Method for preparing glyceric acid by catalytically oxidizing glycerol with non-noble metal catalyst

Abstract

The invention discloses a method for preparing glyceric acid by catalytically oxidizing glycerol with a non-noble metal catalyst, which comprises the following steps of: catalytically oxidizing glycerol under the action of oxygen by taking a CuZrOx composite oxide as a catalyst to obtain glyceric acid; wherein the CuZrOx composite oxide is prepared by a deposition-precipitation method through high-temperature calcination. The internal structure of the catalyst is changed due to introduction of Cu, two metal components are combined more tightly and have strong interaction due to doping of Cu, and meanwhile, compared with a single-metal catalyst, the number of oxygen vacancies of the composite oxide catalyst is increased, the number of strongly acidic sites and strongly basic sites on the surface is increased, and the catalytic activity of the catalyst is improved. According to the present invention, the catalyst has a certain acid-base property so as to produce the good catalysis effect, such that the high glycerol conversion rate and the high glyceric acid selectivity are achieved while the production cost is reduced, and the catalyst can be repeatedly used.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of catalysis, and particularly relates to a method for preparing glyceric acid by catalytic oxidation of glycerol through a non-noble metal catalyst. BACKGROUND

[0002] Under the background of the current era of sustainable development, biomass energy has become a global focus of energy research and development due to its advantages of less pollution and renewability, and biodiesel, as an important renewable energy, has attracted more and more attention, which has led to an oversupply of glycerol and a certain degree of impact on the price of glycerol. Therefore, the conversion of glycerol into other high-value-added products has become a current research hotspot.

[0003] There are many conversion pathways for glycerol, and compared with other pathways, oxidation is an effective way to generate high-value-added products. The typical catalysts for glycerol oxidation to obtain value-added products are three noble metals Au, Pt and Pd and their corresponding alloys. Carretin et al. found that in the presence of base, a 1% Au / C catalyst has a glyceric acid selectivity of 100% at a glycerol conversion rate of 56%, while in the absence of NaOH, there is no glycerol conversion on the Au catalyst (Chem Commun. 2002, 7, 696-697); Carretin et al. also found that one of the main advantages of using supported Pt and Pd catalysts is that glycerol oxidation can be carried out even without base, but the main disadvantage is that the active sites are easily deactivated (Phys. Chem. Chem. Phys. 2003, 5, 1329-1336). It can be seen that such noble metal supported catalysts have problems such as dependence on alkaline conditions, easy deactivation of active sites, and low recovery rate, and Kimura, Dumeignil and their colleagues pointed out that due to the presence of noble metals, even if reused 10 times, the price of the catalyst still accounts for 95% of the production cost of dihydroxyacetone, propylene glycol acid and glycolic acid (Green Chem. 2011, 13; 1960-1979), so more attention has been paid to the exploration of non-noble metal catalysts.

[0004] Glyceric acid, as a multifunctional and highly valuable fine chemical, has shown important application potential in many fields. In the pharmaceutical field, glyceric acid and its derivatives are involved in the synthesis of many drugs, and play a key role in the activity and efficacy of drugs; in the food industry, glyceric acid can be used as a food additive to improve the quality, taste and shelf life of food. More importantly, glyceric acid is also an extremely important organic synthesis intermediate, which can derive a variety of compounds with special properties, further expanding its application range in industrial production. SUMMARY

[0005] The application aims at reducing the production cost of the catalyst, and provides a method for preparing glyceric acid by catalytic oxidation of glycerol with a non-noble metal catalyst with low production cost and good stability.

[0006] To achieve the above object, the application adopts the technical scheme of: using CuZrO x as the catalyst, reacting glycerol and oxygen at 80-110 DEG C to obtain glyceric acid; after the reaction, the catalyst is filtered, washed with deionized water and reused.

[0007] Further, the above technical scheme is preferably: the glycerol aqueous solution and CuZrO x are added into a high-pressure reaction kettle, and the stirring reaction is carried out at 80-110 DEG C under the oxygen pressure of 0.5-1 MPa for 2-9 h to obtain glyceric acid.

[0008] Further, the concentration of glycerol in the above glycerol aqueous solution is preferably 0.1-0.2 mol·L -1 .

[0009] Further, the above CuZrO x has a mass / volume ratio of 1 mg:0.6-3 mL with the glycerol aqueous solution.

[0010] The above CuZrO x has a molar ratio of Cu to Zr of 1:1-1:4, and the preparation method is as follows: copper nitrate and zirconium nitrate are added into deionized water, the mixture is stirred and heated to 70-80 DEG C, 1-2 mol·L -1 of ammonium carbonate aqueous solution is added to adjust the pH of the mixed solution to 6-7, the stirring and aging are continued at the temperature for 2-3 h, the mixture is cooled to room temperature, the precipitate is washed with deionized water to neutral, dried at 100-110 DEG C, and then calcined at 300-700 DEG C in static air for 4-6 h to obtain the CuZrO x .

[0011] Further, the above CuZrO x has a molar ratio of Cu to Zr of 1:2.

[0012] Further, in the preparation method of the above CuZrO x , the copper nitrate and zirconium nitrate are added into deionized water, the mixture is stirred and heated to 70 DEG C, 1 mol·L -1 of ammonium carbonate aqueous solution is added to adjust the pH of the mixed solution to 6.5, the stirring and aging are continued at the temperature for 2 h, the mixture is cooled to room temperature, the precipitate is washed with deionized water to neutral, dried at 110 DEG C, and then calcined at 500 DEG C in static air for 4 h to obtain the CuZrO x .

[0013] The beneficial effects of the present application are as follows:

[0014] The present application successfully prepares a non-noble metal CuZrO x As a catalyst, the composite oxide changes the internal structure due to the introduction of Cu, and the two metal components are combined more closely due to Cu doping, resulting in strong interaction. Compared with a single metal catalyst, the CuZrO x The increase in the number of oxygen vacancies of the composite oxide catalyst, the increase in the number of strong acid sites and strong basic sites on the surface, and the certain acid and base properties of the catalyst result in better catalytic effect, achieve the purpose of reducing production cost while obtaining high glycerol conversion rate and glyceric acid selectivity, and the catalyst can be reused. At the same time, no additional alkaline substance is needed in the method of the present application, reducing the burden of neutralization wastewater treatment. DETAILED DESCRIPTION

[0015] The present application will be described clearly and completely in conjunction with examples. Obviously, the described examples are only some of the embodiments of the present application, but not all. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0016] Example 1

[0017] 1. Preparation of CuZrO x composite oxide

[0018] 6.4154 g (26.55 mmol) of copper nitrate trihydrate, 11.4 g (26.55 mmol) of zirconium nitrate pentahydrate (molar ratio of Cu to Zr is 1:1) were added to a beaker, and 350 mL of deionized water was added. After stirring and heating to 70℃, 1 mol·L -1 Ammonium carbonate aqueous solution was added dropwise to the resulting mixed solution until the pH of the solution was 6.5, and the strong magnetic stirring was continued at 70℃ for 2h. After cooling to room temperature, the precipitate was washed with deionized water until it was neutral, dried at 110℃ for 24h, then heated to 500℃ at a heating rate of 5℃ / min in static air, and calcined at constant temperature for 4h to obtain CuZrO x composite oxide (denoted as CuZrO x -1:1).

[0019] 2. CuZrO x composite oxide catalytic oxidation of glycerol to prepare glyceric acid

[0020] 30 mL of glycerol aqueous solution and 30 mg of CuZrO xThe composite oxide was added into a high-pressure reaction kettle, and nitrogen and oxygen were each filled and discharged three times. The fourth oxygen was retained, and the oxygen pressure was 1 MPa. The reaction was stirred at 100 °C for 5 h at a working speed of 600 r / min. After the reaction was completed, the catalyst was filtered, washed with deionized water, and recovered for reuse. It was detected that the conversion rate of glycerol was 61.74%, and the selectivity of glyceric acid was 42.98%.

[0021] Example 2

[0022] 1. Preparation of CuZrO x Composite oxide

[0023] 3.2077 g (13.28 mmol) of copper nitrate trihydrate, 11.4 g (26.55 mmol) of zirconium nitrate pentahydrate (molar ratio of Cu to Zr is 1:2), and 350 mL of deionized water were added into a beaker. After stirring and heating to 70 °C, 1 mol·L -1 Ammonium carbonate aqueous solution was added dropwise into the resulting mixed solution until the pH of the solution was 6.5. After continuing to stir and age at 70 °C for 2 h, the solution was cooled to room temperature. The precipitate was washed with deionized water until it was neutral. The precipitate was dried at 110 °C for 24 h, and then heated to 500 °C at a heating rate of 5 °C / min in static air. The temperature was kept constant for 4 h to obtain CuZrO x Composite oxide (denoted as CuZrO x -1:2).

[0024] 2. CuZrO x Composite oxide catalyzing oxidation of glycerol to prepare glyceric acid

[0025] The CuZrO x Composite oxide prepared in this example was used to catalyze oxidation of glycerol to prepare glyceric acid according to the method of step 2 in Example 1. It was detected that the conversion rate of glycerol was 73.16%, and the selectivity of glyceric acid was 48.81%.

[0026] The recovered catalyst was repeatedly used to catalyze oxidation of glycerol to prepare glyceric acid according to the above method. The results showed that after being used for 5 times, the conversion rate of glycerol could still reach 65.76%, and the selectivity of glyceric acid was 39.49%.

[0027] Example 3

[0028] 1. Preparation of CuZrO x Composite oxide

[0029] 1.6038 g (6.64 mmol) of copper nitrate trihydrate, 11.4 g (26.55 mmol) of zirconium nitrate pentahydrate (molar ratio of Cu to Zr is 1:4), and 350 mL of deionized water were added into a beaker. After stirring and heating to 70 °C, 1 mol·L-1 The dropping of the aqueous ammonium carbonate solution into the mixed solution was stopped when the pH of the solution was 6.5, and the solution was aged at 70°C under strong magnetic stirring for 2h, then cooled to room temperature, and the precipitate was washed with deionized water until neutral, dried at 110°C for 24h, then heated to 500°C at a heating rate of 5°C / min in static air, and calcined at 500°C for 4h to obtain CuZrO x The composite oxide (denoted as CuZrO x -1:4).

[0030] 2.CuZrO x Preparation of glyceric acid by catalytic oxidation of glycerol using the composite oxide

[0031] The CuZrO x The composite oxide prepared in this example was used to catalytically oxidize glycerol to prepare glyceric acid according to the method of step 2 of Example 1. The conversion rate of glycerol was 55.69%, and the selectivity of glyceric acid was 40.34%.

[0032] Example 4

[0033] In this example, the CuZrO x The preparation method of the composite oxide was the same as that of step 1 in Example 2. 30mL of an aqueous glycerol solution and 30mg of CuZrO x The composite oxide was added to a high-pressure reaction kettle, and nitrogen and oxygen were each filled and discharged three times, the fourth oxygen was retained, and the oxygen pressure was 1MPa. The reaction was stirred at 80°C for 5h, and the working speed was 600r / min. After the reaction was completed, the catalyst was filtered and washed with deionized water for recovery and reuse. The conversion rate of glycerol was 53.48%, and the selectivity of glyceric acid was 43.88%.

[0034] Example 5

[0035] In this example, the CuZrO x The preparation method of the composite oxide was the same as that of step 1 in Example 2. 30mL of an aqueous glycerol solution and 30mg of CuZrO x The composite oxide was added to a high-pressure reaction kettle, and nitrogen and oxygen were each filled and discharged three times, the fourth oxygen was retained, and the oxygen pressure was 1MPa. The reaction was stirred at 80°C for 5h, and the working speed was 600r / min. After the reaction was completed, the catalyst was filtered and washed with deionized water for recovery and reuse. The conversion rate of glycerol was 53.48%, and the selectivity of glyceric acid was 43.88%.

[0036] Example 6

[0037] In this example, the CuZrO x The preparation method of the composite oxide was the same as that of step 1 in Example 2. 30mL of an aqueous glycerol solution and 30mg of CuZrOx The composite oxide was added into a high-pressure reaction kettle, and each of nitrogen and oxygen was filled and discharged for three times, the fourth oxygen was reserved, and the oxygen pressure was 1 MPa. The stirring reaction was carried out at 110°C for 5h, and the working speed was 600r / min. After the reaction was completed, the catalyst was filtered, washed with deionized water, and recovered for reuse. It was detected that the conversion rate of glycerol was 97.55%, and the selectivity of glyceric acid was 31.66%.

[0038] Example 7

[0039] In this embodiment, CuZrO x The preparation method of the composite oxide was the same as step 1 in example 2. 30mL glycerol aqueous solution and 10mg CuZrO x The composite oxide was added into a high-pressure reaction kettle, and each of nitrogen and oxygen was filled and discharged for three times, the fourth oxygen was reserved, and the oxygen pressure was 1 MPa. The stirring reaction was carried out at 110°C for 5h, and the working speed was 600r / min. After the reaction was completed, the catalyst was filtered, washed with deionized water, and recovered for reuse. It was detected that the conversion rate of glycerol was 97.55%, and the selectivity of glyceric acid was 31.66%.

[0040] Example 8

[0041] In this embodiment, CuZrO x The preparation method of the composite oxide was the same as step 1 in example 2. 30mL glycerol aqueous solution and 40mg CuZrO x The composite oxide was added into a high-pressure reaction kettle, and each of nitrogen and oxygen was filled and discharged for three times, the fourth oxygen was reserved, and the oxygen pressure was 1 MPa. The stirring reaction was carried out at 110°C for 5h, and the working speed was 600r / min. After the reaction was completed, the catalyst was filtered, washed with deionized water, and recovered for reuse. It was detected that the conversion rate of glycerol was 97.55%, and the selectivity of glyceric acid was 31.66%.

[0042] Example 9

[0043] In this embodiment, CuZrO x The preparation method of the composite oxide was the same as step 1 in example 2. 30mL glycerol aqueous solution and 50mg CuZrO x The composite oxide was added into a high-pressure reaction kettle, and each of nitrogen and oxygen was filled and discharged for three times, the fourth oxygen was reserved, and the oxygen pressure was 1 MPa. The stirring reaction was carried out at 110°C for 5h, and the working speed was 600r / min. After the reaction was completed, the catalyst was filtered, washed with deionized water, and recovered for reuse. It was detected that the conversion rate of glycerol was 97.55%, and the selectivity of glyceric acid was 31.66%.

[0044] Example 10

[0045] In this embodiment, CuZrO x The preparation method of the composite oxide is the same as step 1 in Example 2. 30 mL of a glycerol aqueous solution and 30 mg of CuZrO x The composite oxide was added to a high-pressure reaction kettle, and nitrogen and oxygen were each filled and discharged three times, the fourth oxygen was retained, and the oxygen pressure was 1 MPa. The reaction was stirred at 100℃ for 3h, and the working speed was 600r / min. After the reaction was completed, the catalyst was filtered, washed with deionized water, and recovered for reuse. It was detected that the conversion rate of glycerol was 72.70%, and the selectivity of glyceric acid was 48.69%.

[0046] Example 11

[0047] In this embodiment, CuZrO x The preparation method of the composite oxide is the same as step 1 in Example 2. 30 mL of a glycerol aqueous solution and 30 mg of CuZrO x The composite oxide was added to a high-pressure reaction kettle, and nitrogen and oxygen were each filled and discharged three times, the fourth oxygen was retained, and the oxygen pressure was 1 MPa. The reaction was stirred at 100℃ for 7h, and the working speed was 600r / min. After the reaction was completed, the catalyst was filtered, washed with deionized water, and recovered for reuse. It was detected that the conversion rate of glycerol was 80.70%, and the selectivity of glyceric acid was 45.44%.

[0048] Example 12

[0049] In this embodiment, CuZrO x The preparation method of the composite oxide is the same as step 1 in Example 2. 30 mL of a glycerol aqueous solution and 30 mg of CuZrO x The composite oxide was added to a high-pressure reaction kettle, and nitrogen and oxygen were each filled and discharged three times, the fourth oxygen was retained, and the oxygen pressure was 1 MPa. The reaction was stirred at 100℃ for 9h, and the working speed was 600r / min. After the reaction was completed, the catalyst was filtered, washed with deionized water, and recovered for reuse. It was detected that the conversion rate of glycerol was 95.03%, and the selectivity of glyceric acid was 33.71%.

[0050] Comparative Example 1

[0051] In step 1 of Example 1, no copper nitrate trihydrate was added, and the other steps were the same as step 1 of Example 1 to obtain a single metal catalyst ZrO2. The other steps were the same as Example 1. The single metal catalyst ZrO2 was used to catalyze the oxidation of glycerol to prepare glyceric acid according to the method of step 2 of Example 1. It was detected that the conversion rate of glycerol was 48.48%, and the selectivity of glyceric acid was 34.60%.

[0052] Comparative Example 2

[0053] In step 1 of Example 1, no zirconium nitrate pentahydrate was added, only 11.4 g (47.18 mmol) of copper nitrate trihydrate was added, and the other steps were the same as those in step 1 of Example 1 to obtain a monometallic catalyst CuO. The monometallic catalyst CuO was used to catalyze the oxidation of glycerol to prepare glyceric acid according to the method of step 2 of Example 1. It was detected that the conversion rate of glycerol was 51.39%, and the selectivity of glyceric acid was 13.16%.

Claims

1. A method for preparing glyceric acid by catalytic oxidation of glycerol using a non-precious metal catalyst, characterized in that: CuZrO x Using composite oxide as catalyst, glycerol and oxygen react at 80-110°C to produce glyceric acid; after the reaction, the catalyst is filtered, washed with deionized water and reused; The CuZrO x The molar ratio of Cu to Zr in the composite oxide is 1:1 to 1:

4. The preparation method is as follows: add copper nitrate and zirconium nitrate into deionized water, stir and heat to 70 to 80 ° C, then add 1 to 2 mol·L -1 The pH of the mixed solution is adjusted to 6-7 with an aqueous solution of ammonium carbonate, and the mixture is stirred and aged for 2-3 hours at the same temperature, then cooled to room temperature, washed with deionized water until the precipitate is neutral, dried at 100-110°C, and then calcined at 300-700°C in static air for 4-6 hours to obtain CuZrO x Composite oxides.

2. The method for preparing glyceric acid by catalytic oxidation of glycerol using a non-noble metal catalyst according to claim 1, characterized in that: Glycerol aqueous solution and CuZrO x The composite oxide is added into a high-pressure reactor, and stirred and reacted at 80-110° C. for 2-9 hours under an oxygen pressure of 0.5-1 MPa to obtain glyceric acid.

3. The method for preparing glyceric acid by catalytic oxidation of glycerol using a non-noble metal catalyst according to claim 2, characterized in that: The concentration of glycerol in the glycerol aqueous solution is 0.1 to 0.2 mol·L -1 .

4. The method for preparing glyceric acid by catalytic oxidation of glycerol using a non-noble metal catalyst according to claim 2 or 3, characterized in that: The CuZrO x The volume ratio of the added mass of the composite oxide to the glycerol aqueous solution is 1 mg:0.6-3 mL.

5. The method for preparing glyceric acid by catalytic oxidation of glycerol using a non-noble metal catalyst according to claim 1, wherein: The CuZrO x In the composite oxide, the molar ratio of Cu to Zr is 1:

2.

6. The method for preparing glyceric acid by catalytic oxidation of glycerol using a non-noble metal catalyst according to claim 1 or 5, characterized in that: The CuZrO x The preparation method of the composite oxide is as follows: copper nitrate and zirconium nitrate are added to deionized water, stirred and heated to 70°C, and then 1 mol·L -1 The pH of the mixed solution was adjusted to 6.5 with an aqueous solution of ammonium carbonate, and the mixture was stirred and aged for 2 h at the same temperature, then cooled to room temperature, washed with deionized water until the precipitate was neutral, dried at 110 ° C, and then calcined at 500 ° C in static air for 4 h to obtain CuZrO x Composite oxides.