Natural Borneol Recycling from Cinnamomum camphor chvar. Borneol Oil Residue by Fractional Distillation and Recrystallization

Purpose: To establish an efficient method to recycle natural borneol from Cinnamomum camphor chvar. Borneol oil residue. Methods: The fractions and raffinate of the oil residue of Cinnamomum camphor chvar. Borneol were obtained by fractional distillation, and analyzed by gas chromatography with flame ionization detector (GC-FID) and gas chromatographymass spectrometry (GC-MS). Natural borneol was purified by recrystallization and suction filtration. Fractional distillation and recrystallization parameters, including reflux ratio, solvent and solvent amount, were optimized. The physicochemical properties of natural borneol were determined by melting point and optical rotation techniques. Results: The total yield of natural borneol was 7.6 % under the optimal conditions, viz, reflux ratios of 3:1 and 1:1, with n-hexane as recrystallizing solvent. The purity of recrystallized natural borneol was > 99 % at the solvent ratio of 1:1.8 (natural borneol crystal : n-hexane). The optical rotation ([α]D = + 37°) and melting point (207 °C) of natural borneol were in accord with those of the standard. Conclusion: These findings indicate that the developed fractional distillation and recrystallization method can be applied to recycle natural borneol from C. camphor chvar. Borneol oil residue.