Purification of menthol by supercritical CO2 precision separation technology
The use of supercritical CO2 precision separation technology to purify menthol from mint crude oil was carried out, and the influence of operating parameters such as the temperature gradient of the rectification column and the pressure rise rate on the separation effect was investigated. The results show that the formation of a certain temperature gradient in the separation and rectification column or changing the pressure increase rate under a certain temperature gradient can effectively improve the separation effect. When the temperature gradient in the column is 20℃, the pressure increase rate is 0.1MPa·(15min) ⁻¹ When menthol is >90%, the product yield is 80%; the second separation of menthol=90% product can get menthol=99.9% product.
Keywords: supercritical CO2, menthol; menthol oil; mint crude oil;
Cheng Jian, Wang Cunwen, Ding Yigang, Bai Zhengwu, Li Shirong, Yu Faquan, Wu Yuanxin(Wuhan Institute of Chemical Technology, Hubei Province Key Laboratory of New Type Reactor and Green Chemical Process, Wuhan 430074, Hubei)
Purification of menthol with supercritical CO2 precision separation technology shows that:
The establishment of the temperature gradient in the rectifying column has an important influence on the separation and purification of menthol. Within the scope of the experimental investigation, the suitable temperature gradient is 20°C.
The pressure rise rate is also an important factor affecting the separation and purification of menthol. The appropriate pressure rise rate is 0.1 MPa.(15 min)⁻¹.
Re-separation of menthol oil after one separation can obtain menthol = 90% and a yield of 35%. Refining the crude menthol obtained in one separation can obtain menthol = 99.9% and a yield of more than 50%. Distillation