CN110639554B - Method for preparing ultrahigh-thermal-stability carbon-silicon composite solid superacid and reversibly regulating and controlling thermal stability of ultrahigh-thermal-stability carbon-silicon composite solid superacid - Google Patents

Abstract

The invention relates to the field of material synthesis, and discloses a method for preparing ultra-high thermally stable carbon-silicon composite solid superacid and reversibly regulating its thermal stability, and a method for preparing n-butyl levulinate by catalyzing furfuryl alcohol alcoholysis. The preparation method includes the following steps: (1) using bamboo charcoal (referred to as BC) prepared by hydrothermal catalysis method and acidic silica sol as main raw materials, BC is swelled with aqueous sodium hydroxide solution, hexadecyl trimethyl ammonium bromide is successively used It was treated with silica sol, then dehydrated at 250 ^o C, and finally sulfonated with concentrated sulfuric acid to prepare silicon-carbon composite solid superacid SIBCSA; (2) SIBCSA materials were treated with steam in a reactor, heat-treated in a tube furnace, And the combination of two treatment methods to reversibly tune the thermal stability of its sulfonic acid group. Among them, the silicon-carbon composite solid superacid SIBCSA‑H with thermal stability up to 401 ^o C can be obtained by water vapor treatment. The reversible control method is simple to operate, and the prepared SIBCSA-H shows stronger superacidity than SIBCSA, and has higher catalytic efficiency and better stability in catalyzing furfuryl alcohol alcoholysis to prepare n-butyl levulinate.

Description

A method for preparing ultra-high thermally stable carbon-silicon composite solid superacid and reversibly regulating its thermal stability

technical field

The invention relates to a method for preparing ultra-high thermally stable carbon-silicon composite solid superacid and reversibly regulating its thermal stability.

Background technique

Acids are widely used as catalysts in organic reactions, such as rearrangement, esterification, hydration, hydrolysis, alkylation, etherification, isomerization, polymerization, addition and polycondensation, so acid catalysis is important in the production of fuels and industries. One of the key transformation technologies for chemicals. In the traditional chemical industry, although liquid acid such as hydrofluoric acid has high catalytic efficiency, it is difficult to recover and produces a large amount of waste liquid that is difficult to handle during use, causing serious environmental pollution and damage to equipment. The corrosion is serious and cannot meet the requirements of green chemistry. People have carried out in-depth research on various solid acids, such as solid superacids, molecular sieves and macroporous sulfonic acid resins, in order to solve the shortage of liquid acids and maintain the efficient catalysis of solid acids ( Acc. Chem. Res. , 2002; 35(9) : 686-694; Green Chem. , 2002, 297(5582) : 799-803; Chem. Rev. , 2002; 102(10) : 3641-3666.). However, solid acids cannot compete with concentrated sulfuric acid in terms of cost and acid strength, which limits their wide industrial application.

Biomass carbon-based solid sulfonic acid is widely used in reactions such as hydrolysis, esterification , rearrangement, and condensation due to its advantages such as low cost and easy availability of raw materials, high acid density, good chemical stability, and low corrosion to equipment. . Rev. Chem. Eng. , 2013, 5(2) : 133-144). This type of solid acid is composed of polymerized aromatic olefins with a size of about 1-1.5 nm through the strong hydrogen bonding force of their edge polar functional groups to form a dense graphene-like layered non-porous structure, resulting in the blocked sulfonic acid site ( ACS Catal ). . , 2012, 2 : 1296-1304), which is not conducive to the mass transfer of some non-polar substances; in addition, due to the low degree of carbonization, some of its small molecular carbon sheets will fall off the catalyst during the acid catalysis process, resulting in the repeated use of the catalyst Sexual Variation ( J. Catal. , 2008, 254 : 332-338). In order to solve the problem of biomass carbon-based solid sulfonic acid, researchers directly use biomass such as wood flour ( Catal. Lett. , 2009, 131(1-2) : 242-249) as carbon source through high temperature chemical activation heat However, the catalyst prepared by this method has many micropores, low acid content and low catalytic efficiency ( J. Am. Chem. Soc. , 2009, 131 : 12787-12793). Although researchers have used the template method ( J. Am. Chem. Soc., 2001, 123(37) : 9208-9209; J. Am. Chem. Soc. , 2006, 128(31) : 10026-10027; Angew. Chem . Int. Ed. , 2005, 44 : 7053) to prepare biocarbon-based materials with disordered or ordered mesoporous structure, but this method has the disadvantages of high raw material cost, complicated preparation process, difficult control, low yield, and sulfonation ability. The poor and other problems limit its industrial application as a solid acid. In addition, the stability and acid strength of biomass carbon-based solid sulfonic acid itself is not high ( Cellulose , 2017, 24(1) : 95-106.), which limits its application in some reactions.

Therefore, the development of biocarbon-based solid sulfonic acid with a large specific surface area and stable pore structure, as well as excellent stability and high dew degree of super acid sites is of high application value. The present invention provides a kind of bamboo charcoal prepared by hydrothermal carbonization of cheap and easy-to-obtain bamboo powder as a raw material on the basis of the original application patent "a new type of biomass carbon-based solid super acid preparation method" (CN201810741544.1), through Swelling with aqueous sodium hydroxide solution, followed by treatment with cetyltrimethylammonium bromide followed by silica sol solution, dehydration and sulfonation, finally by steam treatment, tube furnace heat treatment, and a combination of the two treatments , realizes a method for reversibly regulating the thermal stability of carbon-silicon composite solid superacid, and provides a method for preparing ultra-high thermally stable carbon-silicon composite solid superacid by steam treatment. The prepared solid acid catalyst has the advantages of high catalytic efficiency and good stability in catalyzing the alcoholysis reaction of furfuryl alcohol. It overcomes the shortcomings of low catalytic efficiency and poor stability of traditional non-porous biomass carbon sulfonic acid.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for preparing ultra-high thermally stable carbon-silicon composite solid superacid and reversibly regulating its thermal stability.

A method for preparing ultra-high thermally stable carbon-silicon composite solid superacid and reversibly regulating its thermal stability according to the present invention comprises the following steps:

(1) Weigh 1.0 g of bamboo charcoal BC prepared by hydrothermal catalytic carbonization (see patent for the preparation method of BC, Fu Zaihui, etc., a preparation method of ultra-high sulfonic acid density biomass carbon solid acid CN 201710129798.3), hydrogen 0.6 g of sodium oxide and 20 mL of distilled water were added to a 100 mL round-bottomed flask, and treated at 100 ° C for 12 hours to swell bamboo charcoal, cooled to room temperature after the reaction, and the treated mixed solution was treated with 6 mol·L ^-1 hydrochloric acid solution Adjust its pH to 8-9, add 0.7g trimethylammonium bromide CTMA, stir in a 60 ^o C water bath for 6 hours, the treated mixture is filtered, washed with distilled water, and dried at 100 ° C for 8 hours to obtain a solid mixture CTMA-BC; then the ground CTMA-BC powder was dispersed with distilled water in a water bath at 50 °C, and 22 mL of silica sol with a concentration of 0.55 mol·L ^-1 was added dropwise to it, and stirred in a water bath at 50 ^° C for 3 hours. , after the reaction, filtered, washed, dried at 100°C for 8 hours, the obtained solid sample was dehydrated at 250°C for 5h in a nitrogen atmosphere to obtain a black solid CTMA-SiO ₂ -BC, and the CTMAB-SiO ₂ -BC solid was milled to obtain powder, Weigh 2 g of this powder material, add 60 mL of 3 mol·L ^-1 ammonium nitrate, exchange 3 times at 100 ^° C for 3 hours each time, filter, wash, and then dry at 100 °C for 8 hours to obtain the CTMA-removed powder. Finally, 2 g of this powder material was weighed, 20 mL of concentrated sulfuric acid was added, and sulfonated at 100 ^o C for 3 hours. The obtained sulfonated material was washed with distilled water until the filtrate was free of sulfate radicals, and dried at 100 ^o C for 8 Obtain biological carbon-based solid superacid SIBCSA within hours;

(2) The thermal stability of the sulfonic acid group of the SIBCSA material obtained in step (1) is reversibly regulated by steam treatment in the reactor, and the sample treated with steam is marked as SIBCSA-H _n ; The reversible regulation of the thermal stability of the sulfonic acid group was achieved by combining steam treatment with heat treatment in a tube furnace, and the treated samples were labeled as SIBCSA-H ₁ -T, SIBCSA-TH ₁ and SIBCSA-H ₁ -TH, respectively ₁ .

The water vapor treatment temperature of SIBCSA in step (2) is 100-150 ^o C, preferably 120 ^o C; the water vapor treatment time is 8-14 h, preferably 10 h.

When the water vapor treatment temperature and time of SIBCSA in step (2) were 120 ^oC and 10 h, respectively, the sulfonic acid group of the obtained SIBCSA-H ₁ had ultra-high thermal stability and stronger ultra-strong acidity than SIBCSA.

The water vapor treatment temperature and time of the SIBCSA-H ₁ -T, SIBCSA-TH ₁ and SIBCSA-H ₁ -TH ₁ materials prepared in step (2) were 120 ^o C and 10 h, respectively; The time was 250 ^o C and 5 h, respectively.

The invention has the following advantages: (1) the raw materials used are cheap and easy to obtain, the synthesis method is simple and easy to operate; (2) the new carbon-silicon composite solid super acid SIBCSA-H ₁ prepared by the invention has the highest density of sulfonic acid groups. It reaches about 1.35 mmol·g ^-1 , and its thermal decomposition temperature can reach up to 401 ^o C. It has high catalytic efficiency and good stability in catalyzing sucrose hydrolysis and furfuryl alcohol hydrolysis.

Description of drawings

Fig. 1 is the differential thermogravimetric curve (DTG) of the thermogravimetric analysis of SIBCSA and SIBCSA-H ₁ ; Fig. 2 is the ³¹ P-NMR graph of TMPO adsorption of SIBCSA and SIBCSA-H ₁ ; Fig. 3 is the low temperature of SIBCSA-H ₁ Nitrogen adsorption and desorption curves and their pore size distribution.

Detailed ways

The following examples are further illustrations of the present invention, but are not limited to the embodiments described by the specific examples set forth in the present invention.

Example 1 (Example 1-1): a method for preparing ultra-high thermally stable carbon-silicon composite solid superacid and reversibly regulating its thermal stability according to the present invention, comprising the following steps:

(1) Weigh 1.0 g of bamboo carbon BC prepared by hydrothermal catalytic carbonization (see patent for the preparation method of BC, Fu Zaihui, etc., a preparation method of ultra-high sulfonic acid density biomass carbon solid acid CN 201710129798.3), hydrogen 0.6 g of sodium oxide and 20 mL of distilled water were added to a 100 mL round-bottomed flask, and treated at 100 ° C for 12 hours to swell bamboo charcoal, cooled to room temperature after the reaction, and the treated mixed solution was treated with 6 mol·L ^-1 hydrochloric acid solution Adjust its pH to 8-9, add 0.7g trimethylammonium bromide CTMA, stir in a 60 ^o C water bath for 6 hours, the treated mixture is filtered, thoroughly washed with distilled water, and dried at 100 ° C for 8 hours to obtain a solid mixture CTMA-BC; then the ground CTMA-BC powder was dispersed with distilled water in a water bath at 50 °C, and 22 mL of silica sol with a concentration of 0.55 mol·L ^-1 was added dropwise, and stirred in a water bath at 50 ^° C for 3 hours. , after the reaction, filtered, washed, dried at 100 °C for 8 hours, the obtained solid sample was dehydrated at 250 °C for 5 hours in a nitrogen atmosphere to obtain a black solid CTMA-SiO ₂ -BC, and the CTMAB-SiO ₂ -BC solid was milled to obtain powder, Weigh 2 g of this powder material, add 60 mL of 3 mol·L ^-1 ammonium nitrate, exchange 3 times at 100 ^° C for 3 hours each time, filter, wash, and then dry at 100 °C for 8 hours to obtain the CTMA-removed powder. Finally, 2 g of this powder material was weighed, 20 mL of concentrated sulfuric acid was added, and sulfonated at 100 ^o C for 3 hours. The obtained sulfonated material was washed with distilled water until the filtrate was free of sulfate radicals, and dried at 100 ^o C for 8 Obtain biological carbon-based solid superacid SIBCSA within hours;

(2) Put 1.0 g of the catalyst SIBCSA obtained in step (1) in the middle and upper part of the 100 mL reaction kettle, add 40 mL of water to the lower part of the reaction kettle, and treat the sample with steam heated to 120 ^o C for 10 h to obtain the target catalyst mark. is SIBCSA-H ₁ .

The SIBCSA-H ₁ material prepared in Example 1-1 was characterized by TGA, and the results are shown in Figure 1 of the accompanying drawings. The thermal decomposition temperature of the sulfonic acid group of SIBCSA-H ₁ is 401 ^o C, which is higher than that of the reference substance SIBCSA (see the patent for its preparation method, Fu Zaihui, etc., a new biomass carbon-based solid superacid preparation method CN201810741544.1). out of 120 ^o C; the TMPO adsorption ³¹ P-NMR characterization in Figure 2 shows that the acid strength of SIBCSA-H ₁ is much higher than that of 100% sulfuric acid, and also slightly higher than that of SIBCSA, with super acidity; the measured sulfonic acid group The content is 1.35 mmol·g ^-1 ; the BET specific surface area of SIBCSA-H ₁ is 104 m ² ·g ^-1 and the pore volume is 0.10 cm ³ ·g ^-1 by adopting low-temperature nitrogen adsorption-desorption method in accompanying drawing 3 , with an average pore size of 9.4 nm.

Comparative Example 1: A method for preparing ultra-high thermally stable carbon-silicon composite solid superacid and reversibly regulating its thermal stability according to the present invention is carried out according to the method of Example 1-1, the difference is that step (1) is used. 1.0 g of the SIBC powder material prepared in ) was treated with the steam treatment conditions in step (2) to obtain SIBC-H ₁ material, and finally SIBC-H ₁ was subjected to the sulfonation conditions of SIBC in step (1). Sulfonation affords SIBCSA-H ₁ (a).

The SIBCSA-H ₁ (a) material prepared from Comparative Example 1 was characterized by TGA. The thermal decomposition temperature of sulfonic acid group in SIBCSA-H ₁ (a) was 400 ^o C, and the measured sulfonic acid group content was 1.38 mmol·g ^-1 .

Example 2 (Examples 2-1 to 2-3): a method for preparing ultra-high thermally stable carbon-silicon composite solid superacid and reversibly regulating its thermal stability according to the present invention, including the following steps: according to Example 1 -1 ^method , the difference is that in step (2), the ^{steam treatment} temperature is different. The effect of sulfonic acid group density and thermal stability of SIBCSA- _Hn (labeled as SIBCSA-H ₂ , SIBCSA-H ₃ and SIBCSA-H ₄ ), the results are shown in Table 1;

Table 1

It can be seen from Table 1 that the decomposition temperature of the sulfonic acid group of ^SIBCSA can be increased by 100 ^oC under the water vapor treatment of ^{100 oC} ; The highest temperature was 401 ^o C; however, further increasing the water vapor temperature to 150 ^o C and 180 ^o C resulted in a significant decrease in the decomposition temperature of the sulfonic acid group to 307 ^o C and 226 ^o C. In addition, the sulfonic acid group density of SIBCSA decreased gradually with the increase of steam treatment temperature (from 1.57 mmol·g ^-1 to 1.08 mmol·g ^-1 ). Therefore, the optimum temperature for steam treatment is 120 ^o C.

Example 3 (Examples 3-1 to 3-3): a method for preparing ultra-high thermally stable carbon-silicon composite solid superacid and reversibly regulating its thermal stability according to the present invention, including the following steps: according to Example 1 -1 method, the difference is that in step (2), the steam treatment time is different, the steam treatment time is 8 h, 12 h, 14 h, and the effect of steam treatment time on SIBCSA sulfonic acid group is investigated. The effect of density and thermal stability (labeled as SIBCSA-H ₅ , SIBCSA-H ₆ and SIBCSA-H ₇ ), the results of which are shown in Table 2;

Table 2

It can be seen from Table 2 that the water vapor treatment time also has a significant regulation effect on the thermal stability of the SIBCSA sulfonic acid group. When the treatment time is 8 h and 10 h, the thermal decomposition temperature of the sulfonic acid group is increased to 379 ^o C and 379 o C, respectively. 401 ^o C; but when the treatment time was extended to 12 h and 14 h, the thermal decomposition temperature of the sulfonic acid group dropped significantly to about 310 ^o C, and it can be seen from Table 2 that the density of the sulfonic acid group of SIBCSA increased with the steam treatment time. Prolonged and gradually decreased (from 1.57 mmol·g ^-1 to 1.19 mmol·g ^-1 ). Therefore, the optimal time for water vapor treatment is 10 h.

Example 4 (Examples 4-1 to 4-4): a method for preparing ultra-high thermally stable carbon-silicon composite solid superacid and reversibly regulating its thermal stability according to the present invention, including the following steps: according to Example 1 -1 method, the difference is that the steam treatment in step (2) is different, using a tube furnace to heat 250 ^o C for 5 h (referred to as T treatment), 120 ^o C steam for 10 h (H ₁ processing for short) and T processing combined mode. The samples treated as above are marked as SIBCSA-T, SIBCSA-TH ₁ , SIBCSA-H ₁ -T and SIBCSA-H ₁ -TH ₁ , and the results are shown in Table 3;

table 3

After SIBCSA and SIBCSA-H ₁ were heat-treated in a tube furnace, the sulfonic acid group density of the obtained SIBCSA-T and SIBCSA-H ₁ -T decreased, especially the thermal decomposition temperature of the sulfonic acid group decreased by 25 ^o C, respectively and 150 ^o C. After SIBCSA-T and SIBCSA-H ₁ -T are further treated with steam, the sulfonic acid group density of the obtained SIBCSA-TH ₁ and SIBCSA-H ₁ -TH ₁ will further decrease, but the thermal decomposition temperature of the sulfonic acid group will increase respectively. 33 ^o C and 149 ^o C. It is shown that the combination of tube furnace heat treatment and steam treatment can realize the reversible regulation of the thermal stability of the sulfonic acid group of SIBCSA-2.

Example 5 (Examples 5-1~5-3): SIBCSA-H ₁ prepared by Example 1-1, SIBCSA prepared by the method of patent application CN201810741544., HTBCSA (sulfonic acid) prepared by the method of patent application CN 201710129798.3 The acid group density, 3.46 mmol·g ^-1 ) was used as the catalyst, and the reaction conditions for catalyzing the alcoholysis of furfuryl alcohol were as follows: the amount of catalyst in mmol of sulfonic acid was 2% of the mmol of furfuryl alcohol, and the molar ratio of furfuryl alcohol to n-butanol was 1:60. , the reaction temperature is 80-110 ^o C, and the reaction is stirred for 10 h; after the reaction is completed, it is cooled to room temperature, the internal standard is added, the upper reaction liquid is collected by centrifuging the catalyst, and then analyzed by gas chromatography to determine n-butyl levulinate (BL ) ) to evaluate the activity of the catalyst, and the results are shown in Table 4;

Table 4

It can be seen from Table 4 that the BL yield of SIBCSA-H ₁ is higher than that of SIBCSA, especially HTBCSA, in the reaction of furfuryl alcohol alcoholysis to n-butyl levulinate (BL), especially at a lower reaction temperature of 90 ^o C and At 80 ^o C, its catalytic activity advantage is more prominent due to its super acidity.

Example 6: Using the SIBCSA-H ₁ prepared in Example 1-1 as a catalyst, catalyzing the alcoholysis of furfuryl alcohol to synthesize n-butyl levulinate (BL) according to the method described in Example 5-1. The catalyst dosage is 2% of the furfuryl alcohol amount mmol with its sulfonic acid amount mmol, the reaction temperature is 110 ℃, the mol ratio of furfuryl alcohol and ⁿ -butanol is 1:120, and the reaction time is 2-16h, and the results are shown in Table 5;

table 5

It can be seen from Table 5 that in the reaction of SIBCSA-H ₁ catalyzing the synthesis of n-butyl levulinate (BL) by alcoholysis of furfuryl alcohol, the BL yield gradually increased with the prolongation of the reaction time, and reached the highest 86.05% at 14 h.

Example 7: Using the SIBCSA-H ₁ prepared in Example 1-1 as a catalyst, catalyzing the alcoholysis of furfuryl alcohol to synthesize n-butyl levulinate (BL) according to the method described in Example 5-1. The catalyst dosage is 0.5-2.5% of the furfuryl alcohol amount mmol with its sulfonic acid amount mmol, the reaction temperature is 110 ℃, the time is 14 ^h , and the mol ratio of furfuryl alcohol and n-butanol is 1:120, and the results are shown in Table 6;

Table 6

It can be seen from Table 6 that in the reaction of SIBCSA-H ₁ catalyzing the alcoholysis of furfuryl alcohol to synthesize n-butyl levulinate (BL), the BL yield gradually increased with the increase of the catalyst dosage, reaching 86.05% at 2.0%, further increasing the catalyst amount. With the dosage, the BL yield basically no longer increases.

Example 8: Using the SIBCSA-H ₁ prepared in Example 1-1 as a catalyst, catalyzing the alcoholysis of furfuryl alcohol to synthesize n-butyl levulinate (BL) according to the method described in Example 5-1. The catalyst dosage is 2% of the furfuryl alcohol amount mmol with its sulfonic acid amount mmol, the reaction temperature is 110 ℃, the time is 14 ^h , and the mol ratio of furfuryl alcohol and n-butanol is 1:40-1:130, and the results are shown in Table 7 ;

Table 7

Molar ratio of furfuryl alcohol to n-butanol 1:40 1:60 1:80 1:100 1:120 1:130 BL yield/% 67.19 71.44 77.14 81.4 86.05 86.09

It can be seen from Table 7 that in the reaction of SIBCSA-H ₁ catalyzing the alcoholysis of furfuryl alcohol to synthesize n-butyl levulinate (BL), the BL yield gradually increased with the increase of the amount of n-butanol, and the amount of n-butanol was the amount of furfuryl alcohol. 120 times higher than that of 86.05%, further increasing the amount of n-butanol, the BL yield basically no longer increases.

Example 9: Using the SIBCSA-H ₁ prepared in Example 1-1 as a catalyst, catalyzing the alcoholysis of furfuryl alcohol to synthesize n-butyl levulinate (BL) according to the method described in Example 5-1. The amount of catalyst was 2% of the mmol of furfuryl alcohol, the reaction temperature was 110 ^o C, the reaction time was 14 h, and the molar ratio of furfuryl alcohol to n-butanol was 1:120. The recovery and reuse performance of the catalyst was investigated. The used catalyst was washed three times with hot methanol and dried for the next catalytic reaction. The results are shown in Table 8;

Table 8

As can be seen from Table 8, SIBCSA-H ₁ was repeated four times in the reaction of catalyzing furfuryl alcohol alcoholysis to synthesize n-butyl levulinate (BL), and its BL yield only decreased by about 2%, indicating that the ultra-high thermally stable silicon carbon The composite solid super acid has excellent reusability.

The invention provides a simple, effective and reversible method for regulating the thermal stability of a carbon-silicon composite solid superacid and a method for preparing a carbon-silicon composite solid superacid with ultra-high thermal stability.

Claims (5)

1. A method for preparing ultra-high thermal stable carbon-silicon composite solid superacid and reversibly regulating and controlling the thermal stability of the carbon-silicon composite solid superacid is characterized by comprising the following steps:

(1) weighing 1.0g of bamboo charcoal BC, 0.6g of sodium hydroxide and 20 mL of distilled water prepared by a hydrothermal catalytic carbonization method, adding the bamboo charcoal BC, the sodium hydroxide and the distilled water into a 100mL round-bottom flask, treating at 100 ℃ for 12 hours to swell bamboo charcoal, cooling to room temperature after the reaction is finished, and using 6 mol/L of treated mixed solution^-1Adjusting pH to 8-9 with hydrochloric acid solution, adding 0.7g trimethyl ammonium bromide (CTMA) at 60%^oC, stirring in a water bath for 6 hours, filtering the treated mixed solution, fully washing with distilled water, and drying at 100 ℃ for 8 hours to obtain a solid mixture CTMA-BC;then, the ground CTMA-BC powder was dispersed by stirring with distilled water in a water bath at 50 ℃ and 0.55 mol. L was added dropwise thereto^-1Silica sol 22 mL at 50^oC water bath stirring for 3 hours, after the reaction is finished, filtering, washing, drying for 8 hours at 100 ℃, dehydrating the obtained solid sample for 5 hours at 250 ℃ in nitrogen atmosphere to obtain black solid CTMA-SiO₂-BC，CTMAB-SiO₂Grinding the-BC solid to obtain powder, weighing 2 g of the powder material, adding 3 mol.L^-1Ammonium nitrate 60mL at 100^oC, exchanging for 3 times, filtering and washing for 3 hours each time, and drying for 8 hours at 100 ℃ to obtain a powder material with CTMA removed; finally weighing 2 g of the powder material, adding 20 mL of concentrated sulfuric acid into the powder material, and dissolving the mixture in 100^oSulfonating for 3 hours at C, washing the obtained sulfonated material with distilled water until the filtrate is free of sulfate radical at 100 deg.C^oC, drying for 8 hours to obtain biochar-based solid super acid SIBCSA;

(2) reversibly regulating and controlling the thermal stability of the sulfonic acid group of the SIBCSA material obtained in the step (1) through water vapor treatment in a reaction kettle, wherein a sample SIBCSA-H subjected to water vapor treatment₁The reversible regulation and control of the sulfonic acid group thermal stability of the SIBCSA are realized by combining water vapor treatment in a reaction kettle and heat treatment in a tube furnace, and treated samples are respectively marked as SIBCSA-H₁-T、SIBCSA-T-H₁And SIBCS SA-H₁-T-H₁。

2. The method as claimed in claim 1, wherein the temperature of the steam treatment of the SIBCS SA in step (2) is 100-150-^oC, the water vapor treatment time is 8-14 h.

3. The method according to claim 1, wherein the temperature and time of the steam treatment of the sibcas in the step (2) are 120 ℃ and 120 ℃ respectively^oC and 10H, obtaining SIBCSA-H₁The sulfonic acid group of (A) has ultrahigh thermal stability and stronger super strong acidity than that of SIBCSA.

4. The method according to claim 1, wherein the SIBCSA-H prepared in step (2)₁-T、SIBCSA-T-H₁And SIBCS SA-H₁-T-H₁The water vapor treatment temperature and time of the material are respectively 120 DEG^oC and 10 h; the temperature and time in the tube furnace were 250 deg.C and 250 deg.C, respectively^oC and 5 h.

5. A method for synthesizing n-butyl levulinate by catalyzing furfuryl alcohol alcoholysis, which comprises the step of reacting the catalyst with the catalyst, wherein the catalyst is SIBCSA-H as defined in claim 1₁The dosage of the compound is 0.5-2.5mol% of the dosage of furfuryl alcohol calculated by sulfonic acid, and the molar ratio of furfuryl alcohol to n-butyl alcohol is 1: 40-1: 130, the reaction temperature is 80-110 DEG C^oAnd C, the reaction time is 2-16 h.

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