CN115990485B - Bimetallic composite biochar catalyst for sugar acid synthesis, sugar acid synthesis method and application - Google Patents

Abstract

The invention discloses a bimetallic composite biochar catalyst for sugar acid synthesis, which comprises the following steps: pulverizing biomass, and sieving to obtain biomass powder; adding biomass powder and platinum salt and/or zinc salt and alkali salt into an organic solvent for solvothermal reaction; and (3) washing the obtained material with absolute ethyl alcohol and ultrapure water, and drying to obtain the bimetallic composite biochar catalyst for sugar acid synthesis. The invention takes the straw as the raw material, thus realizing the recycling of the straw; the straw-based porous biochar material loaded with Pt and Zn bimetal is synthesized by a solvothermal method in one step, and the synthesis way is more green and safer; the polyol solution reduces part of platinum at high temperature, and meanwhile, transition metal zinc is introduced, so that the biomass derivative C5/C6 unit can be efficiently converted into sugar acid, and the reaction time is short and the selectivity is high. The catalyst of the invention is used as a catalyst, so that 100 percent of conversion rate and 65 to 88 percent of sugar acid yield are obtained.

Description

A kind of bimetallic composite biochar catalyst for sugar acid synthesis and sugar acid synthesis method and application

technical field

The invention belongs to the technical field of chemically synthesizing sugar acids, in particular to a bimetallic composite biochar catalyst for sugar acid synthesis, and a sugar acid synthesis method and application.

Background technique

The fossil energy crisis and environmental problems are becoming increasingly serious. As a renewable resource, lignocellulosic biomass can be converted into liquid fuels and furfural and other C5/C6 chemicals with high added value. Among them, gluconic acid/xylonic acid, the oxidation product of biomass derivative C5/C6 unit, is an important material in food, pharmaceutical, construction and other industries. Compared with the problems of harsh conditions and long time in the preparation of sugar and acid by traditional methods such as enzyme fermentation, metal heterogeneous catalytic systems have attracted more and more attention. However, the current solid catalysts have the problems of cumbersome synthesis process, harsh conditions, low activity and poor selectivity, and most reaction systems need to add alkali source, and further acid treatment is required to finally obtain sugar acid.

Through searching, no patent publications related to the patent application of the present invention were found.

Contents of the invention

The purpose of the present invention is to overcome the disadvantages of cumbersome solid catalyst synthesis process, harsh conditions and poor selectivity in the prior art, and provide a bimetallic composite biochar catalyst for sugar acid synthesis, sugar acid synthesis method and application.

The technical solution adopted by the present invention to solve its technical problems is:

A bimetallic composite biochar catalyst for sugar acid synthesis, the preparation method of the catalyst comprises the steps:

(1) Crushing and sieving the biomass to obtain biomass powder;

(2) adding the biomass powder obtained in step (1) and platinum salt and/or zinc salt, alkali salt into an organic solvent, and performing a solvothermal reaction to obtain the material;

(3) The material in step (2) was washed with absolute ethanol and ultrapure water, and dried to obtain a bimetallic composite biochar catalyst for the synthesis of sugar and acid.

Further, the platinum salt in step (2) is a platinum-containing inorganic salt, the zinc salt is a zinc-containing inorganic salt, the alkali salt is a hydroxide, and the organic solvent is a polyhydric alcohol. More preferably 1,4-butanediol and ethylene glycol;

Alternatively, the biomass in step (1) is one or more of rice straw, wheat straw, corn straw, peanut straw, and sorghum straw;

Alternatively, use a pulverizer or a ball mill to pulverize;

Alternatively, crush through a 60-mesh sieve.

Further, the amount of platinum atoms in the platinum salt in step (2): the amount of zinc atoms in the zinc salt is 1:4-8; the amount of platinum atoms in the platinum salt in step (2): alkali The amount of salt substance is 1:8-12. The mass ratio of the straw to the organic solution is 1:30-60; the mass ratio of the straw to the platinum atom in the platinum salt is 1:2-5.

Further, the mass ratio of the straw to the organic solution is 1:55; the mass ratio of the straw to the platinum atom in the platinum salt is 1:4.2; the amount of the platinum atom in the platinum salt: the zinc atom in the zinc salt The amount of substance is 1:6-8, most preferably 1:6; the amount of substance of platinum atom in platinum salt: the amount of substance of alkali salt is 1:10-12, most preferably 1:10.

Further, when the biomass powder, platinum salt, zinc salt, and alkali salt are added to the organic solvent in step (2), the platinum salt, zinc salt, and alkali salt are magnetically stirred and dissolved in the polyol solution, and the biomass powder is magnetically Stir and disperse evenly in the polyol solution, the speed of magnetic stirring is 500-1000rpm; the rotation time is 0.5-4h;

Alternatively, the temperature of the solvothermal reaction in step (2) is 150°C-250°C, and the reaction time is 8-24h. In the present invention, the temperature of the solvothermal is preferably controlled within the above range. If the solvothermal temperature is too low, the metal loading is low, and the temperature is too high, which wastes energy.

Alternatively, the cleaning process in step (3) is specifically: the product obtained in step (2) is mixed with absolute ethanol and ultrapure water in sequence, then stirred and centrifuged; the stirring time is 5-10min, and the stirring rate is 200 -300rmp, the stirring method is magnetic stirring, the number of times of washing with absolute ethanol is 2-3 times, and the number of times of washing with ultrapure water is 1-2 times; the rotating speed of the centrifugation is 10000rpm, and the centrifugation time is 2min;

Alternatively, the drying temperature in step (3) is 55-80° C.; the drying time is 10-24 hours.

Further, the rotation speed is 600-900rpm, most preferably 900rpm, and the rotation time is 1-2h, most preferably 1h;

The temperature of the solvothermal reaction is 180°C-220°C, most preferably 195°C; the time of the solvothermal reaction is 12-24h, most preferably 12h;

The drying temperature in step (3) is 80° C.; the drying time is 12 hours.

The application of the above-mentioned bimetallic composite biochar catalyst in the catalytic oxidation of biomass derivatives.

Utilize the method for catalyzing and oxidizing biomass derivatives with the above-mentioned bimetallic composite biochar catalyst, comprising the following steps:

The biomass derivative C5/C6 unit is added to water to configure a reaction solution with a substrate mass concentration of 1-10%. The bimetallic composite biochar catalyst used for the synthesis of sugar and acid is used as a catalyst in a magnetically stirred high-pressure reactor Fill the medium with oxygen and heat it. After the reaction is over, cool it with running water, release the pressure, and take out the upper layer liquid to obtain sugar acid.

Further, the sugar acid is gluconic acid or xylonic acid;

Alternatively, the Pt content on the surface of the bimetallic composite biochar catalyst is 0.10-0.26mmol/g; the Zn content on the material surface is 0.30-0.77mmol/g.

Alternatively, the biomass derivative: catalyst mass ratio is 1:1.5-10; the heating temperature is 50-120°C; the heating time is 0.1h-8h; the oxygen pressure is 0.2-2MPa; In the present invention, the temperature and time of the oxidation reaction are preferably controlled within the above range, which is beneficial to promote the complete oxidation of the C5/C6 unit of the biomass derivative.

Alternatively, it can be configured as a reaction solution with a substrate mass concentration of 1-5%;

Alternatively, the water is ultrapure water. In the present invention, the water is only used as a solvent and does not play a catalytic role. In the present invention, there is no special limitation on the source of the water, and products well known to those skilled in the art can be used.

Further, the Pt content on the surface of the bimetallic composite biochar catalyst is 0.10-0.15mmol/g; the Zn content on the surface of the material is 0.30-0.46mmol/g;

The mass ratio of the biomass derivative: catalyst is 1:2.5;

The heating temperature is 80-100°C; the heating time is 1-4h; the oxygen pressure is 0.2-1MPa;

Alternatively, the rate of the magnetic stirring is 500-800rmp.

Advantage and positive effect that the present invention obtains are:

1. The present invention uses straw as a raw material to realize the recycling of straw; the straw-based porous biochar material loaded with Pt and Zn bimetals is synthesized in one step through the solvothermal method, and the synthesis method is greener and safer; the polyol solution is reduced at high temperature Part of the platinum, and the present invention introduces the transition metal zinc into the catalyst through the solvothermal process. This material can not only efficiently convert the C5/C6 unit of the biomass derivative into sugar acid, but also has short reaction time and high selectivity. The results show that the conversion rate of 100% and the yield of sugar acid of 65%-88% are obtained by using the bimetallic composite biochar catalyst for sugar acid synthesis prepared by the preparation method provided by the invention as a catalyst.

2. The method of the present invention uses renewable biomass straw as a carbon source, and prepares a bimetallic composite biochar catalyst for sugar-acid synthesis by one-step carbonization and metal reduction by a solvothermal method, and selectively catalyzes and oxidizes biomass in a neutral reaction system The derivative C5/C6 unit synthesis of sugar acid provides a theoretical broad prospect for the chemical catalytic conversion of agricultural waste such as straw to synthesize sugar acid.

3. The catalyst of the present invention contains platinum, zinc and oxygen-containing functional groups; the existing forms of platinum are Pt ⁴⁺ , Pt ²⁺ , and Pt ⁰ , the existing forms of zinc are ZnO, and the oxygen-containing functional groups include hydroxyl functional groups and carboxyl functional groups .

4. The present invention uses agricultural waste stalks as raw materials to prepare bimetallic composite biochar catalysts for sugar-acid synthesis through one-step carbonization and metal reduction by solvothermal method, and the bimetals are platinum and zinc. The oxygen-containing functional group contained in the bimetallic composite biochar catalyst for sugar acid synthesis provided by the invention is beneficial to the adsorption of the C5/C6 unit of the biomass derivative and promotes the mass transfer of the reaction substrate. Platinum and zinc can promote the C5/C6 unit of the biomass derivative. The oxidation product of the C6 unit is sugar acid, thereby realizing the efficient progress of the catalytic reaction.

Description of drawings

Figure 1 is a TEM image of the product in the present invention; among them, (a), (b), and (c) are the product images prepared in Example 1 to Example 3 in turn; it proves that the metal is successfully loaded on the carbon carrier;

Fig. 2 is the XPS figure of the product in the present invention; Among them, (a), (b), (c) are the product pictures prepared in order from Example 1 to Example 3; prove that there is metal on the surface of the material, and part of the platinum is covered Organic solvent reduction;

Fig. 3 is a graph showing the yield and conversion rate of gluconic acid produced by catalytic oxidation of biomass derivative C6 unit glucose for 1.5h at 100°C and 1MPa oxygen by the material prepared in the examples of the present invention;

Fig. 4 is a graph showing the variation of the yield of gluconic acid produced by the catalytic oxidation of biomass derivative C6 glucose at different reaction temperatures with the reaction time of the material prepared in Example 3 of the present invention.

Detailed ways

Below in conjunction with embodiment, the present invention is further described, and following embodiment is descriptive, not limiting, can not limit protection scope of the present invention with following embodiment.

The various experimental operations involved in the specific embodiments are all conventional techniques in the art, and there are no special notes in this paper. Those of ordinary skill in the art can refer to various commonly used reference books and scientific and technological documents before the filing date of the present invention. Or related instructions, manuals, etc. to implement.

A bimetallic composite biochar catalyst for sugar acid synthesis, the preparation method of the catalyst comprises the steps:

(1) Crushing and sieving the biomass to obtain biomass powder;

(2) adding the biomass powder obtained in step (1) and platinum salt and/or zinc salt, alkali salt into an organic solvent, and performing a solvothermal reaction to obtain the material;

(3) The material in step (2) was washed with absolute ethanol and ultrapure water, and dried to obtain a bimetallic composite biochar catalyst for the synthesis of sugar and acid.

Further, the platinum salt in step (2) is a platinum-containing inorganic salt, the zinc salt is a zinc-containing inorganic salt, the alkali salt is a hydroxide, and the organic solvent is a polyhydric alcohol. More preferred are 1,4-butanediol and ethylene glycol.

Alternatively, the biomass in step (1) is one or more of rice straw, wheat straw, corn straw, peanut straw, and sorghum straw;

Alternatively, use a pulverizer or a ball mill to pulverize;

Alternatively, crush through a 60-mesh sieve.

Preferably, the amount of platinum atoms in the platinum salt in step (2): the amount of zinc atoms in the zinc salt is 1:4-8; the amount of platinum atoms in the platinum salt in step (2): The amount of the substance of the alkali salt is 1:8-12. The mass ratio of the straw to the organic solution is 1:30-60; the mass ratio of the straw to the platinum atom in the platinum salt is 1:2-5.

Preferably, the mass ratio of the straw to the organic solution is 1:55; the mass ratio of the straw to the platinum atom in the platinum salt is 1:4.2; the amount of the platinum atom in the platinum salt: the zinc atom in the zinc salt The amount of substance in platinum salt is 1:6-8, most preferably 1:6; the amount of substance in platinum salt: the amount of substance in alkali salt is 1:10-12, most preferably 1:10.

Preferably, when the biomass powder, platinum salt, zinc salt, and alkali salt are added to the organic solvent in step (2), the platinum salt, zinc salt, and alkali salt are magnetically stirred and dissolved in the polyol solution, and the biomass powder The magnetic stirring is uniformly dispersed in the polyol solution, the rotating speed of the magnetic stirring is 500-1000rpm; the rotation time is 0.5-4h;

Alternatively, the temperature of the solvothermal reaction in step (2) is 150°C-250°C, and the reaction time is 8-24h. In the present invention, the temperature of the solvothermal is preferably controlled within the above range. If the solvothermal temperature is too low, the metal loading is low, and the temperature is too high, which wastes energy.

Alternatively, the cleaning process in step (3) is specifically: the product obtained in step (2) is mixed with absolute ethanol and ultrapure water in sequence, then stirred and centrifuged; the stirring time is 5-10min, and the stirring rate is 200 -300rmp, the stirring method is magnetic stirring, the number of times of washing with absolute ethanol is 2-3 times, and the number of times of washing with ultrapure water is 1-2 times; the rotating speed of the centrifugation is 10000rpm, and the centrifugation time is 2min;

Alternatively, the drying temperature in step (3) is 55-80° C.; the drying time is 10-24 hours.

Preferably, the rotating speed is 600-900rpm, most preferably 900rpm, and the rotation time is 1-2h, most preferably 1h;

The temperature of the solvothermal reaction is 180°C-220°C, most preferably 195°C; the time of the solvothermal reaction is 12-24h, most preferably 12h;

The drying temperature in step (3) is 80° C.; the drying time is 12 hours.

The application of the above-mentioned bimetallic composite biochar catalyst in the catalytic oxidation of biomass derivatives.

Utilize the method for catalyzing and oxidizing biomass derivatives with the above-mentioned bimetallic composite biochar catalyst, comprising the following steps:

The biomass derivative C5/C6 unit is added to water to configure a reaction solution with a substrate mass concentration of 1-10%. The bimetallic composite biochar catalyst used for the synthesis of sugar and acid is used as a catalyst in a magnetically stirred high-pressure reactor Fill the medium with oxygen and heat it. After the reaction is over, cool it with running water, release the pressure, and take out the upper layer liquid to obtain sugar acid.

Preferably, the sugar acid is gluconic acid or xylonic acid;

Alternatively, the Pt content on the surface of the bimetallic composite biochar catalyst is 0.10-0.26mmol/g; the Zn content on the material surface is 0.30-0.77mmol/g.

Alternatively, the biomass derivative: catalyst mass ratio is 1:1.5-10; the heating temperature is 50-120°C; the heating time is 0.1h-8h; the oxygen pressure is 0.2-2MPa; In the present invention, the temperature and time of the oxidation reaction are preferably controlled within the above range, which is beneficial to promote the complete oxidation of the C5/C6 unit of the biomass derivative.

Alternatively, it can be configured as a reaction solution with a substrate mass concentration of 1-5%;

Alternatively, the water is ultrapure water. In the present invention, the water is only used as a solvent and does not play a catalytic role. In the present invention, there is no special limitation on the source of the water, and products well known to those skilled in the art can be used.

Preferably, the Pt content on the surface of the bimetallic composite biochar catalyst is 0.10-0.15mmol/g; the Zn content on the surface of the material is 0.30-0.46mmol/g;

The mass ratio of the biomass derivative: catalyst is 1:2.5;

The heating temperature is 80-100°C; the heating time is 1-4h; the oxygen pressure is 0.2-1MPa;

Alternatively, the rate of the magnetic stirring is 500-800rmp.

In the present invention, there is no special requirement for the equipment in the pulverization process, and a pulverizer or a ball mill well-known to those skilled in the art can be used. In a specific embodiment of the present invention, the pulverizing equipment is preferably a pulverizer.

After the solvothermal treatment is completed, in the present invention, the product after the solvothermal treatment is preferably filtered, washed and dried in sequence to obtain a bimetallic composite biochar catalyst for the synthesis of sugar and acid. The present invention has no special limitation on the operations of filtering, washing and drying, and the technical solution of washing and drying well known to those skilled in the art can be adopted.

The present invention has no special requirements on the drying equipment, and a common blast drying oven in the field can be used.

In the present invention, there is no special limitation on the operation of mixing the composite biochar catalyst and biomass derivative C5/C6 unit, water and filling with oxygen, and the technical scheme of mixing well known to those skilled in the art can be adopted.

Specifically, the relevant preparation and detection are as follows:

Example 1

A preparation method of a platinum metal composite biochar catalyst for sugar acid synthesis, the steps are as follows:

(1) Take 0.2g of chloroplatinic acid and 0.2g of sodium hydroxide and dissolve them in 20ml of ethylene glycol solution; crush the rice straw through a 60-mesh sieve, take 0.4g of the crushed rice straw and add it to the above-mentioned ethylene glycol solution. Stir and mix well, magnetic stirring conditions: speed 900rpm, time 1h;

(2) After mixing, put it into a high-temperature and high-pressure reactor for solvothermal reaction, and the solvothermal conditions are: heating temperature 195° C., heating time 12 hours. After solvothermal, take out the carbonized bimetallic composite material, wash 2-3 times with ethanol, wash 1-2 times with ultrapure water, centrifuge to obtain the carbonized material, and finally dry it at 80°C for 12 hours to obtain the straw-based composite material. Platinum-containing porous biochar material (Pt/C).

Figure 1(a) is the TEM image of the product, which proves that metallic platinum is successfully loaded on the carbon support.

Figure 2(a) is the XPS pattern of the product, which proves that platinum exists on the surface of the material, and the surface Pt content is preferably 0.05-0.10mmol/g.

Figure 3 shows the yield and conversion rate of the material Pt/C prepared in Example 1 to catalyze the oxidation of glucose at 100° C. and 1 MPa oxygen for 1.5 h to produce gluconic acid.

Example 2

A kind of preparation method of zinc metal composite biochar catalyst for sugar acid synthesis, the steps are as follows:

(1) Take 0.4g of zinc chloride and 0.2g of sodium hydroxide and dissolve them in 20ml of ethylene glycol solution; crush the rice straw through a 60-mesh sieve, take 0.4g of the crushed rice straw and add it to the above-mentioned ethylene glycol solution. Stir and mix well, magnetic stirring conditions: speed 900rpm, time 1h;

(2) After mixing, put it into a high-temperature and high-pressure reactor for solvothermal reaction, and the solvothermal conditions are: heating temperature 195° C., heating time 12 hours. After solvothermal, take out the carbonized bimetallic composite material, wash 2-3 times with ethanol, wash 1-2 times with ultrapure water, centrifuge to obtain the carbonized material, and finally dry it at 80°C for 12 hours to obtain the straw-based composite material. Zinc-containing porous biochar material (Zn/C).

Figure 1(b) is the TEM image of the product, which proves that metallic zinc is evenly loaded on the carbon support.

Figure 2(b) is the XPS diagram of the product, which proves that zinc exists on the surface of the material, and the surface Zn content is preferably 2.00-3.00mmol/g.

Figure 3 shows the yield and conversion rate of the material Pt/C prepared in Example 2 to catalyze the oxidation of glucose at 100° C. and 1 MPa oxygen for 1.5 h to produce gluconic acid.

Example 3

A method for preparing a bimetallic composite biochar catalyst for sugar acid synthesis, the steps are as follows:

(1) Dissolve 0.2g of chloroplatinic acid, 0.4g of zinc chloride and 0.2g of sodium hydroxide in 20ml of ethylene glycol solution; crush the rice straw through a 60-mesh sieve, take 0.4g of the crushed rice straw and add the above-mentioned ethylene glycol solution In the alcohol solution, mix evenly by magnetic stirring, magnetic stirring conditions: speed 900rpm, time 1h;

(2) After mixing, put it into a high-temperature and high-pressure reactor for solvothermal reaction, and the solvothermal conditions are: heating temperature 195° C., heating time 12 hours. After solvothermal, take out the carbonized bimetallic composite material, wash 2-3 times with ethanol, wash 1-2 times with ultrapure water, centrifuge to obtain the carbonized material, and finally dry it at 80°C for 12 hours to obtain sugar acid Bimetallic composite biochar catalyst (Pt/Zn/C) for synthesis.

Calculated by XPS results, the surface Pt content in the bimetallic composite biochar catalyst prepared by the present embodiment is preferably 0.10-0.26mmol/g, more preferably 0.10-0.15mmol/g; the material surface Zn The content is preferably 0.30-0.77 mmol/g, more preferably 0.30-0.46 mmol/g.

Figure 1(c) is the TEM image of the product, which proves that the metal was successfully supported on the carbon support.

Figure 2 (c) is the XPS pattern of the product, which proves that platinum and zinc exist on the surface of the material, and part of the platinum is reduced by the polyol solution.

Figure 3 shows the yield and conversion rate of the material Pt/Zn/C prepared in Example 3 to catalyze the oxidation of glucose at 100° C. and 1 MPa oxygen for 1.5 h to produce gluconic acid.

Fig. 4 is a graph showing the variation of the yield of gluconic acid produced by the catalytic oxidation of glucose at different reaction temperatures with the reaction time of the material prepared in Example 3.

Application example 1

A method for synthesizing sugar and acid, the steps are as follows:

Get 0.02 g of the straw-based platinum-containing porous biochar material (Pt/C) prepared in Example 1, mix with 0.05 g of glucose, and 5 ml of ultrapure water to obtain a mixed solution (the mass concentration of glucose in the mixed solution is 1%, and the straw-based The mass ratio of platinum-containing porous biochar catalyst to glucose is 1:2.5), and then the mixed solution is transferred to a high-pressure reactor, filled with 1MPa oxygen, and the oxidation reaction is carried out at 100°C, accompanied by magnetic stirring, and the stirring rate is 800rmp; after 1.5h, the reaction was completed, and the reaction mixture was quickly cooled with an ice-water bath, and then filtered through a filter membrane, and the filtered solution was used for liquid chromatography to determine the product, and the yield of gluconic acid was calculated.

Wherein, the conditions of the liquid chromatography are as follows: the chromatographic column is Shodex SH1011, the mobile phase is 0.5ml/min sulfuric acid solution (5mM), the column temperature is 50°C, and the injection volume is 10uL. The gluconic acid detector is an ultraviolet detector to measure the sample components at 210nm, and the detector temperature is 25°C. The glucose detector is a differential detector, and the detector temperature is 35°C.

Finally, the yield of gluconic acid was measured to be 21.0%, and the conversion rate of glucose was 28.7%.

Application example 2

A method for synthesizing sugar and acid, the steps are as follows:

Get the straw-based zinc-containing porous biochar material (Zn/C) 0.02g prepared in Example 2, mix with glucose 0.05g, and ultrapure water 5ml to obtain a mixed solution (the mass concentration of glucose in the mixed solution is 1%, and the straw-based The mass ratio of zinc-containing porous biochar catalyst to glucose is 1:2.5), and then the mixed solution is transferred to a high-pressure reactor, filled with 1MPa oxygen, and the oxidation reaction is carried out at 100°C, accompanied by magnetic stirring, and the stirring rate is 800rmp; after 1.5h, the reaction was completed, and the reaction mixture was quickly cooled with an ice-water bath, and then filtered through a filter membrane, and the filtered solution was used for liquid chromatography to determine the product, and the yield of gluconic acid was calculated.

Wherein, the conditions of the liquid chromatography are as follows: the chromatographic column is Shodex SH1011, the mobile phase is 0.5ml/min sulfuric acid solution (5mM), the column temperature is 50°C, and the injection volume is 10uL. The gluconic acid detector is an ultraviolet detector to measure the sample components at 210nm, and the detector temperature is 25°C. The glucose detector is a differential detector, and the detector temperature is 35°C.

Finally, the yield of gluconic acid was measured to be 0.5%, and the conversion rate of glucose was 4.2%.

Application example 3

A method for synthesizing sugar and acid, the steps are as follows:

Get the bimetallic composite biochar catalyst (Pt/Zn/C) 0.02g and glucose 0.05g for the synthesis of sugar and acid prepared in Example 3, and mix homogeneously with ultrapure water 5ml to obtain a mixed solution (the mass concentration of glucose in the mixed solution is 1 %, the mass ratio of bimetallic composite biochar catalyst for sugar-acid synthesis to glucose is 1:2.5), and then transfer the mixture to a high-pressure reactor, fill it with 1MPa oxygen, and carry out oxidation reaction at 100°C, accompanied by magnetic force Stir, the stirring rate is 800rmp; after 1.5h, the reaction is completed, and the reaction mixture is quickly cooled with an ice-water bath, and then filtered with a filter membrane, and the filtered solution is used for liquid chromatography to determine the product and calculate the yield of gluconic acid.

Wherein, the conditions of the liquid chromatography are as follows: the chromatographic column is Shodex SH1011, the mobile phase is 0.5ml/min sulfuric acid solution (5mM), the column temperature is 50°C, and the injection volume is 10uL. The gluconic acid detector is an ultraviolet detector to measure the sample components at 210nm, and the detector temperature is 25°C. The glucose detector is a differential detector, and the detector temperature is 35°C.

Finally, it was measured that the yield of gluconic acid was 88%, and the conversion rate of glucose was 100%.

Application example 4

A method for synthesizing sugar and acid, the steps are as follows:

Get the bimetallic composite biochar catalyst (Pt/Zn/C) 0.02g and xylose 0.05g of the sugar-acid synthesis prepared by Example 3, mix homogeneously with ultrapure water 5ml, obtain mixed solution (the mass concentration of xylose in the mixed solution 1%, the mass ratio of bimetallic composite biochar catalyst for sugar-acid synthesis to xylose is 1:2.5), then the mixed solution was transferred to a high-pressure reactor, filled with 1MPa oxygen, and the oxidation reaction was carried out at 100°C. And accompanied by magnetic stirring, the stirring rate is 800rmp; after 1.5h, the reaction is completed, and the reaction mixture is quickly cooled with an ice-water bath, and then filtered with a filter membrane, and the filtered solution is taken for liquid chromatography to determine the product, and calculate the yield of xylonic acid .

Wherein, the conditions of the liquid chromatography are as follows: the chromatographic column is Shodex SH1011, the mobile phase is 0.5ml/min sulfuric acid solution (5mM), the column temperature is 50°C, and the injection volume is 10uL. The xylonic acid detector is an ultraviolet detector to measure the sample components at 210nm, and the detector temperature is 25°C. The xylose detector is a differential detector, and the detector temperature is 35°C.

Finally, it was found that the yield of xylonic acid was 65%, and the conversion rate of xylose was 100%.

The calculation formula of the productive rate in the above-mentioned application example is:

Gluconic acid yield (mol%) = gluconic acid production (mol) / glucose sugar unit (mol) × 100%

Yield of xylose acid (mol%) = amount of xylose acid produced (mol)/xylose sugar unit (mol) × 100%.

Although the embodiments of the present invention are disclosed for the purpose of illustration, those skilled in the art will understand that various alternatives, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims, therefore However, the scope of the present invention is not limited to the content disclosed in the embodiments.

Claims (6)

1. a bimetallic composite biochar catalyst for sugar acid synthesis, is characterized in that: the preparation method of said catalyst comprises the steps: (1) Crushing and sieving the biomass to obtain biomass powder; (2) adding the biomass powder, platinum salt, zinc salt, and alkali salt obtained in step (1) into an organic solvent, and performing a solvothermal reaction to obtain the material; (3) washing the material in step (2) with absolute ethanol and ultrapure water, and drying to obtain a bimetallic composite biochar catalyst for the synthesis of sugar and acid; The platinum salt in step (2) is a platinum-containing inorganic salt, the zinc salt is a zinc-containing inorganic salt, the alkali salt is a hydroxide, and the organic solvent is a polyhydric alcohol; The biomass in step (1) is one or more of rice straw, wheat straw, corn straw, peanut straw, and sorghum straw; When crushing, use a pulverizer or a ball mill to pulverize; Crushed through a 60-mesh sieve; The amount of substance of platinum atom in platinum salt in step (2): the amount of substance of zinc atom in zinc salt is 1:4-8; the amount of substance of platinum atom in platinum salt in step (2): substance of alkali salt The amount of the biomass is 1:8-12; the mass ratio of the biomass powder to the organic solution is 1:30-60; the mass ratio of the biomass powder to the platinum atom in the platinum salt is 1:2-5; When the biomass powder, platinum salt, zinc salt, and alkali salt are added to the organic solvent in step (2), the platinum salt, zinc salt, and alkali salt are magnetically stirred and dissolved in the polyol solution, and the biomass powder is evenly dispersed by magnetic stirring In the polyol solution, the magnetic stirring speed is 500-1000rpm; the rotation time is 0.5-4h; The temperature of the solvothermal reaction in step (2) is 150°C-250°C, and the reaction time is 8-24h; The cleaning process in step (3) is as follows: the product obtained in step (2) is mixed with absolute ethanol and ultrapure water in sequence, then stirred and centrifuged; the stirring time is 5-10min, and the stirring rate is 200-300rmp , the way of stirring is magnetic stirring, the number of times of washing with absolute ethanol is 2-3 times, and the number of times of washing with ultrapure water is 1-2 times; the rotating speed during the centrifugation is 10000rpm, and the centrifugation time is 2min; The drying temperature in step (3) is 55-80°C; the drying time is 10-24h; The rotation speed is 600-900rpm, and the rotation time is 1-2h. 2. The bimetallic composite biochar catalyst for sugar-acid synthesis according to claim 1, characterized in that: the mass ratio of the straw to the organic solution is 1:55; the mass ratio of the straw to the platinum atom in the platinum salt It is 1:4.2; the amount of substance of platinum atom in platinum salt: the amount of substance of zinc atom in zinc salt is 1:6-8; the amount of substance of platinum atom in platinum salt: the amount of substance of alkali salt is 1: 10-12; The temperature of the solvothermal reaction in step (2) is 180°C-220°C, and the time of the solvothermal reaction is 12-24h; The drying temperature in step (3) is 80° C.; the drying time is 12 hours. 3. The application of the bimetallic composite biochar catalyst as claimed in claim 1 or 2 in the catalytic oxidation of xylose or glucose. 4. utilize the method for catalyzed oxidation xylose or glucose as claimed in claim 1 or 2, it is characterized in that: comprise the steps: Add xylose or glucose into water to configure a reaction solution with a substrate mass concentration of 1-10%. The sugar-acid synthesis uses a bimetallic composite biochar catalyst as a catalyst, and oxygen is filled in a magnetically stirred high-pressure reactor Heating afterward, cooling with running water after the reaction is over, and taking out the upper layer liquid after releasing the pressure to obtain sugar acid; the sugar acid is gluconic acid or xylonic acid. 5. The method according to claim 4, characterized in that: the Pt content on the surface of the bimetallic composite biochar catalyst is 0.10-0.26mmol/g; the Zn content on the material surface is 0.30-0.77mmol/g; Alternatively, the biomass derivative: catalyst mass ratio is 1:1.5-10; the heating temperature is 50-120°C; the heating time is 0.1h-8h; the oxygen pressure is 0.2-2MPa; Alternatively, it can be configured as a reaction solution with a substrate mass concentration of 1-5%; Alternatively, the water is ultrapure water. 6. The method according to claim 5, characterized in that: the Pt content on the surface of the bimetallic composite biochar catalyst is 0.10-0.15mmol/g; the Zn content on the material surface is 0.30-0.46mmol/g; The mass ratio of the biomass derivative: catalyst is 1:2.5; The heating temperature is 80-100°C; the heating time is 1-4h; the oxygen pressure is 0.2-1MPa; or, the magnetic stirring rate is 500-800rmp.

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