A gas phase selective hydrogenation of c3 and the hydrogenation product obtained

Abstract

The present invention provides a C3 gas phase selective hydrogenation reaction and the hydrogenation reaction product obtained. The C3 gas phase selective hydrogenation reaction provided by the present invention comprises the step of contacting a C3 gas phase fraction with a catalyst, wherein the catalyst comprises a support, and a primary active metal component and optionally an auxiliary active metal component supported on the support, wherein the support has a surface oxygen group density of 0.1 to 6 mmol / m 2 The surface oxygen groups of the support promote uniform distribution of the metal active components, so that the catalyst has higher activity and selectivity in the C3 gas phase selective hydrogenation reaction.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a C3 gas-phase selective hydrogenation reaction and the resulting hydrogenation reaction products. Background Technology

[0002] In steam pyrolysis units producing ethylene and propylene, the separated C3 fraction typically contains 1 mol% to 6 mol% of propyne (MA) and propadiene (PD), collectively referred to as MAPD. The propylene obtained after C3 fraction distillation contains trace amounts of MAPD, which increases the consumption of polypropylene catalyst and reduces the performance of the polypropylene product; therefore, removal is necessary. Industrially, selective hydrogenation is generally used to convert propyne and propadiene into propylene, which removes impurities and increases propylene yield. There are two methods for removing propyne and propadiene: gas-phase hydrogenation and liquid-phase hydrogenation. The former has advantages such as better MAPD removal and lower MAPD content at the reactor outlet; the latter has advantages such as more efficient energy utilization, less green oil generation, and longer operating cycles.

[0003] C3 gas-phase selective hydrogenation catalysts typically use palladium as the main active component, silver as a promoter, and alumina as the support. To suppress green oil formation, extend the catalyst's operating cycle, and further improve activity and selectivity, catalyst modification methods such as adding other metal promoters, using novel alumina supports, and optimizing the catalyst preparation process are commonly employed. Chinese patent CN1279126A discloses a Pd catalyst modified with Bi promoter using diatomaceous earth, SiO2, TiO2, Al2O3, etc., as supports, exhibiting high selectivity in alkyne selective hydrogenation reactions, reducing green oil formation, and extending the catalyst's operating cycle. Chinese patent CN1958155A discloses an alkyne selective hydrogenation catalyst with an Al2O3 coating on an inert support of talc, refractory clay, or silicon carbide, using Pd as the main active component and Ag, alkali metals, etc., as co-active components. By controlling the thickness of the alumina coating, the distribution of the metal active components on the support surface is promoted, thereby improving activity and selectivity.

[0004] Existing C3 gas-phase selective hydrogenation catalysts and their preparation methods are easily affected by fluctuations in the properties of the alumina support; catalysts prepared from alumina supports produced in different batches exhibit varying performance. Therefore, there is a need to develop a C3 gas-phase selective hydrogenation catalyst with a simple preparation method, stable performance for mass production, and good activity and selectivity. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a C3 gas-phase selective hydrogenation reaction. The catalyst used in the hydrogenation reaction comprises a support, a main active metal component and a co-active metal component supported on the support. The surface of the support is rich in oxygen-containing groups, and the surface-loaded active metal components are more uniform, thereby enabling the catalyst to exhibit excellent catalytic activity and the C3 gas-phase selective hydrogenation reaction to have higher selectivity.

[0006] One objective of this invention is to provide a C3 gas-phase selective hydrogenation reaction, comprising the step of contacting a C3 gas-phase fraction with a catalyst, wherein the catalyst comprises a support, a primary active metal component supported on the support, and optionally added co-active metal components, wherein the surface oxygen-containing group density of the support is 0.1–6 mmol / m³. 2 .

[0007] According to the present invention, in the C3 gas-phase selective hydrogenation reaction:

[0008] The surface oxygen-containing group density of the carrier is 0.1–4 mmol / m³. 2 ;

[0009] In the carrier, the surface oxygen-containing groups are at least two of hydroxyl, carboxyl, and lactone groups. Preferably, the content of hydroxyl groups is 2-40 mmol / g, the content of carboxyl groups is 2-40 mmol / g, and the content of lactone groups is 1-30 mmol / g.

[0010] The specific surface area of ​​the carrier is 40–200 m². 2 / g, water absorption rate of 30-120%, strength of 30-150N / particle, bulk density of 0.4-1.0g / ml, and pore volume of 0.3-1.2ml / g;

[0011] Optionally, other oxides besides alumina are also added to the carrier. Preferably, the other oxides are selected from at least one of titanium oxide, barium oxide, magnesium oxide, calcium oxide, and silicon oxide.

[0012] According to the present invention, in the C3 gas-phase selective hydrogenation reaction:

[0013] The main active metal component is Pd; the content of the main active metal component in the catalyst is 0.02-0.2% by mass percentage, preferably 0.02-0.15%.

[0014] The co-active metal component is selected from at least one of Ag, Bi, Zn, and Ga; the content of the co-active metal component in the catalyst is 0-0.2% by mass percentage.

[0015] The content of Pd and auxiliary active metal components can be measured by atomic absorption or ICP methods. Those skilled in the art can select the specific test method according to the type and content of the metal.

[0016] According to the present invention, in the carbon three-phase selective hydrogenation reaction:

[0017] The catalyst is first reduced before use. Preferably, the gas used for reduction includes hydrogen and other gases, such as nitrogen or methane, and the molar percentage of hydrogen in the gas is 10-90%. The reduction temperature is 90-350°C and the reduction time is 2-24 hours.

[0018] The total molar percentage of propyne and propadiene in the C3 gas phase fraction is 0.5-6%;

[0019] The conditions for the hydrogenation reaction are: a reaction temperature of 30–150 °C and a reaction space velocity of 500–6000 h⁻¹. -1 .

[0020] According to the present invention, in the C3 gas-phase selective hydrogenation reaction, the catalyst is obtained by the following preparation process: a solution containing a main active metal compound and optionally added co-active metal compounds is loaded onto a support, and the catalyst is obtained by drying and calcining.

[0021] According to the present invention, the catalyst is prepared in the following process:

[0022] The main active metal compound is selected from at least one of palladium-soluble compounds, preferably from at least one of palladium chloride, palladium nitrate, palladium acetate, and palladium sulfate;

[0023] The auxiliary active metal compound is selected from at least one of the chlorides, nitrates, acetates, sulfates, oxides, and organometallic compounds of Ag, Bi, Zn, and Ga, preferably at least one of the chlorides, nitrates, and acetates of Ag, Bi, Zn, and Ga;

[0024] The solvent in the solution is selected from at least one of water, hydrochloric acid, nitric acid, acetic acid, and alcohol, preferably water;

[0025] The metal concentration in the solution containing the metal compound can be adjusted within a wide range. For example, the total content of the metal element in the solution is 0.01 to 350 mg / mL.

[0026] The loading method can adopt the loading methods commonly used in the art. For example, the metal components can be loaded together on the carrier, or different metal components can be loaded onto the carrier step by step.

[0027] The drying process can employ commonly used drying techniques and conditions in the art. The drying process allows the solvent used for impregnation to fully evaporate. The drying time can be selected based on the amount of solvent used and the drying temperature. For example, the drying conditions are: drying temperature of 50–250°C and drying time of 2–36 h; preferably, drying temperature of 50–200°C and drying time of 4–24 h.

[0028] The calcination can be carried out using calcination processes and conditions commonly used in the field. The calcination time varies depending on the content of the active metal component. As the content of the active metal component increases, the calcination time can be appropriately increased. For example, the calcination conditions are: calcination temperature of 250-850℃ and calcination time of 2-36h.

[0029] According to the present invention, the carrier and its preparation can be referred to patent ZL202311028071.8. The relevant contents disclosed in the aforementioned document are incorporated herein by reference. Specifically, the carrier is obtained by the following preparation process: a mixture of components including alumina powder, molding agent, pore-forming agent, inorganic carbon species, and optional oxides other than alumina is mixed to obtain a mixture, and then an acidic solution is added to knead and shape, extruded and granulated, dried, and surface treated to obtain the carrier.

[0030] According to the present invention, during the preparation process of the carrier:

[0031] The alumina powder can be any alumina-containing powder material available in the prior art. For example, the alumina powder is selected from at least one of boehmite powder, alumina trihydrate powder, fast-degrading alumina powder, and γ-Al2O3 powder. The boehmite powder can be commonly used boehmite. Preferably, the specific surface area of ​​the boehmite powder is 200-300 m². 2 / g, pore volume 0.5~1.2ml / g, bulk density 0.2~0.4g / ml; the alumina trihydrate powder can be selected from at least one of gibbsite, diaspore, and boehmite; the rapidly dehydrated alumina powder is obtained by rapidly dehydrating aluminum hydroxide, wherein the mass content of Na and Fe is less than 0.1%; the γ-Al2O3 powder can be obtained by high-temperature calcination of commonly used pseudoboehmite powder;

[0032] The molding agent is selected from at least one of polyethylene glycol cellulose, methyl cellulose, carboxymethyl cellulose, sodium hydroxymethyl cellulose, hydroxypropyl methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and starch; the amount of the molding agent is 0.05 to 8 wt% of the total weight of the mixture.

[0033] The pore-forming agent is selected from at least one of polyvinyl alcohol, polyethylene glycol, polyacrylamide, polypropylene glycol, and guar gum powder; the amount of the pore-forming agent is 0.05 to 10 wt% of the total weight of the mixture.

[0034] The inorganic carbon species are selected from at least one of coke, activated carbon, carbon black, glassy carbon, charcoal, bamboo charcoal, coconut shell carbon, graphene, graphyne, and diamond; the amount of the inorganic carbon species is 0.1 to 12 wt% of the total weight of the mixture.

[0035] The oxides other than alumina are selected from at least one of titanium oxide, barium oxide, magnesium oxide, calcium oxide, and silicon oxide; the amount of the oxides other than alumina is 0 to 20 wt% of the total weight of the mixture.

[0036] The concentration of the acidic solution can be adjusted within a wide range. Preferably, the concentration of the acidic solution is 0.01–0.5 mol / L.

[0037] The solvent in the acidic solution is selected from water or a mixture of water and an organic solvent. Preferably, the organic solvent is selected from at least one of methanol, ethanol, and ethylene glycol. When the solvent in the acidic solution is a mixture of water and an organic solvent, the ratio of organic solvent to water can be adjusted within a wide range. For example, the volume ratio of organic solvent to water is (0.01 to 1):1.

[0038] The acidic compound in the acidic solution is selected from at least one of organic acids and inorganic acids, preferably from at least one of acetic acid, maleic acid, malic acid, citric acid, oxalic acid, formic acid, tartaric acid, ascorbic acid, salicylic acid, succinic acid, nitric acid, sulfuric acid, hydrochloric acid, hypochlorous acid, and phosphoric acid.

[0039] In the preparation method of the carrier, those skilled in the art can adjust the amount of acid in the acidic aqueous solution according to the required data such as specific surface area, strength, and bulk density of the carrier; the kneading and extrusion granulation steps, the kneading time, and the extrusion pressure are related to factors such as the size of the equipment used, the composition of the alumina powder, and the composition of the acid solution, and those skilled in the art can determine them specifically based on experience.

[0040] According to the present invention, during the preparation process of the carrier:

[0041] The drying process is not particularly limited and can use existing drying equipment and conditions, for example, drying at 60-180°C for 4-24 hours.

[0042] The surface treatment is selected from at least one of heat treatment, crystallization, oxidation, alkalization, and irradiation; preferably,

[0043] The heat treatment conditions include: the heat treatment atmosphere includes a first atmosphere and a second atmosphere, the first atmosphere is selected from at least one of carbon dioxide, water vapor, acetylene, ethylene, and methane, the second atmosphere is selected from at least one of air, nitrogen, argon, and helium, the volume ratio of the first atmosphere to the second atmosphere is (0.05~1):1, the heat treatment temperature is 300~1200℃, the heat treatment time is 1~24h, and the pressure is 0.1~3MPa;

[0044] The crystallization conditions are: temperature of 120-250℃, pressure of 0.2-15MPa, time of 4-18h, and the solvent used for crystallization is selected from at least one of water, ethanol, ethylene glycol, and ethylenediamine.

[0045] The oxidation conditions are: temperature of 30-110℃, time of 0.2-10h, the oxidant used for oxidation is selected from at least one of nitric acid, sulfuric acid, ammonium persulfate, hydrogen peroxide, potassium permanganate, and ascorbic acid, and the concentration of the oxidant solution is 0.1-10mol / L.

[0046] The alkalization conditions are as follows: temperature is 30-110℃, time is 0.2-10h, and the alkaline compound used for alkalization is selected from at least one of sodium hydroxide, sodium bicarbonate, sodium carbonate, sodium acetate, sodium oxalate, sodium citrate, potassium hydroxide, potassium bicarbonate, potassium carbonate, potassium acetate, and potassium citrate. The concentration of the alkaline compound solution is 0.1-10mol / L.

[0047] The irradiation treatment conditions are as follows: the radiation source is selected from gamma rays and / or microwaves, wherein the gamma ray irradiation dose rate is 2 to 90 kGy / min and the irradiation time is 0.2 to 24 h; the microwave power is 50 to 1000 W and the irradiation time is 0.5 to 60 min.

[0048] According to the present invention, during the preparation process of the carrier:

[0049] When the inorganic carbon species is at least one of coke, activated carbon, carbon black, and glassy carbon, heat treatment is used, or surface treatment is carried out by crystallization and oxidation.

[0050] When the inorganic carbon species is at least one of wood charcoal, bamboo charcoal, and coconut shell charcoal, heat treatment is used, or surface treatment is performed by a combination of heat treatment and irradiation.

[0051] When the inorganic carbon species is at least one of graphene, graphynylene, and diamond, the surface treatment is carried out by crystallization and oxidation, or by heat treatment and alkalization, or by heat treatment, alkalization, and irradiation.

[0052] A second objective of this invention is to provide a hydrogenation reaction product obtained by the aforementioned selective hydrogenation reaction of C3 gas phase. Preferably, the total molar percentage of propyne and propadiene in the hydrogenation reaction product is less than 1000 μmol / mol.

[0053] The C3 gas-phase hydrogenation catalyst provided by this invention utilizes a support rich in oxygen-containing groups on its surface. A molding precursor, such as boehmite powder or alumina trihydrate powder, is kneaded with inorganic carbon species to form a support, which is then surface-treated to increase the number of oxygen-containing groups. Subsequently, a Pd metal component and a co-active metal component are loaded onto the support, dried, and then calcined at high temperature to obtain the catalyst. This invention employs heat treatment, crystallization, oxidation, and irradiation during support preparation to increase the number of oxygen-containing groups on the support surface, resulting in a more uniform distribution of the loaded metal active components and better catalyst activity and selectivity. Furthermore, surface modification of the alumina after molding leads to more consistent support properties across different batches, better reproducibility in industrial production, and more stable performance of the prepared C3 gas-phase hydrogenation catalyst. Detailed Implementation

[0054] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0055] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0056] Example 1

[0057] Carrier preparation: Take 100g of pseudoboehmite powder (specific surface area 201.5m²) 2 Mix 6g of guar gum powder, 6g of carboxymethyl cellulose, and 6g of coconut shell carbon evenly; add 2.10g of concentrated sulfuric acid to 140g of deionized water to prepare an acid solution; add the acid solution to the evenly mixed powder and knead it, then extrude it to obtain cylindrical particles with a particle size of 2-4mm; dry at 110℃ for 4h; then heat-treat with air and water vapor (volume ratio 0.5:1) at 1200℃ and 0.2MPa for 12h to obtain the carrier.

[0058] Active metal component loading method: Take 10 mL of a 10 mg Pd / mL palladium nitrate solution, weigh 0.158 g of silver nitrate and add it to the palladium nitrate solution. Dilute with deionized water to 65 mL and impregnate 100 g of the support prepared by the above method. The impregnated sample is dried at 120 °C for 4 h and calcined at 500 °C for 4 h to obtain catalyst S1, with a Pd loading of 0.10% and an Ag loading of 0.10% by mass.

[0059] Example 2

[0060] Carrier preparation: Take 100g of boehmite powder, 2g of starch, 3g of methylcellulose, and 10g of bamboo charcoal powder (same as in Example 1) and mix them evenly; take 1.50g of concentrated nitric acid and add it to 120g of deionized water to prepare an acid solution; add the acid solution to the evenly mixed powder and knead it, then extrude it to obtain cylindrical particles with a particle size of 2-4mm; dry at 90℃ for 12h; then heat-treat it at 280℃ and 2MPa with carbon dioxide and nitrogen (volume ratio 1:1) for 1h, then soak it in 3mol / L potassium carbonate solution at 65℃ for 2h, and then irradiate it with γ rays at 2kGy / min for 6h to obtain the carrier.

[0061] Active metal component loading method: Take 10 mL of a 10 mg Pd / mL palladium chloride solution, dilute it to 58 mL with deionized water, and impregnate it onto 100 g of the support prepared by the above method. After drying at 120 °C for 4 h and calcining at 450 °C for 6 h, a Pd-containing catalyst precursor is obtained. Weigh 0.895 g of zinc nitrate, add it to 58 mL of deionized water, stir evenly, and impregnate it onto the Pd-containing catalyst precursor. Then, after drying at 120 °C for 4 h and calcining at 450 °C for 6 h, catalyst S2 is obtained, with a Pd loading of 0.10% and a Zn loading of 0.20% by mass.

[0062] Example 3

[0063] Carrier preparation: Take 90g of alumina trihydrate powder (specific surface area 150.3m²) 2 15g titanium dioxide, 6g polyethylene glycol, 7g methylcellulose, and 12g graphene were mixed evenly. 6g acetic acid was added to 140g deionized water to prepare an acid solution. The acid solution was added to the evenly mixed powder and kneaded, then extruded to obtain cylindrical particles with a particle size of 2-4mm. The particles were crystallized at 250℃ and 12MPa for 4h (crystallization solvent was water), then soaked in a mixed solution of 5mol / L hydrogen peroxide and 5mol / L potassium permanganate at 30℃ for 0.5h, and then freeze-dried at -20℃ for 4h to obtain the carrier.

[0064] Active metal component loading method: Take 12 mL of palladium nitrate solution with 10 mg Pd / mL, dilute with deionized water to 71 mL, add 0.158 g of silver nitrate, stir evenly, and impregnate 100 g of the support prepared by the above method. After drying at 120 °C for 12 h and calcining at 480 °C for 4 h, a catalyst precursor containing Pd and Ag is obtained. Take 0.4 mL of bismuth nitrate solution containing 50 mg Bi / mL, dilute with deionized water to 71 mL, impregnate the catalyst precursor containing Pd and Ag, then dry at 120 °C for 8 h and calcining at 500 °C for 8 h to obtain catalyst S3. By mass content, the Pd loading is 0.12%, the Ag loading is 0.10%, and the Bi loading is 0.02%.

[0065] Example 4

[0066] Carrier preparation: Take 100g of pseudoboehmite powder (properties same as in Example 1), 10g of α-Al2O3 powder, 10g of γ-Al2O3 powder, 6g of guar gum powder, 6g of starch, and 5g of carbon black and mix them evenly; take 2.0g of concentrated nitric acid and 2.0g of acetic acid and add them to 150g of deionized water to prepare a mixed acid solution; add the acid solution to the evenly mixed powder and knead it, then extrude it to obtain cylindrical particles with a particle size of 2-4mm; dry at 120℃ for 4h; crystallize at 120℃ and 0.2MPa for 18h (the crystallization solvent is water), then soak in a mixed solution of 0.1mol / L nitric acid and 0.1mol / L hydrogen peroxide at 80℃ for 8h, and freeze-dry at -20℃ for 8h to obtain the carrier.

[0067] Active metal component loading method: Take 5 mL of 10 mg Pd / mL palladium nitrate solution, dilute it to 65 mL with deionized water, add 0.158 g of silver nitrate, stir evenly, and then impregnate it onto 100 g of the support prepared by the above method. After drying at 120 °C for 8 h and calcining at 450 °C for 6 h, catalyst S4 is obtained. The Pd loading is 0.05% and the Ag loading is 0.10% by mass.

[0068] Example 5

[0069] Carrier preparation: Take 100g of boehmite powder (properties same as in Example 1), 20g of alumina trihydrate powder (properties same as in Example 3), 10g of barium oxide powder, 5g of polyethylene glycol cellulose, 8g of polyvinyl alcohol, and 20g of diamond powder and mix them evenly; take 7.0g of ascorbic acid and 3.1g of acetic acid, add 180g of ethanol and deionized water (volume ratio 1:10) to prepare a mixed acid solution; add the acid solution to the evenly mixed powder and knead it, then extrude it to obtain cylindrical particles with a particle size of 2-4mm; dry at 100℃ for 4h; heat treat at 320℃ and 0.3MPa acetylene and argon atmosphere (volume ratio 0.05:1) for 5h, soak in 0.1mol / L sodium hydroxide solution at 35℃ for 5h, and then irradiate with 50W microwave for 60min to obtain the carrier.

[0070] Method for loading active metal components: 15 mL of a 10 mg Pd / mL palladium chloride solution was diluted to 70 mL with deionized water and impregnated onto 100 g of the support prepared by the above method. After drying at 110 °C for 12 h and calcining at 450 °C for 8 h, a Pd-containing catalyst precursor was obtained. 0.743 g of gallium nitrate was weighed and added to 70 mL of deionized water to impregnate the Pd-containing catalyst precursor. After drying at 120 °C for 12 h and calcining at 500 °C for 12 h, catalyst S5 was obtained, with a Pd loading of 0.15% and a Ga loading of 0.20% by mass.

[0071] Comparative Example 1

[0072] Carrier preparation: Take 100g of pseudoboehmite powder (properties same as in Example 1), 5g of guar gum powder, and 8g of carboxymethyl cellulose, and mix them evenly; take 1.80g of concentrated nitric acid and add it to 150g of deionized water to prepare a mixed acid solution; add the acid solution to the evenly mixed powder and knead it, then extrude it to obtain cylindrical particles with a particle size of 2-4mm; dry it at 110℃ for 4h; then heat it with air at 1200℃ and 0.2MPa for 12h to obtain the carrier.

[0073] Active metal component loading method: Take 16 mL of palladium nitrate solution with 10 mg Pd / mL, dilute it to 65 mL with deionized water, impregnate it onto 100 g of the support prepared by the above method, dry it at 120 °C for 12 h, and calcine it at 500 °C for 8 h to obtain catalyst D1, with a Pd loading of 0.16% by mass.

[0074] Comparative Example 2

[0075] Carrier preparation: Take 100g of pseudoboehmite powder (properties same as in Example 1), 2g of starch, 3g of methylcellulose, and 10g of bamboo charcoal powder and mix them evenly; take 1.50g of concentrated nitric acid and add it to 120g of deionized water to prepare an acid solution; add the acid solution to the evenly mixed powder and knead it, then extrude it to obtain cylindrical particles with a particle size of 2-4mm; then heat treat it with air at 1185℃ and 0.2MPa for 12h to obtain the carrier.

[0076] The active metal component loading method was the same as that of Comparative Example 1, resulting in catalyst D2.

[0077] Comparative Example 3

[0078] Carrier preparation: Take 100g of boehmite powder (properties as in Example 1), 10g of α-Al2O3 powder, 10g of γ-Al2O3 powder, 6g of guar gum powder, and 6g of starch; take 2.0g of concentrated nitric acid and 2.0g of acetic acid, add them to 150g of deionized water to prepare a mixed acid solution; add the acid solution to the uniformly mixed powder and knead it, then extrude it to obtain cylindrical particles with a particle size of 2-4mm; dry at 120℃ for 4h; crystallize at 120℃ and 0.2MPa for 18h (crystallization solvent is water), then soak in a mixed solution of 0.1mol / L nitric acid and 0.1mol / L hydrogen peroxide at 80℃ for 8h, and freeze-dry at -20℃ for 8h to obtain the carrier.

[0079] The active metal component loading method was the same as that of Comparative Example 1, resulting in catalyst D3.

[0080] Test case

[0081] Method for determining oxygen-containing groups on the carrier: The properties and quantity of oxygen-containing groups on the carrier were determined using the Boehm chemical method. Three 0.6 g portions of carrier were weighed and soaked in 40 ml of 0.05 mol / L NaHCO3, Na2CO3, and NaOH solutions, respectively, for 24 h. 10 ml of the soaking solution was titrated with 0.05 mol / L hydrochloric acid. Each sample was titrated three times, and the arithmetic mean was taken. The quantity of each type of oxygen-containing group on the carrier was calculated based on the amount of alkali consumed. The density of oxygen-containing groups was obtained by combining the carrier's specific surface area data. The results are listed in Table 1.

[0082] Table 1. Test results of oxygen-containing groups on the supports of the examples and comparative examples

[0083]

[0084] As shown in Table 1, the content and density of oxygen-containing groups on the surface of the carrier prepared by the method of the present invention are significantly higher than those of the comparative carrier. By adjusting the raw material ratio, preparation process parameters and conditions, the method of the present invention can control the number and type of oxygen-containing groups on the surface of the carrier.

[0085] Test case

[0086] The above catalyst was used to carry out a C3 gas-phase selective hydrogenation reaction under the following experimental conditions:

[0087] 10 ml of catalyst was packed into a stainless steel tubular reactor. After purging with nitrogen, hydrogen was introduced and reduction was performed at 160°C for 2 hours. The temperature was then lowered to room temperature, followed by purging with nitrogen. Subsequently, a C3 gas phase reactant was introduced. The typical molar composition of the reactants was: propane 3.25%, propadiene 0.85%, propyne 1.25%, with propylene as the equilibrium gas. The molar ratio of hydrogen to MAPD was 1.0–2.5, and the reactor inlet temperature was 52°C. Under the same reaction conditions, the MAPD content at the reactor outlet and the propylene selectivity for each catalyst were investigated.

[0088] The method for calculating propylene selectivity (%) is as follows:

[0089]

[0090] In the formula, MAPD represents propyne and propadiene, (MAPD) in The content of MAPD at the reactor inlet, (MAPD) out The content of MAPD (C2H6) at the reactor outlet. in The content of C2H6 at the reactor inlet. out The content of C2H6 at the reactor outlet is given. The contents of the above components were determined by a gas chromatograph equipped with an FID detector.

[0091] Table 2. Catalyst evaluation results obtained from the examples and comparative examples

[0092] catalyst MAPD content (μmol / mol) Selectivity (%) S1 3 61.3 S2 5 55.2 S3 3 65.5 S4 2 61.4 S5 1 61.5 D1 19 41.3 D2 22 40.7 D3 15 47.9

[0093] As can be seen from the results in Tables 1-2, compared with Comparative Examples 1-3, the content of oxygen-containing groups on the surface of the prepared support can be controlled by adding carbon-containing components and different surface treatment methods in Examples 1-5, thereby improving the catalytic activity of the catalyst. When the catalyst is used in the C3 gas-phase selective hydrogenation reaction, the MAPD (propyne and propadiene) content at the reactor outlet of Examples 1-5 is significantly lower than that of the comparative examples, and the selectivity is also higher.

Claims

1. A C3 gas-phase selective hydrogenation reaction, comprising the step of contacting a C3 gas-phase fraction with a catalyst, wherein the catalyst comprises a support, a primary active metal component supported on the support, and optionally added co-active metal components, wherein the surface oxygen-containing group density of the support is 0.1~6 mmol / m³. 2 The carrier is obtained by the following preparation process: a mixture of components including alumina powder, molding agent, pore-forming agent, inorganic carbon species, and optional oxides other than alumina is mixed to obtain a mixture material, which is then kneaded and granulated by adding an acidic solution, extruded and granulated, dried, and surface treated to obtain the carrier; the inorganic carbon species are selected from at least one of coke, activated carbon, carbon black, glassy carbon, charcoal, bamboo charcoal, coconut shell carbon, graphene, graphyne, and diamond; the surface treatment is selected from at least one of heat treatment, crystallization, oxidation, alkalization, and irradiation treatment.

2. The C3 gas-phase selective hydrogenation reaction according to claim 1, characterized in that, The surface oxygen-containing group density of the carrier is 0.1~4 mmol / m³. 2 ; and / or, In the carrier, the surface oxygen-containing groups are at least two of the following: hydroxyl, carboxyl, and lactone groups; and / or, The specific surface area of ​​the carrier is 40~200m². 2 / g, water absorption rate of 30~120%, strength of 30~150N / particle, bulk density of 0.4~1.0g / ml, pore volume of 0.3~1.2ml / g; and / or, The carrier may also optionally contain other oxides besides alumina.

3. The C3 gas-phase selective hydrogenation reaction according to claim 2, characterized in that, The hydroxyl group content is 2-40 mmol / g; and / or, the carboxyl group content is 2-40 mmol / g; and / or, the lactone group content is 1-30 mmol / g; and / or, The other oxides are selected from at least one of titanium oxide, barium oxide, magnesium oxide, calcium oxide, and silicon oxide.

4. The C3 gas-phase selective hydrogenation reaction according to claim 1, characterized in that, The main active metal component is Pd; and / or, The catalyst, by mass percentage, contains 0.02% to 0.2% of the main active metal component; and / or, The auxiliary active metal component is selected from at least one of Ag, Bi, Zn, and Ga; and / or, The catalyst contains 0 to 0.2% by mass percentage of the co-active metal component.

5. The C3 gas-phase selective hydrogenation reaction according to claim 4, characterized in that, The catalyst contains 0.02 to 0.15% of the main active metal component by mass percentage.

6. The C3 gas-phase selective hydrogenation reaction according to claim 1, characterized in that, The catalyst is subjected to reduction treatment before use; and / or, In the C3 gas phase fraction, the total molar percentage of propyne and propadiene is 0.5-6%; and / or, The conditions for the hydrogenation reaction are: a reaction temperature of 30–150 °C, and / or a reaction space velocity of 500–6000 h⁻¹. -1 .

7. The C3 gas-phase selective hydrogenation reaction according to claim 6, characterized in that, The reduction uses gases including hydrogen and other gases, such as nitrogen or methane, with a hydrogen molar percentage of 10-90%; and / or, a reduction temperature of 90-350℃; and / or, a reduction time of 2-24h.

8. The C3 gas-phase selective hydrogenation reaction according to claim 1, characterized in that, The catalyst is obtained by the following preparation process: a solution containing a main active metal compound and optionally added co-active metal compounds is loaded onto a support, and then dried and calcined to obtain the catalyst.

9. The C3 gas-phase selective hydrogenation reaction according to claim 8, characterized in that, The main active metal compound is selected from at least one of palladium-soluble compounds; and / or, The co-active metal compound is selected from at least one of the following: chlorides, nitrates, acetates, sulfates, oxides, and organometallic compounds of Ag, Bi, Zn, and Ga; and / or, The solvent in the solution is selected from at least one of water, hydrochloric acid, nitric acid, acetic acid, and alcohol; and / or, The total content of metal elements in the solution is 0.01~350 mg / mL; and / or, The drying conditions are: a drying temperature of 50~250℃, and a drying time of 2~36h; and / or, The calcination conditions are: calcination temperature of 250~850℃ and calcination time of 2~36h.

10. The C3 gas-phase selective hydrogenation reaction according to claim 9, characterized in that, The main active metal compound is selected from at least one of palladium chloride, palladium nitrate, palladium acetate, and palladium sulfate; and / or, The co-active metal compound is selected from at least one of the chlorides, nitrates, and acetates of Ag, Bi, Zn, and Ga; and / or, The solvent in the solution is water; and / or, The drying conditions are: drying temperature of 50~200℃ and drying time of 4~24h.

11. The C3 gas-phase selective hydrogenation reaction according to claim 1, characterized in that, The alumina powder is selected from at least one of boehmite powder, alumina trihydrate powder, fast-degrading alumina powder, and γ-Al2O3 powder; and / or, The molding agent is selected from at least one of polyethylene glycol cellulose, methylcellulose, carboxymethylcellulose, sodium carboxymethylcellulose, hydroxypropyl methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and starch; and / or, The molding agent is used in an amount of 0.05~8 wt% of the total weight of the mixture; and / or, The pore-forming agent is selected from at least one of polyvinyl alcohol, polyethylene glycol, polyacrylamide, polypropylene glycol, and guar gum powder; and / or, The amount of the pore-forming agent is 0.05~10 wt% of the total weight of the mixture; and / or, The inorganic carbon species are used in an amount of 0.1-12 wt% of the total weight of the mixture; and / or, The oxides other than alumina are selected from at least one of titanium oxide, barium oxide, magnesium oxide, calcium oxide, and silicon oxide; and / or, The amount of the oxides other than alumina is 0-20 wt% of the total weight of the mixture; and / or, The concentration of the acidic solution is 0.01~0.5 mol / L; and / or, The solvent in the acidic solution is selected from water or a mixture of water and an organic solvent; and / or, The acidic compound in the acidic solution is selected from at least one of organic acids and inorganic acids.

12. The C3 gas-phase selective hydrogenation reaction according to claim 11, characterized in that, The organic solvent is selected from at least one of methanol, ethanol, and ethylene glycol, and / or, when the solvent in the acidic solution is a mixture of water and an organic solvent, the volume ratio of the organic solvent to water is (0.01~1):1; and / or, The acidic compound in the acidic solution is selected from at least one of acetic acid, maleic acid, malic acid, citric acid, oxalic acid, formic acid, tartaric acid, ascorbic acid, salicylic acid, succinic acid, nitric acid, sulfuric acid, hydrochloric acid, hypochlorous acid, and phosphoric acid.

13. The C3 gas-phase selective hydrogenation reaction according to claim 1, characterized in that, During the preparation of the carrier: The drying conditions are 60~180℃ for 4~24 hours; and / or, The heat treatment conditions include: the heat treatment atmosphere comprises a first atmosphere and a second atmosphere, wherein the first atmosphere is selected from at least one of carbon dioxide, water vapor, acetylene, ethylene, and methane, and the second atmosphere is selected from at least one of air, nitrogen, argon, and helium; the volume ratio of the first atmosphere to the second atmosphere is (0.05~1):1; the heat treatment temperature is 300~1200℃; the heat treatment time is 1~24h; and the pressure is 0.1~3MPa; and / or, The crystallization conditions are: temperature 120~250 ℃, pressure 0.2~15 MPa, time 4~18 h, and the solvent used for crystallization is selected from at least one of water, ethanol, ethylene glycol, and ethylenediamine; and / or, The oxidation conditions are: temperature 30~110 ℃, time 0.2~10 h, the oxidant used for oxidation is selected from at least one of nitric acid, sulfuric acid, ammonium persulfate, hydrogen peroxide, potassium permanganate, and ascorbic acid, and the concentration of the oxidant solution is 0.1~10 mol / L; and / or, The alkalization conditions are as follows: temperature 30~110 ℃, time 0.2~10 h, the alkaline compound used for alkalization is selected from at least one of sodium hydroxide, sodium bicarbonate, sodium carbonate, sodium acetate, sodium oxalate, sodium citrate, potassium hydroxide, potassium bicarbonate, potassium carbonate, potassium acetate, and potassium citrate, and the concentration of the alkaline compound solution is 0.1~10 mol / L; and / or, The irradiation treatment conditions are as follows: the radiation source is selected from gamma rays and / or microwaves, wherein the gamma ray irradiation dose rate is 2~90 kGy / min and the irradiation time is 0.2~24h; and / or, the microwave power is 50~1000W and the irradiation time is 0.5~60 min.

14. The C3 gas-phase selective hydrogenation reaction according to claim 1, characterized in that, When the inorganic carbon species is at least one of coke, activated carbon, carbon black, and glassy carbon, surface treatment is performed by heat treatment, or by crystallization and oxidation; or... When the inorganic carbon species is at least one of wood charcoal, bamboo charcoal, and coconut shell charcoal, surface treatment is performed by heat treatment, or by a combination of heat treatment and irradiation; or... When the inorganic carbon species is at least one of graphene, graphynylene, and diamond, the surface treatment is carried out by crystallization and oxidation, or by heat treatment and alkalization, or by heat treatment, alkalization, and irradiation.

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