Preparation method and application of catalyst for synthesizing glycollic acid

Abstract

The invention discloses a catalyst for synthesizing glycollic acid and a preparation method. The catalyst comprises the following components in percentage by weight: 5-10% of copper oxide, 15-40% of manganese oxide, zirconium oxide or cerium oxide and 50-80% of modified aluminum oxide. The preparation method comprises the following steps: adding a certain amount of copper-containing compound solution into aluminum oxide powder modified by manganese chloride, zirconium chloride or cerium chloride, adding gel containing water, binder methyl cellulose and peptizing agent, uniformly kneading on a kneading machine, and extruding and molding the kneaded material on a banded extruder to obtain the copper-containing aluminum oxide composite material. And drying and roasting to obtain the catalyst for synthesizing glycollic acid. The catalyst for synthesizing glycollic acid, prepared by the invention, takes modified aluminum oxide as a main component, and has better activity and performance; the preparation process provided by the invention is relatively environment-friendly, and has a relatively good application prospect.

Description

Technical Field

[0001] The invention relates to a preparation method and application of a catalyst for synthesizing glycolic acid, belonging to the technical field of synthetic catalysts. Background Art

[0002] Glycolic acid, also known as glycolic acid, is the simplest aliphatic hydroxycarboxylic acid. Its molecule contains both hydroxyl and carboxyl groups, combining the properties of both an alcohol and an acid. In nature, glycolic acid is primarily found in sugarcane, sugar beets, and unripe grapes, but its concentration is low and its isolation is difficult. Glycolic acid is an important chemical product and intermediate, widely used in many fields, including chemicals, pharmaceuticals, pesticides, feed, fuel, and fragrances. Glycolic acid can self-polymerize into polyglycolic acid, which exhibits excellent biodegradability and biocompatibility and is currently a key development focus in the new materials field. The main methods for synthesizing glycolic acid include cyanidation, hydrolysis with chloroacetic acid, carbonylation with formaldehyde, electrolytic reduction with oxalic acid, coupling of formaldehyde with methyl formate, hydrogenation of dimethyl oxalate, microbial catalysis, and selective oxidation of ethylene glycol. With the continuous development of the industry, the purity of glycolic acid products has continued to improve.

[0003] Chinese Patent CN102584566A discloses a method for preparing glycolic acid. The method uses glyoxal as a raw material, undergoes a disproportionation reaction in the presence of potassium hydroxide and a phase transfer catalyst to produce potassium glycolate, which is then acidified to produce glycolic acid. This method has the advantage of increasing the purity of the product to over 98%. However, this method has the disadvantages of being flammable, toxic, and environmentally harmful. Under increasingly stringent safety and environmental requirements, the selective oxidation of ethylene glycol has attracted increasing attention. Chinese Patent CN114031493A discloses a method for preparing glycolic acid by selectively oxidizing ethylene glycol and sodium hydroxide using oxygen as an oxidant, a primary catalyst with a solvent and palladium as the main active component, and bismuth and cerium dioxide as auxiliary catalysts. The yield of glycolic acid can reach 95%, but the method requires the use of a strong base, which is environmentally unfriendly. Summary of the Invention

[0004] The object of the present invention is to overcome the deficiencies of the prior art and to provide a catalyst for synthesizing glycolic acid and a method for preparing the same.

[0005] The technical solutions of the present invention are as follows:

[0006] The catalyst comprises the following components: 5-15% copper oxide content, 15-40% manganese oxide, zirconium oxide or cerium oxide content, and 50-80% modified aluminum oxide content.

[0007] The preparation method of the catalyst comprises the following steps: adding a certain amount of copper compound solution and gel containing water, methyl cellulose as a binder and nitric acid as a peptizer to alumina powder modified by manganese chloride, zirconium chloride or cerium chloride, kneading the mixture evenly on a kneader, extruding the kneaded material on an extruder, and drying and calcining the mixture to obtain a catalyst for synthesizing glycolic acid.

[0008] The preparation method of the modified alumina is as follows: mixing aluminum chloride solution with a modifier solution, adding an alkaline solution to adjust the pH to 10-12, and after the reaction is completed, performing a post-processing process to obtain the modified alumina. The specific surface area of the modified alumina powder is 150-300m 2 / g.

[0009] The modifier solution is a solution of manganese chloride, zirconium chloride, and cerium chloride; the molar ratio of aluminum chloride to modifier is 2:1 to 2:3; the alkaline solution is a NaOH solution; the reaction temperature is 60 to 80°C, and the reaction time is 4 to 6 hours; the post-treatment process is stirring for 24 to 48 hours, followed by a separation process, a washing process, a drying process, and a calcination process.

[0010] The ratio of the modified alumina, gel and copper ion solution is as follows: 0.1-0.5 ml of gel and 10-35 ml of copper compound solution are required for every 10 g of modified alumina powder, wherein the molar concentration of the copper compound solution is 0.5-1 mol / L.

[0011] The copper ion-containing solution is copper sulfate or copper nitrate solution; the gel containing water, a binder and a peptizing agent comprises methyl cellulose as the binder and nitric acid as the peptizing agent.

[0012] The mixing and pressing process comprises using a kneader to evenly knead the modified alumina, gel and copper ion solution, and then extruding the mixture through an extruder; and the drying and calcining process comprises drying the catalyst to be formed, placing the catalyst in a calcining furnace at 600-800°C for 3-6 hours, and then cooling the catalyst to obtain the catalyst.

[0013] This catalyst catalyzes the synthesis of glycolic acid using ethylene glycol as the raw material, at a reaction temperature of 100-150°C and an oxygen flow rate of 20-60 ml / min. The glycolic acid synthesis reaction was conducted in a round-bottom flask. Activity was measured as ethylene glycol conversion, while selectivity was measured as the amount of glycolic acid produced.

[0014] Beneficial effects

[0015] (1) The catalyst for synthesizing glycolic acid prepared by the present invention has modified alumina as a main component and has better activity and performance.

[0016] (2) The preparation method of the present invention is simple and the reaction is relatively easy to control.

[0017] (3) The preparation process of the catalyst for synthesizing glycolic acid of the present invention is relatively environmentally friendly and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Qualitative spectrum of glycolic acid

[0019] Figure 2 Spectrum of preparation of glycolic acid by the catalyst of the present invention (taking Example 1 as an example) DETAILED DESCRIPTION

[0020] The technical features of the present invention are further described below with reference to the embodiments, but are not limited to the embodiments.

[0021] In this example, glycolic acid was qualitatively analyzed by liquid chromatography, and the relevant spectrum is shown in the accompanying drawings of the specification.

[0022] Example 1

[0023] (1) 1 mol / L manganese chloride solution and 0.5 mol / L aluminum chloride solution were mixed in a ratio of 1:3, and 0.2 mol / L NaOH solution was slowly added dropwise in a constant temperature 60°C water bath. The pH value was maintained at 10, the reaction time was 4 h, and stirring was continued for 24 h. After separation, washing, drying, and calcination, alumina powder modified by manganese chloride was obtained. The specific surface area of the modified alumina powder was 180 m 2 / g. .

[0024] (2) Take 8g of alumina powder modified by manganese chloride, 10ml of 0.5mol / L copper nitrate solution, and add a gel containing water, a binder methyl cellulose, and a peptizer nitric acid, and knead them evenly on a kneader. The kneaded material is extruded on an extruder, and after drying and roasting, a catalyst for synthesizing glycolic acid is obtained. The roasting temperature is 600℃ and the roasting time is 3h. After taking it out and drying, the catalyst for synthesizing glycolic acid can be obtained. The catalyst has a compressive strength of 90N / cm and a specific surface area of 132m 2 / g.

[0025] To prepare glycolic acid using the resulting catalyst for glycolic acid synthesis, 0.2 g of catalyst was added to a round-bottom flask. The reaction conditions were: reaction temperature 100°C, oxygen flow rate 20 ml / min. The conversion of ethylene glycol oxidation and selectivity to glycolic acid were as follows:

[0026] Time (h) 2 4 6 8 10 Conversion rate 86.84％ 87.92％ 88.78％ 89.23％ 90.14％ Selectivity 90.62％ 91.35％ 91.62％ 91.96％ 91.46％

[0027] Example 2

[0028] (1) 1 mol / L zirconium chloride solution and 0.5 mol / L aluminum chloride solution were mixed in a ratio of 1:2, and 0.2 mol / L NaOH solution was slowly added dropwise in a constant temperature 70°C water bath. The pH value was maintained at 11, the reaction time was 6 h, and stirring was continued for 48 h. After separation, washing, drying, and calcination, alumina powder modified by zirconium chloride was obtained. The specific surface area of the modified alumina powder was 180 m 2 / g. .

[0029] (2) Take 4g of alumina powder modified by zirconium chloride, 10ml of 0.5mol / L copper sulfate solution, and add gel containing water, binder methyl cellulose, and peptizer nitric acid, and knead them evenly on a kneader. The kneaded material is extruded on an extruder, and after drying and roasting, a catalyst for synthesizing glycolic acid is obtained. The roasting temperature is 800℃ and the roasting time is 5h. After taking it out and drying, the catalyst for synthesizing glycolic acid can be obtained. The catalyst has a compressive strength of 98N / cm and a specific surface area of 146m 2 / g.

[0030] To prepare glycolic acid using the resulting catalyst for glycolic acid synthesis, 0.2 g of catalyst was added to a round-bottom flask. The reaction conditions were: reaction temperature 100°C, oxygen flow rate 20 ml / min. The conversion of ethylene glycol oxidation and selectivity to glycolic acid were as follows:

[0031] Time (h) 2 4 6 8 10 Conversion rate 85.56％ 86.81％ 87.82％ 88.34％ 90.21％ Selectivity 91.38％ 91.54％ 91.65％ 91.68％ 91.98％

[0032] Example 3

[0033] (1) 1 mol / L cerium chloride solution and 0.5 mol / L aluminum chloride solution were mixed in a ratio of 1:1, and 0.2 mol / L NaOH solution was slowly added dropwise in a water bath at a constant temperature of 70°C. The pH value was maintained at 12, the reaction time was 5 h, and the stirring was continued for 36 h. After separation, washing, drying, and calcination, a modified alumina powder modified by cerium chloride was obtained. The specific surface area of the modified alumina powder was 180 m 2 / g.

[0034] (2) Take 3g of modified alumina powder modified by cerium chloride, 10ml of 0.5mol / L copper nitrate solution, and add gel containing water, binder methyl cellulose, and peptizer nitric acid, and knead them evenly on a kneader. The kneaded material is extruded on an extruder, and after drying and roasting, a catalyst for synthesizing glycolic acid is obtained. The roasting temperature is 600℃ and the roasting time is 6h. After taking it out and drying, the catalyst for synthesizing glycolic acid can be obtained. The catalyst has a compressive strength of 102N / cm and a specific surface area of 164m 2 / g.

[0035] To prepare glycolic acid using the resulting catalyst for glycolic acid synthesis, 0.2 g of catalyst was added to a round-bottom flask. The reaction conditions were: reaction temperature 100°C, oxygen flow rate 20 ml / min. The conversion of ethylene glycol oxidation and selectivity to glycolic acid were as follows:

[0036] Time (h) 2 4 6 8 10 Conversion rate 88.23％ 88.16％ 88.24％ 88.41％ 89.18％ Selectivity 92.16％ 92.43％ 92.52％ 92.63％ 92.75％

[0037] Example 4

[0038] (1) 1 mol / L manganese chloride solution and 0.5 mol / L aluminum chloride solution were mixed in a ratio of 1:3, and 0.2 mol / L NaOH solution was slowly added dropwise in a constant temperature 60°C water bath. The pH value was maintained at 10, the reaction time was 4 h, and stirring was continued for 24 h. After separation, washing, drying, and calcination, alumina powder modified by manganese chloride was obtained. The specific surface area of the modified alumina powder was 180 m 2 / g. .

[0039] (2) Take 8g of alumina powder modified by manganese chloride, 10ml of 0.5mol / L copper nitrate solution, and add a gel containing water, a binder of turpentine powder, and a peptizer of nitric acid, and knead them evenly on a kneader. The kneaded material is extruded on an extruder, and after drying and roasting, a catalyst for synthesizing glycolic acid is obtained. The roasting temperature is 600℃ and the roasting time is 5h. After being taken out and dried, the catalyst for synthesizing glycolic acid is obtained. The catalyst has a compressive strength of 95N / cm and a specific surface area of 156m 2 / g.

[0040] To prepare glycolic acid using the resulting catalyst for glycolic acid synthesis, 0.2 g of catalyst was added to a round-bottom flask. The reaction conditions were: reaction temperature 100°C, oxygen flow rate 20 ml / min. The conversion of ethylene glycol oxidation and selectivity to glycolic acid were as follows:

[0041] Time (h) 2 4 6 8 10 Conversion rate 86.57％ 87.65％ 88.47％ 88.98％ 90.22％ Selectivity 90.73％ 91.54％ 91.71％ 91.92％ 91.49％

[0042] Example 5

[0043] (1) 1 mol / L manganese chloride solution and 0.5 mol / L aluminum chloride solution were mixed in a ratio of 1:3, and 0.2 mol / L NaOH solution was slowly added dropwise in a constant temperature 60°C water bath. The pH value was maintained at 10, the reaction time was 4 h, and stirring was continued for 24 h. After separation, washing, drying, and calcination, alumina powder modified by manganese chloride was obtained. The specific surface area of the modified alumina powder was 180 m 2 / g. .

[0044] (2) Take 8g of alumina powder modified by manganese chloride, 10ml of 0.5mol / L copper nitrate solution, and add gel containing water, binder tianqing powder, and peptizer dilute sulfuric acid, and knead them evenly on a kneader. The kneaded material is extruded on an extruder and dried and calcined to obtain a catalyst for synthesizing glycolic acid. The calcination temperature is 600℃ and the calcination time is 6h. After taking it out and drying, the catalyst for synthesizing glycolic acid can be obtained. The catalyst has a compressive strength of 96N / cm and a specific surface area of 134m 2 / g.

[0045] To prepare glycolic acid using the resulting catalyst for glycolic acid synthesis, 0.2 g of catalyst was added to a round-bottom flask. The reaction conditions were: reaction temperature 100°C, oxygen flow rate 20 ml / min. The conversion of ethylene glycol oxidation and selectivity to glycolic acid were as follows:

[0046] Time (h) 2 4 6 8 10 Conversion rate 87.42％ 88.05％ 88.97％ 89.23％ 90.65％ Selectivity 90.93％ 91.68％ 92.12％ 92.78％ 91.34％

[0047] Example 6

[0048] (1) 1 mol / L manganese chloride solution and 0.5 mol / L aluminum chloride solution were mixed in a ratio of 1:3, and 0.2 mol / L NaOH solution was slowly added dropwise in a constant temperature 60°C water bath. The pH value was maintained at 10, the reaction time was 4 h, and the stirring was continued for 24 h. After separation, washing, drying, and calcination, a modified alumina powder modified by manganese chloride was obtained. The specific surface area of the modified alumina powder was 180 m 2 / g.

[0049] (2) Take 8g of modified alumina powder modified by manganese chloride, 10ml of 1mol / L copper nitrate solution, and add a gel containing water, a binder methyl cellulose, and a peptizer nitric acid, and knead them evenly on a kneader. The kneaded material is extruded on an extruder, and after drying and roasting, a catalyst for synthesizing glycolic acid is obtained. The roasting temperature is 600℃ and the roasting time is 3h. After taking it out and drying, the catalyst for synthesizing glycolic acid can be obtained. The catalyst has a compressive strength of 92N / cm and a specific surface area of 138m 2 / g.

[0050] To prepare glycolic acid using the resulting catalyst for glycolic acid synthesis, 0.2 g of catalyst was added to a round-bottom flask. The reaction conditions were: reaction temperature 110°C, oxygen flow rate 20 ml / min. The conversion of ethylene glycol oxidation and selectivity for glycolic acid were as follows:

[0051] Time (h) 2 4 6 8 10 Conversion rate 92.94％ 93.92％ 94.82％ 96.32％ 95.42％ Selectivity 94.29％ 95.54％ 96.28％ 97.66％ 96.46％

[0052] Comparative Example 1

[0053] This comparative example is compared with Example 1. According to the method of Chinese patent CN201610395465 (a method for preparing glycolic acid)

[0054] Weigh 1.4g of N,N-diethyl-2,3,3,3-tetrafluoropropionamide into 8g of sodium hydroxide solution, heat to 150°C for 2h, filter, and heat the filtrate to 180°C for 5h. Cool to room temperature, adjust the pH to 5.5 with HF, and remove water by vacuum distillation. Add 3.7g of ethanol, slurry, filter, and remove ethanol by vacuum distillation to obtain 0.45g of glycolic acid (84.9% yield).

Claims

1. A method for preparing a catalyst for synthesizing glycolic acid, characterized in that: The preparation method comprises mixing modified alumina, gel, and a solution containing copper ions, performing mixing and pressing processes to form the mixture, and then performing a calcination process to obtain the catalyst. The catalyst comprises: a copper oxide content of 5-15%, a manganese oxide, zirconium oxide, or cerium oxide content of 15-40%, and a modified alumina content of 50-80%. Wherein, the gel is a gel prepared by mixing water, a binder and a peptizing agent; The specific surface area of the modified alumina is 150 to 300 m 2 / g, the preparation method is: mixing aluminum trichloride solution with modifier manganese chloride, zirconium chloride or cerium chloride solution, adjusting the pH to 10-12, and obtaining modified alumina through separation and calcination after the reaction is completed.

2. The preparation method according to claim 1, wherein The ratio of the modified alumina, gel and copper ion solution is as follows: 0.1-0.5 ml of gel and 10-35 ml of copper compound solution are required for every 10 g of modified alumina powder, wherein the molar concentration of the copper compound solution is 0.5-1 mol / L.

3. The preparation method according to claim 1, wherein The copper ion-containing solution is copper sulfate or copper nitrate solution; the binder is methyl cellulose or turmeric powder; and the sol agent is dilute nitric acid or dilute sulfuric acid.

4. The preparation method according to claim 1, wherein In the preparation method of modified alumina, the molar ratio of aluminum trichloride to the modifier manganese chloride, zirconium chloride or cerium chloride is 2:(1-3), the reaction temperature is 60-80° C., and the reaction time is 4-6 hours.

5. The preparation method according to claim 1, wherein The mixing and pressing process comprises kneading the modified alumina, gel and copper ion solution evenly with a kneader, and then extruding the mixture into a strip through an extruder; and the drying and roasting process comprises placing the product obtained through the mixing and pressing process in a roasting furnace and roasting it at 600-800°C for 3-6 hours, and then cooling the mixture to obtain the catalyst.

6. The preparation method according to claim 1, wherein The preparation steps are: mixing a 1-2 mol / L manganese chloride, zirconium chloride or cerium chloride solution with a 0.5-1 mol / L aluminum chloride solution in a volume ratio of 1:(1-3), adjusting the pH to 10-12 for reaction, the reaction temperature to 60-80°C, the reaction time to 4-6 hours, and after the reaction is completed, separating, drying and calcining to obtain modified alumina powder; 3-8 g of modified alumina powder and 0.1-0.5 ml of gel are added to 10 ml of 0.5-1 mol / L copper sulfate or copper nitrate solution, and the mixture is kneaded evenly on a kneader. The kneaded material is extruded on an extruder, and then dried and calcined at 600° C. for 3 hours to obtain a catalyst for synthesizing glycolic acid. The catalyst is then taken out and dried to obtain a catalyst for synthesizing glycolic acid.

7. The preparation method according to claim 1, wherein The preparation steps are as follows: 1 mol / L manganese chloride solution and 0.5 mol / L aluminum chloride solution are mixed in a volume ratio of 1:3, NaOH solution is added to adjust the pH to 10, the reaction temperature is 60°C, the reaction time is 4 hours, and after the reaction is completed, stirring is performed for 24 hours. After separation, washing, drying, and calcination, modified alumina powder is obtained; Take 8g of modified alumina powder and 0.3ml of gel, add them to 10ml of 1mol / L copper nitrate solution, knead them evenly on a kneader, extrude the kneaded material on an extruder, and then obtain a catalyst for synthesizing glycolic acid after drying and calcination at 600℃ for 3h. After taking out and drying, the catalyst for synthesizing glycolic acid is obtained.

8. A catalyst prepared by the preparation method according to claims 1 to 7.

9. The catalyst according to claim 8, characterized in that The catalyst was used to catalyze the synthesis of glycolic acid from ethylene glycol.

10. The catalyst according to claim 8, characterized in that The catalyst is used to catalyze the synthesis of glycolic acid from ethylene glycol at a reaction temperature of 100-150° C. and an oxygen flow rate of 20-60 ml / min.

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