Micro-extraction experiment of star anise anethole*

Zhang Zuzhi

(School of Chemistry and Chemical Engineering, Guangxi Normal University, Guilin, Guangxi 541004)

Abstract: This article uses micro-method to compare the effects of two solvents, 95% ethanol and acetone, on the extraction rate of star anise oil.

Keywords: star anise; star anise anethole; microchemical experiment

Microscale chemical laboratory (M.L for short) is a chemical experiment that has developed rapidly in the past two decades. Technology is an integral part of green chemistry. Practice has proven that micro-chemical experiments can not only save instruments and medicines, but are also safe to operate and easy to carry. They can also stimulate students' interest in learning, cultivate students' environmental awareness, and strengthen students' hands-on ability. It helps to comprehensively improve the quality of students. Therefore, microchemical experiments have received increasing attention from chemists. How to make microscale experiments play a greater role in this field is an urgent topic to be studied.

Illicium verum HooK.F. is an evergreen tree and a specialty aromatic plant in my country. It is mainly distributed in Guangxi, Guangdong, Guizhou, Yunnan and other provinces. Guangxi is my country's main star anise production area, accounting for 85% of the country's output and 70% of the world's. The star anise tree has become one of the important local economic tree species. Star anise and star anise oil are excellent food seasonings that people like to use. Star anise oil has the spicy aroma of anise. In addition to being used as a seasoning, star anise oil is widely used in the food industry, brewing industry, beverage industry, daily cosmetics and pharmaceutical industry. Currently, star anise oil is produced at home and abroad using steam distillation, traditional organic solvent extraction, supercritical CO2 fluid extraction and other processes. Depending on the process, the output and quality of star anise oil are different. This article uses the micro-method to compare the effects of two solvents, 95% ethanol and acetone, on the extraction rate of star anise oil.

1 Experimental part

1.1 Instruments and drugs

A set of micro chemical experimental instruments (developed by Yunnan University) and JD300-3 multifunctional electronic balance.

Star anise (purchased in Guilin City), 95% ethanol (C.P.), acetone (C.P.), petroleum ether (A.R.).

1.2 Experimental Principle

The main component of star anise is anethole, which accounts for about 80%-90%, as well as aniseyl ketone and anisaldehyde. , methylphenidate, dipentene, etc.[1]. Among them, the molecular formula of star anisehole is C10H12O, the molecular weight is 148.20, and its structural formula is:

Star anise oil has a clear and spicy aroma and a sweet taste. Anethole is a colorless to light yellow liquid. It solidifies at low temperature and becomes a white crystal. It is liquid at room temperature and has a special aroma. It can be dissolved in 2-3 times of 95% ethanol and acetone, and is almost insoluble in water.

1.3 Experimental steps

1.3.1 Method 1 [2]:

Use an electronic balance to weigh 2.0000 grams of star anise powder and wrap it in a cylindrical shape with filter paper , put it into the Soxhlet extractor, add 20 ml of 95% ethanol into the flask, heat it in a water bath and reflux it for extraction. The extract liquid when refluxed into the Soxhlet extractor has almost no color, stop heating, cool it naturally, and use the pouring method to remove the contents in the flask. Transfer the extract to a beaker, wash the flask 2 to 3 times with a small amount of ethanol, combine the extracts and concentrate. When more dark green substances appear on the concentrated liquid surface, add an equal amount of distilled water and filter while it is hot. Continue to concentrate the filtrate. When dark green material appears on the surface, add an equal amount of distilled water and filter while it is hot. Repeat this operation until no dark green material appears (the purpose is to remove the chlorophyll in the concentrated liquid), and then evaporate it to dryness in a water bath to obtain a yellow-brown color. The paste - star anise oil, yield 0.1472 grams, extraction rate 7.36%.

1.3.2. Method 2:

Use an electronic balance to weigh 2.0000 grams of crushed star anise powder, wrap it in a cylindrical shape with filter paper, and put it into a Soxhlet extractor. Add 20 ml of acetone to the flask, heat and reflux in the water bath for extraction, and reflux to the Soxhlet extractor. The extract will have almost no color. Stop heating. Use the pouring method to transfer the extract in the flask to the beaker. Wash the flask with a small amount of acetone for 2 ~ 3 times, combine the extracts and concentrate. When more dark green substances appear on the concentrated liquid surface, add an equal amount of distilled water and filter while it is hot. Continue to concentrate the filtrate. When there are dark green substances on the liquid surface, add an equal amount of distilled water. Hot filter, repeat this operation until no dark green matter appears (the purpose is to remove the chlorophyll in the concentrated solution), and then evaporate it to dryness in a water bath to obtain a yellow-brown paste - star anise oil, yield 0.1142 grams. The extraction rate is 5.62%.

2 Experimental results and discussion:

2.1 Compare the effects of 95% ethanol and acetone on the extraction rate of star anise oil:

This article adopts 95% ethanol and acetone Experiments were conducted using two different solvents to determine their effects on the extraction rate of star anise oil. The results are shown in Table 1.

As can be seen from Table 1, the dosage of 95% ethanol and acetone reagents are both 20ml, 95% ethanol is siphoned 8-15 times, and the time is 80-100min. The obtained star anise oil extraction rate is higher than that of acetone siphoning. 10-15 times and a time of 100-120 minutes will result in a higher extraction rate of star anise oil. Therefore, reflux extraction of star anise oil with 95% ethanol is more effective.

2.2 Physical and chemical properties of star anise oil

Star anise oil: a yellow-brown paste, insoluble in water, and mixed with ether, chloroform, benzene, ethyl acetate, acetone, Carbon disulfide and petroleum ether are miscible.

2.3 Experimental Characteristics

Compared with conventional experiments, the use of micro-experimental reagents uses less reagents, effectively saving experimental funds. It has greatly improved the efficiency of running schools. At the same time, it has put forward higher requirements for students to conduct standardized operations, which is conducive to cultivating students to develop a rigorous scientific attitude.

3. Conclusion:

This experiment used the micro-method to compare the effects of two solvents, 95% ethanol and acetone, on the extraction rate of star anise oil. The results showed that: using 95% ethanol and acetone % ethanol reflux extraction of star anise oil has better effect.