Organic solvent extraction is a kind of extraction, using the principle of similar miscibility, because the distribution coefficient or solubility of different components in the solvent is different, so that the extracted components are transferred from one solvent to another solvent And separated. Dipentene was extracted by solvent extraction, the fresh peel of Ou mandarin was crushed and then concentrated under reduced pressure at 50 ℃, and petroleum ether was recovered to obtain 660 g of oily substance, which was determined by gas chromatography-mass spectrometry. The content of Dipentene in the extract is as high as 86.39%.
At present, there are three kinds of distillation methods: steam distillation, vacuum distillation and molecular distillation.
1) steam distillation method
Steam distillation is one of the common methods for purifying and separating organic compounds. The volatile and insoluble substances are soaked in water, heated and distilled together, so that the volatile components are distilled out along with the water vapor without being destroyed. , and then the distillate is condensed and separated to obtain the purified volatile components.
2) Vacuum distillation method
Vacuum distillation is an important method for separating and purifying organic compounds. Since the boiling point of liquid changes with the change of external pressure, a container containing liquid is connected with a vacuum pump. When the pressure in the vacuum pump system is reduced, the boiling point of the liquid can be adjusted accordingly. Reduced, vacuum distillation is the separation achieved by this principle. Dipentene was extracted by vacuum distillation, and the fraction at 61-66 ℃ was collected at a solid-liquid ratio of 3:10 and a vacuum of 1.2×103 Pa, which was the limonene product.
3) Molecular distillation method
Molecular distillation is a liquid-liquid separation technology. Unlike conventional distillation, it does not depend on the splitting up principle of boiling point difference. It has a high level of vacuum in the distillation process and also depends on the distinction in the mean free path of molecular movement of various materials to accomplish splitting up. When the fluid mix streams along the heating plate as well as is heated up, the liquid parts can evaporate in a short time, and also the molecules of different compounds relocate different distances after escaping from the liquid surface. So regarding accomplish the function of material separation.Using a short-path molecular still, under the conditions of distillation pressure of 40 Pa, distillation temperature of 80 °C, feed rate of 1.5 mL/min, and wiped film rotation speed of 280 r/min, a purity of 99% and an extraction rate of 86.54% were obtained. % of the product.
The supercritical extraction method is non-toxic and has low extraction temperature. It has the characteristics of gas mass transfer and liquid dissolution. The principle is that at the critical temperature and critical pressure, the density of the fluid is close to that of liquid, and the diffusion coefficient is close to that of gas. So supercritical fluid is a good separation medium. Use the supercritical fluid CO2 to extract the oil of the thorn fruit, crush the thorn fruit, sieve, the extraction temperature is 50 ℃, the extraction pressure is 30 MPa, the temperature of the separation tank is 40 ℃, and the pressure of the separation tank is 5 MPa, it is found that the extraction The extraction rate is 32.5%; at the same time, it is also found that with the increase of CO2 flow during extraction, the extraction rate will increase accordingly.
Ultrasound is used to assist in the extraction of Dipentene, which utilizes the cavitation and mechanical effects of ultrasound. When the movement speed of medium molecules and the ability to penetrate substances increase, the solvent will quickly enter the tissue cells, so that the solute and the solvent are in more contact. , and dissolve the contained organic components in the solvent as much as possible to obtain a multi-component extract. Using emperor tangerine peel as raw material, limonene was extracted by steam distillation combined with ultrasonic-assisted extraction technology. The research shows that when the ultrasonic power is 100 W and the ultrasonic time is 10 min, the dipentene volume is about 2 mL after distillation of 10 g of fresh orange peel, and the extraction rate of limonene reaches 16.8%.
