Aldehyde hydrogenation catalyst and preparation method thereof

Abstract

The invention provides a preparation method of an aldehyde hydrogenation catalyst, which adopts a step-by-step continuous coprecipitation mode and comprises the following steps: 1) mixing a zinc-aluminum mixed solution and a precipitation solution in a parallel flow manner, and controlling the pH value to be 6.5-6.8; adding the zinc-copper mixed solution and the precipitation solution in a parallel flow manner, controlling the pH value to be 7.5-7.8, and evaporating to form gel; and 2) drying and roasting the gel, adding graphite, tabletting and forming to obtain 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 the advantages that the yield of metal ions in raw materials is high, the loss is small, washing is not needed, the discharge of wastewater is reduced, good activity and selectivity are shown in high-temperature gas phase hydrogenation of high-carbon aldehyde, and meanwhile, the catalyst prepared by the method has a relatively large specific surface area and a relatively large pore volume; therefore, the catalyst has high hydrogenation activity and high alkyl alcohol selectivity.

Description

Technical Field

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

[0002] The catalyst currently used in gas phase aldehyde hydrogenation is mainly copper-zinc (Cu-Zn) catalyst. In Cu-Zn catalyst, copper is the active component and ZnO acts as a carrier and auxiliary agent. Cu-Zn catalyst is generally prepared by coprecipitation method, and the obtained metal oxide powder is pressed into a cylindrical catalyst. In recent years, aluminum is widely used as an auxiliary agent, and the Al2O3 content in the catalyst is generally 1% to 10%. The gas phase aldehyde hydrogenation catalysts OXO series, VAH series, and NCH series used in China are all Cu-Zn catalysts, which are prepared by coprecipitation method and the catalyst is formed by pressing. These catalysts are mainly used for hydrogenation of butyraldehyde and octenaldehyde.

[0003] However, the existing process of preparing copper-zinc-aluminum catalyst by coprecipitation is long, and due to the different pH values ​​of different metal salts forming precipitation, the aluminum salt precipitation is dissolved and precipitated, resulting in the condensation of alcohol and aldehyde in the reaction process. At the same time, 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] For example, Chinese patent document CN114870847B discloses an aldehyde hydrogenation catalyst and a preparation method thereof, wherein a zinc-aluminum spinel precursor is prepared by using zinc salt and sodium aluminate, and a catalyst active component precursor is prepared by using copper salt, zinc salt and a precipitant. The zinc-aluminum spinel precursor and the catalyst active component precursor are ground into powder respectively, mixed, roasted, tableted, crushed and sieved to obtain the copper-zinc-aluminum gas-phase hydrogenation catalyst, which uses sodium aluminate as an aluminum source and a precipitant, and needs to be washed to remove sodium ions, and the process is not environmentally friendly.

[0005] Chinese patent document CN101489934B discloses a method for preparing aluminum-containing spinel nanostructures, by mixing aluminum salt and metal salt in an aqueous solution, and then rotary evaporating, drying and roasting to obtain aluminum-containing spinel nanostructures; the preparation process of this method is relatively simple, and at the same time reduces the harshness of the catalyst preparation operating conditions, but the specific surface area of ​​the catalyst is relatively low.

[0006] Chinese patent document CN 112973710A discloses a method for preparing a copper-chromium catalyst and a method for using the same for preparing alkanols by hydrogenating olefinic aldehydes or aldehydes. The method uses copper salt and chromium salt as reaction liquids, adds sodium-free precipitant salts such as oxalates, ammonium salts, and carbonates, and gels the reaction liquid by heating to produce copper-chromium precipitates. The catalyst is then heated, dried, and calcined to obtain a catalyst. Since no sodium-containing salt is used, no water washing is required. However, the catalyst prepared by this process has a small specific surface area.

[0007] Chinese patent document CN113797933A discloses a copper-chromium catalyst and its preparation method and application. A gel is obtained by mixing copper oxalate and chromium oxalate in an aqueous solution. The preparation process of this method is relatively simple and reduces the severity of the catalyst preparation operating conditions. However, the specific surface area of ​​the catalyst is relatively low.

[0008] Chinese patent document CN100398202C discloses a catalyst for gas phase hydrogenation of aldehydes and its preparation method. The catalyst is prepared by continuous coprecipitation of a mixed solution of copper, zinc and aluminum nitrates. The obtained catalyst has high low temperature activity when used for hydrogenation of butyraldehyde and octenal, but the pore volume of the catalyst is low.

[0009] Chinese patent document CN1087971C discloses a method for preparing an aldehyde hydrogenation catalyst, which includes the following steps: a. preparing a coprecipitation working salt solution with soluble copper salt and zinc salt as raw materials; b. preparing a precipitant solution; c. mixing the solutions obtained in step a and step b for coprecipitation to obtain a suspended coprecipitate; d. aging the suspended coprecipitate in step c to obtain an insoluble coprecipitate; e. filtering the insoluble coprecipitate in step d to obtain a filter cake. f. drying the filter cake obtained in step e to obtain a coprecipitate; g. roasting the coprecipitate 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 pressure aid and pressing them into a catalyst; wherein the precipitant solution used in step b is an organic acid solution. By selecting an organic acid as a precipitant to prepare a copper-zinc oxide catalyst for aldehyde hydrogenation to alcohol, the preparation process is simplified, and the waste of clean water caused by sodium washing and the difficulty of wastewater treatment are reduced. However, the specific surface area of ​​the catalyst prepared by this scheme 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 the catalytic performance, while increasing the yield of metal ions in the raw materials and reducing the discharge of wastewater is the focus of the research on gas-phase aldehyde hydrogenation catalyst technology. Summary of the invention

[0011] The purpose of the present invention is to provide a method for preparing an aldehyde hydrogenation catalyst, which can improve the comprehensive performance of the catalyst such as specific surface area, pore volume, selectivity and activity, improve the utilization rate of metal ions and reduce the discharge of waste liquid.

[0012] To achieve the above object, the present invention provides the following technical solutions:

[0013] A method for preparing an aldehyde hydrogenation catalyst adopts a step-by-step continuous coprecipitation method, comprising the following steps:

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

[0015] 2) drying and calcining the gel, adding graphite to form a sheet, and obtaining an aldehyde hydrogenation catalyst;

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

[0017] The preparation method of the aldehyde hydrogenation catalyst provided by the present invention adopts a step-by-step continuous co-precipitation method, and by adjusting the pH value of different precipitation steps, combining the use of oxalate as a precipitant, and adding a template agent P123 to the precipitation solution, the dissolution and precipitation of aluminum salt precipitation is reduced, the occurrence of side reactions such as aldol condensation and aldehyde self-condensation is effectively reduced, and the utilization rate of raw material metal is greatly improved. 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 high-temperature gas-phase hydrogenation.

[0018] Optionally, in the preparation method of the aldehyde hydrogenation catalyst provided by the present invention, 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, and the mixed solution of ethanol and water is obtained by mixing the azeotropic liquid of ethanol and water collected when evaporating to form a gel with deionized water and / or ethanol. The concentration of ethanol in the mixed solution of ethanol and water is not specifically limited, as long as it can dissolve the corresponding substances; the concentration of ethanol in the mixed solution of ethanol and water recommended by the present invention is 30wt% to 50wt%.

[0019] Optionally, in the preparation method of the aldehyde hydrogenation catalyst provided by the present invention, 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 specific concentrations of the zinc-aluminum mixed solution and the zinc-copper mixed solution are not limited and can be adjusted according to actual needs; the dosage 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. As for aluminum salt, zinc salt and copper salt, no specific limitation is made, and conventional ones in the industry that can be dissolved in a mixed solution of ethanol and water can be used, such as nitrates.

[0020] Optionally, in the method for preparing the aldehyde hydrogenation catalyst provided by the present invention, the oxalate is selected from ammonium oxalate.

[0021] Optionally, in the method for preparing the aldehyde hydrogenation catalyst provided by the present invention, the molar ratio of the oxalate to the total metal salt is 1.1 to 1.3.

[0022] Optionally, in the method for preparing the aldehyde hydrogenation catalyst provided by the present invention, the molar ratio of the oxalate to the template P123 is 670-1200.

[0023] Optionally, in the method for preparing the aldehyde hydrogenation catalyst provided by the present invention, the operating temperature of step 1) is 80-90°C.

[0024] Optionally, in step 2) of the method for preparing the aldehyde hydrogenation catalyst provided by the present invention, the calcination temperature is 360-400° C. and the calcination time is 3-4 hours.

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

[0026] (1) adding deionized water and / or ethanol to a mixed solution of ethanol and water collected during the evaporation process to form a gel, to obtain a mixed solution of ethanol and water having an ethanol content of 50% to 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 the solution to 80-90° C.;

[0028] (3) taking a certain amount of the ethanol-water mixed solution prepared in step (1), adding oxalate and template agent P123 to dissolve, obtaining a precipitation solution, and preheating to 80-90° C.;

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

[0030] (5) adding the zinc-aluminum mixed solution and the precipitation solution into a reactor with heat preservation and stirring in parallel, and controlling the pH value to 6.5-6.8; and controlling the neutralization temperature to 80° C.-90° C.;

[0031] (6) then adding the zinc-copper mixed solution and the precipitation solution in parallel to perform co-precipitation, controlling the pH value to 7.5-7.8, and controlling the neutralization temperature to 80° C.-90° C., 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) The gel obtained in step (6) is dried, calcined at 360-400° C. for 3-4 hours, and then a certain amount of graphite is added to form a pellet to obtain a catalyst.

[0033] The present invention also provides an aldehyde hydrogenation catalyst, which is prepared by the preparation method of the aldehyde hydrogenation catalyst.

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

[0035] Optionally, the specific surface area of ​​the aldehyde hydrogenation catalyst provided by the present invention is 51 to 71 m 2 / g; pore volume is 0.31~0.39ml / g; average pore diameter is 14~18nm.

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

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

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

[0039] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention.

[0040] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0041] Example 1

[0042] This embodiment provides an aldehyde hydrogenation catalyst, and the preparation method thereof comprises the following steps:

[0043] (1) 1100 g of ethanol and 1100 g of deionized water were mixed to obtain 2200 g of a mixed solution of ethanol and water having an ethanol content of 50% by weight, which was set aside;

[0044] (2) 10 g of zinc nitrate hexahydrate and 10 g of aluminum nitrate nonahydrate were added to a mixed solution of ethanol and water having an ethanol content of 50% by mass to prepare 50 ml of a zinc-aluminum mixed solution, which was stirred and heated to 90° C. for later use;

[0045] (3) adding 12.1 g of template P123 and 173.7 g of ammonium oxalate to a mixed solution of 1000 g of ethanol and water having an ethanol content of 50% by mass to obtain a precipitation solution, heating the solution to 90° C. for later use;

[0046] (4) adding 210 g of zinc nitrate hexahydrate and 115 g of copper nitrate trihydrate to a mixed solution of 1000 g of ethanol and water having an ethanol content of 50% by mass to prepare a zinc-copper mixed solution, stirring and heating to 90° C. for later use;

[0047] (5) Add the zinc-aluminum mixed solution and 90 g of the precipitation solution into a reactor with insulation and stirring, and control the neutralization temperature to 90° C. and the pH to about 6.5-6.8;

[0048] (6) adding the zinc-copper solution and 1140 g of the precipitation solution to the reaction system of step (5) in parallel for co-precipitation, controlling the neutralization temperature to 90° C. and the pH to about 7.5 to 7.8, then condensing and collecting the evaporated mixed solution of ethanol and water (collecting 1100 g, wherein the mass content of ethanol is 85%), placing the collected mixed solution of ethanol and water in a collection tank for standby use, and not collecting the remaining water, continuing to evaporate, to obtain a gel;

[0049] (7) The gel obtained in step (6) is dried and calcined at 400° C. for 3 hours to obtain a black powder, and then graphite is added to the black powder to form a sheet to obtain an aldehyde hydrogenation catalyst.

[0050] Example 2

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

[0052] (1) 1000 g of the mixed solution of ethanol and water collected by condensation in Example 1 (ethanol content 85%) was taken, and then 250 g of ethanol (ethanol content ≥ 99%) and 950 g of deionized water were added to obtain 2200 g of a mixed solution of ethanol and water with an ethanol weight content of 50%, which was set aside;

[0053] (2) taking a certain amount of the mixed solution of ethanol and water prepared in step (1), then adding 10 g of zinc nitrate hexahydrate and 13 g of aluminum nitrate nonahydrate to prepare 50 ml of a zinc-aluminum mixed solution, stirring and heating to 90° C. for later use;

[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, heat it to 90° C. and set aside;

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

[0056] (5) Add the zinc-aluminum mixed solution and 90 g of the precipitation solution into a reactor with insulation and stirring, and control the neutralization temperature to 90° C. and the pH to about 6.5-6.8;

[0057] (6) adding the zinc-copper solution and 1140 g of the precipitation solution to the reaction system of step (5) in parallel for co-precipitation, controlling the neutralization temperature to 90° C. and the pH to about 7.5 to 7.8, then condensing and collecting the evaporated mixed solution of ethanol and water (collecting 1100 g, wherein the mass content of ethanol is 85%), placing the collected mixed solution of ethanol and water in a collection tank for standby use, and not collecting the remaining water, continuing to evaporate, 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, and then a certain amount of graphite is added to the black powder to form a sheet to obtain an aldehyde hydrogenation catalyst.

[0059] Example 3

[0060] This embodiment provides an aldehyde hydrogenation catalyst, and the preparation method thereof comprises the following steps:

[0061] (1) 777 g (ethanol content 85%) of the mixed solution of ethanol and water collected by condensation in Example 2 was taken, and then 1423 g of deionized water was added to obtain 2200 g of a mixed solution of ethanol and water with an ethanol weight content of 30%, which was set aside;

[0062] (2) taking a certain amount of the mixed solution of ethanol and water prepared in step (1), then adding 10 g of zinc nitrate hexahydrate and 10 g of aluminum nitrate nonahydrate to prepare 50 ml of a zinc-aluminum mixed solution, stirring and heating to 80° C. for later use;

[0063] (3) taking 1000 g of the mixed solution of ethanol and water prepared in step (1), adding 11.5 g of template P123 and 186.2 g of ammonium oxalate to obtain a precipitation solution, heating it to 80° C. and setting aside;

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

[0065] (5) Add the zinc-aluminum mixed solution and 90 g of the precipitation solution into a reactor with insulation and stirring, and control the neutralization temperature to 90° C. and the pH to about 6.5-6.8;

[0066] (6) adding the zinc-copper solution and 1140 g of the precipitation solution to the reaction system of step (5) for co-precipitation, controlling the neutralization temperature to 80° C. and the pH to about 7.5 to 7.8, then condensing and collecting the evaporated mixed solution of ethanol and water (collecting 730 g, wherein the mass content of ethanol is 90%), placing the collected mixed solution of ethanol and water in a collection tank for standby use, and not collecting the remaining water, continuing to evaporate, to obtain a gel;

[0067] (7) The gel obtained in step (6) is 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 form a sheet to obtain an aldehyde hydrogenation catalyst.

[0068] Example 4

[0069] This embodiment provides an aldehyde hydrogenation catalyst, and the preparation method thereof comprises the following steps:

[0070] (1) 1100 g of ethanol and 1100 g of deionized water were mixed to obtain 2200 g of a mixed solution of ethanol and water having an ethanol content of 50% by weight, which was set aside;

[0071] (2) taking a certain amount of the mixed solution of ethanol and water prepared in step (1), then adding 10 g of zinc nitrate hexahydrate and 18 g of aluminum nitrate nonahydrate to prepare 50 ml of a zinc-aluminum mixed solution, stirring and heating to 90° C. for later use;

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

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

[0074] (5) Add the zinc-aluminum mixed solution and 270 g of the precipitation solution into a reactor with insulation and stirring, and control the neutralization temperature to 90° C. and the pH to about 6.5-6.8;

[0075] (6) adding the zinc-copper solution and 950 g of the precipitation solution to the reaction system of step (5) in parallel for co-precipitation, controlling the neutralization temperature to 90° C. and the pH to about 7.5 to 7.8, then condensing and collecting the evaporated mixed solution of ethanol and water (collecting 1000 g, wherein the mass content of ethanol is 85%), placing the collected mixed solution of ethanol and water in a collection tank for standby use, and not collecting the remaining water, continuing to evaporate, 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, and then a certain amount of graphite is added to the black powder to form a sheet to obtain an aldehyde hydrogenation catalyst.

[0077] Example 5

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

[0079] (1) 1000 g of the mixed solution of ethanol and water collected by condensation in Example 4 (ethanol content 85%) was taken, and then 250 g of ethanol (ethanol content ≥ 99%) and 950 g of deionized water were added to obtain 2200 g of a mixed solution of ethanol and water with an ethanol weight content of 50%, which was set aside;

[0080] (2) taking a certain amount of the mixed solution of ethanol and water prepared in step (1), then adding 10 g of zinc nitrate hexahydrate and 4.5 g of aluminum nitrate nonahydrate to prepare 50 ml of a zinc-aluminum mixed solution, stirring and heating to 90° C. for later use;

[0081] (3) Take 1000 g of the mixed solution of ethanol and water prepared in step (1), add 10.6 g of template P123 and 186.1 g of ammonium oxalate to obtain a precipitation solution, heat it to 90° C. and set aside;

[0082] (4) taking 1000 g of the mixed solution of ethanol and water prepared in step (1), adding 190 g of zinc nitrate hexahydrate and 125 g of copper nitrate trihydrate to prepare a zinc-copper mixed solution, stirring and heating to 90° C. for standby use;

[0083] (5) Add the zinc-aluminum mixed solution and 70 g of the precipitation solution into a reactor with insulation and stirring, and control the neutralization temperature to 90° C. and the pH to about 6.5-6.8;

[0084] (6) adding the zinc-copper solution and 1160 g of the precipitation solution to the reaction system of step (5) for co-precipitation, controlling the neutralization temperature to 90° C. and the pH to about 7.5 to 7.8, then condensing and collecting the evaporated mixed solution of ethanol and water (collecting 1000 g, wherein the mass content of ethanol is 90%), placing the collected mixed solution of ethanol and water in a collection tank for standby use, and not collecting the remaining water, continuing to evaporate, to obtain a gel;

[0085] (7) The gel obtained in step (6) is 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 form a sheet to obtain an aldehyde hydrogenation catalyst.

[0086] Example 6

[0087] This embodiment provides an aldehyde hydrogenation catalyst, and the preparation method thereof comprises the following steps:

[0088] (1) 1000 g of the mixed solution of ethanol and water (ethanol content 90%) collected by condensation in Example 5 was taken, and then 200 g of ethanol (ethanol content ≥ 99%) and 1000 g of deionized water were added to obtain 2200 g of a mixed solution of ethanol and water with an ethanol weight content of 50%, which was set aside;

[0089] (2) taking a certain amount of the mixed solution of ethanol and water prepared in step (1), then adding 10 g of zinc nitrate hexahydrate and 3 g of aluminum nitrate nonahydrate to prepare 50 ml of a zinc-aluminum mixed solution, stirring and heating to 90° C. for later use;

[0090] (3) Take 1000 g of the mixed solution of ethanol and water prepared in step (1), add 8.9 g of template P123 and 179.9 g of ammonium oxalate to obtain a precipitation solution, heat it to 90° C. and set aside;

[0091] (4) taking 1000 g of the mixed solution of ethanol and water prepared in step (1), adding 270 g of zinc nitrate hexahydrate and 62 g of copper nitrate trihydrate to prepare a zinc-copper mixed solution, stirring and heating to 90° C. for standby use;

[0092] (5) Add the zinc-aluminum mixed solution and 90 g of the precipitation solution into a reactor with insulation and stirring, and control the neutralization temperature to 90° C. and the pH to about 6.5-6.8;

[0093] (6) adding the zinc-copper solution and 1140 g of the precipitation solution to the reaction system of step (5) in parallel for co-precipitation, controlling the neutralization temperature to 90° C. and the pH to about 7.5 to 7.8, then condensing and collecting the evaporated mixed solution of ethanol and water (collecting 1100 g, wherein the mass content of ethanol is 85%), placing the collected mixed solution of ethanol and water in a collection tank for standby use, and not collecting the remaining water, continuing to evaporate, to obtain a gel;

[0094] (7) The gel obtained in step (6) is 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 form a sheet to obtain an aldehyde hydrogenation catalyst.

[0095] Example 7

[0096] This embodiment provides an aldehyde hydrogenation catalyst, and the preparation method thereof comprises the following steps:

[0097] (1) 1000 g of the mixed solution of ethanol and water collected by condensation in Example 6 (ethanol content 85%) was taken, and then 250 g of ethanol (ethanol content ≥ 99%) and 950 g of deionized water were added to obtain 2200 g of a mixed solution of ethanol and water with an ethanol weight content of 50%, which was set aside;

[0098] (2) taking a certain amount of the mixed solution of ethanol and water prepared in step (1), then adding 10 g of zinc nitrate hexahydrate and 15 g of aluminum nitrate nonahydrate to prepare 50 ml of a zinc-aluminum mixed solution, stirring and heating to 90° C. for later use;

[0099] (3) Take 1000 g of the mixed solution of ethanol and water prepared in step (1), add 13.5 g of template P123 and 193.5 g of ammonium oxalate to obtain a precipitation solution, heat it to 90° C. and set aside;

[0100] (4) taking 1000 g of the mixed solution of ethanol and water prepared in step (1), adding 160 g of zinc nitrate hexahydrate and 145 g of copper nitrate trihydrate to prepare a zinc-copper mixed solution, stirring and heating to 90° C. for standby use;

[0101] (5) Add the zinc-aluminum mixed solution and 90 g of the precipitation solution into a reactor with insulation and stirring, and control the neutralization temperature to 90° C. and the pH to about 6.5-6.8;

[0102] (6) adding the zinc-copper solution and 1140 g of the precipitation solution to the reaction system of step (5) in parallel for co-precipitation, controlling the neutralization temperature to 90° C. and the pH to about 7.5 to 7.8, then condensing and collecting the evaporated mixed solution of ethanol and water (collecting 1100 g, wherein the mass content of ethanol is 85%), placing the collected mixed solution of ethanol and water in a collection tank for standby use, and not collecting the remaining water, continuing to evaporate, to obtain a gel;

[0103] (7) The gel obtained in step (6) is 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 form a sheet to obtain an aldehyde hydrogenation catalyst.

[0104] Example 8

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

[0106] (1) 1000 g of the mixed solution of ethanol and water collected by condensation in Example 7 (ethanol content 85%) was taken, and then 250 g of ethanol (ethanol content ≥ 99%) and 950 g of deionized water were added to obtain 2200 g of a mixed solution of ethanol and water with an ethanol weight content of 50%, which was set aside;

[0107] (2) taking a certain amount of the mixed solution of ethanol and water prepared in step (1), then adding 10 g of zinc nitrate hexahydrate and 2 g of aluminum nitrate nonahydrate to prepare 50 ml of a zinc-aluminum mixed solution, stirring and heating to 90° C. for later use;

[0108] (3) Take 1000 g of the mixed solution of ethanol and water prepared in step (1), add 8 g of template P123 and 186.1 g of ammonium oxalate to obtain a precipitation solution, heat it to 90° C. and set aside;

[0109] (4) taking 1000 g of the mixed solution of ethanol and water prepared in step (1), adding 180 g of zinc nitrate hexahydrate and 135 g of copper nitrate trihydrate to prepare a zinc-copper mixed solution, stirring and heating to 90° C. for standby use;

[0110] (5) Add the zinc-aluminum mixed solution and 10 g of the precipitation solution into a reactor with insulation and stirring, and control the neutralization temperature to 90° C. and the pH to about 6.5-6.8;

[0111] (6) adding the zinc-copper solution and 1140 g of the precipitation solution to the reaction system of step (5) in parallel for co-precipitation, controlling the neutralization temperature to 90° C. and the pH to about 7.5 to 7.8, then condensing and collecting the evaporated mixed solution of ethanol and water (collecting 1000 g, wherein the mass content of ethanol is 85%), placing the collected mixed solution of ethanol and water in a collection tank for standby use, and not collecting the remaining water, continuing to evaporate, to obtain a gel;

[0112] (7) The gel obtained in step (6) is dried and calcined at 380° C. for 4 hours to obtain a black powder, and then a certain amount of graphite is added to the black powder to form a sheet to obtain an aldehyde hydrogenation catalyst.

[0113] Example 9

[0114] This embodiment provides an aldehyde hydrogenation catalyst, and the preparation method thereof comprises the following steps:

[0115] (1) 1000 g of the mixed solution of ethanol and water collected by condensation in Example 8 (ethanol content 85%) was taken, and then 250 g of ethanol (ethanol content ≥ 99%) and 950 g of deionized water were added to obtain 2200 g of a mixed solution of ethanol and water with an ethanol weight content of 50%, which was set aside;

[0116] (2) taking a certain amount of the mixed solution of ethanol and water prepared in step (1), then adding 10 g of zinc nitrate hexahydrate and 12 g of aluminum nitrate nonahydrate to prepare 50 ml of a zinc-aluminum mixed solution, stirring and heating to 95° C. for later use;

[0117] (3) Take 1000 g of the mixed solution of ethanol and water prepared in step (1), add 13.4 g of template P123 and 192.3 g of ammonium oxalate to obtain a precipitation solution, heat it to 95° C. and set aside;

[0118] (4) taking 1000 g of the mixed solution of ethanol and water prepared in step (1), adding 260 g of zinc nitrate hexahydrate and 65 g of copper nitrate trihydrate to prepare a zinc-copper mixed solution, stirring and heating to 95° C. for standby use;

[0119] (5) Add the zinc-aluminum mixed solution and 90 g of the precipitation solution into a reactor with insulation and stirring, and control the neutralization temperature to 90° C. and the pH to about 6.5-6.8;

[0120] (6) adding the zinc-copper solution and 1140 g of the precipitation solution to the reaction system of step (5) for co-precipitation, controlling the neutralization temperature to 95° C. and the pH to about 7.5 to 7.8, then condensing and collecting the evaporated mixed solution of ethanol and water (collecting 1100 g, wherein the mass content of ethanol is 85%), placing the collected mixed solution of ethanol and water in a collection tank for standby use, and not collecting the remaining water, continuing to evaporate, to obtain a gel;

[0121] (7) The gel obtained in step (6) is 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 form a sheet to obtain an aldehyde hydrogenation catalyst.

[0122] Comparative Example 1

[0123] This comparative example provides an aldehyde hydrogenation catalyst, and its preparation method comprises the following steps:

[0124] (1) 1100 g of ethanol and 1100 g of deionized water were mixed to obtain 2200 g of a mixed solution of ethanol and water having an ethanol content of 50% by weight, which was set aside;

[0125] (2) 220 g of zinc nitrate hexahydrate, 10 g of aluminum nitrate nonahydrate, and 115 g of copper nitrate trihydrate were added to a mixed solution of 1000 g of ethanol and water with an ethanol content of 50% by mass to prepare a copper-zinc-aluminum mixed solution, which was stirred and heated to 90° C. for later use;

[0126] (3) adding 12.1 g of template P123 and 173.7 g of ammonium oxalate to a mixed solution of 1000 g of ethanol and water having an ethanol content of 50% by mass to obtain a precipitation solution, heating the solution to 90° C. for later use;

[0127] (4) adding the copper-zinc-aluminum mixed solution and the precipitation solution into a reactor with heat preservation and stirring in parallel, controlling the neutralization temperature to 90° C. and the pH to about 7.5-7.8, then condensing and collecting the evaporated mixed solution of ethanol and water (collecting 1100 g, of which the mass content of ethanol is 85%), placing the collected mixed solution of ethanol and water into a collection tank for standby use, and not collecting the remaining water, continuing to evaporate, to obtain a gel;

[0128] (5) The gel obtained in step (4) is dried and calcined at 400° C. for 3 hours to obtain a black powder, and then graphite is added to the black powder to form a sheet to obtain an aldehyde hydrogenation catalyst.

[0129] Comparative Example 2

[0130] The preparation method of the aldehyde hydrogenation catalyst provided in this comparative example is similar to that of Example 1, except that the step of condensing to form a gel is omitted. The preparation method of the aldehyde hydrogenation catalyst provided in this 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): adding the zinc-copper solution and 1140 g of the precipitation solution to the reaction system of step (5) in parallel for co-precipitation, controlling the neutralization temperature to 90° C. and the pH to about 7.5 to 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 form a sheet to obtain an aldehyde hydrogenation catalyst.

[0134] Comparative Example 3

[0135] The preparation method of the aldehyde hydrogenation catalyst provided in this comparative example is similar to that of Example 1, except that the pH controlled in step (5) is different. The pH controlled in step (5) of this comparative example is about 7.5 to 7.8.

[0136] (1) 1100 g of ethanol and 1100 g of deionized water were mixed to obtain 2200 g of a mixed solution of ethanol and water having an ethanol content of 50% by weight, which was set aside;

[0137] (2) 10 g of zinc nitrate hexahydrate and 10 g of aluminum nitrate nonahydrate were added to a mixed solution of ethanol and water having an ethanol content of 50% by mass to prepare 50 ml of a zinc-aluminum mixed solution, which was stirred and heated to 90° C. for later use;

[0138] (3) adding 12.1 g of template agent P123 and 173.7 g of ammonium oxalate to a mixed solution of 1100 g of ethanol and water having an ethanol content of 50% by mass to obtain a precipitation solution, heating the solution to 90° C. for later use;

[0139] (4) adding 210 g of zinc nitrate hexahydrate and 115 g of copper nitrate trihydrate to a mixed solution of 1000 g of ethanol and water having an ethanol content of 50% by mass to prepare a zinc-copper mixed solution, stirring and heating to 90° C. for later use;

[0140] (5) Add the zinc-aluminum mixed solution and 100 g of the precipitation solution into a reactor with insulation and stirring, and control the neutralization temperature to 90° C. and the pH to about 7.5 to 7.8;

[0141] (6) adding the zinc-copper solution and 1140 g of the precipitation solution to the reaction system of step (5) in parallel for co-precipitation, controlling the neutralization temperature to 90° C. and the pH to about 7.5 to 7.8, then condensing and collecting the evaporated mixed solution of ethanol and water (collecting 1100 g, wherein the mass content of ethanol is 85%), placing the collected mixed solution of ethanol and water in a collection tank for standby use, and not collecting the remaining water, continuing to evaporate, to obtain a gel;

[0142] (7) The gel obtained in step (6) is dried and calcined at 400° C. for 3 hours to obtain a black powder, and then graphite is added to the black powder to form a sheet to obtain an aldehyde hydrogenation catalyst.

[0143] Comparative Example 4

[0144] The preparation method of the aldehyde hydrogenation catalyst provided in this comparative example is similar to that of Example 1, except that the pH controlled in step (6) is different. The pH controlled in step (6) of this comparative example is about 6.5 to 6.8.

[0145] (1) 1100 g of ethanol and 1100 g of deionized water were mixed to obtain 2200 g of a mixed solution of ethanol and water having an ethanol content of 50% by weight, which was set aside;

[0146] (2) 10 g of zinc nitrate hexahydrate and 10 g of aluminum nitrate nonahydrate were added to a mixed solution of ethanol and water having an ethanol content of 50% by mass to prepare 50 ml of a zinc-aluminum mixed solution, which was stirred and heated to 90° C. for later use;

[0147] (3) adding 12.1 g of template P123 and 173.7 g of ammonium oxalate to a mixed solution of 1050 g of ethanol and water having an ethanol content of 50% by mass to obtain a precipitation solution, heating the solution to 90° C. for later use;

[0148] (4) adding 210 g of zinc nitrate hexahydrate and 115 g of copper nitrate trihydrate to a mixed solution of 1000 g of ethanol and water having an ethanol content of 50% by mass to prepare a zinc-copper mixed solution, stirring and heating to 90° C. for later use;

[0149] (5) Add the zinc-aluminum mixed solution and 90 g of the precipitation solution into a reactor with insulation and stirring, and control the neutralization temperature to 90° C. and the pH to about 6.5-6.8;

[0150] (6) adding the zinc-copper solution and 1100 g of the precipitation solution to the reaction system of step (5) in parallel for co-precipitation, controlling the neutralization temperature to 90° C. and the pH to about 6.5 to 6.8, then condensing and collecting the evaporated mixed solution of ethanol and water (collecting 1050 g, wherein the mass content of ethanol is 85%), placing the collected mixed solution of ethanol and water in a collection tank for standby use, and not collecting the remaining water, continuing to evaporate, to obtain a gel;

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

[0152] Comparative Example 5

[0153] This comparative example provides an aldehyde hydrogenation catalyst, and its preparation method comprises the following steps:

[0154] (1) 1100 g of ethanol and 1100 g of deionized water were mixed to obtain 2200 g of a mixed solution of ethanol and water having an ethanol content of 50% by weight, which was set aside;

[0155] (2) 10 g of zinc nitrate hexahydrate and 10 g of aluminum nitrate nonahydrate were added to a mixed solution of ethanol and water having an ethanol content of 50% by mass to prepare 50 ml of a zinc-aluminum mixed solution, which was stirred and heated to 90° C. for later use;

[0156] (3) adding 12.1 g of template agent P123 and 50 g of oxalic acid to a mixed solution of 1000 g of ethanol and water having an ethanol content of 50% by mass to obtain a precipitation solution, heating it to 90° C. for later use;

[0157] (4) adding 210 g of zinc nitrate hexahydrate and 115 g of copper nitrate trihydrate to a mixed solution of 1000 g of ethanol and water having an ethanol content of 50% by mass to prepare a zinc-copper mixed solution, stirring and heating to 90° C. for later use;

[0158] (5) adding the zinc-aluminum mixed solution and the precipitation solution into a reactor with heat preservation and stirring in parallel, controlling the neutralization temperature to 90° C. and the pH to about 6.5 to 6.8;

[0159] (6) adding the zinc-copper solution and the precipitation solution to the reaction system of step (5) in parallel for co-precipitation, controlling the neutralization temperature to 90° C. and the pH to about 7.5 to 7.8, then condensing and collecting the evaporated mixed solution of ethanol and water (collecting 1100 g, wherein the mass content of ethanol is 85%), placing the collected mixed solution of ethanol and water in a collection tank for standby use, and not collecting the remaining water, continuing to evaporate, to obtain a gel;

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

[0161] Comparative Example 6

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

[0163] (1) 1100 g of ethanol and 1100 g of deionized water were mixed to obtain 2200 g of a mixed solution of ethanol and water having an ethanol content of 50% by weight, which was set aside;

[0164] (2) 10 g of zinc nitrate hexahydrate and 10 g of aluminum nitrate nonahydrate were added to a mixed solution of ethanol and water having an ethanol content of 50% by mass to prepare 50 ml of a zinc-aluminum mixed solution, which was stirred and heated to 90° C. for later use;

[0165] (3) adding 173.7 g of ammonium oxalate to a mixed solution of 1000 g of ethanol and water having an ethanol content of 50% by mass to obtain a precipitation solution, heating the solution to 90° C. for later use;

[0166] (4) adding 210 g of zinc nitrate hexahydrate and 115 g of copper nitrate trihydrate to a mixed solution of 1000 g of ethanol and water having an ethanol content of 50% by mass to prepare a zinc-copper mixed solution, stirring and heating to 90° C. for later use;

[0167] (5) Add the zinc-aluminum mixed solution and 85 g of the precipitation solution into a reactor with insulation and stirring, and control the neutralization temperature to 90° C. and the pH to about 6.5-6.8;

[0168] (6) adding the zinc-copper solution and 1080 g of the precipitation solution to the reaction system of step (5) for co-precipitation, controlling the neutralization temperature to 90° C. and the pH to about 7.5 to 7.8, then condensing and collecting the evaporated mixed solution of ethanol and water (collecting 1100 g, wherein the mass content of ethanol is 85%), placing the collected mixed solution of ethanol and water in a collection tank for standby use, and not collecting the remaining water, continuing to evaporate, to obtain a gel;

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

[0170] Experimental example

[0171] The aldehyde hydrogenation catalysts prepared in the above-mentioned examples and comparative examples were subjected to performance tests in the following manners. 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 the hydrogenation performance of octenal:

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

[0177] The hydrogenation performance evaluation method of n-butyraldehyde is similar to that of octenal, the only difference is the raw materials used and the feed temperature: the raw material used for the hydrogenation performance evaluation of n-butyraldehyde is industrial n-butyraldehyde (purity>96%), and the feed temperature is 125°C.

[0178]

[0179] Table 1

[0180]

[0181]

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

[0183] Table 2

[0184]

[0185]

[0186] It can be seen from the data in the above table that the catalysts prepared by evaporation and hydrolysis of copper-zinc-aluminum salts and oxalates have high hydrogenation activity and selectivity.

[0187] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing an aldehyde hydrogenation catalyst, using a step-by-step continuous coprecipitation method, characterized in that: The steps include: 1) mixing the zinc-aluminum mixed solution and the precipitation solution in parallel, and controlling the pH value to be 6.5-6.8; then adding the zinc-copper mixed solution and the precipitation solution in parallel, controlling the pH value to be 7.5-7.8, and evaporating to form a gel; 2) drying and calcining the gel, adding graphite to form a sheet, and obtaining an aldehyde hydrogenation catalyst; The precipitation solution is formed by dissolving oxalate and template agent P123 in a solvent.

2. The method for preparing an aldehyde hydrogenation catalyst according to claim 1, wherein 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 the azeotropic solution of ethanol and water collected during evaporation to form a gel in step 1) with deionized water and / or ethanol.

3. The method for preparing an aldehyde hydrogenation catalyst according to claim 1, characterized in that: The oxalate is selected from ammonium oxalate.

4. The method for preparing an aldehyde hydrogenation catalyst according to claim 1, characterized in that: The molar ratio of the oxalate to the total metal salts is 1.1 to 1.

3.

5. The method for preparing an aldehyde hydrogenation catalyst according to claim 1, characterized in that: The molar ratio of the oxalate to the template P123 is 670-1200.

6. The method for preparing an aldehyde hydrogenation catalyst according to claim 1, characterized in that: The operating temperature of step 1) is 80-95°C.

7. The method for preparing an aldehyde hydrogenation catalyst according to claim 1, characterized in that: In step 2), the calcination temperature is 360-400° C. and the calcination time is 3-4 hours.

8. An aldehyde hydrogenation catalyst, characterized in that The aldehyde hydrogenation catalyst is prepared by the preparation method of the aldehyde hydrogenation catalyst according to any one of claims 1 to 7.

9. The aldehyde hydrogenation catalyst according to claim 8, characterized in that Taking the mass of the aldehyde hydrogenation catalyst as 100%, the catalyst comprises: 20% to 50% copper oxide, 40% to 80% zinc oxide, 0.5% to 5% aluminum oxide and 1% to 3% graphite.

10. The aldehyde hydrogenation catalyst according to claim 8, characterized in that The specific surface area of ​​the aldehyde hydrogenation catalyst is 51 to 71 m 2 / g; pore volume is 0.31~0.39ml / g; average pore diameter is 14~18nm.

Images