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, a preparation method and application thereof, the method comprising the following steps: S1, under the condition of stirring, contacting a first metal source, a second metal source, an alkali source, a molecular sieve with water and carrying out a first reaction to obtain a pre-product; S2, carrying out heat treatment on 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; the silica-alumina ratio of the molecular sieve is 150 or less; the above ester hydrogenation catalyst is used for the hydrogenation reaction of bio-based fatty acid methyl ester, and a higher raw material conversion rate and target product fatty alcohol selectivity can be obtained, and the generation of fatty acid fatty ester can be reduced.

Description

Technical Field

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

[0002] Copper-based catalysts are important catalysts for the hydrogenation of fatty acid esters to prepare the corresponding fatty alcohols. Early catalysts were generally based on Cu-Cr composite metal oxides. However, due to the high toxicity of Cr, which causes pollution and harm to the environment, subsequent catalyst development has focused on Cr-free copper-based catalysts, such as various composite oxide catalysts including copper-zinc, copper-zinc-aluminum, and copper-silicon.

[0003] Currently, copper-based catalysts used in important industrial reactions such as CO hydrogenation to methanol and oxalate hydrogenation to ethylene glycol all contain 50% copper by weight or higher. They are generally produced by tableting, resulting in cylindrical catalyst particles with a diameter typically not less than φ3mm and a thickness of 3-10mm. The utilization rate of the active metals within the catalyst is relatively low, and the specific surface area is generally 30-50m². 2 / g. Because the internal and external composition of the catalyst forming agent is essentially the same, it is also called a bulk catalyst. Its advantage lies in its high active metal content, which can control deactivation at a low rate; its disadvantage is that the catalyst powder is bonded together in a stacked manner, resulting in small pore volumes, insufficient unobstructed stacking channels, and low utilization of active metals. Conventional ester hydrogenation catalysts often perform poorly when applied to the hydrogenation reactions of fatty acid esters with large molecular weights and long carbon chains.

[0004] Long-chain fatty alcohols are important basic raw materials for fine chemicals, widely used in plasticizers, detergents, and surfactants. Fatty alcohols prepared by hydrogenation of bio-based fatty acid esters have the advantages of renewable raw materials and biodegradable products, and have broad application prospects in pharmaceuticals, cosmetics, lubricants, and petroleum additives.

[0005] CN105492414A describes a method for producing fatty alcohols from fatty acid methyl esters. First, fatty acid methyl esters are catalytically hydrogenated to produce fatty alcohols. However, a significant amount of wax esters, i.e., high-boiling-point long-chain fatty acid esters, remain in the hydrogenation product. These wax esters are then reacted with methanol on a slightly alkaline catalyst of magnesium oxide or hydrotalcite to undergo a transesterification reaction, regenerating fatty acid methyl esters, which are then recycled back to the inlet for further reaction. The catalyst used in this patent is a conventional copper-based ester hydrogenation catalyst, with no special improvements in side reaction control or hydrogenation activity. Therefore, the suppression of fatty acid esters is crucial.

[0006] CN 105777488A discloses a catalyst for fatty alcohols and its preparation method. This type of catalyst is prepared using a supported method. One type of support is a molecular sieve, including MCM-41, MAS-7, ZSM-5, β-zeolite, etc., or a metal or non-metal oxide, such as ZrO2, CeO2, Al2O3, SiO2, etc. The main active metal includes noble metals Pd and Ru, with a loading generally below 1%, or one of the non-noble metals Cu and Ni, reaching a maximum of 10%. The reaction is carried out in a high-pressure reactor, and the catalyst can be recovered and reused. For non-noble metal catalysts, although the catalyst support has a certain degree of acidity, the catalyst effect is not good due to the low copper loading.

[0007] CN102438972A is a method proposed by BASF for the preparation of fatty alcohols from glycerol triglycerides on a copper-based heterogeneous catalyst. The catalyst has the composition of (CuO). 0.6-0.8 (Al2O3) 0.1-0.34 (La2O3) 0.02-0.2 Because the reactant is triglyceride, the hydrogenation conditions are quite harsh, with hydrogenation pressures ranging from 10.0 to 32.5 MPa. The generated triglycerides are over-hydrogenated, producing propylene glycol. In the application of the catalyst, the effect is not particularly ideal; after two stages of reactors, the yield of the target product, long-chain fatty alcohol, is 85%, lower than the calculated value of 98%.

[0008] CN103282335A discloses a method for preparing fatty alcohols from fatty acids, but the hydrogenation step is essentially the hydrogenation of fatty acid methyl esters. The patent mentions that the fatty acid is first esterified with a lower-carbon fatty alcohol, using an ion exchange resin containing sulfonic acid and carboxylic acid groups as the catalyst. In the hydrogenation stage, a copper-zinc composite metal oxide catalyst, or copper chromite and its modifiers, is used. During the hydrogenation conversion of fatty acid esters, the reaction temperature is 200-220℃, and the hydrogen pressure is 4.0-10.0 MPa, resulting in the production of a relatively large amount of wax esters. Therefore, the patent process requires the cracking of these waxes into methyl esters and the resulting alcohol.

[0009] As can be seen from the above patents, the hydrogenation of fatty acid methyl esters is quite difficult: the carbon chain of the molecule is long, and there is great steric hindrance when the active site is adsorbed during the reaction; the composition of the raw material molecules is complex, often a mixture of fatty acid methyl esters with different carbon chain lengths; the long chain molecules contain double bonds, which increases the probability of side reactions such as polymerization. Summary of the Invention

[0010] 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 fatty alcohol selectivity in the hydrogenation reaction of bio-based fatty acid methyl esters, and can reduce the formation of fatty acid fatty esters.

[0011] 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:

[0012] S1. Under stirring conditions, the first metal source, the second metal source, the alkali source, the molecular sieve, and water are brought into contact and a first reaction is carried out to obtain the preproduct;

[0013] S2. 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] The silica-to-alumina ratio of the molecular sieve is below 150.

[0016] Optionally, step S1 is carried out at a temperature of 20-80℃, the first reaction time is 0.5-12h, and the stirring speed is 100-600rpm.

[0017] Optionally, step S1 includes: under stirring conditions, contacting a first slurry containing the molecular sieve, the first metal source, and the second metal source with a first solution containing the alkali source and carrying out the first reaction;

[0018] Preferably, step S1 includes: adding the first slurry dropwise to the first solution under stirring conditions, or adding the first solution dropwise to the first slurry, and then carrying out the first reaction, with the pH value at the endpoint of the dropwise addition being 6.0-9.0.

[0019] Optionally, step S1 includes: under stirring conditions, contacting a second solution containing the first metal source and the second metal source, a first solution containing the alkali source, and a second slurry containing the molecular sieve to carry out the first reaction;

[0020] Preferably, step S1 includes: adding the first solution and the second solution to the second slurry under stirring conditions to carry out the first reaction, wherein step S1 is carried out under conditions with a pH value of 1.5-9.0.

[0021] Optionally, based on the weight of the oxide, the amount of aluminum source is 0.25-1.5 parts by weight, the amount of zinc source is 0.25-2.5 parts by weight, and the amount of magnesium source is 0.25-1.5 parts by weight relative to 1 part by weight of the copper source.

[0022] The weight ratio of the copper source to the molecular sieve, calculated as copper element, is 1:(0.04-0.45).

[0023] Optionally, in the first slurry, the total content of the first metal source and the second metal source is 5-45% by weight.

[0024] Optionally, in the second solution, the total content of the first metal source and the second metal source is 5-45% by weight.

[0025] Optionally, the content of the alkali source in the first solution is 5-30% by weight.

[0026] Optionally, step S1 includes: under stirring conditions, contacting the third metal source, the first metal source, the second metal source, the alkali source, the molecular sieve, and the water to carry out the first reaction;

[0027] 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, Group VIII metal source and rare earth metal source; preferably, it includes one or more of the following: iron source, vanadium source, manganese source, barium source, calcium source, lanthanum source, rhenium source and cerium source.

[0028] Based on the weight of the oxide, the amount of the third metal source is 0.0025-0.25 parts by weight relative to 1 part by weight of the copper source.

[0029] Optionally, the copper source includes copper sulfate and / or copper nitrate;

[0030] The aluminum source includes aluminum sulfate and / or aluminum nitrate;

[0031] The zinc source includes zinc sulfate and / or zinc nitrate;

[0032] The magnesium source includes magnesium sulfate and / or magnesium nitrate;

[0033] 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.

[0034] The molecular sieve includes one or more of ZSM-5 molecular sieve, ZSM-48 molecular sieve, MCM-11 molecular sieve, MCM-22 molecular sieve, SBA-15 molecular sieve, β molecular sieve, SAPO molecular sieve and Y molecular sieve.

[0035] Optionally, step S1 further includes: washing the solid product obtained from the first reaction until the pH of the washing solution is 6.5-7.0, and then drying it to obtain the preproduct;

[0036] The drying conditions include: a time of 10-24 hours and a temperature of 80-150℃.

[0037] Optionally, in step S2, the heat treatment method includes calcination, and the calcination conditions include: a temperature of 350-600℃ and a time of 2-12h.

[0038] 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.

[0039] Optionally, relative to 1 part by weight of copper oxide, the bio-based fatty acid methyl ester hydrogenation catalyst contains 0.25-1.5 parts by weight of aluminum oxide, 0.01-0.85 parts by weight of silicon oxide, 0.25-2.5 parts by weight of zinc oxide and / or 0.25-1.5 parts by weight of magnesium oxide.

[0040] Optionally, the bio-based fatty acid methyl ester hydrogenation catalyst further contains an auxiliary agent;

[0041] 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, group VIII metal oxides and rare earth metal oxides, preferably including one or more of vanadium oxide, manganese dioxide, barium oxide, calcium oxide, iron oxide, lanthanum oxide, rhenium oxide and cerium oxide.

[0042] The content of the additive is 0.0025-0.25 parts by weight relative to 1 part by weight of copper oxide.

[0043] 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.

[0044] 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 0.1-10℃ / min, a temperature of 220-300℃, and a time of 6-48h;

[0045] The reducing atmosphere comprises a mixture of nitrogen and hydrogen, wherein the volume ratio of hydrogen to nitrogen is 1:(9-40).

[0046] 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 .

[0047] 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.

[0048] Through the above technical solution, this disclosure prepares a bio-based fatty acid methyl ester hydrogenation catalyst containing molecular sieves by adding molecular sieves with a specific silicon-to-aluminum ratio during the catalyst preparation process and limiting their amount. The above method has simple steps and conditions, avoids the use of complex reaction equipment, and is suitable for industrial production. The prepared ester hydrogenation catalyst has a large specific surface area and high dispersion of copper active components. When used for the hydrogenation reaction of complex bio-based fatty acid methyl esters, it can achieve a high feed conversion rate and selectivity for the target product fatty alcohols. Furthermore, it can inhibit the transesterification reaction between fatty acid methyl esters and long-chain fatty alcohols, avoiding the excessive formation of fatty acid fatty esters, i.e., wax esters, which are more difficult to hydrogenate and have higher boiling points.

[0049] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Detailed Implementation

[0050] 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 the scope of this disclosure.

[0051] 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:

[0052] S1. Under stirring conditions, the first metal source, the second metal source, the alkali source, the molecular sieve, and water are brought into contact and a first reaction is carried out to obtain the preproduct;

[0053] S2. The preproduct is subjected to heat treatment;

[0054] 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;

[0055] The silica-to-alumina ratio of the molecular sieve is below 150.

[0056] According to one embodiment of this disclosure, the weight ratio of the copper source to the molecular sieve, calculated as copper element, is 1:(0.04-0.45).

[0057] According to one embodiment of this disclosure, step S1 is carried out at a temperature of 20-80°C, the first reaction time is 0.5-12 h, and the stirring speed is 100-600 rpm.

[0058] According to one embodiment of this disclosure, step S1 includes: under stirring conditions, contacting a first slurry containing the molecular sieve, the first metal source, and the second metal source with a first solution containing the alkali source and carrying out the first reaction; preferably, step S1 includes: under stirring conditions, adding the first slurry dropwise to the first solution, or adding the first solution dropwise to the first slurry, and then carrying out the first reaction, wherein the pH value at the endpoint of the dropwise addition is 6.0-9.0.

[0059] According to one embodiment of this disclosure, step S1 includes: under stirring conditions, contacting a second solution containing the first metal source and the second metal source, a first solution containing the alkali source, and a second slurry containing the molecular sieve to carry out the first reaction; preferably, under stirring conditions, adding the first solution and the second solution to the second slurry to carry out the first reaction, step S1 is carried out under conditions with a pH value of 1.5-9.0, the pH value in step S1 can be controlled by the addition rate and amount of the first solution and the second solution, and can be measured in real time using a pH meter; the first solution and the second solution can be added dropwise.

[0060] In this disclosure, the second slurry does not contain the first metal source or the second metal source.

[0061] In this disclosure, the second solution does not contain molecular sieves.

[0062] In this disclosure, the first solution does not contain a molecular sieve, a first metal source, a second metal source, or a third metal source.

[0063] In this disclosure, neither the first slurry, the second slurry, nor the second solution contains an alkali source.

[0064] According to one embodiment of this disclosure, based on the weight of the oxide, the amount of the aluminum source is 0.25-1.5 parts by weight relative to 1 part by weight of the copper source, the amount of the zinc source is 0.25-2.5 parts by weight, and the amount of the magnesium source is 0.25-1.5 parts by weight.

[0065] According to one embodiment of this disclosure, in the first slurry, the total content of the first metal source and the second metal source is 5-45% by weight.

[0066] According to one embodiment of this disclosure, in the second solution, the total content of the first metal source and the second metal source is 5-45% by weight.

[0067] According to one embodiment of this disclosure, the content of the alkali source in the first solution is 5-30% by weight.

[0068] According to one embodiment of this disclosure, step S1 includes: under stirring conditions, contacting a third metal source, a first metal source, a second metal source, an alkali source, and the molecular sieve with water and carrying out the first reaction; specifically, the first slurry contains a third metal source; and / or, the second slurry contains a third metal source; and / or, the second solution contains a third metal source; the third metal source can be a soluble metal compound and / or a metal oxide, and the third metal source includes Group VB metal sources, Group VIIB metal sources, Group IIA metal sources, and Group IIIA metal sources. The third metal source is selected from one or more of the following: Group IVA metal source, Group VA metal source, Group VIII metal source, and rare earth metal source; preferably, it includes one or more of the following: iron source, vanadium source, manganese source, barium source, calcium source, lanthanum source, rhenium source, and cerium source. Specifically, the third metal source may include, for example, lanthanum nitrate, rhenium nitrate, cerium nitrate, manganese nitrate, barium acetate, iron nitrate, cerium oxide, etc. When the third metal source includes two or more, this disclosure does not impose specific limitations on their proportions; based on the weight of the oxide, the amount of the third metal source is 0.0025-0.25 parts by weight relative to 1 part by weight of the copper source.

[0069] 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.

[0070] In this disclosure, "silicon-to-aluminum ratio" refers to the atomic ratio of silicon to aluminum in the molecular sieve.

[0071] According to one embodiment of this disclosure, the molecular sieve includes one or more of ZSM-5 molecular sieve, ZSM-48 molecular sieve, MCM-11 molecular sieve, MCM-22 molecular sieve, SBA-15 molecular sieve, β molecular sieve, SAPO molecular sieve and Y molecular sieve. When the molecular sieve includes two or more types, this disclosure does not impose specific limitations on their proportions.

[0072] According to one embodiment of the present disclosure, the method further includes: before step S1, grinding the molecular sieve to a particle size of 10-50 μm.

[0073] The pH value disclosed herein is a measurement under standard atmospheric pressure and at 25°C.

[0074] According to one embodiment of this disclosure, step S1 further includes: performing solid-liquid separation on the mixture obtained from the first reaction, washing the obtained solid material until the pH value of the washing liquid is 6.5-7.0, and then drying it to obtain the preproduct; the drying conditions include: time of 10-24h, temperature of 80-150℃, and the drying method is conventional in the art; the solid-liquid separation method is conventional in the art, for example, vacuum filtration.

[0075] According to one embodiment of this disclosure, the heat treatment includes calcination, and the calcination conditions include: a temperature of 350-600°C and a time of 2-12 hours; the calcination method is conventional in the art.

[0076] According to one embodiment of this disclosure, the method further includes: molding the catalyst powder obtained in step S2 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).

[0077] 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.

[0078] In the disclosed method, silica and a portion of alumina are added in the form of molecular sieves and exist in the catalyst in the form of molecular sieve structures.

[0079] 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 0.25-1.5 parts by weight of aluminum oxide, 0.08-0.85 parts by weight of silicon oxide, 0.25-2.5 parts by weight of zinc oxide and / or 0.25-1.5 parts by weight of magnesium oxide; the catalyst having the above component contents has good thermal stability and good ester hydrogenation performance.

[0080] 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, group VIII metal oxides, and rare earth metal oxides, preferably including one or more of vanadium oxide, manganese dioxide, barium oxide, calcium oxide, iron oxide, lanthanum oxide, rhenium oxide, and cerium oxide; the content of the auxiliary agent is 0.0025-0.05 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.

[0081] 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.

[0082] 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.

[0083] According to one embodiment of this disclosure, the method further includes: before carrying out the hydrogenation reaction, reducing the hydrogenation catalyst under a reducing atmosphere, wherein the conditions for the reduction treatment include: a heating rate of 0.1-10℃ / 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.

[0084] 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. -1Preferably, it is 0.15-0.50h. -1 .

[0085] 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 ester may 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 may 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.

[0086] 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.

[0087] Methods for determining the content of each component in the catalyst: XRF fluorescence elemental analysis combined with ICP analysis.

[0088] Chromatographic analysis method and instrument model: Agilent 7890, HP-5 column and FID detector.

[0089] Example 1

[0090] Hydrogenation catalyst A1 was prepared using the following steps:

[0091] (1) Weigh 51.84 g of copper nitrate trihydrate, 63.84 g of zinc nitrate hexahydrate and 40.25 g of aluminum nitrate nonahydrate, add 220 g of deionized water to dissolve them, and obtain a second solution with a metal source content of 41.5% by weight.

[0092] (2) Weigh 45.00g of sodium carbonate pentahydrate and 45.00g of sodium hydroxide, add 300g of deionized water to dissolve them into the first solution, with an alkali source content of 23.1% by weight;

[0093] (3) Weigh 4.70g of β molecular sieve with a particle size of 200 mesh and add it to 100mL of deionized water. Stir quickly to form a second slurry, wherein the β molecular sieve has a silicon-to-aluminum atomic ratio of 22.

[0094] The weight ratio of copper nitrate to molecular sieve, calculated as copper element, is 1:0.34;

[0095] (4) Under the conditions of 55±2℃ and stirring, the second solution and the first solution are slowly added dropwise to the second slurry in step (3), and the reaction is carried out for 6 hours. The pH value is 6.5-7.5 to obtain the first material. The stirring speed is 300 rpm.

[0096] (5) Vacuum filter the first material and filter the filter cake until the pH value of the washing liquid is 7;

[0097] (6) The washed filter cake was dried at 120°C for 12 hours and calcined at 450°C for 4 hours to obtain the hydrogenation catalyst raw powder.

[0098] In the hydrogenation catalyst powder, based on the weight of oxides, relative to 1 part by weight of copper oxide, the content of aluminum oxide is 0.32 parts by weight, the content of silicon oxide is 0.20 parts by weight, and the content of zinc oxide is 1.1 parts by weight.

[0099] The hydrogenation catalyst powder is compressed into tablets and then crushed into 20-40 mesh hydrogenation catalyst A1.

[0100] 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.

[0101] Example 2

[0102] Hydrogenation catalyst A2 was prepared using the following steps:

[0103] (1) Weigh 64.14g of copper nitrate trihydrate, 34.03g of magnesium nitrate hexahydrate, 99.58g of aluminum nitrate nonahydrate, 2.12g of lanthanum nitrate hydrate and 2.66g of ZRP molecular sieve (silicon-aluminum atomic ratio of 150), add 350g of deionized water to obtain the first slurry, the total content of the first metal source and the second metal source is 37.8% by weight;

[0104] (2) Weigh 75.00g of sodium carbonate pentahydrate and 69.34g of sodium hydroxide, add 400g of deionized water to dissolve them into the first solution, with an alkali source content of 26.5% by weight;

[0105] (3) Heat the first slurry to 45°C, and add the first solution dropwise to the first slurry under the condition of stirring at 45°C. The pH value at the end of the dropwise addition is 7.5. Then react for 12 hours to obtain the first material. The stirring speed is 200 rpm.

[0106] The weight ratio of copper nitrate to molecular sieve, calculated as copper element, is 1:0.157;

[0107] (4) Vacuum filter the first material and filter the filter cake until the pH value of the washing liquid is 7;

[0108] (6) The washed filter cake was dried at 120°C for 12 hours and calcined at 550°C for 4 hours to obtain the hydrogenation catalyst powder.

[0109] In the hydrogenation catalyst powder, based on the weight of oxides, relative to 1 part by weight of copper oxide, the content of aluminum oxide is 0.64 parts by weight, the content of silicon oxide is 0.013 parts by weight, the content of magnesium oxide is 0.25 parts by weight, and the content of lanthanum oxide is 0.05 parts by weight.

[0110] The hydrogenation catalyst powder is compressed into tablets and then crushed into 20-40 mesh hydrogenation catalyst A2.

[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 3

[0113] Hydrogenation catalyst A3 was prepared using the following steps:

[0114] (1) Weigh 62.14 g of copper nitrate trihydrate, 49.46 g of magnesium nitrate hexahydrate, 19.13 g of zinc nitrate hexahydrate and 48.24 g of aluminum nitrate nonahydrate, add 260 g of deionized water to dissolve them, and obtain a second solution with a metal source content of 40.0% by weight.

[0115] (2) Weigh 80g of sodium carbonate pentahydrate and 70g of sodium hydroxide, add 400g of deionized water to dissolve them into the first solution, with an alkali source content of 27.3% by weight;

[0116] (3) Weigh 6.66g of ZNP molecular sieve with 200 mesh particles (silicon-aluminum ratio of 150) and 5.05g of ferric nitrate nonahydrate and add them to 100mL of deionized water, and stir quickly to form a second slurry;

[0117] The weight ratio of copper nitrate to molecular sieve, calculated as copper element, is 1:0.40;

[0118] (4) Under the condition of stirring at 40±2℃, the second solution and the first solution are slowly added dropwise to the second slurry in step (3), the pH value is 7.5-8.5. After the addition is completed, the temperature is raised to 50℃ and stirred for 12 hours to obtain the first material. The stirring speed is 500 rpm.

[0119] (5) Vacuum filter the first material and filter the filter cake until the pH value of the washing liquid is 7;

[0120] (6) The washed filter cake was dried at 120°C for 12 hours and calcined at 450°C for 4 hours to obtain the hydrogenation catalyst raw powder.

[0121] In the hydrogenation catalyst powder, based on the weight of oxides, relative to 1 part by weight of copper oxide, the content of aluminum oxide is 0.32 parts by weight, the content of silicon oxide is 0.32 parts by weight, the content of zinc oxide is 0.25 parts by weight, the content of magnesium oxide is 0.38 parts by weight, and the content of ferric oxide is 0.022 parts by weight.

[0122] The hydrogenation catalyst powder is compressed into tablets and then crushed into 20-40 mesh hydrogenation catalyst A3.

[0123] 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.

[0124] Comparative Example 1

[0125] Hydrogenation catalyst D1 was prepared using the method described in Example 1, except that no molecular sieve was added.

[0126] In the hydrogenation catalyst powder, relative to 1 part by weight of copper oxide, the content of aluminum oxide is 0.32 parts by weight and the content of zinc oxide is 1.1 parts by weight.

[0127] Comparative Example 2

[0128] The hydrogenation catalyst D2 was prepared using the method in Example 2, except that no molecular sieve was added.

[0129] In the hydrogenation catalyst powder, relative to 1 part by weight of copper oxide, the content of aluminum oxide is 0.64 parts by weight, the content of magnesium oxide is 0.25 parts by weight, and the content of lanthanum oxide is 0.05 parts by weight.

[0130] Test Example 1

[0131] 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 10 °C / min and a reduction temperature of 230 °C. Hydrogen and nitrogen were introduced at a volume ratio of 1:15, and the reduction time was 24 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 200 °C, reaction pressure 5.0 MPa, hydrogen-to-ester molar ratio 60:1, 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 99.2%, the selectivity of long-chain fatty alcohols (mixed alcohols) was 98.6%, the selectivity of long-chain fatty acid fatty esters was 1.0%, and the highest impurity content was 0.4% by weight.

[0132] Test Example 2

[0133] 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 10 °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 220 °C, reaction pressure 6.0 MPa, hydrogen-to-ester molar ratio 80:1, 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 was diluted with methanol and then analyzed by chromatography. The results of the analysis after 24 hours of stable reaction conditions showed that the hydrogenation conversion rate of cottonseed oil methyl ester was 99.1%, the selectivity of long-chain fatty alcohols (mixed alcohols) was 97.5%, the selectivity of long-chain fatty acid fatty esters was 1.4%, and the highest impurity content was 1.1%.

[0134] Test Example 3

[0135] 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 10 °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 feedstock was soybean oil methyl ester, and the reaction conditions were: reaction temperature 210 °C, reaction pressure 5.0 MPa, hydrogen-to-ester molar ratio 40:1, and soybean oil methyl ester feed mass hourly space velocity (WHSV) 0.2 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 99.0%, the selectivity of long-chain fatty alcohols (mixed alcohols) is 98.9%, the selectivity of long-chain fatty acid fatty esters is 0.6%, and the highest impurity content is 0.5%.

[0136] Test Comparison Example 1

[0137] 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 10 °C / min and a reduction temperature of 230 °C. Hydrogen and nitrogen were introduced at a volume ratio of 1:15, and the reduction time was 24 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 200 °C, reaction pressure 5.0 MPa, hydrogen-to-ester molar ratio 60:1, and coconut oil methyl ester feed mass hourly space velocity (WHSV) of 0.3 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 coconut oil methyl ester is 94.3%, the selectivity of long-chain fatty alcohols (mixed alcohols) is 91.5%, the selectivity of long-chain fatty acid fatty esters is 6.9%, and the impurity content is less than 1.6% by weight.

[0138] Test Comparison Example 2

[0139] 10.0 g of catalyst D2 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 10 °C / min and a reduction temperature of 230 °C. Hydrogen and nitrogen were introduced at a volume ratio of 1:15, and the reduction time was 24 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 200 °C, reaction pressure 5.0 MPa, hydrogen-to-ester molar ratio 60:1, 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 90.0%, the selectivity of long-chain fatty alcohols (mixed alcohols) was 92.5%, the selectivity of long-chain fatty acid fatty esters was 5.1%, and the highest impurity content was 2.4% by weight.

[0140] Based on the above data, it can be seen that the ester hydrogenation catalyst prepared by the method disclosed herein can achieve a high feed conversion rate and fatty alcohol selectivity when applied to the hydrogenation reaction of bio-based fatty acid methyl esters, and can reduce the production of fatty acid fatty esters.

[0141] 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.

[0142] 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.

[0143] 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, the first metal source, the second metal source, the alkali source, the molecular sieve, and water are brought into contact and a first reaction is carried out to obtain the preproduct; S2. 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; The silica-to-alumina ratio of the molecular sieve is below 150; 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. The weight ratio of the copper source to the molecular sieve, calculated as copper element, is 1:(0.04-0.45). Step S1 includes: under stirring conditions, contacting a first slurry containing the molecular sieve, the first metal source, and the second metal source with a first solution containing the alkali source and carrying out the first reaction; or, Step S1 includes: under stirring conditions, contacting a second solution containing the first metal source and the second metal source, a first solution containing the alkali source, and a second slurry containing the molecular sieve to carry out the first reaction; Based on the weight of oxides, relative to 1 part by weight of the copper source, the amount of the aluminum source is 0.25-1.5 parts by weight, the amount of the zinc source is 0.25-2.5 parts by weight, and / or the amount of the magnesium source is 0.25-1.5 parts by weight. In step S2, the heat treatment method includes calcination, and the calcination conditions include a temperature of 350-600℃ and a time of 2-12h.

2. The method according to claim 1, wherein, Step S1 is carried out at a temperature of 20-80℃, the first reaction time is 0.5-12h, and the stirring speed is 100-600rpm.

3. The method according to claim 1, wherein, Step S1 includes: adding the first slurry dropwise to the first solution, or adding the first solution dropwise to the first slurry, under stirring conditions, and then carrying out the first reaction, with the pH value at the endpoint of the addition being 6.0-9.

0.

4. The method according to claim 1, wherein, Step S1 includes: adding the first solution and the second solution to the second slurry under stirring conditions to carry out the first reaction. Step S1 is carried out under conditions where the pH value is 1.5-9.

0.

5. The method according to claim 1, wherein, In the first slurry, the total content of the first metal source and the second metal source is 5-45% by weight.

6. The method according to claim 1, wherein, In the second solution, the total content of the first metal source and the second metal source is 5-45% by weight.

7. The method according to claim 1, wherein, In the first solution, the content of the alkali source is 5-30% by weight.

8. The method according to claim 1, wherein, Step S1 includes: under stirring conditions, contacting the third metal source, the first metal source, the second metal source, the alkali source, the molecular sieve, and the water to carry out the first reaction; 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, Group VIII metal source, and rare earth metal source; Based on the weight of the oxide, the amount of the third metal source is 0.0025-0.25 parts by weight relative to 1 part by weight of the copper source.

9. The method according to claim 8, wherein, The third metal source includes one or more of the following: iron source, vanadium source, manganese source, barium source, calcium source, lanthanum source, rhenium source, and cerium source.

10. 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 alkaline source includes one or more of alkaline carbonates, alkaline bicarbonates, and metal hydroxides; The molecular sieve includes one or more of ZSM-5 molecular sieve, ZSM-48 molecular sieve, MCM-11 molecular sieve, MCM-22 molecular sieve, SBA-15 molecular sieve, β molecular sieve, SAPO molecular sieve and Y molecular sieve.

11. The method according to claim 10, wherein, The alkali source includes one or more of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, potassium bicarbonate, and sodium bicarbonate.

12. The method according to claim 1, wherein, Step S1 further includes: washing the solid product obtained from the first reaction until the pH of the washing solution is 6.5-7.0, and then drying it to obtain the preproduct; The drying conditions include: a time of 10-24 hours and a temperature of 80-150℃.

13. A bio-based fatty acid methyl ester hydrogenation catalyst prepared by any one of claims 1-12.

14. The bio-based fatty acid methyl ester hydrogenation catalyst according to claim 13, wherein, Relative to 1 part by weight of copper oxide, the bio-based fatty acid methyl ester hydrogenation catalyst contains 0.25-1.5 parts by weight of aluminum oxide, 0.01-0.85 parts by weight of silicon oxide, 0.25-2.5 parts by weight of zinc oxide and / or 0.25-1.5 parts by weight of magnesium oxide.

15. The bio-based fatty acid methyl ester hydrogenation catalyst according to claim 13, 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, Group VIII metal oxides, and rare earth metal oxides. The content of the additive is 0.0025-0.25 parts by weight relative to 1 part by weight of copper oxide.

16. The bio-based fatty acid methyl ester hydrogenation catalyst according to claim 15, wherein, The additives include one or more of vanadium oxide, manganese dioxide, barium oxide, calcium oxide, iron oxide, lanthanum oxide, rhenium oxide, and cerium oxide.

17. 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 13-16.

18. The method according to claim 17, 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 0.1-10℃ / 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).

19. The method of claim 17, 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 .

20. The method according to claim 19, wherein, The temperature is 190-240℃.

21. The method according to claim 19, wherein, The pressure is 4.0-8.0 MPa.

22. The method according to claim 19, wherein, The molar ratio of hydrogen ester is (15-40):

1.

23. The method according to claim 19, wherein, The feed mass hourly space velocity (GHSV) of the bio-based fatty acid methyl ester is 0.15-0.50 h⁻¹. -1 .