Extraction of squalene from camellia oil by silver ion complexation

Separation of squalene, a type of terpenoid hydrocarbons with important biological properties, from camellia oil by silver ion complexation was studied. We showed that the UV-visible absorption wavelength of squalene in AgNO₃-methanol solution was obviously red-shifted, and the infra-red vibration wavelength of C=C bond slightly decreased, indicating that complexation between squalene and Ag⁺ took place. The distributions of squalene in AgNO₃ methanol solution/petroleum ether under different conditions were further investigated. We found that the fraction of squalene in AgNO₃-methanol phase was enhanced with increased percentage of methanol and AgNO₃ concentration and decreased extraction temperature. The distribution coefficient of squalene was up to 7.87 under optimum extraction conditions with 70% methanol (v/v), 0.6 mol/L AgNO₃, reaction time of 12 h, and at the temperature of 0 °C. Furthermore, under the optimum conditions, extraction of squalene from the unsaponifiable portion of camellia oil exhibited high selectivity with a raffinate rate and a back-extraction rate of 73.9% and 72.5%, respectively. The purity of extracted squalene was 37.8%, 108 times more concentrated than that in the starting material.