A bio-based fatty acid methyl ester hydrogenation catalyst, and a preparation method and application thereof

Abstract

The present disclosure relates to a bio-based fatty acid methyl ester hydrogenation catalyst and a preparation method and application thereof, the method comprising the following steps: S1, under the condition of stirring, contacting a first solution containing a first metal source and a second metal source, a second solution containing an alkali source and water and carrying out a first reaction to obtain a first material; S2, adjusting the pH value of the first material to 10-11 and carrying out a second reaction to obtain a pre-product; S3, heat treating the pre-product; the first metal source comprises a copper source and an aluminum source, and the second metal source comprises a zinc source and / or a magnesium source; step S1 is carried out under the condition of a pH value of 8-10. The method steps and conditions of the present disclosure are simple, avoid the use of complex reaction instruments, are suitable for industrial production, the ester hydrogenation catalyst prepared by the method of the present disclosure is used for the hydrogenation reaction of bio-based fatty acid methyl ester, a relatively high raw material conversion rate and target product fatty alcohol selectivity can be obtained, and the ester hydrogenation catalyst has good stability.

Description

Technical Field

[0001] This disclosure relates to the field of preparation of hydrogenation catalysts for fatty acid carboxylic esters, specifically to a bio-based fatty acid methyl ester hydrogenation catalyst, its preparation method, and its application. Background Technology

[0002] Higher alcohols are important basic raw materials for fine chemicals, widely used in the production of plasticizers, detergents, and surfactants. Fatty alcohols prepared by hydrogenation of bio-based fatty acid methyl esters have the advantages of renewable raw materials and biodegradable products, showing broad application prospects in pharmaceuticals, cosmetics, lubricants, and petroleum additives.

[0003] The hydrogenation of fatty acid methyl esters to prepare corresponding long-chain fatty alcohols is an important method for producing higher alcohols. Depending on the process and catalyst, the reaction temperature ranges from 200 to 300°C, and the pressure ranges from 20 to 30 MPa. Long-chain fatty acid methyl esters produced from bio-oils, because the raw materials are mainly a mixture of C8-C24 fatty acid methyl esters, and the hydrocarbon chains often contain unsaturated olefin bonds, have high boiling points and poor stability, require special attention to improve reaction selectivity and conversion rates. This necessitates considerations regarding the catalyst's acidity / basicity, pore size, active metal dispersion, and the stability of the main active metal, copper.

[0004] The commonly used catalysts for ester hydrogenation are copper-based catalysts. In the early days, Cu-Cr catalysts were often used. However, due to the high toxicity of Cr, which causes pollution and harm to the environment, recent research has focused on Cr-free catalysts, such as various composite oxide catalysts including copper-zinc, copper-zinc-aluminum, and copper-silicon.

[0005] For example, CN102850181A provides a method for preparing higher alcohols, in which the catalyst is prepared by co-precipitation and is a composite metal oxide ZnCu. a Cr b Zr c O x The complex metal oxide requires hydrogen reduction treatment before reaction. The ester hydrogenation reaction temperature is 200-320℃, and the hydrogen pressure is 3.0-7.5MPa. Fatty acid methyl esters are mixed with lower alcohols and fed into a fixed-bed reactor for hydrogenation reduction. The hydrogenation reaction is carried out when the fatty acid methyl ester space velocity is 0.10-0.20 h⁻¹. -1 At that time, the yield of higher alcohols was 80-96%. The product yield was affected by the type and proportion of lower alcohols. The limitation of this patent is that the catalyst contains the highly toxic metal Cr, and the mixing of lower alcohols in the feed reduces the reaction efficiency.

[0006] For example, CN101468939A provides a method for preparing higher alcohols by hydrogenation of fatty acid methyl esters under supercritical conditions. The method involves reacting fatty acid methyl esters with hydrogen in a supercritical solvent, such as a mixture of n-pentane and n-hexane, to form a supercritical fluid, followed by hydrogenation to convert the methyl ester into a higher alcohol. The catalyst is a Cu-Cr composite metal oxide catalyst prepared by a co-precipitation method. The advantage of this method is that it utilizes a supercritical fluid to improve the transport properties of the hydrogenation system and increase the reaction conversion rate. The disadvantage is that the catalyst also uses the highly toxic metal Cr.

[0007] Although the use of metallic Cr can effectively improve the ester hydrogenation performance and stability of catalysts, due to the high toxicity of Cr, it is necessary to develop Cr-free catalysts with performance close to or better than Cr.

[0008] CN111701591A discloses a Cu-based titanium-containing ester hydrogenation catalyst and describes its preparation method and application in the hydrogenation of fatty acid methyl esters. In the catalyst preparation process, copper nitrate is first precipitated as copper oxalate using oxalic acid, then dissolved in ethanol using tetrabutyl titanate. After nitric acid treatment, a titanium dioxide dispersion is obtained. The copper oxalate and titanium dioxide dispersions are then mixed and evaporated at 120°C with stirring to obtain a paste. This paste is then dried and calcined to obtain a Cu-Ti composite metal oxide catalyst. Evaluation in a fixed-bed reactor showed that a copper oxide mass fraction of 60% resulted in the best conversion of hexadecanoic acid methyl ester and the optimal selectivity for 16-ethanol, reaching 97.98% and 97.57%, respectively. However, after 150 hours, the conversion rate decreased to 87.21%, while the selectivity remained relatively stable at 97.19%, indicating poor catalyst stability. Summary of the Invention

[0009] The purpose of this disclosure is to provide a bio-based fatty acid methyl ester hydrogenation catalyst, its preparation method, and its application. The method and conditions of this disclosure are simple and suitable for industrial production. The ester hydrogenation catalyst prepared by the method of this disclosure can achieve a high feed conversion rate and selectivity for the target product fatty alcohol when used in the hydrogenation reaction of bio-based fatty acid methyl esters, and it also has good stability.

[0010] To achieve the above objectives, the first aspect of this disclosure provides a method for preparing a bio-based fatty acid methyl ester hydrogenation catalyst, the method comprising the following steps:

[0011] S1. Under stirring conditions, a first solution containing a first metal source and a second metal source, a second solution containing an alkaline source, and water are brought into contact and a first reaction is carried out to obtain a first material.

[0012] S2. Adjust the pH of the first material to 10-11 and carry out the second reaction to obtain the preproduct;

[0013] S3. The preproduct is subjected to heat treatment;

[0014] The first metal source includes a copper source and an aluminum source, and the second metal source includes a zinc source and / or a magnesium source;

[0015] Step S1 is carried out under conditions of pH 8-10.

[0016] Optionally, the first solution contains a third metal source; and / or, the water contains the third metal source.

[0017] The third metal source includes one or more of the following: Group VB metal source, Group VIIB metal source, Group IIA metal source, Group IIIA metal source, Group IVA metal source, Group VA metal source and rare earth metal source, preferably including one or more of the following: vanadium source, manganese source, barium source, calcium source, lanthanum source, rhenium source and cerium source.

[0018] Based on the weight of the metal oxide, the amount of the third metal source is 0.002-0.2 parts by weight relative to 1 part by weight of the copper source.

[0019] Optionally, the copper source includes copper sulfate and / or copper nitrate;

[0020] The aluminum source includes aluminum sulfate and / or aluminum nitrate;

[0021] The zinc source includes zinc sulfate and / or zinc nitrate;

[0022] The magnesium source includes magnesium sulfate and / or magnesium nitrate;

[0023] The alkaline source includes one or more of alkaline carbonates, alkaline bicarbonates, and metal hydroxides, preferably one or more of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, potassium bicarbonate, and sodium bicarbonate.

[0024] Based on the weight of the metal oxides, relative to 1 part by weight of the copper source, the amount of the aluminum source is 0.3-2 parts by weight, the amount of the zinc source is 0.2-2.4 parts by weight, and the amount of the magnesium source is 0.1-1.6 parts by weight.

[0025] Optionally, step S1 includes: adding the first solution and the second solution to the water to carry out the first reaction;

[0026] In step S1, the content of the metal source in the first solution is 10-50% by weight, and the content of the alkali source in the second solution is 5-45% by weight.

[0027] The conditions for the first reaction include: a temperature of 35-80℃, a time of 0.5-3h, and a stirring speed of 100-500rpm.

[0028] Optionally, step S2 includes: adding an alkaline solution to the first material to obtain a slurry with a pH value of 10-11 and carrying out the second reaction under stirring conditions;

[0029] The conditions for the second reaction include: time of 2-12 hours, temperature of 40-65°C, and stirring speed of 100-500 rpm;

[0030] The alkaline solution includes one or more of sodium hydroxide solution, potassium hydroxide solution, sodium carbonate solution, and sodium bicarbonate solution.

[0031] Optionally, step S2 includes: washing and drying the solid product obtained from the second reaction to obtain the preproduct;

[0032] The drying conditions include: a time of 4-12 hours and a temperature of 60-150°C.

[0033] In step S3, the heat treatment method includes calcination, and the calcination conditions include a temperature of 300-550℃ and a time of 2-8h.

[0034] The second aspect of this disclosure provides a bio-based fatty acid methyl ester hydrogenation catalyst prepared using the method described in the first aspect of this disclosure.

[0035] Optionally, relative to 1 part by weight of copper oxide, the bio-based fatty acid methyl ester hydrogenation catalyst contains 0.3-2 parts by weight of aluminum oxide, 0.2-2.4 parts by weight of zinc oxide, and / or 0.1-1.6 parts by weight of magnesium oxide.

[0036] Optionally, the bio-based fatty acid methyl ester hydrogenation catalyst further contains an auxiliary agent;

[0037] The additives include one or more of group VB metal oxides, group VIIB metal oxides, group IIA metal oxides, group IIIA metal oxides, group IVA metal oxides, group VA metal oxides and rare earth metal oxides, preferably including one or more of vanadium oxide, manganese dioxide, barium oxide, calcium oxide, lanthanum oxide, rhenium oxide and cerium oxide.

[0038] The content of the additive is 0.002-0.2 parts by weight relative to 1 part by weight of copper oxide.

[0039] The third aspect of this disclosure provides a method for the hydrogenation reaction of a bio-based fatty acid methyl ester, the method comprising: contacting a bio-based fatty acid methyl ester, a catalyst, and hydrogen to carry out the hydrogenation reaction, wherein the catalyst comprises the bio-based fatty acid methyl ester hydrogenation catalyst described in the second aspect of this disclosure.

[0040] Optionally, the method further includes: before carrying out the hydrogenation reaction, reducing the bio-based fatty acid methyl ester hydrogenation catalyst under a reducing atmosphere, wherein the conditions for the reduction treatment include: a heating rate of 0.1-5.0℃ / min, a temperature of 220-300℃, and a time of 6-48h;

[0041] The reducing atmosphere comprises a mixture of nitrogen and hydrogen, wherein the volume ratio of hydrogen to nitrogen is 1:(9-40).

[0042] Optionally, the hydrogenation reaction is carried out in a fixed-bed reactor under the following conditions: temperature of 160-280℃, preferably 190-240℃; pressure of 3.0-15.0 MPa, preferably 4.0-8.0 MPa; hydrogen-ester molar ratio of (10-120):1, preferably (15-40):1; and a feed space velocity of 0.05-1.5 h⁻¹ for the bio-based fatty acid methyl ester. -1 Preferably, it is 0.15-0.50h. -1 .

[0043] Optionally, the bio-based fatty acid methyl ester includes one or more fatty acid methyl esters with the longest chain having 8-24 carbon atoms.

[0044] Through the above technical solution, this disclosure prepares a bio-based fatty acid methyl ester hydrogenation catalyst with a specific microstructure by means of co-precipitation and limiting the pH value during the reaction process. The above method and conditions are simple, avoid the use of complex reaction instruments, are suitable for industrial production, and can avoid the aggregation of copper active components. The prepared catalyst can be used for the hydrogenation reaction of bio-based fatty acid methyl esters with complex composition, and can obtain high raw material conversion rate and target product fatty alcohol selectivity, and has good stability.

[0045] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Detailed Implementation

[0046] The following provides a detailed description of specific embodiments of this disclosure. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit this disclosure.

[0047] To achieve the above objectives, the first aspect of this disclosure provides a method for preparing a bio-based fatty acid methyl ester hydrogenation catalyst, the method comprising the following steps:

[0048] S1. Under stirring conditions, a first solution containing a first metal source and a second metal source, a second solution containing an alkaline source, and water are brought into contact and a first reaction is carried out to obtain a first material.

[0049] S2. Adjust the pH of the first material to 10-11 and carry out the second reaction to obtain the preproduct;

[0050] S3. The preproduct is subjected to heat treatment;

[0051] The first metal source includes a copper source and an aluminum source, and the second metal source includes a zinc source and / or a magnesium source;

[0052] Step S1 is carried out under conditions of pH 8-10.

[0053] The method disclosed herein uses co-precipitation and limits the pH value during the reaction process to form a specific microstructure of the metal component, avoiding the aggregation of the copper active component, thus giving the catalyst better stability. When catalyzing the hydrogenation reaction of esters at higher temperatures, it is less prone to migration and aggregation, thereby improving the activity and stability of the catalyst.

[0054] According to one embodiment of this disclosure, the first solution contains a third metal source; and / or, the water contains the third metal source; the third metal source is a soluble metal compound and / or a metal oxide, and the third metal source includes one or more of Group VB metal sources, Group VIIB metal sources, Group IIA metal sources, Group IIIA metal sources, Group IVA metal sources, Group VA metal sources, and rare earth metal sources; preferably, it includes one or more of vanadium sources, manganese sources, barium sources, calcium sources, lanthanum sources, rhenium sources, and cerium sources. Specifically, the third metal source may include, for example, lanthanum nitrate, rhenium nitrate, cerium nitrate, manganese nitrate, barium acetate, cerium oxide, etc. When the third metal source includes two or more substances, this disclosure does not impose specific limitations on their proportions; based on the weight of the metal oxide, the amount of the third metal source is 0.002-0.2 parts by weight relative to 1 part by weight of the copper source.

[0055] According to one embodiment of this disclosure, both the first metal source and the second metal source are soluble metal compounds, and their types are conventional in the art. For example, the copper source includes copper sulfate and / or copper nitrate; the aluminum source includes aluminum sulfate and / or aluminum nitrate; the zinc source includes zinc sulfate and / or zinc nitrate; the magnesium source includes magnesium sulfate and / or magnesium nitrate; and the alkali source includes one or more of basic carbonates, basic bicarbonates, and metal hydroxides, preferably one or more of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, potassium bicarbonate, and sodium bicarbonate. When the alkali source includes two or more, their proportions are not limited.

[0056] According to one embodiment of this disclosure, based on the weight of the metal oxide, the amount of the aluminum source is 0.3-2 parts by weight relative to 1 part by weight of the copper source, the amount of the zinc source is 0.2-2.4 parts by weight, and the amount of the magnesium source is 0.1-1.6 parts by weight.

[0057] According to one embodiment of this disclosure, in step S1, the content of the metal source in the first solution is 10-50% by weight, preferably 25-40% by weight, wherein "metal source" refers to all compounds containing metal elements in the first solution, that is, the metal source in the first solution includes a first metal source, a second metal source and an optional third metal source; in the second solution, the content of the alkali source is 5-45% by weight, preferably 20-35% by weight; the conditions for the first reaction include: a temperature of 35-80°C and a time of 0.5-3h; preferably, a time of 1-2h and a temperature of 40-60°C; and a stirring speed of 100-500rpm.

[0058] In this disclosure, the pH value in step S1 can be controlled by the addition rate and amount of the first and second solutions, and can be measured in real time using a pH meter. The pH values ​​in this disclosure are all measured under normal pressure conditions at 25°C.

[0059] According to one embodiment of this disclosure, step S1 includes: adding the first solution and the second solution to the water to carry out the first reaction; the method of adding the first solution and the second solution is conventional in the art, such as adding them directly, adding them by a pump, or adding them dropwise.

[0060] According to one embodiment of this disclosure, step S2 includes: adding an alkaline solution to the first material to obtain a slurry with a pH value of 10-11 and carrying out the second reaction under stirring conditions; the conditions for the second reaction include: a time of 2-12 hours, a temperature of 40-65°C, and a stirring speed of 100-500 rpm; the alkaline solution includes one or more of sodium hydroxide solution, potassium hydroxide solution, sodium carbonate solution, and sodium bicarbonate solution. This disclosure does not impose specific limitations on the concentration of the alkaline solution, and when the alkaline solution includes two or more types, its proportion is not limited.

[0061] In this disclosure, the first solution does not contain an alkaline source, and the second solution does not contain a first metal source, a second metal source, or a third metal source.

[0062] According to one embodiment of this disclosure, step S2 includes: performing solid-liquid separation on the second material obtained from the second reaction to obtain a solid product, then washing the solid product until the pH value of the washing liquid is 7, and then drying it to obtain the pre-product; the drying conditions include: time of 4-12h, temperature of 60-150℃, and the drying method is conventional in the art; the solid-liquid separation method is conventional in the art, for example, vacuum filtration.

[0063] According to one embodiment of this disclosure, in step S3, the heat treatment includes calcination, and the calcination conditions include: a time of 2-8 hours and a temperature of 300-550°C; preferably, a time of 4-6 hours and a temperature of 350-450°C, and the calcination method is conventional in the art; after XRD testing, at least a portion of the catalyst powder obtained by the heat treatment has a hydrotalcite structure and / or a spinel structure.

[0064] According to one embodiment of this disclosure, the method further includes: molding the catalyst powder obtained in step S3 to obtain a hydrogenation catalyst; the molding process is conventional in the art, such as tablet molding, extrusion molding, and ball forming. The inert binder used in the molding process includes, but is not limited to, silica sol, amorphous or mineral-structured titanium dioxide, zirconium oxide, and viscous graphite. The weight ratio of the inert binder to the catalyst powder is conventional in the art, for example, (1.5-30):(70-98.5).

[0065] The second aspect of this disclosure provides a bio-based fatty acid methyl ester hydrogenation catalyst prepared using the method described in the first aspect of this disclosure.

[0066] According to one embodiment of this disclosure, relative to 1 part by weight of copper oxide, the bio-based fatty acid methyl ester hydrogenation catalyst contains 0.3-2 parts by weight of aluminum oxide, 0.2-2.4 parts by weight of zinc oxide, and / or 0.1-1.6 parts by weight of magnesium oxide. The catalyst with the above component contents has good thermal stability and good ester hydrogenation performance.

[0067] According to one embodiment of this disclosure, the bio-based fatty acid methyl ester hydrogenation catalyst further contains an auxiliary agent; the auxiliary agent includes one or more of group VB metal oxides, group VIIB metal oxides, group IIA metal oxides, group IIIA metal oxides, group IVA metal oxides, group VA metal oxides, and rare earth metal oxides, preferably including one or more of vanadium oxide, manganese dioxide, barium oxide, calcium oxide, lanthanum oxide, rhenium oxide, and cerium oxide; the content of the auxiliary agent is 0.002-0.2 parts by weight relative to 1 part by weight of copper oxide. The catalyst with the above component content has good thermal stability. When there are two or more types of auxiliary agents, their proportion is not specifically limited.

[0068] According to one embodiment of this disclosure, the hydrogenation catalyst also contains a molding component, which is a component generated from an inert binder through subsequent preparation steps.

[0069] The third aspect of this disclosure provides a method for the hydrogenation reaction of a bio-based fatty acid methyl ester, the method comprising: contacting a bio-based fatty acid methyl ester, a catalyst, and hydrogen to carry out the hydrogenation reaction, wherein the catalyst comprises the bio-based fatty acid methyl ester hydrogenation catalyst described in the second aspect of this disclosure.

[0070] According to one embodiment of this disclosure, the method further includes: before carrying out the hydrogenation reaction, reducing the bio-based fatty acid methyl ester hydrogenation catalyst under a reducing atmosphere, wherein the conditions for the reduction treatment include: a heating rate of 0.1-5.0℃ / min, a temperature of 220-300℃, and a time of 6-48h; the reducing atmosphere includes a mixed atmosphere of nitrogen and hydrogen, wherein the volume ratio of hydrogen to nitrogen is 1:(9-40), and after the reduction treatment, the oxidation state of copper in the catalyst includes +1 and / or 0, and the ratio of the two is not limited.

[0071] According to one embodiment of this disclosure, the hydrogenation reaction is carried out in a fixed-bed reactor, and the reaction conditions include: a temperature of 160-280°C, preferably 190-240°C; a pressure of 3.0-15.0 MPa, preferably 4.0-8.0 MPa; a hydrogen-ester molar ratio of (10-120):1, preferably (15-40):1; and a feed space velocity of 0.05-1.5 h⁻¹ for the bio-based fatty acid methyl ester. -1 Preferably, it is 0.15-0.50h. -1 .

[0072] According to one embodiment of this disclosure, the bio-based fatty acid methyl ester includes one or more fatty acid methyl esters with the longest chain having 8-24 carbon atoms. The aforementioned bio-based fatty acid methyl esters include, for example, one or more fatty acid methyl esters prepared from palm oil, coconut oil, cottonseed oil, rapeseed oil, soybean oil, and castor oil. Specifically, it can be one or more of palm oil methyl ester, cottonseed oil methyl ester, coconut oil methyl ester, rapeseed oil methyl ester, soybean oil methyl ester, and castor oil methyl ester.

[0073] The present disclosure will be further illustrated by the following examples, but the present disclosure is not limited thereto. Unless otherwise specified, the instruments and reagents used in the embodiments of the present disclosure are instruments and reagents commonly used by those skilled in the art.

[0074] Methods for determining the content of each component in the catalyst: XRF fluorescence elemental analysis combined with ICP analysis.

[0075] Chromatographic analysis method and instrument model: Agilent 7890, HP-5 column and FID detector.

[0076] Example 1

[0077] Hydrogenation catalyst A1 was prepared using the following steps:

[0078] (1) Weigh 40.43g of copper nitrate trihydrate, 66.37g of zinc nitrate hexahydrate, 62.77g of aluminum nitrate nonahydrate and 2.12g of lanthanum nitrate hydrate, add 240g of deionized water to dissolve and obtain the first solution, the content of metal source is 41.7% by weight;

[0079] (2) Weigh 35.48g of sodium carbonate pentahydrate and 40.16g of sodium hydroxide, add 300g of deionized water to dissolve them into a second solution with an alkali source content of 20.1% by weight;

[0080] (3) Under the condition of 45℃ and stirring, the first solution and the second solution were added to 100mL of deionized water, reacted for 2h, the pH value was 9.5, and the first material was obtained. The stirring speed was 300rpm.

[0081] (4) Add sodium hydroxide solution to the first material to obtain a slurry with a pH value of 11, and stir at 45°C for 6 hours to obtain the second material. The stirring speed is 300 rpm.

[0082] (5) Vacuum filter the second material and filter the filter cake until the pH value of the washing liquid is 7;

[0083] (6) The washed filter cake was dried at 120°C for 12 hours and calcined at 450°C for 4 hours to obtain hydrogenation catalyst raw powder.

[0084] XRD analysis of the hydrogenation catalyst powder revealed that it exhibited distinct characteristic peaks of a hydrotalcite structure.

[0085] In the hydrogenation catalyst powder, relative to 1 part by weight of copper oxide, the content of zinc oxide is 1.36 parts by weight, the content of aluminum oxide is 0.61 parts by weight, and the content of lanthanum oxide, an auxiliary agent, is 0.061 parts by weight.

[0086] The hydrogenation catalyst powder is compressed into tablets and then crushed into 20-40 mesh hydrogenation catalyst A1.

[0087] The specific steps for tableting are as follows: Grind the catalyst powder and sieve it into a powder smaller than 120 mesh. Add graphite binder (the weight ratio of binder to catalyst powder is 0.015:1), mix thoroughly, and then compress the mixture into tablets using a hydraulic tablet press. The catalyst particle size is a φ5mm × 5mm cylinder, and the lateral compressive strength of the tableted catalyst is 25-32 N / cm. When used in a laboratory-scale fixed-bed reactor, the above-mentioned tableted catalyst is crushed to 20-40 mesh particles.

[0088] Example 2

[0089] Hydrogenation catalyst A2 was prepared using the following steps:

[0090] (1) Weigh 65.41g of copper nitrate trihydrate, 52.06g of magnesium nitrate hexahydrate, and 76.17g of aluminum nitrate nonahydrate, add 240g of deionized water to dissolve them, and obtain the first solution with a metal source content of 43.6% by weight.

[0091] (2) Weigh 79.59g of sodium carbonate pentahydrate and 48.73g of sodium hydroxide, add 400g of deionized water to dissolve them into a second solution with an alkali source content of 24.3% by weight.

[0092] (3) Under the condition of 45℃ and stirring, the first solution and the second solution were added to 100mL of deionized water containing 1.2g of cerium oxide, and the reaction was carried out for 1.5h. The pH value was 8.5, and the first material was obtained. The stirring speed was 400rpm.

[0093] (4) Add sodium hydroxide solution to the first material to form a slurry with a pH value of 11, and stir at 45°C for 6 hours to obtain the second material. The stirring speed is 400 rpm.

[0094] (5) Vacuum filter the second material and filter the filter cake until the pH value of the washing liquid is 7;

[0095] (6) The washed filter cake was dried at 120°C for 12 hours and calcined at 550°C for 4 hours to obtain hydrogenation catalyst raw powder.

[0096] XRD analysis of the hydrogenation catalyst powder revealed that it exhibited distinct characteristic peaks of a hydrotalcite structure.

[0097] In the hydrogenation catalyst powder, relative to 1 part by weight of copper oxide, the content of magnesium oxide is 0.38 parts by weight, the content of aluminum oxide is 0.48 parts by weight, and the content of cerium oxide (an auxiliary agent) is 0.058 parts by weight.

[0098] The hydrogenation catalyst powder is compressed into tablets and then crushed into 20-40 mesh hydrogenation catalyst A2.

[0099] The specific steps for tableting are as follows: Grind the catalyst powder and sieve it into a powder smaller than 120 mesh. Add graphite binder (the weight ratio of binder to catalyst powder is 0.02:1), mix thoroughly, and then tablet using a hydraulic tablet press. The catalyst particle size is a φ5mm × 5mm cylinder, and the lateral compressive strength of the tableted catalyst is 25-32 N / cm. When used in a laboratory-scale fixed-bed reactor, the above-mentioned tableted catalyst is crushed to 20-40 mesh particles.

[0100] Example 3

[0101] Hydrogenation catalyst A3 was prepared using the following steps:

[0102] (1) Weigh 42.91g of copper nitrate trihydrate, 15.18g of magnesium nitrate hexahydrate, 52.83g of zinc nitrate hexahydrate and 66.62g of aluminum nitrate nonahydrate, add 220g of deionized water to dissolve and obtain the first solution, the content of metal source is 44.7% by weight;

[0103] (2) Weigh 69.62g of sodium carbonate pentahydrate and 42.62g of sodium hydroxide, add 500g of deionized water to dissolve them into a second solution with an alkali source content of 18.3% by weight;

[0104] (3) Under the condition of stirring at 45℃, the first solution and the second solution were added to 100mL of deionized water containing 1.645g manganese nitrate and 1.09g barium chloride. The reaction was carried out for 3h, the pH value was 9.0, and the first material was obtained. The stirring speed was 400rpm.

[0105] (4) Add sodium hydroxide solution to the first material to form a slurry with a pH value of 11, and stir at 45°C for 6 hours to obtain the second material. The stirring speed is 400 rpm.

[0106] (5) Vacuum filter the second material and filter the filter cake until the pH value of the washing liquid is 7;

[0107] (6) The washed filter cake was dried at 120°C for 12 hours and calcined at 500°C for 4 hours to obtain hydrogenation catalyst raw powder.

[0108] XRD analysis of the hydrogenation catalyst powder revealed distinct characteristic peaks of both hydrotalcite and spinel structures.

[0109] In the hydrogenation catalyst powder, relative to 1 part by weight of copper oxide, the content of magnesium oxide is 0.14 parts by weight, the content of zinc oxide is 1.03 parts by weight, the content of aluminum oxide is 0.63 parts by weight, and the total content of the additives manganese dioxide and barium oxide is 0.057 parts by weight.

[0110] The hydrogenation catalyst powder is compressed into tablets and then crushed into 20-40 mesh hydrogenation catalyst A3.

[0111] The specific steps for tableting are as follows: Grind the catalyst powder and sieve it into a powder smaller than 120 mesh. Add graphite binder (the weight ratio of binder to catalyst powder is 0.025:1), mix thoroughly, and then tablet using a hydraulic tablet press. The catalyst particle size is a φ5mm × 5mm cylinder, and the lateral compressive strength of the tableted catalyst is 25-32 N / cm. When used in a laboratory-scale fixed-bed reactor, the above-mentioned tableted catalyst is crushed to 20-40 mesh particles.

[0112] Example 4

[0113] Hydrogenation catalyst A4 was prepared using a similar procedure to that in Example 1, except that lanthanum nitrate was not added, i.e., the catalyst did not contain any promoters.

[0114] XRD analysis of the hydrogenation catalyst powder revealed that it exhibited distinct characteristic peaks of a hydrotalcite structure.

[0115] Comparative Example 1

[0116] Hydrogenation catalyst D1 was prepared using the following steps:

[0117] (1) Weigh 40.43g of copper nitrate trihydrate, 66.37g of zinc nitrate hexahydrate, 62.77g of aluminum nitrate nonahydrate and 2.12g of lanthanum nitrate hydrate, add 200g of deionized water to dissolve them and obtain the first solution;

[0118] (2) Weigh 100g of sodium hydroxide and add 350g of deionized water to dissolve it into a second solution;

[0119] (3) Under the condition of stirring at 45℃, the second solution is added dropwise to the first solution until the pH value reaches 7.5 to reach the endpoint of the addition, and the slurry is obtained. The mixture is stirred at 45℃ for 6 hours to obtain the mixture. The stirring speed is 400 rpm.

[0120] (4) Vacuum filter the mixture and filter the filter cake until the pH of the washing liquid is 7;

[0121] (5) The washed filter cake was dried at 120℃ for 12h, and the obtained preproduct was subjected to XRD test. According to the spectrum, the characteristic peaks of anhydrous talc structure and spinel structure were observed.

[0122] (6) The preproduct was calcined at 450°C for 4 hours to obtain hydrogenation catalyst powder;

[0123] XRD analysis of the hydrogenation catalyst powder revealed characteristic peaks of both anhydrous talc and spinel structures.

[0124] The hydrogenation catalyst powder is compressed into tablets and then crushed into 20-40 mesh hydrogenation catalyst D1.

[0125] The specific steps for tableting are as follows: Grind the catalyst powder and sieve it into a powder smaller than 120 mesh. Add graphite binder (the weight ratio of binder to catalyst powder is 0.02:1), mix thoroughly, and then tablet using a hydraulic tablet press. The catalyst particle size is a φ5mm × 5mm cylinder, and the lateral compressive strength of the tableted catalyst is 25-32 N / cm. When used in a laboratory-scale fixed-bed reactor, the above-mentioned tableted catalyst is crushed to 20-40 mesh particles.

[0126] Test Example 1

[0127] 10.0 g of catalyst A1 was weighed and loaded into a fixed-bed reactor. The fixed-bed reactor had an inner diameter of 12 mm. Before use, the catalyst underwent hydrogenation reduction at a heating rate of 3 °C / min and a reduction temperature of 250 °C. Hydrogen and nitrogen were introduced at a volume ratio of 1:9, and the reduction time was 16 h. Then, the mixed gas feed was stopped, and pure hydrogen was introduced instead. The feedstock was coconut oil methyl ester, and the reaction conditions were: reaction temperature 220 °C, reaction pressure 5.0 MPa, hydrogen-to-ester molar ratio 40:1, and coconut oil feed mass hourly space velocity (HHSV) 0.3 h⁻¹. -1 The ester hydrogenation reaction occurs in a single pass. After sampling, the product was diluted with methanol and then analyzed by chromatography. The results of the analysis after 24 hours of stable reaction conditions showed that the conversion rate of coconut oil methyl ester hydrogenation was 99.0%, the selectivity of long-chain fatty alcohols (mixed alcohols) was 97.2%, the selectivity of long-chain fatty acid fatty esters was 2.4%, and the highest impurity content was 0.4% by weight.

[0128] Test Example 2

[0129] Weigh 12.0 g of catalyst A2 and load it into a fixed-bed reactor. The fixed-bed reactor has an inner diameter of 12 mm. Before use, the catalyst undergoes hydrogenation reduction at a heating rate of 3 °C / min and a reduction temperature of 260 °C. Hydrogen and nitrogen are introduced at a volume ratio of 1:9, and the reduction time is 16 h. Then, the mixed gas feed is stopped, and pure hydrogen is used instead. The feedstock is cottonseed oil methyl ester, and the reaction conditions are: reaction temperature 240 °C, reaction pressure 6.0 MPa, hydrogen-to-ester molar ratio 60:1, and coconut oil feed mass hourly space velocity (HHSV) 0.5 h⁻¹. -1 The ester hydrogenation reaction occurs in a single pass. After sampling, the product is diluted with methanol and then analyzed by chromatography. The results of the analysis after 24 hours of stable reaction conditions show that the hydrogenation conversion rate of cottonseed oil methyl ester is 98.5%, the selectivity of long-chain fatty alcohols (mixed alcohols) is 96.5%, the selectivity of long-chain fatty acid fatty esters is 3.0%, and the highest impurity content is 0.5% by weight.

[0130] Test Example 3

[0131] 10.0 g of catalyst A3 was weighed and loaded into a fixed-bed reactor. The fixed-bed reactor had an inner diameter of 12 mm. Before use, the catalyst underwent hydrogenation pre-reduction at a heating rate of 5 °C / min and a reduction temperature of 240 °C. Hydrogen and nitrogen were introduced at a volume ratio of 1:9, and the reduction time was 16 h. Then, the mixed gas feed was stopped, and pure hydrogen was introduced instead. The raw material was soybean oil methyl ester. The reaction conditions were: reaction temperature of 200 °C, reaction pressure of 5.0 MPa, hydrogen-ester molar ratio of 30:1, soybean oil methyl ester feed mass hourly space velocity of 0.2 h⁻¹, and single-pass hydrogenation of the ester. After sampling, the product was diluted with methanol and then analyzed by chromatography. The analysis results after 24 h of stable reaction conditions showed that the hydrogenation conversion rate of cottonseed oil methyl ester was 99.3%, the selectivity of long-chain fatty alcohols (mixed alcohols) was 97.8%, the selectivity of long-chain fatty acid fatty esters was 1.8%, and the highest impurity content was 0.4 wt%.

[0132] Test Example 4

[0133] The hydrogenation reaction of coconut oil methyl ester was carried out using hydrogenation catalyst A4 and the method of Test Example 1. After the product was sampled, it was diluted with methanol and then analyzed by chromatography. The analysis results of samples taken 24 hours after the reaction conditions stabilized showed that the hydrogenation conversion rate of coconut oil methyl ester was 98.5%, the selectivity of long-chain fatty alcohols (mixed alcohols) was 95.0%, the selectivity of long-chain fatty acid fatty esters was 3.2%, and the highest impurity content was 1.8% by weight.

[0134] Test Comparison Example 1

[0135] 10.0 g of catalyst D1 was weighed and loaded into a fixed-bed reactor. The fixed-bed reactor had an inner diameter of 12 mm. The catalyst underwent hydrogen pre-reduction before use, with a heating rate of 5 °C / min and a reduction temperature of 250 °C. Hydrogen and nitrogen were introduced at a volume ratio of 1:9, and the reduction time was 16 h. Then, the mixed gas feed was stopped, and pure hydrogen was introduced instead. The feedstock was coconut oil methyl ester, and the reaction conditions were: reaction temperature 220 °C, reaction pressure 5.0 MPa, hydrogen-to-ester molar ratio 40:1, and coconut oil methyl ester feed mass hourly space velocity (WHSV) 0.3 h⁻¹. -1 The ester hydrogenation reaction occurs in a single pass. After sampling, the product was diluted with methanol and then analyzed by chromatography. The results of the analysis after 24 hours of stable reaction conditions showed that the conversion rate of coconut oil methyl ester hydrogenation was 89.0%, the selectivity of long-chain fatty alcohols (mixed alcohols) was 90.5%, the selectivity of long-chain fatty acid fatty esters was 7.7%, and the highest impurity content was 1.8% by weight.

[0136] Test Example 6

[0137] Using the test conditions of Test Example 1, a 500-hour long-term experiment was conducted on catalyst A1. The analysis results after sampling at different times are shown in Table 1 below.

[0138] Table 1

[0139] reaction time Coconut oil methyl ester conversion rate / % Long-chain fatty alcohol selectivity / % 100 99.2 97.1 200 99.1 96.9 300 99.3 97.3 400 99.1 97.2 500 99.2 97.1

[0140] Test Comparison Example 2

[0141] Using the test conditions of Comparative Example 1, the catalyst D1 was subjected to a 500-hour long-term experiment. The analysis results after sampling at different times are shown in Table 2 below.

[0142] Table 2

[0143] reaction time Coconut oil methyl ester conversion rate / % Long-chain fatty alcohol selectivity / % 100 89.0 90.2 200 89.2 88.5 300 85.5 85.1 400 82.1 82.3 500 78.4 82.0

[0144] Based on the above data, it can be seen that the ester hydrogenation catalyst prepared by the method disclosed herein has a specific microstructure. When applied to the hydrogenation reaction of bio-based fatty acid methyl esters, it can achieve a high conversion rate of fatty acid methyl esters, a high selectivity for the target product fatty alcohols, and good stability.

[0145] The preferred embodiments of this disclosure have been described in detail above. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0146] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0147] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for preparing a bio-based fatty acid methyl ester hydrogenation catalyst, characterized in that, The method includes the following steps: S1. Under stirring conditions, a first solution containing a first metal source and a second metal source, a second solution containing an alkaline source, and water are brought into contact and a first reaction is carried out to obtain a first material. S2. Adjust the pH of the first material to 10-11 and carry out the second reaction to obtain the preproduct; S3. The preproduct is subjected to heat treatment; The first metal source includes a copper source and an aluminum source, and the second metal source includes a zinc source and / or a magnesium source; Step S1 is carried out under conditions where the pH value is 8-10; Steps S1 and S2 were performed under different pH conditions; The bio-based fatty acid methyl esters include one or more of palm oil methyl ester, cottonseed oil methyl ester, coconut oil methyl ester, rapeseed oil methyl ester, soybean oil methyl ester, and castor oil methyl ester. Based on the weight of the metal oxide, relative to 1 part by weight of the copper source, the amount of the aluminum source is 0.3-2 parts by weight, the amount of the zinc source is 0.2-2.4 parts by weight, and / or the amount of the magnesium source is 0.1-1.6 parts by weight. In step S3, the heat treatment method includes calcination, and the calcination conditions include a temperature of 300-550℃ and a time of 2-8h.

2. The method according to claim 1, wherein, The first solution contains a third metal source; and / or, the water contains the third metal source. The third metal source includes one or more of the following: vanadium source, manganese source, barium source, lanthanum source, rhenium source, and cerium source; Based on the weight of the metal oxide, the amount of the third metal source is 0.002-0.2 parts by weight relative to 1 part by weight of the copper source.

3. The method according to claim 1, wherein, The copper source includes copper sulfate and / or copper nitrate; The aluminum source includes aluminum sulfate and / or aluminum nitrate; The zinc source includes zinc sulfate and / or zinc nitrate; The magnesium source includes magnesium sulfate and / or magnesium nitrate; The alkali source includes one or more of basic carbonates, basic bicarbonates, and metal hydroxides.

4. The method according to claim 3, wherein, The alkali source includes one or more of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, potassium bicarbonate, and sodium bicarbonate.

5. The method according to claim 1, wherein, Step S1 includes: adding the first solution and the second solution to the water to carry out the first reaction; In step S1, the content of the metal source in the first solution is 10-50% by weight, and the content of the alkali source in the second solution is 5-45% by weight. The conditions for the first reaction include: a temperature of 35-80℃, a time of 0.5-3h, and a stirring speed of 100-500rpm.

6. The method according to claim 1, wherein, Step S2 includes: adding an alkaline solution to the first material to obtain a slurry with a pH value of 10-11 and carrying out the second reaction under stirring conditions; The conditions for the second reaction include: time of 2-12 hours, temperature of 40-65°C, and stirring speed of 100-500 rpm; The alkaline solution includes one or more of sodium hydroxide solution, potassium hydroxide solution, sodium carbonate solution, and sodium bicarbonate solution.

7. The method according to claim 1, wherein, Step S2 includes: washing and drying the solid product obtained from the second reaction to obtain the preproduct; The drying conditions include: a time of 4-12 hours and a temperature of 60-150℃.

8. The bio-based fatty acid methyl ester hydrogenation catalyst prepared by any one of claims 1-7.

9. The bio-based fatty acid methyl ester hydrogenation catalyst according to claim 8, wherein, Relative to 1 part by weight of copper oxide, the bio-based fatty acid methyl ester hydrogenation catalyst contains 0.3-2 parts by weight of aluminum oxide, 0.2-2.4 parts by weight of zinc oxide, and / or 0.1-1.6 parts by weight of magnesium oxide.

10. The bio-based fatty acid methyl ester hydrogenation catalyst according to claim 9, wherein, The bio-based fatty acid methyl ester hydrogenation catalyst also contains an auxiliary agent; The additives include one or more of the following: Group VB metal oxides, Group VIIB metal oxides, Group IIA metal oxides, Group IIIA metal oxides, Group IVA metal oxides, Group VA metal oxides, and rare earth metal oxides. The content of the additive is 0.002-0.2 parts by weight relative to 1 part by weight of copper oxide.

11. The bio-based fatty acid methyl ester hydrogenation catalyst according to claim 10, wherein, The additives include one or more of vanadium oxide, manganese dioxide, barium oxide, lanthanum oxide, rhenium oxide, and cerium oxide.

12. A method for hydrogenating a bio-based fatty acid methyl ester, the method comprising: The hydrogenation reaction is carried out by contacting bio-based fatty acid methyl esters, a catalyst, and hydrogen, characterized in that the catalyst comprises any one of the bio-based fatty acid methyl ester hydrogenation catalysts according to claims 8-11.

13. The method according to claim 12, wherein, The method further includes: before carrying out the hydrogenation reaction, reducing the bio-based fatty acid methyl ester hydrogenation catalyst under a reducing atmosphere, wherein the conditions for the reduction treatment include: a heating rate of 0.1-5.0℃ / min, a temperature of 220-300℃, and a time of 6-48h; The reducing atmosphere comprises a mixture of nitrogen and hydrogen, wherein the volume ratio of hydrogen to nitrogen is 1:(9-40).

14. The method according to claim 12, wherein, The hydrogenation reaction is carried out in a fixed-bed reactor under the following conditions: temperature 160-280℃, pressure 3.0-15.0 MPa, hydrogen-ester molar ratio of (10-120):1, and mass hourly space velocity (HHSV) of the bio-based fatty acid methyl ester feed at 0.05-1.5 h⁻¹. -1 .

15. The method according to claim 14, wherein, The temperature is 190-240℃.

16. The method of claim 14, wherein, The pressure is 4.0-8.0 MPa.

17. The method of claim 14, wherein, The molar ratio of hydrogen ester is (15-40):

1.

18. The method according to claim 14, wherein, The feed mass hourly space velocity (GHSV) of the bio-based fatty acid methyl ester is 0.15-0.50 h⁻¹. -1 .