A catalyst for synthesizing 2-methylpyridine from pyridinemethanol methyl compound and a preparation method thereof

Abstract

The application belongs to the technical field of catalysts, and provides a catalyst for synthesizing 2-methylpyridine through pyridine methanol methylation and a preparation method thereof. The catalyst for synthesizing 2-methylpyridine through pyridine methanol methylation provided by the application comprises a carrier, an active component and an additive. The carrier is modified gamma-Al2O3. The active component is elemental nickel. The additive is one or more of lanthanum oxide, cerium oxide, a tin-containing substance, a zinc-containing substance, a cobalt-containing substance, palladium and ruthenium. The modified gamma-Al2O3 further comprises SiO2 and / or ZrO2. The gamma-Al2O3 is modified by SiO2 and / or ZrO2, so that the gamma-Al2O3 and the catalyst can be stabilized. Meanwhile, the additive can improve the catalytic activity, stability and regenerability of the catalyst.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and in particular to a catalyst for the synthesis of 2-methylpyridine by methylation of pyridine with methanol and its preparation method. Background Technology

[0002] 2-Methylpyridine is an important chemical intermediate for the production of high-value-added fine chemicals and has wide applications in synthetic materials, pharmaceuticals, pesticides, and feed additives. Currently, the main methods for synthesizing 2-methylpyridine are: (1) reacting acetylene or ethylene with ammonia to prepare 2-methylpyridine. This process produces a large amount of acetonitrile byproducts, and the products have similar boiling points, making separation difficult; (2) producing 2-methylpyridine via the gas-phase method using acetaldehyde and ammonia. This process results in a low molar yield of 2-methylpyridine and complex products; (3) reacting acetone with acrylonitrile at atmospheric pressure to synthesize 2-methylpyridine. This process has a low yield, many side reactions, and makes product purification difficult; (4) synthesizing 2-methylpyridine from aldehydes, ketones, and ammonia via ammonium aldehyde condensation. This process makes product separation difficult. In addition, patent WO2023071891 discloses a process for the continuous production of 2-methylpyridine from aniline, but this process results in a low yield of 2-methylpyridine. Chinese patents with publication numbers CN105218431A, CN109174168A, and CN109174168A all disclose methods for synthesizing 2-methylpyridine using pyridine and methanol as raw materials. The synthesis of 2-methylpyridine using pyridine and methanol not only involves simple reaction components and utilizes widely available and inexpensive methanol, but also improves the pyridine industry chain, reduces companies' dependence on the market for pyridine bases, and is an environmentally friendly and efficient synthesis process.

[0003] Chinese patent CN109174168A discloses a catalyst for the preparation of 2-methylpyridine by pyridine alkylation. It uses a sodium-type molecular sieve as the matrix and employs a first promoter (one or more of Ba, Mg, Ni, Ca, and Fe) and a second promoter (one or more of Co, Bi, Cu, and Zn) to improve the catalyst's activity. However, this catalyst exhibits low catalytic activity. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a catalyst for the synthesis of 2-methylpyridine by pyridine-methanol methylation and a method for its preparation. The catalyst of this invention has high activity.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a catalyst for the synthesis of 2-methylpyridine by pyridine methanol methylation, comprising a support, an active component, and an auxiliary agent;

[0007] The carrier is modified γ-Al2O3;

[0008] The active component is elemental nickel;

[0009] The additive is one or more of lanthanum oxide, cerium oxide, tin-containing substances, zinc-containing substances, cobalt-containing substances, palladium, and ruthenium;

[0010] The modified γ-Al2O3 also includes SiO2 and / or ZrO2;

[0011] The tin-containing substance includes tin and / or tin oxide;

[0012] The zinc-containing substances include zinc and / or zinc oxide;

[0013] The cobalt-containing material includes cobalt and / or cobalt oxide.

[0014] Preferably, the modified γ-Al2O3 contains 0-30% SiO2 and 0-5% ZrO2, and the mass fractions of SiO2 and ZrO2 are not both 0.

[0015] This invention also provides a method for preparing the catalyst for the synthesis of 2-methylpyridine by pyridine-methanol methylation as described in the above technical solution, comprising the following steps:

[0016] The carrier, active precursor, auxiliary agent precursor and solvent are mixed and then subjected to standing, rotary evaporation and drying in sequence to obtain a mixed powder;

[0017] The mixed powder was calcined to obtain a catalyst precursor;

[0018] The catalyst precursor was reduced and activated to obtain the catalyst for the synthesis of 2-methylpyridine by methylation of pyridine methanol.

[0019] Preferably, the active precursor is a nickel salt, which includes one or more of nickel nitrate, nickel chloride, and nickel acetate; the auxiliary precursor includes one or more of lanthanum compounds, cerium compounds, tin compounds, zinc compounds, palladium compounds, cobalt compounds, and ruthenium compounds; the lanthanum compound includes lanthanum nitrate, the cerium compound includes cerium oxide, the tin compound includes tin oxide and / or tin chloride, the zinc compound includes zinc nitrate, the palladium compound includes palladium nitrate, the cobalt compound includes cobalt nitrate, and the ruthenium compound includes ruthenium chloride.

[0020] Preferably, the solvent is ethanol or water. When the solvent is ethanol, the raw materials for preparation also include a complexing agent, which includes one or more of ethylenediamine, citric acid, acetylacetone, and ethyl acetoacetate.

[0021] Preferably, the mixing of the carrier, active precursor, auxiliary precursor and solvent is carried out under stirring conditions, the stirring temperature is room temperature and the time is 2 to 10 hours; the standing time is 1 to 24 hours; the rotary evaporation temperature is 60 to 90 degrees Celsius; the drying temperature is 90 to 150 degrees Celsius and the time is 6 to 12 hours.

[0022] Preferably, the calcination temperature is 400–600°C and the time is 3–9 hours.

[0023] Preferably, the catalyst precursor comprises a support, an oxidized active component, and an oxidized auxiliary component; wherein the mass fraction of the oxidized active component in the catalyst precursor is 10-40%, and the mass fraction of the oxidized auxiliary component is 0.5-10%.

[0024] Preferably, the volume fraction of hydrogen in the reduction and activation atmosphere is 10-50%, the reduction and activation temperature is 400-550°C, and the time is 2-6 hours.

[0025] Preferably, the method for preparing the carrier includes the following steps:

[0026] One or more of silicon and zircon sources are mixed with boehmite powder, binder and water, and then extruded, dried and calcined in sequence to obtain the carrier.

[0027] The silicon source includes SiO2 powder and / or SiO2 sol;

[0028] The zirconium source includes ZrO2 and / or zirconium nitrate;

[0029] The adhesive comprises guar gum powder and / or hydroxymethyl cellulose;

[0030] The drying temperature is 90–150°C, and the time is 3–24 hours;

[0031] The roasting temperature is 500–1000℃, and the time is 3–12 hours.

[0032] This invention provides a catalyst for the synthesis of 2-methylpyridine by methylation of pyridine with methanol, comprising a support, an active component, and an auxiliary agent; the support is modified γ-Al₂O₃; the active component is elemental nickel; the auxiliary agent is one or more of lanthanum oxide, cerium oxide, tin-containing substances, zinc-containing substances, cobalt-containing substances, palladium, and ruthenium; the modified γ-Al₂O₃ further comprises SiO₂ and / or ZrO₂; the tin-containing substances include tin and / or tin oxide; the zinc-containing substances include zinc and / or zinc oxide; and the cobalt-containing substances include cobalt and / or cobalt oxide.

[0033] This invention utilizes SiO2 and / or ZrO2 to modify γ-Al2O3, which can stabilize γ-Al2O3 and the catalyst. At the same time, the addition of the additives improves the dispersion of Ni and prevents Ni agglomeration, thus improving the stability and regeneration performance of the catalyst. The electronic effect of the additives on Ni improves the activity of the catalyst. Detailed Implementation

[0034] This invention provides a catalyst for the synthesis of 2-methylpyridine by pyridine methanol methylation, comprising a support, an active component, and an auxiliary agent;

[0035] The carrier is modified γ-Al2O3;

[0036] The active component is elemental nickel;

[0037] The additive is one or more of lanthanum oxide, cerium oxide, tin-containing substances, zinc-containing substances, cobalt-containing substances, palladium, and ruthenium;

[0038] The modified γ-Al2O3 also includes SiO2 and / or ZrO2;

[0039] The tin-containing substance includes tin and / or tin oxide;

[0040] The zinc-containing substances include zinc and / or zinc oxide;

[0041] The cobalt-containing material includes cobalt and / or cobalt oxide.

[0042] The catalyst for the synthesis of 2-methylpyridine by pyridine-methanol methylation provided by this invention includes a support, wherein the support is modified γ-Al₂O₃. In this invention, the modified γ-Al₂O₃ further includes SiO₂ and / or ZrO₂. Preferably, the mass fraction of SiO₂ in the modified γ-Al₂O₃ is 0–30%, and the mass fraction of ZrO₂ is 0–5%, wherein the mass fractions of SiO₂ and ZrO₂ are not both 0; more preferably, the mass fraction of SiO₂ is 5%, and the mass fraction of ZrO₂ is 0%, or the mass fraction of SiO₂ is 0%, and the mass fraction of ZrO₂ is 1%.

[0043] The catalyst for the synthesis of 2-methylpyridine by pyridine-methanol methylation provided by this invention comprises an active component. In this invention, the active component is elemental nickel.

[0044] The catalyst for the synthesis of 2-methylpyridine by pyridine-methanol methylation provided by the present invention includes an auxiliary agent, which is one or more of lanthanum oxide, cerium oxide, tin-containing substances, zinc-containing substances, cobalt-containing substances, palladium and ruthenium, more preferably lanthanum oxide and / or palladium, more preferably lanthanum oxide, or a mixture of lanthanum oxide and palladium.

[0045] This invention also provides a method for preparing the catalyst for the synthesis of 2-methylpyridine by pyridine-methanol methylation as described in the above technical solution, comprising the following steps:

[0046] The carrier, active precursor, auxiliary agent precursor and solvent are mixed and then subjected to standing, rotary evaporation and drying in sequence to obtain a mixed powder;

[0047] The mixed powder was calcined to obtain a catalyst precursor;

[0048] The catalyst precursor was reduced and activated to obtain the catalyst for the synthesis of 2-methylpyridine by methylation of pyridine methanol.

[0049] Unless otherwise specified, all raw materials used in this invention are preferably commercially available products.

[0050] The present invention involves mixing a carrier, an active precursor, an auxiliary precursor, and a solvent, followed by standing, rotary evaporation, and drying to obtain a mixed powder.

[0051] In this invention, the preparation method of the carrier preferably includes the following steps: mixing one or more of a silicon source and a zirconium source with boehmite powder, a binder, and water, followed by extrusion molding, drying, and calcination to obtain the carrier. In this invention, the silicon source preferably includes SiO2 powder and / or SiO2 sol, more preferably SiO2 powder. In this invention, the zirconium source preferably includes ZrO2 and / or zirconium nitrate, more preferably zirconium nitrate, and even more preferably zirconium nitrate pentahydrate, wherein the zirconium nitrate is preferably used in the form of an aqueous solution of zirconium nitrate. In this invention, the binder preferably includes guar gum powder and / or hydroxymethyl cellulose, more preferably guar gum powder; the mass ratio of the binder to the boehmite powder is preferably 1:10. This invention does not specifically limit the extrusion molding operation; any operation well known to those skilled in the art can be used. In this invention, the drying temperature is preferably 90–150°C, more preferably 120–130°C, and the drying time is preferably 3–24 h, more preferably 12–18 h. In this invention, the roasting temperature is preferably 500-1000℃, more preferably 600-900℃, and even more preferably 700-800℃, and the roasting time is preferably 3-12h, and even more preferably 4-6h.

[0052] In this invention, the active precursor is a nickel salt, which preferably includes one or more of nickel nitrate, nickel chloride and nickel acetate, more preferably nickel nitrate, and even more preferably nickel nitrate hexahydrate.

[0053] In this invention, the auxiliary precursor preferably comprises one or more of lanthanum compounds, cerium compounds, tin compounds, zinc compounds, palladium compounds, cobalt compounds, and ruthenium compounds, more preferably lanthanum compounds and / or palladium compounds, specifically preferably lanthanum compounds, or mixtures of lanthanum compounds and palladium compounds. In this invention, the lanthanum compound preferably comprises lanthanum nitrate, more preferably lanthanum nitrate hexahydrate. In this invention, the cerium compound preferably comprises cerium oxide. In this invention, the tin compound preferably comprises tin oxide and / or tin chloride. In this invention, the zinc compound preferably comprises zinc nitrate. In this invention, the palladium compound preferably comprises palladium nitrate. In this invention, the cobalt compound preferably comprises cobalt nitrate. In this invention, the ruthenium compound preferably comprises ruthenium chloride.

[0054] In this invention, the solvent is preferably ethanol or water, and more preferably ethanol. When the solvent is preferably ethanol, the raw materials preferably also include a complexing agent, which preferably includes one or more of ethylenediamine, citric acid, acetylacetone, and ethyl acetoacetate, and more preferably ethylenediamine; the molar ratio of the total metal ions of the active precursor and the auxiliary precursor to the complexing agent is preferably 1:2.

[0055] In this invention, the mixing of the carrier, active precursor, auxiliary precursor and solvent is preferably carried out under stirring conditions, the stirring temperature is preferably room temperature, that is, neither additional heating nor additional cooling is required, and the stirring time is preferably 2 to 10 hours.

[0056] In this invention, the settling time is preferably 1 to 24 hours.

[0057] In this invention, the preferred temperature for rotary evaporation is 60–90°C. The present invention does not specifically limit the time for rotary evaporation, as long as the solvent can be removed.

[0058] In this invention, the drying temperature is preferably 90-150°C, and the drying time is preferably 6-12 hours.

[0059] After obtaining the mixed powder, the present invention calcines the mixed powder to obtain a catalyst precursor.

[0060] In this invention, the calcination temperature is preferably 400-600°C, and the calcination time is preferably 3-9 hours.

[0061] In this invention, the catalyst precursor preferably comprises a support, an oxidized active component, and an oxidized auxiliary component; in the catalyst precursor, the mass fraction of the oxidized active component is preferably 10-40%, and the mass fraction of the oxidized auxiliary component is preferably 0.5-10%.

[0062] After obtaining the catalyst precursor, the present invention reduces and activates the catalyst precursor to obtain the catalyst for the synthesis of 2-methylpyridine by methylation of pyridine methanol.

[0063] In this invention, the volume fraction of hydrogen in the reduction and activation atmosphere is preferably 10-50%, the reduction and activation temperature is preferably 400-550°C, and the time is preferably 2-6 hours.

[0064] The catalyst for the synthesis of 2-methylpyridine by pyridine methanol methylation provided by the present invention and its preparation method are described in detail below with reference to the embodiments. However, these should not be construed as limiting the scope of protection of the present invention.

[0065] Example 1

[0066] 5% SiO2 modified γ-Al2O3: 21g SiO2 powder and 40g guar gum powder were added to 400g pseudoboehmite powder, 300g water was added, the mixture was mechanically stirred and mixed, extruded into strips, dried at 120℃ for 12h, and calcined at 600℃ for 4h to obtain the carrier.

[0067] 120g of support was added to 100mL of an ethanol solution containing 175g of nickel nitrate hexahydrate, 7.3g of lanthanum nitrate hexahydrate, and ethylenediamine (ethylenediamine: metal ions = 2:1). The mixture was stirred at room temperature for 3h, rotary evaporated at 60℃, dried at 120℃ for 12h, and calcined at 450℃ for 3h to obtain a catalyst precursor with a loading of 26.8% NiO-1.6% La2O3. The catalyst precursor was reduced with H2 (10%) at 450℃ for 4h to obtain the catalyst.

[0068] Example 2

[0069] 5% SiO2 modified γ-Al2O3: 21g SiO2 powder and 40g guar gum powder were added to 400g pseudoboehmite powder, 300g water was added, the mixture was mechanically stirred and mixed, extruded into strips, dried at 120℃ for 12h, and calcined at 600℃ for 4h to obtain the carrier.

[0070] 120g of support was added to 100mL of an ethanol solution containing 175g of nickel nitrate hexahydrate, 7.3g of lanthanum nitrate hexahydrate, and ethylenediamine (ethylenediamine: metal ions = 2:1). The mixture was stirred at room temperature for 3h, rotary evaporated at 60℃, dried at 120℃ for 12h, and calcined at 550℃ for 3h to obtain a catalyst precursor with a loading of 26.8% NiO-1.6% La2O3. The catalyst precursor was reduced with H2 (10%) at 450℃ for 4h to obtain the catalyst.

[0071] Example 3

[0072] 5% SiO2 modified γ-Al2O3: 21g SiO2 powder and 40g guar gum powder were added to 400g pseudoboehmite powder, 300g water was added, the mixture was mechanically stirred and mixed, extruded into strips, dried at 120℃ for 12h, and calcined at 800℃ for 4h to obtain the carrier.

[0073] 120g of support was added to 100mL of an ethanol solution containing 175g of nickel nitrate hexahydrate, 7.3g of lanthanum nitrate hexahydrate, and ethylenediamine (ethylenediamine: metal ions = 2:1). The mixture was stirred at room temperature for 3h, rotary evaporated at 60℃, dried at 120℃ for 12h, and calcined at 450℃ for 3h to obtain a catalyst precursor with a loading of 26.8% NiO-1.6% La2O3. The catalyst precursor was reduced with H2 (10%) at 450℃ for 4h to obtain the catalyst.

[0074] Example 4

[0075] 1% ZrO2 modified γ-Al2O3: Add 40g of guar gum powder to 400g of pseudoboehmite powder, mix mechanically, add 300g of an aqueous solution containing 14g of zirconium nitrate pentahydrate, continue mechanical stirring and mixing, extrude into strips, dry at a certain temperature of 120℃ for 12h, and calcine at 800℃ for 4h to obtain the carrier.

[0076] 120g of support was added to 100mL of an ethanol solution containing 175g of nickel nitrate hexahydrate, 7.3g of lanthanum nitrate hexahydrate, and ethylenediamine (ethylenediamine: metal ions = 2:1). The mixture was stirred at room temperature for 3h, rotary evaporated at 60℃, dried at 120℃ for 12h, and calcined at 450℃ for 3h to obtain a catalyst precursor with a loading of 26.8% NiO-1.6% La2O3. The catalyst precursor was reduced with H2 (10%) at 450℃ for 4h to obtain the catalyst.

[0077] Example 5

[0078] 5% SiO2 modified γ-Al2O3: 21g SiO2 powder and 40g guar gum powder were added to 400g pseudoboehmite powder, 300g water was added, the mixture was mechanically stirred and mixed, extruded into strips, dried at 120℃ for 12h, and calcined at 800℃ for 4h to obtain the carrier.

[0079] 120g of support was added to 100mL of an aqueous solution containing 175g of nickel nitrate hexahydrate and 7.3g of lanthanum nitrate hexahydrate. The mixture was stirred at room temperature for 3h, rotary evaporated at 80℃, dried at 120℃ for 12h, and calcined at 450℃ for 3h to obtain a catalyst precursor with a loading of 26.8% NiO-1.6% La2O3. The catalyst precursor was reduced with H2 (10%) at 450℃ for 4h to obtain the catalyst.

[0080] Example 6

[0081] 5% SiO2 modified γ-Al2O3: 21g SiO2 powder and 40g guar gum powder were added to 400g pseudoboehmite powder, 300g water was added, the mixture was mechanically stirred and mixed, extruded into strips, dried at 120℃ for 12h, and calcined at 800℃ for 4h to obtain the carrier.

[0082] 120 g of support was added to 100 mL of an aqueous solution containing 175 g nickel nitrate hexahydrate, 7.3 g lanthanum nitrate hexahydrate, and 0.34 g palladium nitrate. The mixture was stirred at room temperature for 3 h, rotary evaporated at 80 °C, dried at 120 °C for 12 h, and calcined at 450 °C for 3 h to obtain a catalyst precursor with a loading of 26.8% NiO, 1.6% La₂O₃, and 0.09% palladium oxide (calculated as palladium element). The catalyst precursor was reduced with 10% H₂ at 400 °C for 4 h to obtain the catalyst.

[0083] Example 7

[0084] γ-Al2O3 modified with 5% SiO2 and 1% ZrO2: 21g SiO2 powder and 40g guar gum powder were added to 400g pseudoboehmite powder, and 300g aqueous solution containing 14g zirconium nitrate pentahydrate was added. The mixture was mechanically stirred and mixed, extruded into strips, dried at 120℃ for 12h, and calcined at 600℃ for 4h to obtain the carrier.

[0085] 120 g of support was added to 100 mL of an ethanol solution containing 175 g of nickel nitrate hexahydrate, 7.3 g of lanthanum nitrate hexahydrate, and ethylenediamine (ethylenediamine:metal ions = 2:1). The mixture was stirred at room temperature for 3 h, rotary evaporated at 60 °C, dried at 120 °C for 12 h, and calcined at 450 °C for 3 h to obtain a catalyst precursor with a loading of 26.8% NiO-1.6% La2O3. The catalyst precursor was reduced with H2 (10%) at 450 °C for 4 h to obtain the catalyst.

[0086] Example 8

[0087] 5% SiO2 modified γ-Al2O3: 21g SiO2 powder and 40g guar gum powder were added to 400g pseudoboehmite powder, 300g water was added, the mixture was mechanically stirred and mixed, extruded into strips, dried at 120℃ for 12h, and calcined at 800℃ for 4h to obtain the carrier.

[0088] 30 g of support was added to 100 mL of an aqueous solution containing 46.6 g of nickel nitrate hexahydrate, 2.56 g of lanthanum nitrate hexahydrate, and 0.43 g of palladium nitrate. The mixture was stirred at room temperature for 3 h, rotary evaporated at 80 °C, dried at 120 °C for 12 h, and calcined at 400 °C for 3 h to obtain a catalyst precursor with a loading of 27.8% NiO, 2.2% La₂O₃, and 0.5% oxidized Pd (calculated as Pd elemental). The catalyst precursor was reduced with 10% H₂ at 400 °C for 4 h to obtain the catalyst.

[0089] Example 9

[0090] 5% SiO2 modified γ-Al2O3: 21g SiO2 powder and 40g guar gum powder were added to 400g pseudoboehmite powder, 300g water was added, the mixture was mechanically stirred and mixed, extruded into strips, dried at 120℃ for 12h, and calcined at 800℃ for 4h to obtain the carrier.

[0091] 50 g of support was added to 100 mL of an aqueous solution containing 19.6 g of nickel nitrate hexahydrate and 1.4 g of cerium nitrate hexahydrate. The mixture was stirred at room temperature for 3 h, rotary evaporated at 80 °C, dried at 120 °C for 12 h, and calcined at 450 °C for 3 h to obtain a catalyst precursor with a loading of 9.05% NiO-1.0% CeO2. The catalyst precursor was reduced with 10% H2 at 450 °C for 4 h to obtain the catalyst.

[0092] Comparative Example 1

[0093] γ-Al2O3: Add 40g of guar gum powder and 300g of water to 400g of pseudoboehmite powder, mix by mechanical stirring, extrude into strips, dry at 120℃ for 12h, and calcine at 800℃ for 4h to obtain the carrier.

[0094] 120 g of support was added to 100 mL of an aqueous solution containing 175 g of nickel nitrate hexahydrate, stirred at room temperature for 3 h, rotary evaporated at 80 °C, dried at 120 °C for 12 h, and calcined at 450 °C for 3 h to obtain a catalyst with a NiO loading of 30%. The catalyst was reduced with H2 (10%) at 450 °C for 4 h.

[0095] Catalyst performance evaluation

[0096] The catalytic performance of the catalyst was evaluated using a fixed-bed reactor. The specific method was as follows: 10 mL of 20–40 mesh catalyst was loaded into the isothermal section of the fixed-bed reactor. Methanol and pyridine were mixed at a molar ratio of 2:1 and fed into the preheater. After the temperature was raised to 220°C, the mixture was introduced into the reactor (feed rate 0.1 mL / min). -1 The reactor pressure was maintained at 4 MPa using high-purity N2, and the reaction temperature was 210 °C. Samples were taken every two hours for analysis, and the yield of 2-methylpyridine was calculated. The catalytic performance of each catalyst after 20 days of reaction is shown in Table 1. The deactivated catalyst was calcined at 450 °C in air for 3 h, and then reduced with H2 (10%) at 450 °C for 4 h.

[0097] Table 1 Performance of the catalyst in the synthesis of 2-methylpyridine

[0098]

[0099] Modified Al2O3-supported Ni catalysts exhibit improved activity, stability, and regeneration performance through Al2O3 modification and the addition of promoters. The addition of promoters improves Ni dispersion and inhibits Ni agglomeration, thus enhancing catalyst stability and regeneration performance. The electronic effects of the promoters on Ni further enhance catalyst activity.

[0100] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The application of a catalyst in the synthesis of 2-methylpyridine by pyridine-methanol methylation, characterized in that, The catalyst includes a support, an active component, and an auxiliary agent; The carrier is modified γ-Al2O3; The active component is elemental nickel; The auxiliary agent is lanthanum oxide and palladium; The modified γ-Al2O3 includes SiO2; the mass fraction of SiO2 in the modified γ-Al2O3 is 5%. The method for preparing the carrier includes the following steps: The silicon source was mixed with boehmite powder, binder and water, and then extruded, dried and calcined in sequence to obtain the carrier. The silicon source includes SiO2 powder and / or SiO2 sol; The roasting temperature is 800℃ and the time is 4 hours.

2. The application according to claim 1, characterized in that, The method for preparing the catalyst includes the following steps: The carrier, active precursor, auxiliary agent precursor and solvent are mixed and then subjected to standing, rotary evaporation and drying in sequence to obtain a mixed powder; The mixed powder was calcined to obtain a catalyst precursor; The catalyst precursor was reduced and activated to obtain the catalyst for the synthesis of 2-methylpyridine by methylation of pyridine methanol.

3. The application according to claim 2, characterized in that, The active precursor is a nickel salt, which includes one or more of nickel nitrate, nickel chloride, and nickel acetate; the auxiliary precursor includes a lanthanum compound and a palladium compound; the lanthanum compound includes lanthanum nitrate, and the palladium compound includes palladium nitrate.

4. The application according to claim 2, characterized in that, The solvent is ethanol or water. When the solvent is ethanol, the raw materials also include a complexing agent, which includes one or more of ethylenediamine, citric acid, acetylacetone, and ethyl acetoacetate.

5. The application according to claim 2, characterized in that, The carrier, active precursor, auxiliary precursor and solvent are mixed under stirring conditions, the stirring temperature is room temperature and the time is 2~10h; the standing time is 1~24h; the rotary evaporation temperature is 60~90℃; the drying temperature is 90~150℃ and the time is 6~12h.

6. The application according to claim 2, characterized in that, The calcination temperature is 400~600℃, and the time is 3~9h.

7. The application according to claim 2, characterized in that, The catalyst precursor includes a support, an oxidized active component, and an oxidized auxiliary component; in the catalyst precursor, the mass fraction of the oxidized active component is 10-40%, and the mass fraction of the oxidized auxiliary component is 0.5-10%.

8. The application according to claim 2, characterized in that, The volume fraction of hydrogen in the reduction and activation atmosphere is 10-50%, the reduction and activation temperature is 400-550℃, and the time is 2-6h.

9. The application according to claim 1, characterized in that, The adhesive comprises guar gum powder and / or hydroxymethyl cellulose; The drying temperature is 90~150℃, and the time is 3~24h.

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