), respectively. The mole fraction solubility of CBD was 2.44 x10(-3) at 253.1 K and 2.15 x 10(-1) at 301.1 K in n-pentane, 2.22 x 10(-3) at 253.1 K and 3.75 x 10(-1) at 309.1 K in n-hexane, 2.43 x 10(-3) at 254.1 Kand 3.73 x 10(-1) at 310.1 K in n-heptane, and 1.36 x 10(-3) at 253.1 K and 2.61x 10(-1) at 309.6 K in iso-octane. Finally, theWilson model was found to be the model that best reproduces the experimentaldata.