Method for separating n-butyric acid from aqueous solution by using eucalyptol and application thereof

Abstract

The application discloses a method for separating n-butyric acid in an aqueous solution by using eucalyptol and application thereof. According to the technical scheme, the eucalyptol is used as an extractant to extract the n-butyric acid in the aqueous solution, the n-butyric acid can be separated and extracted under relatively mild conditions, the separation efficiency is improved while the purity of the n-butyric acid is maintained, and the energy loss of the separation operation is reduced. The treated water body is high in safety, the residual amount of the eucalyptol and the n-butyric acid in the water is extremely low, and the wastewater can be discharged and recycled in a standard way.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for separating n-butyric acid in aqueous solution and its application, in particular to a method for separating n-butyric acid in aqueous solution by using eucalyptol and its application. BACKGROUND

[0002] Eucalyptol, also known as 1,8-eucalyptol, eucalyptol, is a colorless oily liquid, with strong and fragrant smell and pungent taste. Eucalyptol belongs to a kind of essential oil with camphor smell, and has the effects of antibacterial, anti-inflammatory and antioxidant. The boiling point of eucalyptol is 176℃, the melting point is 1-1.5℃, the relative density is 0.921-0.927g / mL, the freezing point is 1℃, the flash point is 47-48℃, and it is soluble in ethanol, diethyl ether, chloroform, glacial acetic acid, glycerol and most non-volatile oils, and slightly soluble in water. Eucalyptol is usually obtained by water vapor distillation from eucalyptus leaves, which is a major by-product of eucalyptus forestry, and has the characteristics of green environmental protection and renewable, which conforms to the current sustainable development industrial production strategy. At present, there is no research and industrial application of eucalyptol in n-butyric acid extraction.

[0003] N-butyric acid is an organic compound, which belongs to lower monobasic carboxylic acid, also known as butyric acid, and is also called killing chrysanthemum acid in the industry. It is a colorless transparent liquid with special smell. It is soluble in water, alcohol, ether, benzene, chloroform and most organic solvents. N-butyric acid is an important chemical product and raw material. It is mainly used for edible flavorings, such as butter, cheese and fruit essence, and can also be used as a decalcifying agent and the synthesis of butyric acid ester compounds.

[0004] N-butyric acid can be mixed with water, ethanol, diethyl ether and chloroform. It can be miscible with water in any proportion, and can form a minimum boiling point binary azeotropic mixture (azeotropic temperature 94.4℃, composition 81.5%w water-18.5%w n-butyric acid) at normal pressure. Therefore, simple distillation or fractional distillation cannot achieve separation, and it is difficult to effectively separate n-butyric acid in aqueous solution in the prior art. SUMMARY

[0005] Therefore, the present application discloses a method for effectively separating n-butyric acid from aqueous solution.

[0006] The present application also discloses the application of the above method.

[0007] The purpose of the present application is achieved by the following technical solutions:

[0008] A method for separating n-butyric acid in aqueous solution by using eucalyptol, comprising the following steps in sequence:

[0009] S1. Adding eucalyptol to the aqueous solution containing n-butyric acid to configure a mixture; stirring the mixture and then standing, and obtaining the upper layer of the extraction phase and the lower layer of the raffinate phase after the mixture is layered;

[0010] S2. separating the extraction phase from the raffinate phase and collecting the extraction phase;

[0011] S3. separating eucalyptol from the extraction phase to obtain n-butyric acid.

[0012] Further, the n-butyric acid aqueous solution separation method described above, the butyric acid is n-butyric acid.

[0013] Further, the volume ratio of eucalyptol to n-butyric acid-containing aqueous solution is 1:1.

[0014] Further, the method for separating n-butyric acid from aqueous solution using eucalyptol described above, characterized in that: it further comprises pretreatment: filtering to remove other impurities in the n-butyric acid aqueous solution, and collecting the n-butyric acid-containing aqueous solution.

[0015] After many experiments, the volume ratio of eucalyptol to n-butyric acid-containing aqueous solution is 1:1, the extraction rate of n-butyric acid in the n-butyric acid-containing aqueous solution by eucalyptol reaches the highest, and further increasing the amount of eucalyptol cannot further increase the extraction rate, but will increase the production cost.

[0016] Further, the method for separating n-butyric acid from aqueous solution using eucalyptol described above, characterized in that: the stirring of the mixture in step S1 is to stir the mixture at room temperature at a speed of 350 rpm for 1 hour.

[0017] The inventors found in the research that the extraction effect of the mixture eucalyptol on n-butyric acid is relatively stable and has weak dependence on temperature, and this method can achieve good results at room temperature, but this method is not limited to room temperature. This method can achieve good results when stirring at a speed of 350 rpm for 1 hour, and increasing the speed and prolonging the time cannot significantly improve the extraction rate, but may cause emulsification of the mixture.

[0018] Further, the method for separating n-butyric acid from aqueous solution using eucalyptol described above, the standing in step S1 refers to standing the mixture at the same temperature as the stirring temperature for more than 1 hour.

[0019] The application also provides an application of the method for separating n-butyric acid from aqueous solution using eucalyptol as described above in sewage treatment, n-butyric acid production, and n-butyric acid recovery.

[0020] Compared with the prior art, the application has the following advantages and beneficial effects:

[0021] (1) Eucalyptus oil is non-toxic and non-corrosive, belongs to renewable resources, and is an environmentally friendly solvent.

[0022] (2) China has abundant eucalyptol raw material-eucalyptus oil, which is mainly from the by-product eucalyptus leaves of agriculture and forestry. In the past, it was directly burned. The present application is beneficial to the recycling of eucalyptus leaves and turning waste into treasure. The selection of eucalyptol as the extractant is innovative and in line with green environmental protection research;

[0023] (3) The solubility of eucalyptol in water is very low, lower than that of general extractants. The solubility in water at 20°C is 0.3%, and at 40°C is only 0.2%. The loss of solvent is minimal in the extraction process.

[0024] (4) Eucalyptol has excellent extraction effect. The treatment method of the present application can very effectively reduce the content of n-butyric acid in the n-butyric acid aqueous solution. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is the gas chromatogram of the n-butyric acid aqueous solution with a concentration of 50000 ppm before extraction by eucalyptol;

[0026] Figure 2 is the gas chromatogram of the n-butyric acid aqueous solution with a concentration of 50000 ppm after extraction by eucalyptol

[0027] Figure 3 is the gas chromatogram of the n-butyric acid aqueous solution with a concentration of 10000 ppm before extraction by eucalyptol;

[0028] Figure 4 is the gas chromatogram of the n-butyric acid aqueous solution with a concentration of 10000 ppm after extraction by eucalyptol

[0029] Figure 5 is the gas chromatogram of the n-butyric acid aqueous solution with a concentration of 2000 ppm before extraction by eucalyptol;

[0030] Figure 6 is the gas chromatogram of the n-butyric acid aqueous solution with a concentration of 2000 ppm after extraction by eucalyptol DETAILED DESCRIPTION

[0031] The claims of the present application will be further described in detail below in conjunction with specific embodiments, but do not constitute any limitation on the present application. Any limited modifications made by anyone within the scope of the claims of the present application are still within the scope of the claims of the present application.

[0032] Example 1

[0033] 5.00 g of n-butyric acid was weighed using an analytical balance and added to a 100 ml volumetric flask and diluted to 100 ml with deionized water. Shake to mix the solution uniformly. Calibrate as the standard concentration. At the same time, the content of n-butyric acid in the solution was calibrated by gas chromatography to be 50000 ppm.

[0034] The 50 ml of the above water solution containing n-butyric acid with a concentration of 50,000 ppm was placed in an equilibrium kettle, and eucalyptol and the water solution containing n-butyric acid were added into the equilibrium kettle at a volume ratio of 1:1. Under the condition of 25°C, the stirring speed of the magnetic stirrer was 350 rpm, and the solution was stirred for 1 hour and then was left to stand in a thermostat with a temperature of 25°C for more than 1 hour. After standing, the solution was divided into two phases, and the lower phase was separated. The content of n-butyric acid in the lower phase was determined by gas chromatography, and the single-stage extraction rate of n-butyric acid in this process was 84%.

[0035] Example 2

[0036] The 20 ml of the water solution containing n-butyric acid with a concentration of 50,000 ppm in Example 1 was placed in a 100 ml volumetric flask, and was diluted to 100 ml with deionized water, and was shaken to mix the solution uniformly. The solution was calibrated as a standard solution, and the content of n-butyric acid in the solution was determined by gas chromatography, and the content of n-butyric acid was 10,000 ppm.

[0037] The 50 ml of the above water solution containing n-butyric acid with a concentration of 10,000 ppm was placed in an equilibrium kettle, and eucalyptol and the water solution containing n-butyric acid were added into the equilibrium kettle at a volume ratio of 1:1. Under the condition of 25°C, the stirring speed of the magnetic stirrer was 350 rpm, and the solution was stirred for 1 hour and then was left to stand in a thermostat with a temperature of 25°C for more than 1 hour. After standing, the solution was divided into two phases, and the lower phase was separated. The content of n-butyric acid in the lower phase was determined by gas chromatography, and the single-stage extraction rate of n-butyric acid in this process was 86%.

[0038] Example 3

[0039] The 20 ml of the water solution containing n-butyric acid with a concentration of 10,000 ppm in Example 2 was placed in a 100 ml volumetric flask, and was diluted to 100 ml with deionized water, and was shaken to mix the solution uniformly. The solution was calibrated as a standard solution, and the content of n-butyric acid in the solution was determined by gas chromatography, and the content of n-butyric acid was 2,000 ppm.

[0040] The 50 ml of the above water solution containing n-butyric acid with a concentration of 2,000 ppm was placed in an equilibrium kettle, and eucalyptol and the water solution containing n-butyric acid were added into the equilibrium kettle at a volume ratio of 1:1. Under the condition of 25°C, the stirring speed of the magnetic stirrer was 350 rpm, and the solution was stirred for 1 hour and then was left to stand in a thermostat with a temperature of 25°C for more than 1 hour. After standing, the solution was divided into two phases, and the lower phase was separated. The content of n-butyric acid in the lower phase was determined by gas chromatography, and the single-stage extraction rate of n-butyric acid in this process was 87%.

[0041] The specific chromatogram is shown in Figure 1 is the gas chromatogram of the water solution containing n-butyric acid with a concentration of 50,000 ppm before extraction; 1.60 min is the water peak, and 2.19 min is the n-butyric acid peak; Figure 2is the gas chromatogram of the raffinate phase after extraction of the n-butyric acid aqueous solution with a concentration of 50000 ppm; 1.59 min is the water peak, 2.18 min is n-butyric acid, and 3.63 min is eucalyptol. Figure 3 is the gas chromatogram before extraction of the n-butyric acid aqueous solution with a concentration of 10000 ppm; 1.57 min is the water peak, and 2.17 min is n-butyric acid; Figure 4 is the gas chromatogram of the raffinate phase after extraction of the n-butyric acid aqueous solution with a concentration of 10000 ppm; 1.58 min is the water peak, 2.18 min is n-butyric acid, and 3.62 min is eucalyptol; Figure 5 is the gas chromatogram before extraction of the n-butyric acid aqueous solution with a concentration of 2000 ppm; 1.57 min is the water peak, and 2.17 min is n-butyric acid; Figure 6 is the gas chromatogram of the raffinate phase after extraction of the n-butyric acid aqueous solution with a concentration of 2000 ppm; 1.57 min is the water peak, 2.23 min is n-butyric acid, and 3.61 min is eucalyptol.

[0042] As can be seen from the above examples, the technical scheme provided by the present application extracts n-butyric acid in the aqueous solution by taking eucalyptol as an extractant, can separate and extract n-butyric acid under relatively mild conditions, improves the separation efficiency while maintaining the purity of n-butyric acid, and is conducive to reducing the energy consumption of separation operation; eucalyptus oil is derived from eucalyptus leaves and is obtained by water vapor distillation, and belongs to renewable resource materials, is often used for pharmaceutical and industrial solvents, and is a biodegradable environmentally friendly solvent. The treated water has high safety, and the residual amount of eucalyptol and n-butyric acid in the water is extremely low, which ensures that the wastewater meets the discharge standard and is recycled.

[0043] The above is one of the specific implementation manners of the present application, which is described in detail and specifically, but it cannot be understood as a limitation on the scope of the present application.

Claims

1. A method for separating n-butyric acid from an aqueous solution using eucalyptol, characterized by, Comprising the following steps in sequence: S1. Adding eucalyptol to an aqueous solution containing n-butyric acid to configure a mixture; stirring the mixture and then standing until the mixture is layered to obtain an upper extraction phase and a lower raffinate phase; S2. Separating the extraction phase from the raffinate phase and collecting the extraction phase; S3. Separating eucalyptol from the extraction phase to obtain n-butyric acid; The volume ratio of eucalyptol to the aqueous solution containing n-butyric acid in step S1 is 1:1; The stirring of the mixture in step S1 is stirring the mixture at room temperature at a rotation speed of 350 rpm for 1 hour.

2. The method for separating n-butyric acid from aqueous solution by using eucalyptol according to claim 1, characterized in that: Further comprising a pretreatment: filtering to remove other impurities in the aqueous solution containing n-butyric acid and collecting the aqueous solution containing n-butyric acid.

3. The method for separating n-butyric acid from aqueous solution by using eucalyptol according to claim 1, characterized in that: The standing in step S1 refers to standing the mixture at the same temperature as the stirring temperature for more than 1 hour.

4. Use of the method for separating n-butyric acid from an aqueous solution with eucalyptol according to any one of claims 1-3 in wastewater treatment, n-butyric acid production, and n-butyric acid recovery.

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