WO2016143988A1

WO2016143988A1 - Method for simultaneously producing biodiesel, biodiesel additive, and alkyl formate from microalgae

Info

Publication number: WO2016143988A1
Application number: PCT/KR2015/013657
Authority: WO
Inventors: 이재우; 임한진
Original assignee: 한국과학기술원
Priority date: 2015-03-11
Filing date: 2015-12-14
Publication date: 2016-09-15
Also published as: KR20160109453A; KR101778257B1

Abstract

The present invention relates to a method for simultaneously producing, from microalgae, a biodiesel, and at least one compound selected from the group consisting of an alkyl levulinate, an alkyl formate, and a dialkyl ether. According to the present invention, the alkyl levulinate, the alkyl formate, and the dialkyl ether, which are high value added compounds, can be produced using the cellulose portion of the microalgae which was wasted during the production of biodiesel using microalgae in the past.

Description

Simultaneous preparation of biodiesel, biodiesel additives and alkylformates from microalgae

The present invention relates to a method for simultaneously preparing biodiesel and at least one compound selected from the group consisting of alkyl levulinate, alkyl formate and dialkyl ether in microalgae. .

The energy currently being used is mainly produced from fossil fuels, and the world has sought alternative energy for it since it has been found to have a negative impact on global climate. One of its candidates, bioenergy, has been spotlighted as an alternative to fossil fuels because of its recyclability and eco-friendliness (J.Y. Lee et al., Bioresource Technol., 101: S75-S77, 2010).

Among these bioenergy, biodiesel can be prepared using methanol and fats and fats of plants and animals. Biodiesel production from microalgae requires extraction of lipids from microalgae harvested from microalgae broth (L. Brennan and P. Owende, Renew. Sust.Energy Rev., 14: 557-577, 2010). ). After extraction of lipids, the addition of lipids and methanol results in the transesterification of triglycerides and methanol contained in lipids to form fatty acid methyl esters, which are biodiesel (Y. Chisti, Biotechnol. Adv., 3). : 294-306, 2007). If the extraction process is carried out without drying the microalgae in the biodiesel production process, the lipid extraction efficiency is remarkably decreased due to the moisture remaining in the microalgae. There is also. However, the drying process is energy intensive and has a huge impact on the cost of producing biodiesel (L. Xu et al., Bioresource Technol., 102, 5113-5122, 2011). As an alternative, additional solvent addition, heating with microwave (J. Cheng et al., Bioresource Technol., 131: 531-535, 2013), supercritical methanol (S. Lim and K. Lee, Bioresource Tehchnol., 142: 121-130, 2013) or water (YA Tsigie et al., Chem. Eng. Journal, 213: 104-108, 2012) and other high temperature and high pressure (Z. Shuping et al., Energy , 35: 5406-5411, 2010) have been actively conducted to carry out lipid extraction and biodiesel conversion processes.

On the other hand, when the microalgae itself is treated under an acid catalyst, the cellulose portion of the cell is hydrolyzed to generate levulinic acid and formic acid from Hydroxymethylfurfural (HMF) (Weingarten et al., Energy Environment). Science, 5: 7559-7574, 2012). The esterification reaction of alcohol, which is used in biodiesel production, with levulinic acid and formic acid produces alkyl levulinate and alkyl formate. Alkyl levulinates can be used as flavours (RH Leonard., Eng. Chem., 48: 1330-1341, 1956) and have been reported to improve the low temperature properties of fuels when mixed with biodiesel fuels (H. Joshi et al., Biomass and Bioenergy, 34: 14-20, 2010). Alkyl formate can also be used to make other compounds such as formamide and dimethylformamide.

It is also known that alcohols, when applied at high temperatures under acid catalysts, dehydrate to produce dialkyl ethers that can be used as fuel. (Xu et al., Applied Catalysis A, 149: 289-301, 1997; Semelsberger et al., Journal of Power Sources, 156: 497-511, 2006).

The levulinic acid and formic acid are formed through the glucose produced by the hydrolysis of cellulose in cells, and in the existing biodiesel production process, cellulose is not suitable for hydrolysis.

Accordingly, the present inventors have made diligent efforts to develop a method for simultaneously producing biodiesel, alkyl levulinate, alkyl formate and dialkyl ether from microalgae. The present invention has been accomplished by confirming that biodiesel can be produced from the above, and that alkyl levulinate and alkyl formate and dialkyl ether can be produced.

발명의 요약Summary of the Invention

An object of the present invention is to provide a method for simultaneously producing biodiesel, alkyl levulinate, alkyl formate and dialkyl ether from microalgae.

In order to achieve the above object, the present invention (a) by adding an alcohol, an organic solvent and an acid to the cultured microalgae, heated to 95 ~ 200 ℃, alkyl levulinate, alkyl formate (alkyl simultaneously producing biodiesel with at least one compound selected from the group consisting of formate and dialkyl ethers; And (b) provides a method for the simultaneous production of biodiesel and compounds in the microalgae comprising the step of recovering the produced compound and biodiesel.

1 shows biodiesel and ethyl levulinate yield changes with temperature change.

Figure 2 shows the biodiesel and ethyl levulinate yield change according to chloroform.

Figure 3 shows the biodiesel and ethyl levulinate yield change according to the amount of sulfuric acid.

Figure 4 shows the biodiesel and ethyl levulinate yield change depending on the amount of ethanol.

Figure 5 shows the biodiesel and ethyl levulinate yield change with water content changes.

Figure 6 shows the biodiesel and ethyl levulinate yield according to the change in the ratio of microalgae and cellulose.

발명의 상세한 설명 및 구체적인 Detailed description and specifics of the invention 구현예Embodiment

Although levulinic acid and formic acid are formed through the glucose produced by the hydrolysis of cellulose, in the existing biodiesel production process, cellulose is not suitable for hydrolysis.

The inventors of the present invention used levulinic acid and formic acid by using levulinic acid and formic acid when the alcohol and acid catalyst were added to the microalgae during biodiesel production, while cellulose, which is a cell component of the microalgae, was hydrolyzed. It was confirmed that an excess of alkyl levulinate, alkyl formate and dialkyl ether was produced.

Therefore, the present invention (a) by adding alcohol, organic solvent and acid to the cultured microalgae, and heated to 95 ~ 200 ℃, alkyl levulinate, alkyl formate and dialk Simultaneously generating biodiesel with at least one compound selected from the group consisting of dialkyl ethers; And (b) recovering the resultant compound and biodiesel, in the group consisting of alkyl levulinate, alkyl formate and dialkyl ether in microalgae. A method for the simultaneous preparation of biodiesel with one or more compounds selected.

In the present invention, the alcohol may be an alcohol selected from the group consisting of alcohols having 1 to 15 carbon atoms, preferably methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, furnace Nanol or decanol may be used, more preferably methanol, ethanol, butanol.

The biodiesel yield of the present invention and the yield of alkyl levulinate tend to increase as the number of carbon atoms of each alcohol increases, and the alkyl levulinate may be normally produced even by experimenting with other alcohol groups.

In the present invention, the water content of the microalgae used for the simultaneous production of biodiesel and the compound may be characterized in that 0 to 95%.

The biodiesel content increased with increasing temperature, and FAEE yield reached 97% when tested in dry condition.

In one embodiment of the present invention, when the wet microalgae was used, the biodiesel yield was relatively low at 61.4% at 95 ° C. In the case of ethyl levulinate yield, it was hardly produced when it was 95 degrees C or less, but it produced more and more from 110 degreeC, and the amount produced as much as 20% or more of the weight of lipid from 125 degreeC.

Therefore, it is preferable that the heating temperature of this invention is 95-200 degreeC, More preferably, it may be 110-150 degreeC. Almost no alkyl formate is produced at 95 ° C. or lower, and when heated to 200 ° C. or higher, the production of alkyl formate no longer increases, which is uneconomical.

In step (a) of the present invention, a source of cellulose with microalgae, in the group consisting of organisms having cellulose (Cellulose) or lignocellulose, sawdust, activated sludge, bacteria, plant cells and animal cells The organics selected can be further added.

The organic solvent used in the present invention may be characterized in that the organic solvent selected from the group consisting of chloroform, toluene, xylene, cyclohexane and benzene or a mixed solvent thereof.

In the present invention, chloroform is believed to promote the hydrolysis of the cellulose of the microalgal cell wall and promote the reaction of lipids are extracted and converted into biodiesel by cell wall destruction.

In one embodiment of the present invention, biodiesel yield and ethyl levulinate yield were found to increase with the addition of chloroform. In the case of ethyl levulinate and biodiesel, the amount of chloroform was increased.

The acid used as a catalyst in the present invention may be sulfuric acid, hydrochloric acid, nitric acid, acetyl chloride or amberlyst which is a solid catalyst.

In the present invention, since the acid is used as a catalyst for the transesterification reaction, the biodiesel yield increases as the amount of acid used increases.

In the present invention, the microalgae used for the biodiesel and compound co-production are Chlorella, Chlamydomonas, Nanochloropsis, Chrococcus, Chatoceros, Ancanthes, Amphora, etc. may be used, but is not limited thereto.

In one embodiment of the present invention, when using N.gaditana and Chlorella vulgaris as a microalgae, it was confirmed that both show high biodiesel and ethyl levulinate production yield.

In the present invention, 0 to 2000 parts by weight of an organic solvent, 25 to 1200 parts by weight of alcohol and 0.01 to 1000 parts by weight of an acid may be added to 100 parts by weight of the microalgae of the step (a). The organic solvent may be added 0.1 to 2000 parts by weight of organic solvent, 25 to 1200 parts by weight of alcohol and 1 to 1000 parts by weight of acid, more preferably 100 to 2000 parts by weight of organic solvent, 25 to 1200 parts by weight of alcohol and 50 to 1000 parts of acid. Parts by weight may be added.

In the present invention, the alkyl levulinate is methyl levulinate, ethyl levulinate, propyl levulinate, butyl levulinate, pentyl levulinate, hexyl levulinate, heptyl levulinate, octyl levulinate , Nonyl levulinate or tequil levulinate, wherein the alkyl formate is methyl formate, ethyl formate, propyl formate, butyl formate, pentyl formate, hexyl formate, heptyl formate, octyl formate , Diethyl ether, diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, dihexyl ether, diheptyl ether, dioctyl ether, dino It may be a neyl ether or a diedecyl ether.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. These examples are only for illustrating the present invention in more detail, and it will be apparent to those skilled in the art that the scope of the present invention is not limited only to these examples according to the gist of the present invention.

In a later embodiment of the invention Nannochloropsis as a microalgae gaditana (AlgaSpring, The Netherlands) was used, Nannochloropsis The lipid content convertible to biodiesel in gaditana cells was 12.05% each. Ethyl Revulinate Conversion Complete Nannochloropsis The gaditana cells were made to have a moisture content of 65% by mass and then proceeded. Ethanol, chloroform and sulfuric acid were added to the wet microalgae, heated to a certain temperature, and the sulfuric acid was neutralized to separate the layers. The lower layer was analyzed to calculate the amount of converted biodiesel to 12.05% total lipids. In addition, the amount of EL generated was also calculated and shown in the same way to compare against the total lipids.

Example 1: Confirmation of biodiesel and ethyl levulinate yield with temperature change

In the production of biodiesel and ethyl levulinate, in order to confirm the change in yield of biodiesel and ethyl levulinate with temperature change, ethanol 1 in 0.857 g of wet microalgae (N.gaditana) containing 65% water was used. ml, 2 ml of chloroform and 0.3 ml of sulfuric acid were added, and heated at 95 ° C., 110 ° C., 125 ° C. and 140 ° C. for 2 hours, and then the amount of ether levulinate and biodiesel was confirmed.

In addition, the ethyl reblate and the biodiesel content were determined after excluding the water content under the above conditions.

As a result, as shown in Figure 1, the amount of biodiesel increased with increasing temperature, FAEE yield reached 97% when tested in a dry state.

In the case of using wet microalgae, the biodiesel yield was relatively low as 61.4% at 95 ° C. In the case of ethyl levulinate yield, it was hardly produced at 95 ° C., but gradually increased from 110 ° C. to 125 ° C., resulting in an amount exceeding 20% or more of the weight of the lipid.

Example 2: Confirmation of biodiesel and ethyl levulinate yield with or without chloroform

In order to confirm the role of chloroform in the production of biodiesel and ethyl levulinate, other variables except the amount of chloroform in the conditions of Example 1 produced biodiesel and ethyl levulinate under the same conditions, and the temperature Was tested at 125 ° C.

As a result, as shown in Figure 2, when chloroform was not added, the biodiesel yield and ethyl levulinate yield were low as 66% and 11.3%, respectively, and when 0.5 ml of chloroform was added, the biodiesel yield was The yield of and ethyl levulinate was found to be 86.3% and 17.6%, respectively, and the biodiesel yield and ethyl levulinate yield were confirmed to increase with the addition of chloroform. Both ethyl levulinate and biodiesel tend to be produced as the amount of chloroform increases, and chloroform promotes the hydrolysis of cellulose in the cell wall and lipids are extracted and converted into biodiesel by cell wall destruction. Judging.

Example 3: Confirmation of biodiesel and ethyl levulinate yields according to the amount of sulfuric acid

In order to confirm the role of sulfuric acid in producing biodiesel and ethyl levulinate, other variables except the amount of sulfuric acid added were the same as in Example 1 to produce biodiesel and ethyl levulinate at 125 ° C. . Since sulfuric acid is used as a catalyst for transesterification, biodiesel yield can be expected to increase as the amount of sulfuric acid increases.

As a result, as shown in Fig. 3, it can be seen that the FAEE yield and the EL yield increase rapidly as the amount of sulfuric acid added increases. When a small amount of sulfuric acid was used as 0.03ml / ml ethanol, the EL yield was very low as 1.63%, which means that the hydrolysis of cellulose could not proceed if the acid strength was weak. The FAEE yield was also low at 32.1%, and the lipid walls were not properly extracted because the cell walls were not destroyed.

Example 4: Confirmation of biodiesel and ethyl levulinate yield according to the change of ethanol amount

Ethyl levulinate is a compound in which levulinic acid, which is the result of hydrolysis sequencing of cells, is produced by esterification under ethanol and an acid catalyst. Biodiesel (fatty acid ethyl ester) is also the product of lipids produced by transesterification under ethanol and acid catalyst. Therefore, increasing the amount of ethanol will change the yield of ethyl levulinate and biodiesel, so the yield of biodiesel and ethyl levulinate was confirmed while changing the amount of ethanol.

Experimental conditions except for the amount of ethanol and the amount of sulfuric acid are the same as in Example 1. In the fixed catalyst amount condition, the sulfuric acid mass was fixed and the ethanol amount was changed. In the fixed catalyst concentration condition, the ethanol amount was changed while maintaining the sulfuric acid concentration constant compared to the ethanol amount.

As a result, as shown in Figure 4, in the condition that the sulfuric acid concentration is not fixed, as the amount of ethanol increases the strength of the acid decreases, the yield of ethyl levulinate decreased and the condition of maintaining the sulfuric acid concentration As the amount increased, the yield of ethyl levulinate increased. In the case of biodiesel, the yield tended to increase as the amount of ethanol increased regardless of the concentration of sulfuric acid.

Example 5: Confirmation of biodiesel and alkyl levulinate yields using alcohols other than ethanol

When using alcohol other than ethanol, in order to confirm that the alkyl levulinate is produced, using methanol and butanol in place of ethanol under the same conditions as in Example 1, the temperature was heated to 125 ℃ for 2 hours Experiment.

As a result, the biodiesel yield was about 90% in the experiment with methanol, and methyl levulinate was produced as mass of 18.4% based on the lipid mass of 100% microalgae. In the experiment with butanol, the biodiesel yield was 114% and the butyl levulinate yield was 36%. The biodiesel yield and the yield of alkyl levulinate tend to increase as the number of carbon atoms of each alcohol increases, and it can be seen that alkyl levulinate can be produced normally even by experimenting with other alcohol groups.

Example 6: Confirmation of biodiesel and ethyl levulinate yield change with moisture content change

Ethyl levulinate is a compound produced by esterification of levulinic acid produced by hydrolysis of cells with ethanol, and its yield is determined according to the initial water content of the microalgae.

N. gaditana was used as the microalgae and the experimental conditions except for the water content were performed in the same manner as in Example 1.

As a result, as shown in Figure 5, it can be seen that the yield of ethyl levulinate and biodiesel decreases as the moisture content decreases. If the moisture content decreases, the yield of all products increases, so that more products can be obtained, but the additional energy consumed increases, and thus, the optimized conditions may be found.

Example 7: Confirmation of biodiesel and ethyl levulinate yield changes according to the use of organic solvents other than chloroform

Ethyl levulinate compounds are substances having a nonpolar character in their molecular structure. Sulfuric acid and ethanol are polar substances that are well soluble in water. When sulfuric acid and ethanol are added, an organic solvent is added, and ethyl levulinate is dissolved in the organic solvent layer. Because of the presence of very small amounts of water, ethyl levulinate, the reaction is accelerated than when no organic solvent is present. Therefore, even when other organic solvents were used, hexane and benzene were used instead of chloroform to verify whether the yield of ethyl levulinate was improved. The microalgae used in the experiment was N.gaditana and the experimental conditions were the same as in Example 1, and the experimental temperature was 125 ° C.

As a result, when hexane was used, ethyl levulinate was not found by analyzing the hexane layer. The reason is that at room temperature, the density of hexane is 0.655g / ml and ethyl levulinate is 1.02g / ml.In order for large amount of ethyl levulinate to be produced, the organic phase must dissolve ethyl levulinate. Ethyl levulinate and hexane The difference in density is due to the fact that they are not mixed with each other.

In experiments with benzene (0.877 g / ml), which was slightly denser than hexane, analysis of the benzene layer produced ethyl levulinate by mass of 17.0% based on the lipid mass of 100% microalgae. This is less than 22.3% yield when tested with chloroform, but shows that a certain amount of ethyl levulinate can be produced by experimenting with a group of organic solvents having a certain density or more.

Example 8: Confirmation of biodiesel and ethyl levulinate production yield using catalyst other than sulfuric acid

Alkyl levulinates and biodiesel are compounds that can be produced by esterification and transesterification using acid catalysts. In the previous example, sulfuric acid, which is a liquid acid, was used in the previous example, but hydrochloric acid and a solid catalyst were used to verify the effectiveness of other acid catalysts.

As a solid catalyst, amberlyst 36 (Sigma-aldirch, USA) was selected in consideration of the operating temperature range and the strength of the catalyst. For hydrochloric acid, 35% aqueous hydrochloric acid solution was used in the same mass as sulfuric acid, and the other conditions were performed in the same manner as in Example 1 and heated at 125 ° C for 2 hours.

As a result, the biodiesel yield was 84.1%, and the yield of ethyl levulinate was 18.9%. Both yields were not significantly different from those of sulfuric acid.

In the case of the solid catalyst experiment, the same amount of reactants except cell mass and sulfuric acid were made in the same manner as in Example 1, and the amount of amberlyst 36 was added at 1.1 g, which is twice the mass of sulfuric acid as in the previous experiments, at 125 ° C. Heated for 2 hours.

As a result, the biodiesel yield was 50.0% and the ethyl levulinate yield was 5.4%. The yield of biodiesel and ethyl levulinate tends to be lower when using solid acids than when using liquid acids, but considering the convenience of separating catalysts, the yield of biodiesel and This is a meaningful result in that diesel and ethyl levulinate can be simultaneously produced at a certain level.

Example 9: N. gaditana Biodiesel and ethyl levulinate production when using other species of microalgae

Chlorella for the trend of biodiesel and ethyl levulinate production when microalgae other than N. gaditana were used vulgaris (subject Well Life, Korea) was used, and other experimental conditions were the same as in Example 1, and were heated at 125 ° C. for 2 hours.

Chlorella The lipid content of vulgaris was 7.0%, the biodiesel yield was 104%, and the yield of ethyl levulinate was 59% of 100% lipid.

When C. vulgaris is used, the EL yield is higher than that of N. gaditana because C.vulgaris has a high yield of ethyl levulinate because C.vulgaris has a low lipid content but a high amount of cellulose that can be hydrolyzed in cells. It is expected.

Therefore, it was confirmed that biodiesel and ethyl levulinate can be simultaneously produced using other microalgal species as well as N. gaditana species.

Example 10: Confirmation of biodiesel and ethyl levulinate production yield when microalgae and cellulose were used simultaneously

In order to confirm that the production of biodiesel and ethyllevulinate is accelerated when additional microalgae and other organisms with cellulose are added, the following experiments were performed. In order to simplify the experiment, microalgae and cellulose were mixed and experimented, and the mass ratio of microalgae to cellulose was 0:10, 3: 7, 5: 5, 7: 3, and 10: 0, respectively, while maintaining the total mass of 0.3g. Experiment with change.

The water content of the microalgae and cellulose mixture was maintained at 65% and the amounts of chloroform, ethanol and sulfuric acid were used in 2 ml, 1 ml and 0.3 ml, respectively, as in Example 1, and were heated at 125 ° C. for 2 hours. In the case of Examples 1 to 9, only the microalgae is produced in the path of producing ethyl levulinate, and thus the yield was obtained in comparison with the lipid mass of the microalgae. However, EL may be produced even in the added cellulose. As a result, the mass of the EL was calculated and each experiment was compared. As the ratio of cellulose to microalgae increases, the biodiesel yield increases. The biodiesel yield increases because the amount of solution is fixed but the amount of microalgae decreases.

As a result, when the ratio of cellulose to microalgae is 0:10, since only cellulose is present in 0.3g, there is no FAEE yield. When the cellulose ratio to microalgae ratio is 10: 0, the EL mass is 8mg, but the EL mass increases as the graph goes to the right (as the cellulose ratio increases). It can be. Therefore, it can be said that there is no problem in co-production of biodiesel and ethyl levulinate even if animal and plant cells containing lignocellulosic, activated sludge, and organic substances are added instead of cellulose.

Example 11: Biodiesel and Alkyl Formate and Dialkyl Ether Production from Microalgae

Treatment of microalgae under an acid catalyst causes the cellulose portion of the cell to hydrolyze, producing levulinic acid and formic acid from Hydroxymethylfurfural (HMF). The resulting formic acid can be converted to alkyl formate through esterification with alcohol. In addition, since the alcohol is placed in a high temperature environment under an acid catalyst for the transesterification reaction, the alcohol is placed in an environment where the alcohol can be converted into a dialkyl ether through an alcohol dehydration reaction.

Therefore, in this example, the production of alkyl formate and dialkyl ether was confirmed.

First, 0.3 g of N. gaditana was heated to 125 ° C. for 2 hours under the same experimental conditions as in Example 1.

As a result, it was confirmed that the yield similar to that of Example 1, biodiesel yield of 2.5% and 2.5mg of ethyl formate was produced, the ethyl levulinate produced 0.034 mmol, and ethyl formate produced 0.036 mmol. This is close to 1: 1 in molar ratio, but because stoichiometrically, 1: 1 levulinic acid and formic acid are produced from HMF, so it is expected that ethyl levulinate and ethyl formate are produced 1: 1. can see. In the case of diethyl ether, 27 mg was produced, and both ethyl formate and diethyl ether were detected in the organic phase. Diethyl ether (DEE) is expected to be produced by dehydration of ethanol molecules under acid catalyst.

As described above in detail specific parts of the present invention, it will be apparent to those skilled in the art that these specific descriptions are merely preferred embodiments, and thus the scope of the present invention is not limited thereto. will be. Thus, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

According to the present invention, a high value-added compound of alkyl levulinate, alkyl formate, and dialkel, which is discarded in biodiesel production using microalgae, is a high value-added compound. It is possible to produce dialkyl ethers.

Claims

Simultaneous preparation of biodiesel with at least one compound selected from the group consisting of alkyl levulinate, alkyl formate and dialkyl ether in microalgae comprising the following steps:

(a) Alcohol, organic solvent, and acid are added to the cultured microalgae, and heated to 95-200 ° C. to give alkyl levulinate, alkyl formate and dialkyl ether. Simultaneously generating at least one compound selected from the group consisting of biodiesel; And

(b) recovering the resultant compound and biodiesel.
The method of claim 1 wherein the water content of the microalgae is from 0 to 95%.
The method of claim 1, wherein the alcohol is selected from the group consisting of alcohols having 1 to 15 carbon atoms.
The method according to claim 1, wherein in step (a), an organic substance selected from the group consisting of organisms, sawdust, activated sludge, bacteria and plant and animal cells having cellulose or lignocellulose is added. Characterized in that.
The method of claim 1, wherein the alcohol is selected from the group consisting of methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol and decanol.
The method of claim 1, wherein the organic solvent is an organic solvent selected from the group consisting of chloroform, toluene, xylene, cyclohexane and benzene, or a mixed solvent thereof.
The method of claim 1 wherein the acid is selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid, acetylchloride and amberlyst.
The method of claim 1, wherein the microalgae are Chlorella, Chlamydomonas , Nannochloropsis , Chroococcus , Chaetoceros , Achnanthes and Empo . And Amphora .
The method according to claim 1, wherein 0 to 2000 parts by weight of organic solvent, 25 to 1200 parts by weight of alcohol and 0.01 to 1000 parts by weight of acid are added to 100 parts by weight of the microalgae of step (a).
The method of claim 1, wherein the alkyl levulinate is methyl levulinate, ethyl levulinate, propyl levulinate, butyl levulinate, pentyl levulinate, hexyl levulinate, heptyl levulinate, octyl levulin Nate, nonyl levulinate and tequil levulinate.
The method of claim 1, wherein the alkyl formate is methyl formate, ethyl formate, propyl formate, butyl formate, pentyl formate, hexyl formate, heptyl formate, octyl formate, nonyl formate, and dekill formate. And selected from the group consisting of:
According to claim 1, wherein the dialkyl ether is dimethyl ether, diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, dihexyl ether, diheptyl ether, dioctyl ether, dinonyl ether, diedecyl ether Method selected from the group consisting of.