Method for purifying trans-anethole

Abstract

The invention discloses a method for purifying trans-anethole. In the method, star anise oil is purified mainly by two steps of coupling freezing crystallization and molecular distillation so as to obtain the trans-anethole. The method comprises the following steps of: freezing the star anise oil at a low temperature, crushing the frozen product, performing separation of a crystal and residue liquid on the crushed frozen product by filtration, high-speed centrifugation or pressure filtration, melting the crystal, and performing molecular distillation on the liquid obtained by melting to obtain high-purity anethole. The method has the advantages of no need of solvent, mild operating conditions, low cost, low energy consumption, high purity, simple process and the like.

Description

technical field [0001] The invention relates to a method for purifying trans-anethole. Background technique [0002] Fennel oil, namely star anise oil, is an advantageous characteristic resource in southern my country, accounting for more than 90% of world trade. Its main component is trans-anethole, with a content of 83%-90%. Anethole is widely used in food, medicine, daily necessities, veterinary drugs, feed, pesticides and other fields; it can also be used to produce anisaldehyde, anisonitrile, anisyl alcohol, raspberry ketone, ethestrol and other products. [0003] With the development of refined products of fennel oil, especially in the fields of high-end spices, daily necessities, and pharmaceuticals, the demand for high-purity natural anethole is also increasing, and the market prospect is very broad. However, the composition of fennel oil extracted from natural plants is complex. In addition to containing a large amount of trans-anethole, other components with highe...

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Problems solved by technology

[0005] 1. Solvent freezing and crystallization method (Wang Haiying et al., Natural Product Research and Development, 2000, 12(4): 105-108), this method is to utilize each component in fennel oil in an organic solvent (such as methanol, ethanol) at low temperature and acetone, etc.) for separation, but repeated freezing and crystallization treatment is required to consume a large amount of organic solvents and energy consumption, and the product has problems such as solvent residues that affect its quality

[0006] 2. Molecular distillation (Wang Qin et al., Forest Products Chemistry and Industry, 2007, 27 (3): 77-80), the operating conditions of this method are relatively mild, and can protect the unique biological activity of anethole to the greatest extent, but due to There are many components with the same or similar molecular weight and volatility as anethole in fennel oil. It is difficult to obtain high-purity anethole by this method, and the purity is generally only 90%.

[0007] 3. Combination of freeze crystallization and rectification (Lu Shunzhong et al., Food and Fermentation Industry, 2009, 35(8): 183-186). This method uses freeze crystallization pretreatment to remove some light components in the fennel oil, and then Rectification can obtain high-purity anethole, but the solvent consumption is large, the process is long, the energy consumption is high, the cost is high, and the rectification temperature is above 120°C, which is not conducive to protecting the unique biological activity of natural anethole. In addition, Excessive temperatures can also cause oxidation or polymerization of anethole

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