Aldehyde hydrogenation catalyst and method for preparing the same

Abstract

The application provides a preparation method of an aldehyde hydrogenation catalyst, which adopts a step-by-step continuous co-precipitation mode and comprises the following steps: 1) mixing a zinc-aluminum mixed solution and a precipitation solution in parallel flow and controlling the pH to be 6.5-6.8; then adding a zinc-copper mixed solution and the precipitation solution in parallel flow, controlling the pH to be 7.5-7.8, and evaporating to form a gel; 2) drying and calcining the gel, adding graphite to press and form into a tablet, and obtaining the aldehyde hydrogenation catalyst; wherein the precipitation solution is formed by dissolving oxalate and a template agent P123 in a solvent. The aldehyde hydrogenation catalyst prepared by the method has high yield of metal ions in raw materials, small loss, no need of washing, reduced discharge of waste water, good activity and selectivity in high-carbon aldehyde high-temperature gas-phase hydrogenation, and the catalyst prepared by the method has large specific surface area and pore volume, so that the catalyst has high hydrogenation activity and high alkyl alcohol selectivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical catalysts, in particular to an aldehyde hydrogenation catalyst and a preparation method thereof. BACKGROUND

[0002] The current catalyst used for aldehyde hydrogenation by gas phase method is mainly copper-zinc (Cu-Zn) catalyst. Copper is the active component in the Cu-Zn catalyst, and ZnO acts as a carrier and an additive. The Cu-Zn catalyst is generally prepared by co-precipitation method, and the obtained metal oxide powder is pressed into tablets to form a cylindrical catalyst. In recent years, aluminum is used as an additive more frequently, and the content of Al2O3 in the catalyst is generally 1% to 10%. The domestic gas phase aldehyde hydrogenation catalysts OXO series, VAH series, and NCH series are all Cu-Zn catalysts prepared by co-precipitation method, and the catalysts are formed by tablet pressing method. These catalysts are mainly used for hydrogenation of butyraldehyde and octenyl aldehyde.

[0003] However, the existing process for preparing copper-zinc-aluminum catalyst by co-precipitation method is long, and since there are differences in the pH values at which different types of metal salts form precipitates, the dissolution and precipitation of aluminum salt occurs, causing condensation of aldehyde and alcohol during the reaction process. Meanwhile, the catalyst preparation process requires washing, the yield of metal ions is low, and a large amount of nitrogen-containing wastewater is generated, which is difficult to treat.

[0004] Chinese patent document CN114870847B discloses an aldehyde hydrogenation catalyst and a preparation method thereof. Zinc salt and sodium metaaluminate are used to prepare a zinc-aluminum spinel precursor, and copper salt, zinc salt, and a precipitant are used to prepare a catalyst active component precursor. The zinc-aluminum spinel precursor and the catalyst active component precursor are ground into powder respectively, mixed uniformly, calcined, pressed into tablets, broken, and sieved to obtain the copper-zinc-aluminum gas phase hydrogenation catalyst. Sodium metaaluminate is used as the aluminum source and the precipitant, and washing is required to remove sodium ions, which is not environmentally friendly.

[0005] Chinese patent document CN101489934B discloses a preparation method of an aluminum-containing spinel nanostructure. Aluminum salt and metal salt are mixed in an aqueous solution, and then rotary evaporation, drying, and calcination are performed to obtain the aluminum-containing spinel nanostructure. The preparation process is relatively simple, and the harshness of the catalyst preparation operating conditions is reduced. However, the specific surface area of the catalyst is relatively low.

[0006] Chinese patent document CN112973710A discloses a preparation method of a copper-chromium catalyst and a method for preparing alkanol by hydrogenation of alkenyl aldehyde or aldehyde using the catalyst. Copper salt and chromium salt are used as the reaction solution, and oxalate, ammonium salt, and carbonate salt without sodium are added as the precipitant salt. The mixture is heated to gel, thereby producing copper-chromium precipitate. Then, the catalyst is obtained by heating, drying, and calcination. Since no sodium-containing salt is used, washing is not required. However, the specific surface area of the catalyst prepared by the process is relatively small.

[0007] Chinese patent document CN113797933A discloses a copper-chromium catalyst, its preparation method and application. By mixing copper oxalate and chromium oxalate in an aqueous solution, a gel is obtained. The preparation process is relatively simple, and the harshness of the catalyst preparation operating conditions is reduced, but the specific surface area of the catalyst is low.

[0008] Chinese patent document CN100398202C discloses an aldehyde gas phase hydrogenation catalyst and its preparation method. The catalyst is prepared by using a mixed solution of nitrates of copper, zinc and aluminum by continuous co-precipitation method. The catalyst obtained has high low-temperature activity when used for hydrogenation of butyl aldehyde and octene aldehyde, but the pore volume of the catalyst is low.

[0009] Chinese patent document CN1087971C discloses a preparation method of an aldehyde hydrogenation catalyst, comprising the following steps: a. preparing a co-precipitation working salt solution with soluble copper and zinc salts as raw materials; b. preparing a precipitant solution; c. mixing the solutions obtained in steps a and b to co-precipitate, obtaining a suspended co-precipitate; d. aging the suspended co-precipitate obtained in step c to obtain an insoluble co-precipitate; e. filtering the insoluble co-precipitate obtained in step d to obtain a filter cake; f. drying the filter cake obtained in step e to obtain a co-precipitate; g. calcining the co-precipitate obtained in step f to obtain a mixture of copper oxide and zinc oxide; h. mixing the mixture of copper oxide and zinc oxide obtained in step g with a pore-forming agent uniformly and pressing into a catalyst; wherein the precipitant solution used in step b is an organic acid solution. The copper-zinc catalyst for aldehyde hydrogenation to alcohol is prepared by selecting an organic acid as a precipitant, which simplifies the preparation process, reduces the waste of clean water caused by sodium washing and the difficulty of wastewater treatment. However, the specific surface area of the catalyst prepared by this method is low.

[0010] In summary, how to simplify the production process, improve the specific surface area and pore volume of the aldehyde hydrogenation catalyst, and improve the catalytic performance, as well as improve the yield of metal ions in the raw material and reduce the discharge of wastewater, is the key point of the research on the aldehyde hydrogenation catalyst technology. SUMMARY

[0011] The purpose of the present application is to provide a preparation method of an aldehyde hydrogenation catalyst, which improves the comprehensive performance of the catalyst such as specific surface, pore volume, selectivity and activity, improves the utilization rate of metal ions and reduces the discharge of waste liquid.

[0012] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0013] A preparation method of an aldehyde hydrogenation catalyst, which adopts a step-by-step continuous co-precipitation method, comprising the following steps:

[0014] 1) mixing zinc-aluminum mixed solution and precipitation solution in parallel, and controlling pH to be 6.5-6.8; then mixing zinc-copper mixed solution and precipitation solution in parallel, and controlling pH to be 7.5-7.8, and then evaporating to form a gel;

[0015] 2) after drying and calcining the gel, adding graphite to press and form tablets to obtain an aldehyde hydrogenation catalyst;

[0016] The precipitation solution is formed by dissolving oxalate and a template agent P123 in a solvent.

[0017] The preparation method of the aldehyde hydrogenation catalyst provided by the application adopts a step-by-step continuous co-precipitation mode, controls the pH value of different precipitation steps, uses oxalate as a precipitant, and adds a template agent P123 to the precipitation solution, thereby reducing the dissolution and precipitation of aluminum salt, effectively reducing the occurrence of side reactions such as aldol condensation and self-condensation of aldehyde, and greatly improving the utilization rate of raw materials. The aldehyde hydrogenation catalyst prepared by the method has a high specific surface area and exhibits good hydrogenation activity and high alkyl alcohol selectivity in high-carbon aldehyde gas-phase hydrogenation at high temperature.

[0018] Optionally, in the preparation method of the aldehyde hydrogenation catalyst provided by the application, the solvent in the zinc-aluminum mixed solution, the precipitation solution and the zinc-copper mixed solution is a mixed solution of ethanol and water, the mixed solution of ethanol and water is obtained by mixing the azeotrope of ethanol and water collected when the mixed solution is evaporated to form a gel and deionized water and / or ethanol, and the concentration of ethanol in the mixed solution of ethanol and water is not limited in particular, and the corresponding substances can be dissolved; the concentration of ethanol in the mixed solution of ethanol and water recommended by the application is 30wt%-50wt%.

[0019] Optionally, in the preparation method of the aldehyde hydrogenation catalyst provided by the application, the zinc-aluminum mixed solution is obtained by dissolving zinc salt and aluminum salt in a mixed solution of ethanol and water; the zinc-copper mixed solution is obtained by dissolving zinc salt and copper salt in a mixed solution of ethanol and water; the concentration of the zinc-aluminum mixed solution and the zinc-copper mixed solution is not limited in particular, and can be adjusted according to actual needs; the amount ratio of the zinc-aluminum mixed solution and the zinc-copper mixed solution can be added according to the ratio of zinc oxide, copper oxide and aluminum oxide in the target catalyst. The aluminum salt, the zinc salt and the copper salt are not limited in particular, and can be any conventional salt that can be dissolved in a mixed solution of ethanol and water, such as nitrate.

[0020] Optionally, in the preparation method of the aldehyde hydrogenation catalyst provided by the application, the oxalate is selected from ammonium oxalate.

[0021] Optionally, in the preparation method of the aldehyde hydrogenation catalyst provided by the application, the molar ratio of the oxalate to the total metal salt is 1.1-1.3.

[0022] Optionally, in the preparation method of the aldehyde hydrogenation catalyst, the molar ratio of the oxalate to the template P123 is 670-1200.

[0023] Optionally, in the preparation method of the aldehyde hydrogenation catalyst, the operation temperature of step 1) is 80-90℃.

[0024] Optionally, in step 2) of the preparation method of the aldehyde hydrogenation catalyst, the calcination temperature is 360-400℃, and the time is 3-4 hours.

[0025] Optionally, the preparation method of the aldehyde hydrogenation catalyst specifically comprises the following steps:

[0026] (1) adding deionized water and / or ethanol to the mixed solution of ethanol and water collected in the evaporation process to form a gel to obtain a mixed solution of ethanol and water with an ethanol content of 50%-80%;

[0027] (2) taking a certain amount of the mixed solution of ethanol and water prepared in step (1), adding and dissolving aluminum salt and zinc salt to prepare a zinc-aluminum mixed solution, and preheating to 80-90℃;

[0028] (3) taking a certain amount of the ethanol-water mixed solution prepared in step (1), adding and dissolving oxalate and template P123 to obtain a precipitate solution, and preheating to 80-90℃;

[0029] (4) adding and dissolving zinc salt and copper salt in a certain amount of the mixed solution of ethanol and water prepared in step (1) to obtain a zinc-copper mixed solution, and preheating to 80-90℃;

[0030] (5) adding the zinc-aluminum mixed solution and the precipitate solution into a reaction kettle with heat preservation and stirring in parallel flow, and controlling the pH to be 6.5-6.8 and the neutralization temperature to be 80-90℃;

[0031] (6) then adding the zinc-copper mixed solution and the precipitate solution into the reaction kettle in parallel flow for co-precipitation, controlling the pH to be 7.5-7.8 and the neutralization temperature to be 80-90℃, and then condensing and collecting the evaporated ethanol and water mixed solution to a certain weight (which can be recycled) to obtain a gel;

[0032] (7) drying the gel obtained in step (6), calcining at 360-400℃ for 3-4 hours, and then adding a certain amount of graphite to press into a tablet to obtain a catalyst.

[0033] The application further provides an aldehyde hydrogenation catalyst prepared by the above preparation method of the aldehyde hydrogenation catalyst.

[0034] Optionally, the aldehyde hydrogenation catalyst comprises, based on 100% by mass of the aldehyde hydrogenation catalyst: copper oxide 20% to 50%, zinc oxide 40% to 80%, aluminum oxide 0.5% to 5%, and graphite 1% to 3%.

[0035] Optionally, the aldehyde hydrogenation catalyst provided by the present application has a specific surface area of 51 to 71 m 2 / g, a pore volume of 0.31 to 0.39 ml / g, and an average pore diameter of 14 to 18 nm.

[0036] Compared with the prior art, the present application has the following advantages:

[0037] Beneficial effect 1: The preparation method of the aldehyde hydrogenation catalyst provided by the present application reduces the dissolution and precipitation of aluminum salt by adjusting the pH value of different precipitation steps, which is conducive to reducing the occurrence of side reactions; oxalate is used as a precipitant, and organic template P123 is used as a dispersant, the complexation of oxalate facilitates the molecular-level mixing of copper oxalate, zinc oxalate, and aluminum oxalate, and inhibits the aggregation of copper oxide of the catalyst, thereby obtaining highly dispersed copper oxide grains, so that the copper-zinc-aluminum catalyst prepared has high specific surface area and hydrogenation activity, and the solvent evaporation process and the preparation process are optimized, thereby greatly improving the utilization rate of raw metal materials.

[0038] 2. The preparation method of the aldehyde hydrogenation catalyst provided by the present application, after the second co-precipitation, collects the evaporated ethanol and water mixed solution in the condensation process and recycles it as a solvent for the zinc-aluminum mixed solution, the zinc-copper mixed solution, and the precipitation solution, thereby recycling the ethanol and water used in the preparation process, effectively reducing the catalyst preparation cost, and reducing environmental pollution. DETAILED DESCRIPTION

[0039] The present application will be described in detail below through examples. It is necessary to point out here that the following examples are only used to further illustrate the present application and cannot be understood as limiting the protection scope of the present application, and those skilled in the art can make some non-essential improvements and adjustments to the present application according to the above content of the present application.

[0040] If the specific experimental steps or conditions are not specified in the examples, the operations or conditions can be performed according to the conventional experimental steps described in the literature in the art. If the reagents or instruments used are not specified by the manufacturer, they are all conventional reagent products that can be obtained by purchase.

[0041] Example 1

[0042] The present embodiment provides an aldehyde hydrogenation catalyst, and a preparation method thereof, which comprises the following steps:

[0043] (1) Take 1100g ethanol and 1100g deionized water to mix, get 2200g ethanol and water mixed solution with 50% ethanol content, ready for use;

[0044] (2) Take 10g zinc nitrate hexahydrate and 10g aluminum nitrate nonahydrate to add into the ethanol and water mixed solution with 50% ethanol content, prepare 50ml zinc-aluminum mixed solution, stir and heat to 90℃, ready for use;

[0045] (3) Take 12.1g template P123 and 173.7g ammonium oxalate to add into 1000g ethanol and water mixed solution with 50% ethanol content, get precipitation solution, heat to 90℃, ready for use;

[0046] (4) Take 210g zinc nitrate hexahydrate and 115g copper nitrate trihydrate to add into 1000g ethanol and water mixed solution with 50% ethanol content, prepare zinc-copper mixed solution, stir and heat to 90℃, ready for use;

[0047] (5) Take the above zinc-aluminum mixed solution and 90g precipitation solution to flow into the reaction kettle with heat preservation and stirring, control the neutralization temperature at 90℃, and control the pH at about 6.5-6.8;

[0048] (6) Take the above zinc-copper solution and 1140g precipitation solution to flow into the reaction system of step (5) for co-precipitation, control the neutralization temperature at 90℃, and control the pH at about 7.5-7.8, then condense and collect the evaporated ethanol and water mixed solution (collect 1100g, with 85% ethanol content), put the collected ethanol and water mixed solution into the collection tank for standby, the remaining water is not collected, continue to evaporate to get the gel;

[0049] (7) Dry the gel obtained in step (6), calcine at 400℃ for 3 hours to get black powder, then add graphite to the black powder to press into a tablet to get an aldehyde hydrogenation catalyst.

[0050] Example 2

[0051] The present embodiment provides an aldehyde hydrogenation catalyst, and the preparation method thereof comprises the following steps:

[0052] (1) Take 1000g of the ethanol and water mixed solution collected by condensation in Example 1 (with 85% ethanol content), then add 250g of ethanol (with ≥99% ethanol content) and 950g of deionized water to get 2200g of ethanol and water mixed solution with 50% ethanol content, ready for use;

[0053] (2) Take a certain amount of the mixed solution of ethanol and water prepared in step (1), then add 10 g of zinc nitrate hexahydrate and 13 g of aluminum nitrate nonahydrate to prepare a zinc-aluminum mixed solution of 50 ml, and heat to 90°C under stirring for standby;

[0054] (3) Take 1000 g of the mixed solution of ethanol and water prepared in step (1), add 12.1 g of template P123 and 173.7 g of ammonium oxalate to obtain a precipitation solution, and heat to 90°C for standby;

[0055] (4) Take 1000 g of the mixed solution of ethanol and water prepared in step (1), add 232 g of zinc nitrate hexahydrate and 88 g of copper nitrate trihydrate to prepare a zinc-copper mixed solution, and heat to 90°C under stirring for standby;

[0056] (5) The zinc-aluminum mixed solution and 90 g of the precipitation solution are added into a reaction kettle with heat preservation and stirring in a concurrent manner, the neutralization temperature is controlled at 90°C, and the pH is controlled at about 6.5-6.8;

[0057] (6) The zinc-copper solution and 1140 g of the precipitation solution are added into the reaction system of step (5) in a concurrent manner for co-precipitation, the neutralization temperature is controlled at 90°C, the pH is controlled at about 7.5-7.8, then the mixed solution of ethanol and water evaporated is condensed and collected (1100 g of which contains 85% of ethanol), and the collected mixed solution of ethanol and water is placed into a collection tank for standby, the remaining water is not collected, and the evaporation is continued to obtain a gel;

[0058] (7) The gel obtained in step (6) is dried and calcined at 400°C for 3 hours to obtain a black powder, then a certain amount of graphite is added into the black powder to be pressed into a tablet for forming an aldehyde hydrogenation catalyst.

[0059] Example 3

[0060] The present embodiment provides an aldehyde hydrogenation catalyst, and a preparation method thereof includes the following steps:

[0061] (1) Take 777 g of the mixed solution of ethanol and water collected by condensation in Example 2 (containing 85% of ethanol), then add 1423 g of deionized water to obtain a mixed solution of ethanol and water with an ethanol content of 30% by weight of 2200 g, and standby;

[0062] (2) Take a certain amount of the mixed solution of ethanol and water prepared in step (1), then add 10 g of zinc nitrate hexahydrate and 10 g of aluminum nitrate nonahydrate to prepare a zinc-aluminum mixed solution of 50 ml, and heat to 80°C under stirring for standby;

[0063] (3) Take 1000g of the ethanol and water mixed solution prepared in step (1), add 11.5g of template agent P123 and 186.2g of ammonium oxalate to obtain a precipitation solution, and heat to 80°C for standby;

[0064] (4) Take 1000g of the ethanol and water mixed solution prepared in step (1), add 246g of zinc nitrate hexahydrate and 75g of copper nitrate trihydrate to prepare a zinc-copper mixed solution, and heat to 80°C under stirring for standby;

[0065] (5) The above zinc-aluminum mixed solution is added into a reaction kettle with heat preservation and stirring in a concurrent manner with 90g of the precipitation solution, the neutralization temperature is controlled at 90°C, and the pH is controlled at about 6.5-6.8;

[0066] (6) The above zinc-copper solution is added into the reaction system of step (5) in a concurrent manner with 1140g of the precipitation solution for co-precipitation, the neutralization temperature is controlled at 80°C, and the pH is controlled at about 7.5-7.8, then the mixed solution of ethanol and water evaporated is condensed and collected (730g is collected, of which the mass content of ethanol is 90%), the collected mixed solution of ethanol and water is placed into a collection tank for standby, the remaining water is not collected, and evaporation is continued to obtain a gel;

[0067] (7) The gel obtained in step (6) is dried, calcined at 400°C for 3 hours to obtain a black powder, then a certain amount of graphite is added into the black powder to be pressed into a tablet for molding to obtain an aldehyde hydrogenation catalyst.

[0068] Example 4

[0069] The present embodiment provides an aldehyde hydrogenation catalyst, and a preparation method thereof includes the following steps:

[0070] (1) 1100g of ethanol is mixed with 1100g of deionized water to obtain 2200g of a mixed solution of ethanol and water with an ethanol content of 50%, which is standby;

[0071] (2) A certain amount of the mixed solution of ethanol and water prepared in step (1) is taken, then 10g of zinc nitrate hexahydrate and 18g of aluminum nitrate nonahydrate are added to prepare a 50ml zinc-aluminum mixed solution, which is heated to 90°C under stirring for standby;

[0072] (3) Take 1000g of the ethanol and water mixed solution prepared in step (1), add 6.8g of template agent P123 and 173.7g of ammonium oxalate to obtain a precipitation solution, and heat to 90°C for standby;

[0073] (4) Take 1000g of the ethanol and water mixed solution prepared in step (1), add 150g of zinc nitrate hexahydrate and 150g of copper nitrate trihydrate to prepare a zinc-copper mixed solution, and heat to 90°C under stirring for standby;

[0074] (5) The zinc-aluminum mixed solution is added into the reactor with heat preservation and stirring, the neutralization temperature is controlled at 90°C, and the pH is controlled at about 6.5-6.8;

[0075] (6) The zinc-copper solution is added into the reaction system of step (5) for co-precipitation, the neutralization temperature is controlled at 90°C, and the pH is controlled at about 7.5-7.8, then the mixed solution of ethanol and water evaporated is condensed and collected (1000g is collected, and the mass content of ethanol is 85%), the collected mixed solution of ethanol and water is placed in a collection tank for standby, the remaining water is not collected, and the evaporation is continued to obtain a gel;

[0076] (7) The gel obtained in step (6) is dried and calcined at 400°C for 3 hours to obtain a black powder, then a certain amount of graphite is added into the black powder to be pressed into a tablet to obtain an aldehyde hydrogenation catalyst.

[0077] Example 5

[0078] The embodiment provides an aldehyde hydrogenation catalyst, and a preparation method thereof comprises the following steps:

[0079] (1) 1000g of the mixed solution of ethanol and water (the ethanol content is 85%) condensed and collected in the example 4 is taken, then 250g of ethanol (the ethanol content is ≥99%) and 950g of deionized water are added to obtain 2200g of a mixed solution of ethanol and water with an ethanol content of 50%, which is used for standby;

[0080] (2) A certain amount of the mixed solution of ethanol and water prepared in step (1) is taken, then 10g of zinc nitrate hexahydrate and 4.5g of aluminum nitrate nonahydrate are added to prepare 50ml of a zinc-aluminum mixed solution, which is heated and stirred to 90°C for standby;

[0081] (3) 1000g of the mixed solution of ethanol and water prepared in step (1) is taken, 10.6g of a template P123 and 186.1g of ammonium oxalate are added to obtain a precipitation solution, which is heated to 90°C for standby;

[0082] (4) 1000g of the mixed solution of ethanol and water prepared in step (1) is taken, 190g of zinc nitrate hexahydrate and 125g of copper nitrate trihydrate are added to prepare a zinc-copper mixed solution, which is heated and stirred to 90°C for standby;

[0083] (5) The zinc-aluminum mixed solution is added into the reactor with heat preservation and stirring, the neutralization temperature is controlled at 90°C, and the pH is controlled at about 6.5-6.8;

[0084] (6) The zinc copper solution is added to the reaction system of step (5) for co-precipitation with 1160 g of the precipitation solution, the neutralization temperature is controlled at 90°C, the pH is controlled at about 7.5-7.8, then the mixed solution of ethanol and water evaporated is condensed and collected (1000 g of the mixed solution of ethanol and water is collected, the mass content of ethanol is 90%), the collected mixed solution of ethanol and water is put into a collection tank for standby, the remaining water is not collected, and the evaporation is continued to obtain a gel;

[0085] (7) The gel obtained in step (6) is dried, and the black powder obtained by calcining at 400°C for 3 hours is pressed into a tablet with a certain amount of graphite to obtain an aldehyde hydrogenation catalyst.

[0086] Example 6

[0087] The embodiment provides an aldehyde hydrogenation catalyst, and a preparation method thereof includes the following steps:

[0088] (1) 1000 g of the mixed solution of ethanol and water (the content of ethanol is 90%) condensed and collected in example 5 is taken, then 200 g of ethanol (the content of ethanol is ≥99%) and 1000 g of deionized water are added to obtain 2200 g of a mixed solution of ethanol and water with an ethanol content of 50%, which is used for standby;

[0089] (2) A certain amount of the mixed solution of ethanol and water prepared in step (1) is taken, then 10 g of zinc nitrate hexahydrate and 3 g of aluminum nitrate nonahydrate are added to prepare 50 ml of a zinc-aluminum mixed solution, which is heated to 90°C under stirring for standby;

[0090] (3) 1000 g of the mixed solution of ethanol and water prepared in step (1) is taken, 8.9 g of a template P123 and 179.9 g of ammonium oxalate are added to obtain a precipitation solution, which is heated to 90°C for standby;

[0091] (4) 1000 g of the mixed solution of ethanol and water prepared in step (1) is taken, 270 g of zinc nitrate hexahydrate and 62 g of copper nitrate trihydrate are added to prepare a zinc-copper mixed solution, which is heated to 90°C under stirring for standby;

[0092] (5) The zinc-aluminum mixed solution is added to a reaction kettle with heat preservation and stirring for co-precipitation with 90 g of the precipitation solution, the neutralization temperature is controlled at 90°C, and the pH is controlled at about 6.5-6.8;

[0093] (6) The zinc copper solution is added to the reaction system of step (5) for co-precipitation with 1140 g of the precipitation solution, the neutralization temperature is controlled at 90°C, the pH is controlled at about 7.5-7.8, then the mixed solution of ethanol and water evaporated is condensed and collected (1100 g of the mixed solution of ethanol and water is collected, the mass content of ethanol is 85%), the collected mixed solution of ethanol and water is put into a collection tank for standby, the remaining water is not collected, and the evaporation is continued to obtain a gel;

[0094] (7) The gel obtained in step (6) is dried, and the black powder obtained by calcining at 400°C for 3 hours is pressed into a tablet with a certain amount of graphite to obtain an aldehyde hydrogenation catalyst.

[0095] Example 7

[0096] The embodiment provides an aldehyde hydrogenation catalyst, and a preparation method thereof includes the following steps:

[0097] (1) 1000 g of the mixed solution of ethanol and water (the mass content of ethanol is 85%) condensed and collected in example 6 is taken, then 250 g of ethanol (the mass content of ethanol is ≥99%) and 950 g of deionized water are added to obtain 2200 g of a mixed solution of ethanol and water with a mass content of 50% of ethanol, which is used for standby;

[0098] (2) A certain amount of the mixed solution of ethanol and water prepared in step (1) is taken, then 10 g of zinc nitrate hexahydrate and 15 g of aluminum nitrate nonahydrate are added to prepare 50 ml of a zinc-aluminum mixed solution, which is heated to 90°C under stirring for standby;

[0099] (3) 1000 g of the mixed solution of ethanol and water prepared in step (1) is taken, 13.5 g of a template P123 and 193.5 g of ammonium oxalate are added to obtain a precipitation solution, which is heated to 90°C for standby;

[0100] (4) 1000 g of the mixed solution of ethanol and water prepared in step (1) is taken, 160 g of zinc nitrate hexahydrate and 145 g of copper nitrate trihydrate are added to prepare a zinc-copper mixed solution, which is heated to 90°C under stirring for standby;

[0101] (5) The zinc-aluminum mixed solution is added to a reaction kettle with heat preservation and stirring for co-precipitation with 90 g of the precipitation solution, the neutralization temperature is controlled at 90°C, and the pH is controlled at about 6.5-6.8;

[0102] (6) The zinc copper solution is added to the reaction system of step (5) for co-precipitation, the neutralization temperature is controlled at 90°C, the pH is controlled at about 7.5-7.8, then the mixed solution of ethanol and water evaporated is condensed and collected (1100 g of the mixed solution of ethanol and water is collected, the mass content of ethanol is 85%), the collected mixed solution of ethanol and water is put into a collection tank for standby, the remaining water is not collected, and the evaporation is continued to obtain a gel;

[0103] (7) The gel obtained in step (6) is dried, and the black powder obtained by calcining at 400°C for 3 hours is pressed into a tablet with a certain amount of graphite to obtain an aldehyde hydrogenation catalyst.

[0104] Example 8

[0105] The embodiment provides an aldehyde hydrogenation catalyst, and a preparation method thereof comprises the following steps:

[0106] (1) 1000 g of the mixed solution of ethanol and water (the mass content of ethanol is 85%) condensed and collected in example 7 is taken, then 250 g of ethanol (the mass content of ethanol is ≥99%) and 950 g of deionized water are added to obtain 2200 g of a mixed solution of ethanol and water with a mass content of 50% of ethanol, which is used for standby;

[0107] (2) A certain amount of the mixed solution of ethanol and water prepared in step (1) is taken, then 10 g of zinc nitrate hexahydrate and 2 g of aluminum nitrate nonahydrate are added to prepare 50 ml of a zinc-aluminum mixed solution, which is heated to 90°C under stirring for standby;

[0108] (3) 1000 g of the mixed solution of ethanol and water prepared in step (1) is taken, 8 g of a template agent P123 and 186.1 g of ammonium oxalate are added to obtain a precipitation solution, which is heated to 90°C for standby;

[0109] (4) 1000 g of the mixed solution of ethanol and water prepared in step (1) is taken, 180 g of zinc nitrate hexahydrate and 135 g of copper nitrate trihydrate are added to prepare a zinc-copper mixed solution, which is heated to 90°C under stirring for standby;

[0110] (5) The zinc-aluminum mixed solution is added to a reaction kettle with heat preservation and stirring for co-precipitation, the neutralization temperature is controlled at 90°C, and the pH is controlled at about 6.5-6.8;

[0111] (6) The zinc copper solution is added to the reaction system of step (5) for co-precipitation with 1140 g of the precipitation solution, the neutralization temperature is controlled at 90°C, the pH is controlled at about 7.5-7.8, then the mixed solution of ethanol and water evaporated is condensed and collected (1000 g of the mixed solution of ethanol and water is collected, the mass content of ethanol is 85%), the collected mixed solution of ethanol and water is put into a collection tank for standby, the remaining water is not collected, and the evaporation is continued to obtain a gel;

[0112] (7) The gel obtained in step (6) is dried, and the black powder obtained by calcining at 380°C for 4 hours is pressed into a tablet with a certain amount of graphite to obtain an aldehyde hydrogenation catalyst.

[0113] Example 9

[0114] The embodiment provides an aldehyde hydrogenation catalyst, and a preparation method thereof includes the following steps:

[0115] (1) 1000 g of the mixed solution of ethanol and water (the mass content of ethanol is 85%) condensed and collected in the example 8 is taken, then 250 g of ethanol (the mass content of ethanol is ≥99%) and 950 g of deionized water are added to obtain 2200 g of the mixed solution of ethanol and water with a mass content of 50% of ethanol, which is used for standby;

[0116] (2) A certain amount of the mixed solution of ethanol and water prepared in step (1) is taken, then 10 g of zinc nitrate hexahydrate and 12 g of aluminum nitrate nonahydrate are added to prepare 50 ml of a zinc-aluminum mixed solution, which is heated to 95°C under stirring for standby;

[0117] (3) 1000 g of the mixed solution of ethanol and water prepared in step (1) is taken, 13.4 g of a template P123 and 192.3 g of ammonium oxalate are added to obtain a precipitation solution, which is heated to 95°C for standby;

[0118] (4) 1000 g of the mixed solution of ethanol and water prepared in step (1) is taken, 260 g of zinc nitrate hexahydrate and 65 g of copper nitrate trihydrate are added to prepare a zinc-copper mixed solution, which is heated to 95°C under stirring for standby;

[0119] (5) The zinc-aluminum mixed solution is added to a reaction kettle with heat preservation and stirring for co-precipitation with 90 g of the precipitation solution, the neutralization temperature is controlled at 90°C, and the pH is controlled at about 6.5-6.8;

[0120] (6) The zinc copper solution is added to the reaction system of step (5) in parallel with 1140 g of the precipitation solution to co-precipitate, the neutralization temperature is controlled at 95°C, the pH is controlled at about 7.5-7.8, then the mixed solution of ethanol and water evaporated is condensed and collected (1100 g is collected, the mass content of ethanol is 85%), the collected mixed solution of ethanol and water is put into a collection tank for standby, the remaining water is not collected, and the evaporation is continued to obtain a gel;

[0121] (7) The gel obtained in step (6) is dried, calcined at 400°C for 3 hours to obtain a black powder, then a certain amount of graphite is added to the black powder to be pressed into a tablet to obtain an aldehyde hydrogenation catalyst.

[0122] Comparative Example 1

[0123] The present comparative example provides an aldehyde hydrogenation catalyst, and the preparation method thereof comprises the following steps:

[0124] (1) 1100 g of ethanol is mixed with 1100 g of deionized water to obtain 2200 g of a mixed solution of ethanol and water with an ethanol content of 50%, which is prepared for standby;

[0125] (2) 220 g of zinc nitrate hexahydrate, 10 g of aluminum nitrate nonahydrate, and 115 g of copper nitrate trihydrate are added to 1000 g of the mixed solution of ethanol and water with an ethanol content of 50% to prepare a copper-zinc-aluminum mixed solution, which is heated to 90°C under stirring for standby;

[0126] (3) 12.1 g of a template agent P123 and 173.7 g of ammonium oxalate are added to 1000 g of the mixed solution of ethanol and water with an ethanol content of 50% to obtain a precipitation solution, which is heated to 90°C for standby;

[0127] (4) The copper-zinc-aluminum mixed solution and the precipitation solution are added to a reaction kettle with heat preservation and stirring in parallel, the neutralization temperature is controlled at 90°C, the pH is controlled at about 7.5-7.8, then the mixed solution of ethanol and water evaporated is condensed and collected (1100 g is collected, the mass content of ethanol is 85%), the collected mixed solution of ethanol and water is put into a collection tank for standby, the remaining water is not collected, and the evaporation is continued to obtain a gel;

[0128] (5) The gel obtained in step (4) is dried, calcined at 400°C for 3 hours to obtain a black powder, then a certain amount of graphite is added to the black powder to be pressed into a tablet to obtain an aldehyde hydrogenation catalyst.

[0129] Comparative Example 2

[0130] The preparation method of the aldehyde hydrogenation catalyst provided by the present comparative example is similar to that of Example 1, with the only difference being that the step of condensing to form a gel is omitted. The preparation method of the aldehyde hydrogenation catalyst provided by the present comparative example comprises the following steps:

[0131] Step (1), step (2), step (3), step (4) and step (5): the same as Example 1.

[0132] Step (6): the above zinc-copper solution and 1140 g of the precipitation solution are added to the reaction system of step (5) for co-precipitation, with the neutralization temperature being controlled at 90°C and the pH being controlled at about 7.5-7.8;

[0133] (7) The system obtained in step (6) is filtered, washed, dried, and calcined at 400°C for 3 hours to obtain a black powder, and then a certain amount of graphite is added to the black powder to be pressed into a tablet to obtain an aldehyde hydrogenation catalyst.

[0134] Comparative Example 3

[0135] The preparation method of the aldehyde hydrogenation catalyst provided by the present comparative example is similar to that of Example 1, with the only difference being that the pH controlled in step (5) is different. The pH controlled in step (5) of the present comparative example is about 7.5-7.8.

[0136] (1) 1100 g of ethanol is mixed with 1100 g of deionized water to obtain a mixed solution of ethanol and water with an ethanol content of 50% by weight, for standby use;

[0137] (2) 10 g of zinc nitrate hexahydrate and 10 g of aluminum nitrate nonahydrate are added to the mixed solution of ethanol and water with an ethanol content of 50% by weight to prepare a 50 ml zinc-aluminum mixed solution, which is heated to 90°C under stirring for standby use;

[0138] (3) 12.1 g of template P123 and 173.7 g of ammonium oxalate are added to the mixed solution of ethanol and water with an ethanol content of 50% by weight to obtain a precipitation solution, which is heated to 90°C for standby use;

[0139] (4) 210 g of zinc nitrate hexahydrate and 115 g of copper nitrate trihydrate are added to 1000 g of the mixed solution of ethanol and water with an ethanol content of 50% by weight to prepare a zinc-copper mixed solution, which is heated to 90°C under stirring for standby use;

[0140] (5) The above zinc-aluminum mixed solution and 100 g of the precipitation solution are added to a reaction kettle with heat preservation and stirring in a parallel flow, with the neutralization temperature being controlled at 90°C and the pH being controlled at about 7.5-7.8;

[0141] (6) The zinc copper solution is added to the reaction system of step (5) for co-precipitation in parallel with 1140 g of the precipitation solution, the neutralization temperature is controlled at 90°C, the pH is controlled at about 7.5-7.8, then the mixed solution of ethanol and water evaporated is condensed and collected (1100 g of the mixed solution of ethanol and water is collected, the mass content of ethanol is 85%), the collected mixed solution of ethanol and water is put into a collection tank for standby, the remaining water is not collected, and the evaporation is continued to obtain a gel;

[0142] (7) The gel obtained in step (6) is dried, and the black powder obtained by calcining at 400°C for 3 hours is pressed into a tablet with graphite to obtain an aldehyde hydrogenation catalyst.

[0143] Comparative Example 4

[0144] The preparation method of the aldehyde hydrogenation catalyst provided in the present comparative example is similar to that in Example 1, the only difference is that the pH in step (6) is controlled differently. The pH in step (6) of the present comparative example is controlled at about 6.5-6.8.

[0145] (1) 1100 g of ethanol is mixed with 1100 g of deionized water to obtain 2200 g of a mixed solution of ethanol and water with a mass content of 50% of ethanol, which is used for standby;

[0146] (2) 10 g of zinc nitrate hexahydrate and 10 g of aluminum nitrate nonahydrate are added to the mixed solution of ethanol and water with a mass content of 50% of ethanol to prepare a 50 ml zinc-aluminum mixed solution, which is heated to 90°C under stirring for standby;

[0147] (3) 12.1 g of template P123 and 173.7 g of ammonium oxalate are added to 1050 g of the mixed solution of ethanol and water with a mass content of 50% of ethanol to obtain a precipitation solution, which is heated to 90°C for standby;

[0148] (4) 210 g of zinc nitrate hexahydrate and 115 g of copper nitrate trihydrate are added to 1000 g of the mixed solution of ethanol and water with a mass content of 50% of ethanol to prepare a zinc-copper mixed solution, which is heated to 90°C under stirring for standby;

[0149] (5) The zinc-aluminum mixed solution is added to a reaction kettle with heat preservation and stirring in parallel with 90 g of the precipitation solution, the neutralization temperature is controlled at 90°C, and the pH is controlled at about 6.5-6.8;

[0150] (6) The zinc copper solution is added to the reaction system of step (5) for co-precipitation in parallel flow with 1100 g of the precipitation solution, the neutralization temperature is controlled at 90°C, the pH is controlled at about 6.5-6.8, then the mixed solution of ethanol and water evaporated is condensed and collected (1050 g is collected, the mass content of ethanol is 85%), the collected mixed solution of ethanol and water is placed in a collection tank for standby, the remaining water is not collected, and the evaporation is continued to obtain a gel;

[0151] (7) The gel obtained in step (6) is dried, calcined at 400°C for 3 hours to obtain a black powder, then the black powder is pressed into a tablet with graphite to obtain an aldehyde hydrogenation catalyst.

[0152] Comparative Example 5

[0153] The present comparative example provides an aldehyde hydrogenation catalyst, and the preparation method thereof comprises the following steps:

[0154] (1) 1100 g of ethanol is mixed with 1100 g of deionized water to obtain 2200 g of a mixed solution of ethanol and water with an ethanol mass content of 50%, which is prepared for standby;

[0155] (2) 10 g of zinc nitrate hexahydrate and 10 g of aluminum nitrate nonahydrate are added to the mixed solution of ethanol and water with an ethanol mass content of 50% to prepare a 50 ml zinc-aluminum mixed solution, which is heated to 90°C under stirring for standby;

[0156] (3) 12.1 g of template P123 and 50 g of oxalic acid are added to 1000 g of the mixed solution of ethanol and water with an ethanol mass content of 50% to obtain a precipitation solution, which is heated to 90°C for standby;

[0157] (4) 210 g of zinc nitrate hexahydrate and 115 g of copper nitrate trihydrate are added to 1000 g of the mixed solution of ethanol and water with an ethanol mass content of 50% to prepare a zinc-copper mixed solution, which is heated to 90°C under stirring for standby;

[0158] (5) The zinc-aluminum mixed solution and the precipitation solution are added to a reaction kettle with heat preservation and stirring in parallel flow, the neutralization temperature is controlled at 90°C, and the pH is controlled at about 6.5-6.8;

[0159] (6) The zinc copper solution is added to the reaction system of step (5) for co-precipitation in parallel flow with 1100 g of the precipitation solution, the neutralization temperature is controlled at 90°C, the pH is controlled at about 6.5-6.8, then the mixed solution of ethanol and water evaporated is condensed and collected (1050 g is collected, the mass content of ethanol is 85%), the collected mixed solution of ethanol and water is placed in a collection tank for standby, the remaining water is not collected, and the evaporation is continued to obtain a gel;

[0160] (7) The gel obtained in step (6) is dried, calcined at 400°C for 3 hours to obtain a black powder, and then the black powder is added with graphite to be tablet-molded to obtain an aldehyde hydrogenation catalyst.

[0161] Comparative Example 6

[0162] The preparation method of the aldehyde hydrogenation catalyst provided in the present comparative example is similar to that in Example 1, except that no P123 template is added in the precipitant solution of the present comparative example, and the specific preparation process of the present comparative example is as follows:

[0163] (1) 1100 g of ethanol is mixed with 1100 g of deionized water to obtain a mixed solution of ethanol and water with an ethanol mass content of 50%, for standby use;

[0164] (2) 10 g of zinc nitrate hexahydrate and 10 g of aluminum nitrate nonahydrate are added into the mixed solution of ethanol and water with an ethanol mass content of 50% to prepare a 50 ml zinc-aluminum mixed solution, which is heated to 90°C under stirring for standby use;

[0165] (3) 173.7 g of ammonium oxalate is added into 1000 g of the mixed solution of ethanol and water with an ethanol mass content of 50% to obtain a precipitant solution, which is heated to 90°C for standby use;

[0166] (4) 210 g of zinc nitrate hexahydrate and 115 g of copper nitrate trihydrate are added into 1000 g of the mixed solution of ethanol and water with an ethanol mass content of 50% to prepare a zinc-copper mixed solution, which is heated to 90°C under stirring for standby use;

[0167] (5) The above zinc-aluminum mixed solution and 85 g of the precipitant solution are added into a reaction kettle with heat preservation and stirring in a concurrent manner, and the neutralization temperature is controlled at 90°C, and the pH is controlled at about 6.5-6.8;

[0168] (6) The above zinc-copper solution and 1080 g of the precipitant solution are added into the reaction system of step (5) in a concurrent manner for co-precipitation, and the neutralization temperature is controlled at 90°C, and the pH is controlled at about 7.5-7.8, then the mixed solution of ethanol and water evaporated is condensed and collected (1100 g of which is collected, and the ethanol mass content is 85%), and the collected mixed solution of ethanol and water is put into a collection tank for standby use, and the remaining water is not collected and is continuously evaporated to obtain a gel;

[0169] (7) The gel obtained in step (6) is dried, calcined at 400°C for 3 hours to obtain a black powder, and then the black powder is added with graphite to be tablet-molded to obtain an aldehyde hydrogenation catalyst.

[0170] Experimental Example

[0171] The aldehyde hydrogenation catalysts prepared in the above examples and comparative examples were respectively subjected to performance test in the following manner. The specific test results are described in the following table.

[0172] Specific surface area: tested according to GB / T 19587 method;

[0173] Pore volume: tested according to GB / T 21650.2 method;

[0174] Average pore size: tested according to GB / T 21650.2 method.

[0175] Evaluation of hydrogenation performance of octene aldehyde:

[0176] The evaluation was carried out on a 200ml fixed bed hydrogenation evaluation device, and the reduction conditions were as follows: hydrogen reduction, reduction temperature 205℃, reduction time 3 hours, and nitrogen cooling after reduction. The evaluation conditions were as follows: the raw material was industrial octene aldehyde (purity > 95.5%), the feed temperature was 145℃, the volume ratio of hydrogen to octene aldehyde was 8000:1, the reaction space velocity was 0.35h-1, and the reaction pressure was 0.45MPa. -1

[0177] The evaluation of hydrogenation performance of n-butyraldehyde was similar to the evaluation method of hydrogenation performance of octene aldehyde, except that the raw material and the feed temperature were different: the raw material for the evaluation of hydrogenation performance of n-butyraldehyde was industrial n-butyraldehyde (purity > 96%), and the feed temperature was 125℃.

[0178]

[0179] Table 1

[0180]

[0181]

[0182] From the comparison of the examples and comparative examples in the above table, it can be seen that the addition of template P123 during preparation is beneficial to improve the specific surface area, pore volume and pore size of the catalyst, and the use of evaporation condensation process is beneficial to improve the metal yield.

[0183] Table 2

[0184]

[0185]

[0186] From the data in the above table, it can be seen that the catalyst prepared by evaporation and hydrolysis of copper-zinc-aluminum salt and oxalate has high hydrogenation activity and selectivity.

[0187] ​Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application, and these corresponding changes and modifications shall all belong to the protection scope of the claims of the present application.

Claims

1. A process for the preparation of an aldehyde hydrogenation catalyst by means of a stepwise continuous co-precipitation, characterized in that, The method comprises the following steps: 1) mixing zinc-aluminum mixed solution and precipitation solution in parallel, controlling pH to be 6.5-6.8, then mixing zinc-copper mixed solution and precipitation solution in parallel, controlling pH to be 7.5-7.8, and evaporating to form a gel; 2) drying and calcining the gel, adding graphite to press into a tablet to obtain an aldehyde hydrogenation catalyst; The precipitation solution is formed by dissolving oxalate and template P123 in a solvent; The molar ratio of the oxalate to the template P123 is 670-1200; The temperature of the operation of step 1) is 80-95℃.

2. The process for preparing an aldehyde hydrogenation catalyst according to claim 1, characterized by, The solvent in the zinc-aluminum mixed solution, the precipitation solution and the zinc-copper mixed solution is a mixed solution of ethanol and water; The mixed solution of ethanol and water is a mixed solution obtained by mixing azeotrope of ethanol and water collected during the evaporation to form the gel in step 1) and deionized water and / or ethanol.

3. The preparation method of an aldehyde hydrogenation catalyst according to claim 1, characterized by, The oxalate is selected from ammonium oxalate.

4. The process for preparing an aldehyde hydrogenation catalyst according to claim 1, characterized by, The molar ratio of the oxalate to total metal salt is 1.1-1.

3.

5. The preparation method of an aldehyde hydrogenation catalyst according to claim 1, characterized by, In step 2), the calcination temperature is 360-400℃, and the time is 3-4h.

6. An aldehyde hydrogenation catalyst characterized by, The aldehyde hydrogenation catalyst is prepared by the method of any one of claims 1-5.

7. The aldehyde hydrogenation catalyst of claim 6, wherein the catalyst comprises a metal selected from the group consisting of platinum, palladium, rhodium, ruthenium, iridium, osmium, rhenium, and combinations thereof. The aldehyde hydrogenation catalyst comprises, based on 100% of the mass of the aldehyde hydrogenation catalyst: 20%-50% of copper oxide, 40%-80% of zinc oxide, 0.5%-5% of aluminum oxide and 1%-3% of graphite.

8. The aldehyde hydrogenation catalyst of claim 6, wherein the catalyst comprises a metal selected from the group consisting of platinum, palladium, rhodium, ruthenium, iridium, osmium, rhenium, and combinations thereof. The specific surface area of the aldehyde hydrogenation catalyst is 51-71 m 2 / g; the pore volume is 0.31-0.39 ml / g; and the average pore diameter is 14-18 nm.

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