KR20190131283A - Method for producing of silica using biomass - Google Patents

Abstract

The present invention relates to a silica manufacturing method, wherein the silica manufacturing method comprises following steps of: preparing a biomass; primary heat treatment to reduce a volume and a mass of the biomass by heating the biomass; secondary heat treatment conducting a reaction of the primarily heat treated biomass with either an acidic solution, an ionic solution or a microbial fermentation broth to remove metal ions from the biomass; washing and filtering the secondarily heat treated biomass; and tertiary heat treatment of the washed biomass for final pyrolysis of carbon components and other residues from the washed biomass, thereby capable of shortening a process time as well as a process volume.

Description

Silica manufacturing method using biomass {METHOD FOR PRODUCING OF SILICA USING BIOMASS}

The present invention relates to a silica production method, and to a silica production method using a biomass to add a heat treatment step in the initial step.

Biomass, especially ligno cellulose-based biomass, is present in a large amount of silica, and in particular, rice hulls and rice straws are known to contain about 10% by weight of silica.

Such biomass-derived silicas include silicon raw materials (JAAmick, J. Electrochem. Soc. 129,864 (1982); LPHunt, J. Electrochem. Soc. 131,1683 (1984)), raw materials of silicon carbide (RVKrishnarao, J Am. Chem. Soc. 74,2869 (1991)), cement additives (Jose James, et.r, J. Sci. Ind. Res. 51, 383 (1992)).

In order to obtain silica from biomass, research on technology development to remove organic matter (cellulose, hemicellulose, lignin, etc.) of biomass has been continuously conducted.

On the other hand, plants, including chaff is about 0.1g / mL is a very dense raw material, despite a very small mass, the volume is very large, the process volume is large, and excess water is used for washing and chemical treatment.

In this case, not only the amount of water increases but also the volume of the reactor and the washing machine becomes large, and the handling volume of the plant during the washing process is large, which makes handling difficult, and the cost of the facility increases due to the increase of the related facilities. There was a problem that was not suitable for commercial grade process.

It is an object of the present invention to solve the above and other problems. Another object is to provide a method for producing silica from a plant.

According to an aspect of the present invention to achieve the above or another object, preparing a biomass (biomass); Heating the biomass to reduce the volume and mass of the biomass; A second heat treatment step of removing the metal ions from the biomass by reacting the first heat treated biomass with any one of an acidic solution, an ionic solution or a microbial fermentation broth; Washing and filtering the secondary heat-treated biomass; And a third heat treatment step for final pyrolysis of carbon components and other residues from the washed biomass.

According to one aspect of the invention, the first heat treatment step, may be made in a temperature range of 450 ~ 750 ℃.

According to an aspect of the present invention, the first heat treatment step may be performed for 1 to 6 hours.

According to one aspect of the invention, the acid solution in the second heat treatment step may be a sulfuric acid solution or hydrochloric acid solution.

According to an aspect of the present invention, the biomass may be at least one selected from rice bran, rice husk, rice straw, reeds, corn leaves and corn stalks.

According to an aspect of the present invention, when the sulfuric acid solution is used in the secondary heat treatment step, the secondary heat treatment step is performed at a temperature range of 20 to 40 ° C., and when the hydrochloric acid solution is used in the secondary heat treatment step, The secondary heat treatment step may be made in the temperature range of 80 ~ 100 ℃.

According to an aspect of the present invention, in the case of using the ionic solution in the secondary heat treatment step, the secondary heat treatment step may be made in a temperature range of 110 ~ 150 ℃.

According to an aspect of the present invention, when using the microbial fermentation broth in the secondary heat treatment step, the secondary heat treatment step may be made in a temperature range of 170 ~ 230 ℃.

According to one aspect of the invention, the third heat treatment step may be made in a temperature range of 850 ~ 1050 ℃.

According to one aspect of the invention, the ionic liquid, 1-allyl-3-methylimidazonium chloride, 1,3-dimethylimidazonium chloride, 1-butyl-3-methylimidazonium chloride, 1- Butyl-3-methylimidazonium dicyanamide, 1-butyl-3-methylimidazonium hexafluorouromonate, 1-butyl-3-methylimidazonium hexafluorophosphate, 1-butyl- 3-methylimidazonium hydrogencarbonate, 1-butyl-3-methylimidazonium hydrogensulfate, 1-butyl-3-methylimidazonium methylsulfate, 1-butyl-3-methylimidazonium tetrachloroalumi Nate, 1-butyl-3-methylimidazonium tetrachloroborate, 1-butyl-3-methylimidazonium thiocyanate, 1-dodecyl-3-methylimidazonium iodide, 1-ethyl-2 , 3-dimethylimidazonium chloride, 1-ethyl-3-methylimidazonium bromide, 1-ethyl-3-methylimidazonium chloride, 1-ethyl-3- From thilimidazonium hexafluorophosphate, 1-ethyl-3-methylimidazonium tetrafluoroborate, 1-hexyl-3-methylimidazonium tetrafluoroborate and 1-butyl-4-methylpyridium chloride It may include any one selected.

Referring to the effects of the silica production method according to the present invention.

According to at least one of the embodiments of the present invention, it is possible to reduce the volume of the initial raw material by undergoing a pyrolysis process at the beginning of the process.

In addition, according to at least one of the embodiments of the present invention, by decomposing organic matter through pyrolysis at the beginning of the process, the washing process is unnecessary and the final pyrolysis time can be reduced, thereby reducing the process volume as well as process time. have.

In addition, according to at least one of the embodiments of the present invention, there is an advantage that the washing process performed in lukewarm water by decomposing organic matter through pyrolysis at the beginning of the process can be omitted.

Further scope of the applicability of the present invention will become apparent from the following detailed description. However, various changes and modifications within the spirit and scope of the present invention can be clearly understood by those skilled in the art, and therefore, specific embodiments, such as the detailed description and the preferred embodiments of the present invention, should be understood to be given by way of example only.

1 is a flow chart of a silica manufacturing method related to the present invention.
2 is a thermogravimetric analysis graph according to the temperature related to the present invention.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, and the same or similar components will be given the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. The suffix "part" for components used in the following description is given or mixed in consideration of ease of specification, and does not have meanings or roles that are distinguished from each other. In addition, in describing the embodiments disclosed herein, when it is determined that the detailed description of the related known technology may obscure the gist of the embodiments disclosed herein, the detailed description thereof will be omitted. In addition, the accompanying drawings are only for easily understanding the embodiments disclosed herein, the technical spirit disclosed in the specification by the accompanying drawings are not limited, and all changes included in the spirit and scope of the present invention. It should be understood to include equivalents and substitutes.

Terms including ordinal numbers such as first and second may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

Singular expressions include plural expressions unless the context clearly indicates otherwise.

In this application, the terms "comprises" or "having" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

One embodiment of the present invention relates to a method for producing silica from a biomass (biomass), a method for reducing the overall process time by reducing the volume of the biomass at the beginning of the process for the convenience of the mid-to-late process is disclosed. .

1 is a flow chart of a silica manufacturing method according to an embodiment of the present invention, will be described below with reference to FIG.

First, at least one of biomass (biomass), which is a starting material of silica, for example chaff, rice bran, rice straw, reeds, corn leaves and stems is prepared (S110). By heating the prepared biomass in the temperature range of 450 ~ 750 ℃ (S120) to reduce the volume of the biomass. In an embodiment of the present invention, the organic material is removed from the biomass by thermally decomposing the biomass at the beginning of the process. Hereinafter, this process will be referred to as a primary heat treatment step (S120). At this time, when the pyrolysis temperature is lower than 450 ℃ in the organic material is not removed well because the volume reduction effect may not be large, and because the metal cations attached to the organic material may not be removed well in one embodiment of the present invention 450 ℃ Pyrolysis is performed at the above temperature. In addition, when the pyrolysis temperature exceeds 750 ° C., the pyrolysis temperature in the exemplary embodiment of the present invention is limited to a temperature of 750 ° C. or less because the purity of the silica may be reduced by converting to SiC instead of silica.

As such, the first step of pyrolysis at the beginning of the process reduces the volume of the biomass, thereby facilitating subsequent processes, and thus eliminating unnecessary lukewarm water washing process by initially decomposing organic matter through pyrolysis.

Thereafter, the first pyrolyzed biomass is reacted with any one of an acidic solution, an ionic solution or a microbial fermentation broth to remove metal ions from the biomass (S130). Metal ion removal process according to an embodiment of the present invention is to decompose microorganisms using an acidic solution, ionic solution or microbial fermentation broth, etc., the secondary heat treatment step (S130) to remove the metal ions is rich in silicon (Si -rich) step of preparing a biomass.

Hereinafter, the microbial decomposition process by the acidic solution will be described first.

The acidic solution is not particularly limited, but sulfuric acid solution may be used as an example. Biomass is a raw material for producing silica, and may be at least one selected from rice bran, rice husk, rice straw, reeds, corn leaves and corn stalks. Specifically, the step of mixing biomass and sulfuric acid with a purity of 70 ~ 75wt% and reacting for 1 hour, adjusting the concentration of sulfuric acid to 2 ~ 5wt% by adding distilled water, 1 hour in a high temperature and high pressure reactor of 115 ~ 125 ℃ During the reaction to decompose organic matters such as cellulose, hemi cellulose, and lignin, and elute metal ions, and then filter them to remove the decomposed organic matter and the eluted metal ions, and then wash with distilled water. Drying for 26 hours may include sequentially preparing a silicon-rich biomass.

In addition, a hydrochloric acid solution may be used as the acidic solution. When using a hydrochloric acid solution, biomass and hydrochloric acid having a purity of 8 to 15 wt% are mixed and reacted for 1 hour, in a high temperature and high pressure reactor at 115 to 125 ° C. Reacting for hours to decompose organic matters such as cellulose, hemi cellulose, lignin, eluting metal ions, by filtration to remove the decomposed organic matter and the eluted metal ions, washed with distilled water, and then at about 60 ℃ 22 Drying for 26 hours may sequentially include preparing a silicon-rich biomass.

In addition, the second heat treatment step in an embodiment of the present invention may use an ionic liquid instead of an acidic solution to remove metal ions from the biomass and to produce a silicon-rich biomass.

The ionic liquid refers to a liquid composed only of ions, and is generally composed of a large cation containing nitrogen and a smaller anion. This structure reduces the lattice energy of the crystal structure, resulting in low melting point and high thermal stability.

When the ionic solution is brought into contact with the biomass, the hydrogen bonds of the hydroxyl groups present in the biomass are weakened by the ionic solution and the crystalline portion is transformed into amorphous, resulting in cellulose, hemicellulose, lignin and the like. To promote the hydrolysis reaction.

In other words, the anion of the ionic solution binds to the hydrogen of the hydroxyl group, and the cation binds to the oxygen of the hydroxyl group, thereby interfering with complex hydrogen bonds between the hydroxyl groups, resulting in dissolution of the dietary fibers of the biomass.

As such, according to an embodiment of the present invention, the use of an ionic solution is not only environmentally friendly than using a harmful compound such as a strong acid, but also a heat treatment temperature or time because the decomposition of the biomass is made under milder conditions. It is easy to control the structure of the silica produced by adjusting the synthesis conditions.

The ionic solution is selected from a) substituted or unsubstituted imidazonium, pyridium, ammonium, phosphonium, sulfonium, pyrazollium and pyrrolidium so as to have high thermal stability while promoting decomposition of biomass. any one of the cation, and ^{_{b) BF 4 -, PF 6}} -, Cl -, Br -, I -, OH -, NO 3 -, SO 4 2-, CF 3 CO 2 -, CF 3 SO 3 -, AlCl ^{_{4 -, SCN -, (CF}} 3 SO 2) 2 N -, CH 3 CO 2 - it is preferable to include at least one of the anion is selected from ^- and CH ₃ SO _4.

More specifically, the ionic solution is 1-allyl-3-methylimidazonium chloride, 1,3-dimethylimidazonium chloride, 1-butyl-3-methylimidazonium chloride, 1-butyl-3-methyl Imidazonium dicyanamide, 1-butyl-3-methylimidazonium hexafluoroantimonate, 1-butyl-3-methylimidazonium hexafluorophosphate, 1-butyl-3-methylimida Zonium Hydrogencarbonate, 1-Butyl-3-methylimidazonium hydrogensulfate, 1-Butyl-3-methylimidazonium methylsulfate, 1-butyl-3-methylimidazonium tetrachloroaluminate, 1-butyl 3-methylimidazonium tetrachloroborate, 1-butyl-3-methylimidazonium thiocyanate, 1-dodecyl-3-methylimidazonium iodide, 1-ethyl-2,3-dimethyl Midanium chloride, 1-ethyl-3-methylimidazonium bromide, 1-ethyl-3-methylimidazonium chloride, 1-ethyl-3-methylimida At least one of zonium hexafluorophosphate, 1-ethyl-3-methylimidazonium tetrafluoroborate, 1-hexyl-3-methylimidazonium tetrafluoroborate, and 1-butyl-4-methylpyridium chloride This can be used.

As such, when the biomass and the ionic solution are prepared, the biomass and the ionic solution are mixed and then subjected to the second heat treatment (S130). In this case, the second heat treatment mixes 0.5 to 2 L of the ionic solution per 100 g of the biomass. After that, the reaction may be performed at 100 to 200 ° C. for 24 to 72 hours. At this time, in order to increase the reaction efficiency, the secondary heat treatment is preferably performed under stirring at 100 to 400 rpm.

On the other hand, in order to remove metal ions from the biomass and to produce a silicon-rich biomass, microbial fermentation broth may be used instead of the acid solution. When using a microbial fermentation broth, there is no need to use a strong acid such as sulfuric acid can have an effect to ensure more safety.

Specifically, the step of mixing 0.5 ~ 2L of microbial fermentation broth with respect to 100g of biomass, and reacted for 1 to 5 hours at a reaction condition of 120 ~ 200 ℃, 1 ~ 5atm under carbon dioxide atmosphere, such as cellulose, hemi cellulose, lignin The organic material is decomposed and subjected to a second heat treatment step of eluting metal ions.

Thereafter, the organic matter and eluted metal ions are removed by filtration, washed with distilled water (S140), and dried at about 60 ° C. for 22 to 26 hours to produce silicon-rich biomass (Si-rich). The steps may be sequentially included. Alternatively, after the microbial fermentation broth is mixed to reduce the reaction time, the reaction is carried out for 30 minutes to 2 hours at 120 to 200 ° C. and 250 to 1,200 atm under an air atmosphere to decompose organic substances such as cellulose, hemi cellulose, and lignin. It is also possible to elute metal ions.

The microbial fermentation broth is preferably a fermentation broth of phytopathogenic fungi or saprophytic fungi, and in the case of the phytopathogenic fungi or fungi fungi, various active ingredients that can decompose plant cell walls are discharged. It is known.

Particularly, in the case of tree root fungus containing oxaloacetate hydolase as a cytoplasmic enzyme, the hydrolase is cellulose, hemicellulose, and lignin, such as organic acids (oxalic acid) during fermentation. By discharging the active ingredients that can decompose organic materials, such as to further promote the removal of impurities in the biomass.

These bio-derived components are not only environmentally friendly than using harmful synthetic materials such as strong acids, but because the decomposition of biomass is carried out under milder conditions, the structure of silica produced by controlling the synthesis conditions such as heat treatment temperature and time is controlled. Easy to control

The fungus having the oxaloacetate hydolase may be used in various kinds, but in one embodiment, Aspergillus niger, Paxillus involutus, etc. may be used.

In this case, in order to increase the decomposition efficiency of cellulose, hemicellulose, lignin and other organic substances, the fungus is preferably cultivated under the conditions of pH 5-6 using a hexasaccharide as a carbon source.

When the biomass and the microbial fermentation broth are prepared as described above, the biomass and the microbial fermentation broth are mixed and then subjected to a second heat treatment (S130) to remove organic matters. After mixing 0.5 ~ 2L of microbial fermentation broth per 100g of biomass, it can be made by reacting for 1 to 5 hours under the reaction conditions of 120 ~ 200 ℃, 1 ~ 5atm under carbon dioxide atmosphere, in this case heat treatment after washing 700 ~ 1,000 It is preferably made for 3 to 5 days at ℃.

In another embodiment, the secondary heat treatment, after mixing 0.5 ~ 2L of microbial fermentation broth per 100g of biomass, the reaction for 30 minutes ~ 2 hours at 120 ~ 200 ℃, 250 ~ 1,200atm reaction conditions in an air atmosphere It may be made, in this case after the heat treatment may be made for 1 to 3 days at 700 ~ 1,000 ℃.

The mixed solution in which the secondary heat treatment is completed is subjected to a process of separating the filtrate through a filter and then washing (S140).

The washing process is preferably made until a clear color water comes out as hot water so that all of the fermentation broth components can be removed, but is not limited thereto, and organic matter (ethanol, methanol) may be used as the washing solution.

After the washing process is completed, the filtrate is subjected to a third heat treatment (S150) step for the final pyrolysis of carbon components and other residues such as cellulose, hemicellulose, lignin, the third heat treatment depends on the second heat treatment conditions It may be, for example, may be made for 1 to 3 days or 3 to 5 days at a temperature of 700 ~ 1,000 ℃. The silica thus produced has a high purity of at least 95%.

 Example 1

50 g of rice husk was heated at 600 ° C. for 2 hours to reduce the volume of rice husk, and then was added to 500 mL of 72 wt% sulfuric acid for 1 hour at room temperature.

Subsequently, distilled water was added to adjust the concentration of sulfuric acid to 4 wt%, and the reaction was carried out in a high temperature high pressure reactor at 121 ° C. for 1 hour. After washing with distilled water to remove impurities such as metal cations eluted in the solution and dried for 12 hours at 60 ℃ drying oven to prepare a solid sample (silicon-rich biomass). The solid sample was placed in 80 mL of 2.5 M NaOH solution to produce a silicate. Subsequently, 4.6 g of polymer polyethylene glycol was added and stirred for 3 hours in an oil bath at 110 ° C. to completely dissolve the polymer, and remove solid residue through filtration. Collected. Igepal, a surfactant, was added to the filtrate, and then stirred. Then, 5 M sulfuric acid was added thereto to pH 2.0 and stirred for 3 hours to prepare a solid product (polymer-silica complex). Thereafter, the solid product was washed with distilled water, dried in a 60 ° C. drying oven, and pyrolyzed at 900 ° C. for 3 hours to prepare silica.

Example 2

50g of rice husk was heated for 2 hours for the first heat treatment at 600 ℃ to reduce the volume of rice husk, and then 750mL of 1-butyl-3-methylimidazolium chloride was added and reacted for 36 hours while stirring at 300rpm in an 130 ℃ oil bath. Washed with hot water until the clear color came out from the Vaccum pump filter. Thereafter, the washed slurry was transferred to a crucible and thermally decomposed at 800 ° C. for 48 hours to finally prepare silica.

Example 3

Aspergillus niger was incubated at pH 6 using sugar as a carbon source, and then the fermentation broth was separated. By heating for 2 hours the chaff 20g to a primary heat treatment at 600 ℃ into the reduced volume of the rice hull, and then, rice hull 20g heat treated first in the fermentation broth 200mL CO ₂ 20psi, and then reacted at 200 ℃ for 3 hours, Vaccum The filter was washed with hot water until a clear color came out. Thereafter, the washed slurry was transferred to a crucible, and thermally decomposed at 800 ° C. for 96 hours to finally prepare silica.

The purity of the silica prepared by Examples 1 to 3 was found to be 99.65%, 99.5% and 99.55%, respectively. That is, even though the process was simplified, it was found that silica purity was not significantly different from the conventional process.

Figure 2 is a thermogravimetric analysis graph according to the temperature associated with the present invention is a graph of the results of experiments of Examples 1 to 3 by varying the first heat treatment temperature, referring to Figure 2, TGA (thermogravimetric analysis of rice husk) ) Shows the change in mass of the rice hull at different temperatures. As can be seen in Figure 2 it can be seen that the organic matter of the chaff is completely removed at a temperature of 450 ℃ or more, the inorganic impurities are crystallized (crystalline) at a temperature of 750 ℃ or more is not performed by the chemical process and from 1000 ℃ or more SiC can be formed.

In addition, Table 1 below shows the mass of the rice hull before and after the first heat treatment according to the temperature. Referring to Table 1, the lignin was not completely removed at 325 ° C., and thus the weight loss was not completely achieved. At 450 ° C., some hemicellulose was not obtained. It can be seen that the organic matter is completely removed at 600 ℃. That is, it can be seen that the mass of the rice husk was reduced to 18.52g, 13.58g, and 11.95g by first heat-treating 100g rice husk at the temperature of 325 ° C, 450 ° C and 600 ° C before the first heat treatment.

<Residual chaff according to the first heat treatment temperature> Temperature Before the first heat treatment (g) After primary heat treatment (g) 325 ℃ 100 18.52 450 ℃ 100 13.58 600 ℃ 100 11.95

Table 2 shows the amount of water used when sulfuric acid solution is used for 100 g of rice husk, and Table 3 shows the amount of water used when hydrochloric acid solution is used for 100 g of rice husk. That is, the amount of chaff in the previous Example 1 is 100 g, and the amount of water used when sulfuric acid and hydrochloric acid solution are used. Hydrochloric acid at this time was used 10wt% hydrochloric acid, hydrochloric acid treatment was carried out for 1 hour. The rest of the process is the same as using sulfuric acid.

<Water usage in sulfuric acid treatment process> fair Existing Process Example 1st wash water 30L 0 72% sulfuric acid 1L 0.2L 4% sulfuric acid diluted water 18L 3.6L 2nd wash water 10L 0.2L Total water volume 59L 4.0L

<Water usage in hydrochloric acid treatment process> fair Existing Process Example 1st wash water 30L 0 10% hydrochloric acid 1L 0.2L 2nd wash water 10L 0.2L Total water 41L 0.4L

Table 2 and Table 3 compare the volume of water used, and by using the technology according to an embodiment of the present invention can significantly reduce the amount of water used, which in turn reduces the process volume to reduce facility equipment costs and It is easy to implement a large-capacity process, which is an essential process for commercialization.

In addition, since the organic impurities are removed through the initial pyrolysis process, the first washing process is not required, and as shown in Table 1, the third heat treatment time can be shortened.

The foregoing detailed description should not be construed as limiting in all respects, but should be considered as illustrative. The scope of the present invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present invention are included in the scope of the present invention.

Claims (10)

Preparing a biomass;
A first heat treatment step of reducing the volume and mass of the biomass by heating the biomass;
A second heat treatment step of removing the metal ions from the biomass by reacting the first heat treated biomass with any one of an acidic solution, an ionic solution or a microbial fermentation broth;
Washing and filtering the secondary heat-treated biomass; And
And a third heat treatment for final pyrolysis of the carbon component and other residues from the washed biomass. The method of claim 1,
The first heat treatment step,
Silica production method characterized in that made in the temperature range of 450 ~ 750 ℃. The method of claim 2,
The first heat treatment step,
Silica production method characterized in that performed for 1 to 6 hours. The method of claim 1,
In the second heat treatment step, the acid solution is a silica production method, characterized in that the sulfuric acid solution or hydrochloric acid solution. The method of claim 1,
The biomass is a method for producing silica, characterized in that at least one selected from rice bran, rice husk, rice straw, reeds, corn leaves and corn stalks. The method of claim 4, wherein
In the case of using the sulfuric acid solution in the second heat treatment step, the second heat treatment step is made in a temperature range of 20 ~ 40 ℃,
When the hydrochloric acid solution is used in the secondary heat treatment step, the secondary heat treatment step is a silica production method, characterized in that made in the temperature range of 80 ~ 100 ℃. The method of claim 1,
When the ionic solution is used in the secondary heat treatment step, the secondary heat treatment step is characterized in that the temperature range of 110 ~ 150 ℃ made. The method of claim 1,
When the microorganism fermentation broth is used in the second heat treatment step, the second heat treatment step is a silica production method, characterized in that made in the temperature range of 170 ~ 230 ℃. The method of claim 1,
The third heat treatment step is a silica manufacturing method, characterized in that made in the temperature range of 850 ~ 1050 ℃. The method of claim 1,
The ionic liquid,
1-allyl-3-methylimidazonium chloride, 1,3-dimethylimidazonium chloride, 1-butyl-3-methylimidazonium chloride, 1-butyl-3-methylimidazonium dicyanamide, 1- Butyl-3-methylimidazonium hexafluorouromonate, 1-butyl-3-methylimidazonium hexafluorophosphate, 1-butyl-3-methylimidazonium hydrogencarbonate, 1-butyl- 3-methylimidazonium hydrogensulfate, 1-butyl-3-methylimidazonium methylsulfate, 1-butyl-3-methylimidazonium tetrachloroaluminate, 1-butyl-3-methylimidazonium tetrachloro Borate, 1-butyl-3-methylimidazonium thiocyanate, 1-dodecyl-3-methylimidazonium iodide, 1-ethyl-2,3-dimethylimidazonium chloride, 1-ethyl-3 -Methylimidazonium bromide, 1-ethyl-3-methylimidazonium chloride, 1-ethyl-3-methylimidazonium hexafluorophosphate, 1-ethyl-3- A method for producing silica, comprising any one selected from methylimidazonium tetrafluoroborate, 1-hexyl-3-methylimidazonium tetrafluoroborate, and 1-butyl-4-methylpyridium chloride.

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