A shaped hydroxyacetone catalyst and its preparation and use

Abstract

The application provides a shaped hydroxypropanone catalyst which is prepared from a hydroxypropanone catalyst powder, a binder, a pore-forming agent and a dilute acid solution. The hydroxypropanone catalyst provided by the application has a catalyst reaction life of not less than 600 hours in a reaction of preparing hydroxypropanone by dehydrating glycerol.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to a shaped hydroxyacetone catalyst, its preparation method, and its application. Background Technology

[0002] Hydroxyacetone is an important chemical raw material widely used in the food, pharmaceutical, and chemical industries. In recent years, the rapid increase in investment in biodiesel has led to a surplus of glycerol, a byproduct of the production process. Therefore, finding new and effective ways to utilize this glycerol has attracted widespread attention. Among these methods, the production of hydroxyacetone through catalytic dehydration of glycerol is considered a potentially valuable and effective approach.

[0003] In the process of preparing hydroxyacetone from glycerol through dehydration, the catalyst plays a crucial role. Since most catalysts studied in the laboratory are powder catalysts, directly applying them to actual industrial applications would lead to large pressure drops in the catalyst bed, causing problems such as catalyst bed blockage, and complex loading and unloading. Therefore, catalysts used in actual industrial applications are mostly shaped catalysts with certain forms, which have advantages such as easy loading, unloading, transportation, and installation. Therefore, exploring the molding process for powder catalysts is an essential step in moving catalysts from the laboratory research stage to practical industrial applications.

[0004] Studies have shown that when catalysts are formed using tableting, the type and amount of additives significantly affect the catalyst's performance and post-formation strength, influencing its specific surface area and pore size distribution. Therefore, the selection of additives can have a major impact on catalyst performance. Generally, a larger catalyst surface area results in higher activity and greater production capacity. Thus, the key issue in catalyst forming is maximizing surface area utilization while ensuring the catalyst's mechanical strength and allowing for sufficient pressure drop.

[0005] It is evident that the catalyst molding method significantly impacts many properties of the catalyst, such as its strength, activity, and product conversion rate. Based on current catalyst molding methods and applications, there is an urgent need to develop a catalyst molding method with high strength and catalytic activity, capable of meeting the industrial requirements and standards for glycerol-to-hydroxyacetone catalysts. This method should exhibit high glycerol conversion rates and selectivity for hydroxyacetone during glycerol dehydration, while simultaneously extending the catalyst's lifespan. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a molded hydroxyacetone catalyst. By studying the effects of molding methods and additives on the catalytic effect and catalyst lifetime after molding, this invention has discovered a catalyst with a long catalytic lifetime and high catalytic efficiency. This catalyst enables glycerol to achieve a high conversion rate, up to 99% or more, and also exhibits high selectivity for the main product, hydroxyacetone. Furthermore, this invention provides a method for preparing this molded catalyst.

[0007] Specifically, on the one hand, the present invention improves a molded hydroxyacetone catalyst, which is prepared from hydroxyacetone catalyst powder, binder, pore-forming agent and dilute acid solution.

[0008] In some embodiments, the catalyst has a BET specific surface area of ​​55–130 m². 2 / g; BJH pore volume is 0.4-0.8cm³. 3 / g; average pore size is 10-20nm; lateral compressive strength is 30-120N / cm.

[0009] In some embodiments, the catalyst is prepared by the following steps:

[0010] (1) After mixing the hydroxyacetone catalyst powder with the binder and pore-forming agent, add dilute acid solution and knead evenly, dry and pulverize to obtain a mixture with a particle size of 40-200 mesh;

[0011] (2) Mix the mixture obtained in step (1) with a liquid or solid lubricant until homogeneous, and compress it into cylindrical particles under a pressure of 2-10 kN.

[0012] (3) The cylindrical particles obtained in step (2) are calcined at 300-600℃ for 2-24h to obtain a hydroxyacetone catalyst.

[0013] In some embodiments, the cylindrical particles have a diameter of 3-5 mm and a length of 5-8 mm.

[0014] In some embodiments, the liquid or solid lubricant is selected from one or more of glycerol, ethylene glycol, and graphite.

[0015] In some embodiments, the amount of liquid or solid lubricant added is 0.5% to 3% of the mass of the hydroxyacetone catalyst powder; preferably, the amount of liquid or solid lubricant added is 1.5% to 2.5% of the mass of the hydroxyacetone catalyst powder; preferably, the amount of liquid or solid lubricant added is 2% of the mass of the hydroxyacetone catalyst powder.

[0016] In some embodiments, the hydroxyacetone catalyst powder is a modified or unmodified copper-based hydroxyacetone catalyst.

[0017] In some embodiments, the hydroxyacetone catalyst powder is a solid catalyst with a copper oxide content of 35%-55%.

[0018] In some embodiments, the hydroxyacetone catalyst powder is selected from at least one of Cu-Zr-Al hydroxyacetone catalyst powder, Cu-Cr hydroxyacetone catalyst powder, and Cu-Cr-Ce hydroxyacetone catalyst powder.

[0019] In some embodiments, the binder is selected from at least one of: boehmite, aluminum phosphate, hydroxypropyl methylcellulose, polyvinyl alcohol, and bentonite.

[0020] In some embodiments, the adhesive is selected from at least one of boehmite, polyvinyl alcohol, and polyacrylic acid.

[0021] In some embodiments, the pore-forming agent is selected from at least one of polyethylene oxide, fatty acid glycerides, polyethylene glycol, and polyvinylpyrrolidone.

[0022] In some embodiments, the pore-forming agent is selected from at least one of polyethylene oxide, fatty acid glycerides, and polyvinylpyrrolidone.

[0023] In some embodiments, the dilute acid solution is an acid that is easily decomposed or oxidized into a gas.

[0024] In some embodiments, the dilute acid solution is selected from at least one of formic acid aqueous solution, nitric acid aqueous solution, acetic acid aqueous solution, oxalic acid aqueous solution, and malonic acid aqueous solution.

[0025] In some embodiments, the mass concentration of the dilute acid solution is 1-10%.

[0026] In some embodiments, the mass concentration of the dilute acid solution is 3-5%.

[0027] In some embodiments, based on the mass of the hydroxyacetone catalyst powder, the amount of binder added is 3-10% of the mass of the hydroxyacetone catalyst powder; the amount of pore-forming agent added is 1-5% of the mass of the hydroxyacetone catalyst powder; and the amount of dilute acid solution added is 10-80% of the mass of the hydroxyacetone catalyst powder.

[0028] In some embodiments, the amount of binder added is 3-5% of the mass of the hydroxyacetone catalyst powder; the amount of pore-forming agent added is 2-4% of the mass of the hydroxyacetone catalyst powder; and the amount of dilute acid solution added is 30-50% of the mass of the hydroxyacetone catalyst powder.

[0029] The hydroxyacetone catalyst provided by this invention has a reaction life of not less than 600 hours in the reaction of glycerol dehydration to prepare hydroxyketone, and can be stored for a long time without performance degradation.

[0030] On the other hand, the present invention provides a method for preparing a shaped hydroxyacetone catalyst, wherein the catalyst is obtained through the following steps:

[0031] (1) After mixing the hydroxyacetone catalyst powder with the binder and pore-forming agent, add dilute acid solution and knead evenly, dry, and pulverize to obtain a mixture with a particle size of 80-200 mesh; wherein the drying temperature is 100-130℃ and the drying time is 2-24h;

[0032] (2) The mixture obtained in step (1) is mixed evenly with a liquid or solid lubricant and pressed into tablets under a pressure of 5-10 kN to form cylindrical particles; the cylindrical particles have a diameter of 3-5 mm and a length of 5-8 mm.

[0033] (3) The cylindrical particles obtained in step (2) are calcined at 300-600℃ for 4-24h to obtain a hydroxyacetone catalyst.

[0034] In some embodiments of the present invention, the tablet compression can be performed using a dry pressing machine.

[0035] In some preparation method embodiments, the liquid or solid lubricant is selected from one or more of glycerol, ethylene glycol, and graphite.

[0036] In some preparation method embodiments, the amount of liquid or solid lubricant added is 0.5% to 3% of the mass of the hydroxyacetone catalyst powder; preferably, the amount of liquid or solid lubricant added is 1.5% to 2.5% of the mass of the hydroxyacetone catalyst powder; preferably, the amount of liquid or solid lubricant added is 2% of the mass of the hydroxyacetone catalyst powder.

[0037] In some preparation method embodiments, the hydroxyacetone catalyst powder is a modified or unmodified copper-based hydroxyacetone catalyst.

[0038] In some preparation method embodiments, the hydroxyacetone catalyst powder is a solid catalyst with a copper oxide content of 35%-55%.

[0039] In some preparation method embodiments, the hydroxyacetone catalyst powder is selected from at least one of Cu-Zr-Al hydroxyacetone catalyst powder, Cu-Cr hydroxyacetone catalyst powder, and Cu-Cr-Ce hydroxyacetone catalyst powder.

[0040] In some preparation method embodiments, the binder is selected from at least one of: boehmite, aluminum phosphate, hydroxypropyl methylcellulose, polyvinyl alcohol, and bentonite.

[0041] In some preparation method embodiments, the binder is selected from at least one of: boehmite, polyvinyl alcohol, and polyacrylic acid.

[0042] In some preparation method embodiments, the pore-forming agent is selected from at least one of: polyethylene oxide, fatty acid glycerides, polyethylene glycol, and polyvinylpyrrolidone.

[0043] In some preparation method embodiments, the pore-forming agent is selected from at least one of polyethylene oxide, fatty acid glycerides, and polyvinylpyrrolidone.

[0044] In some preparation method embodiments, the dilute acid solution is an acid that is easily decomposed or oxidized into gas.

[0045] In some preparation method embodiments, the dilute acid solution is selected from at least one of formic acid aqueous solution, nitric acid aqueous solution, acetic acid aqueous solution, oxalic acid aqueous solution, and malonic acid aqueous solution.

[0046] In some preparation method embodiments, the mass concentration of the dilute acid solution is 1-10%.

[0047] In some preparation method embodiments, the mass concentration of the dilute acid solution is 3-5%.

[0048] In some preparation method embodiments, based on the mass of the hydroxyacetone catalyst powder, the amount of binder added is 3-10% of the mass of the hydroxyacetone catalyst powder; the amount of pore-forming agent added is 1-5% of the mass of the hydroxyacetone catalyst powder; and the amount of dilute acid solution added is 10-80% of the mass of the hydroxyacetone catalyst powder.

[0049] In some preparation method embodiments, the amount of binder added is 3-5% of the mass of the hydroxyacetone catalyst powder; the amount of pore-forming agent added is 2-4% of the mass of the hydroxyacetone catalyst powder; and the amount of dilute acid solution added is 30-50% of the mass of the hydroxyacetone catalyst powder.

[0050] On the other hand, the present invention provides the use of the shaped hydroxyacetone catalyst described in the present invention or the shaped hydroxyacetone catalyst prepared by the preparation method of the shaped hydroxyacetone catalyst described in the present invention in the catalytic dehydration of glycerol to synthesize hydroxyacetone.

[0051] Beneficial effects

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] (1) The catalyst forming process of the present invention is simple and the method has high repeatability, which can ensure the consistency of catalyst performance.

[0054] (2) The catalyst prepared by the catalyst forming method provided by the present invention has a high degree of dispersion of active components and a high specific surface area, which minimizes the problem of reduced activity after catalyst forming. The formed catalyst has high stability and can be stored for a long time without performance degradation.

[0055] (3) The catalyst prepared by the catalyst forming method provided by the present invention has high activity and sufficient stability, which may meet the requirements of long-term production.

[0056] Terminology Explanation

[0057] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0058] In the following content, all figures disclosed herein, whether or not the words "approximately" or "about" are used, are approximate values. The value of each figure may vary by 1%, 2%, 5%, 7%, 8%, 10%, 15%, or 20%, etc. Whenever a figure with a value of N is disclosed, any figure with a value of N+ / -1%, N+ / -2%, N+ / -3%, N+ / -5%, N+ / -7%, N+ / -8%, N+ / -10%, N+ / -15%, or N+ / -20% will be explicitly disclosed, where "+ / -" indicates addition or subtraction.

[0059] The term "at least one" as used in this invention refers to one or more types, including one, two, three, etc.; the maximum number of types is related to the types of components in the modified combination. If the modified combination mentions five types, then it can include up to five types.

[0060] The "hydroxyacetone catalyst powder" described in this invention refers to a catalyst capable of catalyzing the dehydration of glycerol to prepare hydroxyacetone, specifically a modified or unmodified copper-based hydroxyacetone catalyst. In some embodiments of this invention, the hydroxyacetone catalyst powder includes, but is not limited to, Cu-Zr-Al hydroxyacetone catalyst powder, Cu-Cr hydroxyacetone catalyst powder, and Cu-Cr-Ce hydroxyacetone catalyst powder.

[0061] The hydroxyacetone catalyst powder of this invention can be prepared by a co-precipitation method, wherein the hydroxyacetone catalyst powder is a solid catalyst with a copper oxide content of 35%-55%. The preparation method is as follows:

[0062] The "dilute acid solution" mentioned in this invention refers to an aqueous solution of organic or inorganic acid; in some embodiments, the "dilute acid solution" is an acid that is easily decomposed or oxidized into gas; in some embodiments, the "dilute acid solution" includes, but is not limited to, formic acid, nitric acid, acetic acid, oxalic acid, and malonic acid. Detailed Implementation

[0063] To enable those skilled in the art to better understand the technical solutions of the present invention, some non-limiting embodiments are further disclosed below to provide a more detailed description of the present invention.

[0064] All reagents used in this invention can be purchased commercially or prepared by the methods described in this invention.

[0065] Preparation of hydroxyacetone catalyst powder

[0066] 1. Prepare a 40% solution of copper nitrate, zirconium nitrate, aluminum nitrate, chromium nitrate, etc. according to the set catalyst components, and mix them evenly to complete the preparation of metal nitrates.

[0067] 2. Prepare a 30% potassium carbonate-potassium hydroxide solution, wherein the potassium carbonate content is 15-25% and the potassium hydroxide content is 5-15%, thus completing the preparation of the alkaline solution.

[0068] 3. Add metal nitrate and alkaline solution dropwise into the reaction vessel, and maintain the temperature inside the vessel at 45-85℃. Adjust the pH inside the vessel between 7.5 and 9.0 by controlling the dropping rate.

[0069] 4. After the addition is complete, age at 55-85℃ for 6-24 hours.

[0070] 5. Wash the catalyst with deionized water until the potassium salt content in the catalyst is below 0.1%, then heat at 100-140℃.

[0071] Drying.

[0072] 6. The dried catalyst is crushed to 10-30 mesh and calcined at 300-500℃ for 4-16 hours to obtain catalyst powder.

[0073] Preparation Examples

[0074] Example 1

[0075] 500g of Cu-Zr-Al hydroxyacetone catalyst powder, 20g of gibbsite, and 15g of polyethylene oxide were added to a kneader and mixed evenly. 200g of 3% formic acid solution was then added and kneaded further. After thorough kneading, the mixture was placed in a 100℃ oven and dried for 12 hours. The dried material was then pulverized to a particle size of 80-100 mesh. 10g of graphite powder was added and mixed evenly. The mixture was then pressed and granulated under a pressure of 5kN to produce cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the obtained cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0076] Example 2

[0077] 500g of Cu-Zr-Al hydroxyacetone catalyst powder, 20g of gibbsite, and 15g of polyethylene oxide were added to a kneader and mixed evenly. 200g of 3% formic acid solution was then added and kneaded further. After thorough kneading, the mixture was placed in a 100℃ oven and dried for 12 hours. The dried material was then pulverized to a particle size of 100-120 mesh. 10g of graphite powder was added and mixed evenly. The mixture was then pressed and granulated under a pressure of 5kN to produce cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the obtained cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0078] Example 3

[0079] 500g of Cu-Zr-Al hydroxyacetone catalyst powder, 20g of gibbsite, and 15g of polyethylene oxide were added to a kneader and mixed evenly. 200g of 3% formic acid solution was then added and kneaded further. After thorough kneading, the mixture was placed in a 100℃ oven and dried for 12 hours. The dried material was then pulverized to a particle size of 140-160 mesh. 10g of graphite powder was added and mixed evenly. The mixture was then pressed and granulated under a pressure of 5kN to produce cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the obtained cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0080] Example 4

[0081] 500g of Cu-Zr-Al hydroxyacetone catalyst powder, 20g of gibbsite, and 15g of polyethylene oxide were added to a kneader and mixed evenly. 200g of 3% formic acid solution was then added and kneaded further. After thorough kneading, the mixture was placed in a 100℃ oven and dried for 12 hours. The dried material was then pulverized to a particle size of 160-200 mesh. 10g of graphite powder was added and mixed evenly. The mixture was then pressed and granulated under a pressure of 5kN to produce cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the obtained cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0082] Example 5

[0083] 500g of Cu-Zr-Al hydroxyacetone catalyst powder, 20g of gibbsite, and 15g of polyethylene oxide were added to a kneader and mixed evenly. 200g of 3% nitric acid solution was then added and kneaded further. After thorough kneading, the mixture was placed in a 100℃ oven and dried for 12 hours. The dried material was then pulverized to a particle size of 100-120 mesh. 10g of graphite powder was added and mixed evenly. The mixture was then pressed and granulated under a pressure of 5kN to produce cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the obtained cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0084] Example 6

[0085] 500g of Cu-Zr-Al hydroxyacetone catalyst powder, 20g of gibbsite, and 15g of fatty acid glycerides were added to a kneader and mixed evenly. 200g of 3% nitric acid solution was then added and kneaded further. After thorough kneading, the mixture was placed in a 100℃ oven and dried for 12 hours. The dried material was then pulverized to a particle size of 100-120 mesh. 10g of graphite powder was added and mixed evenly. The mixture was then pressed and granulated under a pressure of 5kN to produce cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the obtained cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0086] Example 7

[0087] 500g of Cu-Zr-Al hydroxyacetone catalyst powder, 20g of polyacrylic acid, and 15g of fatty acid glycerides were added to a kneader and mixed evenly. 200g of 3% nitric acid solution was then added and kneaded further. After thorough kneading, the mixture was placed in a 100℃ oven and dried for 12 hours. The dried material was then pulverized to a particle size of 100-120 mesh. 10g of graphite powder was added and mixed evenly. The mixture was then pressed and granulated under a pressure of 5kN to produce cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the obtained cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0088] Example 8

[0089] 500g of Cu-Cr hydroxyacetone catalyst powder, 50g of polyvinyl alcohol, and 15g of polyvinylpyrrolidone were added to a beaker, along with 200g of 3% nitric acid solution. The mixture was kneaded thoroughly and then dried in an oven at 100℃ for 12 hours. The dried material was then pulverized to a particle size of 100-120 mesh. 10g of ethylene glycol was added and stirred until homogeneous. The mixture was then granulated under a pressure of 5kN to form cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0090] Example 9

[0091] 500g of Cu-Cr-Ce hydroxyacetone catalyst powder, 50g of polyvinyl alcohol, and 15g of polyvinylpyrrolidone were added to a beaker, along with 200g of 5% nitric acid solution. The mixture was kneaded thoroughly and then dried in an oven at 100℃ for 12 hours. The dried material was then pulverized to a particle size of 100-120 mesh. 10g of ethylene glycol was added and stirred until homogeneous. The mixture was then granulated under a pressure of 5kN to form cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0092] Comparative Example 1

[0093] Compared to Example 1, Comparative Example 1 did not involve the addition of dilute acid solution for kneading. Specifically, 500g of Cu-Zr-Al hydroxyacetone catalyst powder, 20g of gibbsite, and 15g of polyethylene oxide were added to a kneader and mixed evenly, then dried in an oven at 100℃ for 12 hours. The dried material was then pulverized using a pulverizer to a particle size of 80-120 mesh; 10g of graphite powder was added and stirred evenly. The mixture was then pressed and granulated under a pressure of 5kN to produce cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the obtained cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0094] Comparative Example 2

[0095] Compared to Example 2, 30 g of gibbsite was added for kneading. Specifically, 500g of Cu-Zr-Al hydroxyacetone catalyst powder, 50g of gibbsite, and 15g of polyethylene oxide were added to a kneader and mixed evenly. 200g of 3% formic acid solution was then added for further kneading. After thorough kneading, the mixture was placed in a 100℃ oven and dried for 12 hours. The dried material was then pulverized using a pulverizer to a particle size of 100-120 mesh. 10g of graphite powder was added and stirred until evenly mixed. The mixture was then pressed and granulated under a pressure of 5kN to produce cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the obtained cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0096] Comparative Example 3

[0097] Compared to Example 3, Comparative Example 3 did not include the addition of diaspore for kneading. Specifically, 500g of Cu-Zr-Al hydroxyacetone catalyst powder and 15g of polyethylene oxide were added to a kneader and mixed evenly. 200g of 3% formic acid solution was then added for further kneading. After thorough kneading, the mixture was placed in a 100℃ oven and dried for 12 hours. The dried material was then pulverized using a pulverizer to a particle size of 100-120 mesh. 10g of graphite powder was added and stirred until evenly mixed. The mixture was then pressed and granulated under a pressure of 5kN to produce cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the obtained cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0098] Comparative Example 4

[0099] Compared to Example 4, 15g of polyethylene oxide was added. Specifically, 500g of Cu-Zr-Al hydroxyacetone catalyst powder, 20g of gibbsite, and 30g of polyethylene oxide were added to a kneader and mixed evenly. 200g of 3% formic acid solution was added and the mixture was kneaded further. After thorough kneading, the mixture was placed in a 100℃ oven and dried for 12 hours. The dried material was then pulverized to a particle size of 160-200 mesh. 10g of graphite powder was added and mixed evenly. The mixture was then pressed and granulated under a pressure of 5kN to produce cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the obtained cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0100] Comparative Example 5

[0101] Compared to Example 5, the binder, diaspore, was replaced with starch. Specifically, 500g of Cu-Zr-Al hydroxyacetone catalyst powder, 20g of starch, and 15g of polyethylene oxide were added to a kneader and mixed evenly. 200g of 3% nitric acid solution was then added to further knead the material. After thorough kneading, the mixture was placed in a 100℃ oven and dried for 12 hours. The dried material was then pulverized using a pulverizer to a particle size of 100-120 mesh. 10g of graphite powder was added and mixed evenly. The mixture was then pressed and granulated under a pressure of 5kN to produce cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the obtained cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0102] Comparative Example 6

[0103] Compared to Example 6, the dilute acid solution in Comparative Example 6 was replaced with a 3% boric acid solution. 500g of Cu-Zr-Al hydroxyacetone catalyst powder, 20g of gibbsite, and 15g of fatty acid glycerides were added to a kneader and mixed evenly. Then, 200g of 3% boric acid solution was added and the mixture was kneaded further. After thorough kneading, the mixture was placed in a 100℃ oven and dried for 12 hours. The dried material was then pulverized using a pulverizer to a particle size of 100-120 mm. 10g of graphite powder was added and stirred until evenly mixed. The mixture was then granulated under a pressure of 5kN to produce cylindrical particles with a diameter of 3.5mm and a length of 5mm. Finally, the obtained cylindrical particles were calcined at 400℃ for 5 hours to obtain the hydroxyacetone catalyst.

[0104] Comparative Example 7

[0105] 500g of Cu-Cr hydroxyacetone catalyst powder was pulverized using a pulverizer to achieve a particle size of 140-160 mesh.

[0106] Catalyst performance and lifetime testing

[0107] Test method:

[0108] The hydroxyacetone catalysts prepared in Examples 1-9 and Comparative Examples 1-7 were placed for three, six, nine, and twelve months, respectively. At each corresponding time point, 50 g of the obtained hydroxyacetone catalyst was taken and loaded into a 100 mL YZBPR fixed-bed reactor. A continuous reaction to produce hydroxyacetone from glycerol was carried out at 220 °C, 3 kPa, a feed rate of 15 g / h for 75% glycerol, and an H2 / N2 volume ratio of 1:9 to verify the catalyst performance and lifetime. The reaction ended when the glycerol conversion rate was below 98% or the reaction pressure was above 1.0 bar; the reaction time was defined as the catalyst lifetime.

[0109]

[0110] Test results:

[0111] The reactivity of the hydroxyacetone catalysts prepared in Examples 1-9 is shown in Table 1 below.

[0112] Table 1

[0113]

[0114]

[0115] As can be seen from the above, the hydroxyacetone catalyst of the present invention has good catalytic performance, with a glycerol conversion rate of at least 97%, preferably more than 99%; it also has sufficient stability to meet the requirements of long-term production, with a catalytic life of at least 600 hours, preferably more than 980 hours.

[0116] The reaction performance of the hydroxyacetone catalysts prepared in Comparative Examples 1-7 is shown in Table 2 below.

[0117] Table 2

[0118]

[0119]

[0120] Catalyst parameter testing

[0121] The Cu-Zr-Al hydroxyacetone catalyst powder and the catalyst particles formed in Example 1 were subjected to BET specific surface area measurement and BJH pore size distribution test, and the changes in the catalyst before and after forming were observed. The catalyst was subjected to a reaction for 300 hours for verification. After the reaction, the catalyst was taken out, dried, and then subjected to BET specific surface area measurement and BJH pore size distribution test.

[0122] The results are shown in Table 3 below.

[0123] Table 3. Specific surface area and pore size data of catalyst powder and molded catalyst

[0124]

[0125] In summary, the catalyst described in this invention, by adding dilute acid during the kneading process, not only plays a significant role in assisting molding but also allows the catalyst to be stored for a longer period, maintaining its catalytic lifespan even during extended storage. However, different dilute acids have different effects on catalyst performance; for example, adding boric acid reduces catalyst selectivity.

[0126] This study found that increasing the amount of binder in the components, such as gibbsite, decreases the BET specific surface area of ​​the catalyst and also reduces its lifetime. However, without adding a binder, the shelf life is also affected, and the catalyst stability decreases.

[0127] This study found that, after increasing the amount of pore-forming agent in the components, such as polyethylene oxide, although the specific surface area of ​​the catalyst increases, the storage time decreases significantly. Excessive pore formation will affect the stability of the catalyst, resulting in a decrease in the catalyst storage time and reaction lifetime.

[0128] There are various types of binders in this field, but starch is not suitable for this invention. Replacing the binder with starch will reduce the catalyst's lifespan.

[0129] For catalysts without any additives, such as Comparative Example 7, the catalyst powder is not easy to preserve, while the shaped catalyst has better stability and is more conducive to industrial application.

[0130] This study found that adding additives can alter the internal pore size distribution of the catalyst. Measurements in Example 10 show that the specific surface area and pore size distribution of the catalyst powder changed significantly after molding. Furthermore, after molding, the rate of decrease in specific surface area and pore volume during the reaction was much lower than that of the catalyst powder. Therefore, the catalyst exhibits better stability.

[0131] Comparative studies show that binders, pore-forming agents, and dilute acids all play significant roles in the catalyst forming process. Only by selecting appropriate materials and proportions can a more stable hydroxyacetone catalyst be obtained while maintaining high activity. In summary, this method solves the problem that catalyst powders cannot be directly used industrially. This method has a wide range of applications, is reproducible in practice, and can be scaled up for industrial production. Furthermore, the catalyst formed by this method exhibits good stability, ensuring the production requirements for hydroxyacetone from glycerol.

[0132] The method of this invention has been described through preferred embodiments. Those skilled in the art will readily be able to modify or appropriately alter and combine the methods and applications described herein within the scope, spirit, and context of this invention to implement and apply the technology of this invention. Those skilled in the art can refer to the content herein to appropriately improve process parameters. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the scope of this invention.

Claims

1. The use of a molded hydroxyacetone catalyst in the catalytic dehydration of glycerol to synthesize hydroxyacetone, characterized in that, It is prepared from hydroxyacetone catalyst powder, binder, pore-forming agent and dilute acid solution; the dilute acid solution is selected from at least one of formic acid aqueous solution, nitric acid aqueous solution, acetic acid aqueous solution, oxalic acid aqueous solution and malonic acid aqueous solution, the mass concentration of the dilute acid solution is 3-5%, and the amount of dilute acid solution added is 30-50% of the mass of the hydroxyacetone catalyst powder; based on the mass of the hydroxyacetone catalyst powder, the amount of binder added is 3-10% of the mass of the hydroxyacetone catalyst powder; the amount of pore-forming agent added is 1-5% of the mass of the hydroxyacetone catalyst powder; the binder is selected from at least one of gibbsite, aluminum phosphate, hydroxypropyl methylcellulose and polyvinyl alcohol, and the pore-forming agent is selected from at least one of polyethylene oxide, polyacrylic acid, fatty acid glycerides, polyethylene glycol and polyvinylpyrrolidone; The catalyst is prepared by the following steps: (1) After mixing the hydroxyacetone catalyst powder with the binder and pore-forming agent, add dilute acid solution and knead evenly, dry, and pulverize to obtain a mixture with a particle size of 40-200 mesh; (2) Mix the mixture obtained in step (1) with a liquid or solid lubricant until homogeneous, and compress it into cylindrical particles under a pressure of 2-10 kN. (3) The cylindrical particles obtained in step (2) are calcined at 300-600℃ for 2-24 h to obtain a hydroxyacetone catalyst; The catalyst, after molding, has a BET specific surface area of ​​55-130 m². 2 / g; BJH pore volume is 0.4-0.8 cm³. 3 / g; average pore size is 10-20 nm; lateral compressive strength is 30-120 N / cm; The cylindrical particles have a diameter of 3-5 mm and a length of 5-8 mm. The hydroxyacetone catalyst powder is selected from at least one of Cu-Zr-Al hydroxyacetone catalyst powder, Cu-Cr hydroxyacetone catalyst powder, and Cu-Cr-Ce hydroxyacetone catalyst powder, wherein the hydroxyacetone catalyst powder is a solid catalyst with a copper oxide content of 35%-55%.

2. The use according to claim 1, characterized in that, The liquid or solid lubricant is selected from one or more of glycerin, ethylene glycol, and graphite.

3. The use according to claim 1, characterized in that, The amount of liquid or solid lubricant added is 0.5% to 3% of the mass of the hydroxyacetone catalyst powder.

4. The use according to claim 1, characterized in that, The amount of liquid or solid lubricant added is 1.5% to 2.5% of the mass of the hydroxyacetone catalyst powder.

5. The use according to claim 1, characterized in that, The amount of liquid or solid lubricant added is 2% of the mass of the hydroxyacetone catalyst powder.

6. The use according to claim 1, characterized in that, The amount of binder added is 3-5% of the mass of the hydroxyacetone catalyst powder.

7. The use according to claim 1, characterized in that, The amount of pore-forming agent added is 2-4% of the mass of the hydroxyacetone catalyst powder.

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