Alloy catalyst for preparing 1, 2-cyclohexane dibutyl phthalate through dibutyl phthalate hydrogenation and preparation method
阅读说明：本技术 一种用于邻苯二甲酸二丁酯加氢制备1，2-环己烷二甲酸二丁酯的合金催化剂及制备方法 (Alloy catalyst for preparing 1, 2-cyclohexane dibutyl phthalate through dibutyl phthalate hydrogenation and preparation method ) 是由 刘晓涛 卢小松 张世元 于 2021-09-10 设计创作，主要内容包括：本发明提供一种用于邻苯二甲酸二丁酯加氢制备1,2-环己烷二甲酸二丁酯的合金催化剂及制备方法,本发明使用双金属络合物为金属前体,利用多巴胺在自聚过程中强附着作用,将金属前体锚定在分子筛孔道表面,制备了一种PtMo/SBA-15@NC双金属单原子催化剂,该催化剂有良好的结构,具有较好的表面分布状态。用于合成反应中,不仅能显著提高1,2-环己烷二甲酸二丁酯的选择性及转化率,而且能显著改善催化剂活性稳定性和多孔结构。(The invention provides an alloy catalyst for preparing 1, 2-cyclohexane dibutyl phthalate through dibutyl phthalate hydrogenation and a preparation method thereof, the invention uses a bimetallic complex as a metal precursor, and the metal precursor is anchored on the surface of a molecular sieve pore channel by utilizing the strong adhesion effect of dopamine in the self-polymerization process, so that the PtMo/SBA-15@ NC bimetallic monatomic catalyst is prepared, and the catalyst has a good structure and a better surface distribution state. When the catalyst is used in synthesis reaction, the selectivity and the conversion rate of the 1, 2-cyclohexane dibutyl phthalate can be obviously improved, and the activity stability and the porous structure of the catalyst can be obviously improved.)
1. A preparation method of an alloy catalyst for preparing 1, 2-cyclohexane dibutyl phthalate by hydrogenating dibutyl phthalate is characterized by comprising the following steps: the preparation method comprises the following steps:
(1) according to the mass ratio of 1: 1-1: 1.2 weighing a main catalyst precursor platinum chloride and a cocatalyst precursor potassium permanganate, adding the main catalyst precursor platinum chloride and the cocatalyst precursor potassium permanganate into a beaker containing 40mL of deionized water, and stirring for 1h at room temperature;
(2) adding 0.2-0.3 g of dopamine solid particles into the mixed solution in the step (1), and putting the beaker into a water bath kettle to stir for 3 hours at the temperature of 30-40 ℃;
(3) adding 0.5g of SBA-15 into the solution in the step (2), stirring for 30min, adjusting the pH value to 8-9 by ammonia water, and stirring for 12-14 h;
(4) centrifuging the solution in the step (3) to collect solid, washing the solid with deionized water to be neutral, washing the solid with absolute ethyl alcohol, and then carrying out vacuum drying at 65 ℃ overnight;
(5) and (4) putting the solid dried in the step (4) into a tubular furnace, calcining under the atmosphere condition of hydrogen and nitrogen, and cooling to obtain PtMn/[email protected] NC.
2. The alloy catalyst preparation method according to claim 1, characterized in that: the precursor of the main catalyst in the step (1) is nickel nitrate, and the precursor of the cocatalyst is potassium permanganate.
3. The alloy catalyst preparation method according to claim 1, characterized in that: the pH value of the solution obtained in the step (3) is 8-9, and the temperature is 30-40 ℃.
4. The alloy catalyst preparation method according to claim 1, characterized in that: the mass ratio of dopamine to SBA-15 is 2: 5-3: 5.
5. the alloy catalyst preparation method according to claim 1, characterized in that: the calcining conditions in the step (5) are that hydrogen and nitrogen are 3: under the atmosphere of 7, the introducing speed of hydrogen and nitrogen is 35-50 mL/min, the calcining temperature is 700 ℃, the calcining time is 3h, and the heating rate is 5 ℃/min.
6. An alloy catalyst prepared according to the method of any one of claims 1 to 5, wherein: the catalyst takes PtMn/SBA-15 as a core and NC as a shell, and the mass ratio of Pt and Mn is 1: 1-1: 1.2.
Technical Field
The invention belongs to the technical field of catalyst preparation, and particularly relates to an alloy catalyst for preparing 1, 2-cyclohexane dibutyl phthalate through dibutyl phthalate hydrogenation and a preparation method thereof.
Background
Compared with the traditional supported catalyst and the nanoparticle supported catalyst, the single-atom catalyst has two remarkable advantages of maximized atom utilization rate and high reaction selectivity. This is due to the atomically distributed catalytically active centers. Besides the single atom alloy catalyst has high selectivity of single atom, the conversion rate of catalytic reaction of the catalyst is greatly improved under the synergistic action of bimetal.
Dibutyl 1, 2-cyclohexane dicarboxylate (CDADE) is a hydrogenation product of dibutyl phthalate (DBP), and is characterized by quite low element mobility and excellent toxicological characteristics, is particularly suitable for sensitive materials such as PVC, and is a PVC plasticizer with excellent performance for toys, medical instruments and food contact. The Michael and the group thereof prepare Ru catalysts loaded on different carriers, and the yield of the product is about 99.3 percent; tyndager et Al discusses Pt-Ru/Al2O3The hydrogenation effect of the catalyst, the conversion rate and the selectivity are 98.6 percent and 95.3 percent respectively; rojun language investigates Ni/Al2O3The conversion rate and selectivity of the DBP hydrogenation reaction obtained by the catalyst are respectively 99.93 percent and 92.47 percent, the catalyst can reach a high catalyst, but the selectivity is low, and the noble metal ruthenium as an active center is difficult to recover and has high cost. In order to further improve the selectivity of the product 1, 2-dibutyl cyclohexane dicarboxylate, the invention selects the monatomic alloy catalyst, so that the selectivity of the hydrogenation reaction to the product is improved while the reaction conversion rate is ensured.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides an alloy catalyst for preparing 1, 2-cyclohexane dibutyl phthalate by hydrogenating dibutyl phthalate and a preparation method thereof, and the technical scheme of the invention is as follows:
a preparation method of an alloy catalyst for preparing 1, 2-cyclohexane dibutyl phthalate by hydrogenating dibutyl phthalate comprises the following steps:
(1) according to the mass ratio of 1: 1-1: 1.2 weighing a main catalyst precursor platinum chloride and a cocatalyst precursor potassium permanganate, adding the main catalyst precursor platinum chloride and the cocatalyst precursor potassium permanganate into a beaker containing 40mL of deionized water, and stirring for 1h at room temperature;
(2) adding 0.2-0.3 g of dopamine solid particles into the mixed solution in the step (1), and putting the beaker into a water bath kettle to stir for 3 hours at the temperature of 30-40 ℃;
(3) adding 0.5g of SBA-15 into the solution in the step (2), stirring for 30min, adjusting the pH value to 8-9 by ammonia water, and stirring for 12-14 h;
(4) centrifuging the solution in the step (3) to collect solid, washing the solid with deionized water to be neutral, washing the solid with absolute ethyl alcohol, and then carrying out vacuum drying at 65 ℃ overnight;
(5) and (4) putting the solid dried in the step (4) into a tubular furnace, calcining under the atmosphere condition of hydrogen and nitrogen, and cooling to obtain PtMn/[email protected] NC.
Preferably, in the step (1), the precursor of the main catalyst is nickel nitrate, and the precursor of the cocatalyst is potassium permanganate.
Further preferably, the pH value of the solution obtained in the step (3) is 8-9, and the temperature is 30-40 ℃.
Further preferably, the mass ratio of dopamine to SBA-15 is 2: 5-3: 5.
further preferably, the calcination conditions in step (5) are that hydrogen and nitrogen are 3: under the atmosphere of 7, the introducing speed of hydrogen and nitrogen is 35-50 mL/min, the calcining temperature is 700 ℃, the calcining time is 3h, and the heating rate is 5 ℃/min.
Further, the alloy catalyst prepared by the method takes PtMn/SBA-15 as a core, NC as a shell and the ratio of the amount of Pt and Mn substances is 1: 1-1: 1.2.
The core-shell structure alloy catalyst prepared by the method is used for catalyzing dibutyl phthalate to prepare 1, 2-cyclohexane dibutyl phthalate through hydrogenation, and specifically comprises the following steps:
adding dibutyl phthalate and PtMn/[email protected] NC catalyst serving as raw materials into a fixed bed reactor, carrying out hydrogenation reaction at 140-160 ℃ and 2.2-3 MPa for 0.5-1 h, and diluting the raw materials by using a solvent to disperse reaction heat during the reaction. Wherein the mass of the catalyst is 0.2g, the feeding rate is 0.2mL/min, and the mass ratio of the solvent to the raw materials is 1: 0.05-1: 0.1, the solvent is one or a mixture of two of n-decane and decalin.
The preparation method of the core-shell structure monatomic alloy catalyst has the beneficial effects that:
the invention provides core-shell structure metal oxideThe atom utilization rate of the prepared catalyst is greatly improved, platinum chloride and potassium permanganate are used as active center precursors, and Pt is loaded2+Ions and MnO4 -After mutual attraction and calcination, the synergistic effect of the platinum atoms and the manganese atoms is enhanced, and the conversion rate and the selectivity are also obviously enhanced. In addition, the prepared core-shell structure catalyst is green and clean and is easy to recycle.
Detailed Description
Example 1
A preparation method of a core-shell structure monatomic alloy catalyst comprises the following steps:
(1) weighing 0.03g of platinum chloride and 0.02g of potassium permanganate, adding the platinum chloride and the potassium permanganate into a 50mL beaker, dissolving the platinum chloride and the potassium permanganate with 40mL of deionized water at room temperature, and stirring for 1 h;
(2) adding 0.2g of dopamine into the mixed solution in the step (1), putting a beaker into the mixed solution at 35 ℃, and stirring for 3 hours;
(3) drying 5g of SBA-15 in an oven at 120 ℃ overnight, removing water, adding 0.5g of SBA-15 into the solution in the step (2), stirring for 30min, adding 8mL of ammonia water to adjust the pH value of 9, and stirring for 12h at 35 ℃;
(4) centrifuging the solid collected in the step (3), washing the solid to be neutral by deionized water, washing the solid by absolute ethyl alcohol, and carrying out vacuum drying at 65 ℃ overnight;
(5) and (3) putting the dried product in the step (4) into a tube furnace for hydrogen: nitrogen gas 3: calcining at 700 ℃ for 3h at the gas flow rate of 40mL/min under the atmosphere of 7, wherein the heating rate is 5 ℃/min, and cooling to obtain PtMn/[email protected] NC;
adding 0.2g of PtMn/[email protected] NC catalyst into a fixed bed reactor, filling inert quartz sand into a reaction tube, carrying out hydrogenation reaction at 150 ℃ and 2.4MPa for 1h, diluting 5.6g of dibutyl phthalate by 112g of n-decane during the reaction to prepare a raw material solution, wherein the feeding rate is 0.2 mL/min. The conversion by gas chromatography was 99.1% and the selectivity 98.9%.
Example 2
A preparation method of a core-shell structure monatomic alloy catalyst comprises the following steps:
(1) weighing 0.03g of platinum chloride, adding the platinum chloride into a 50mL beaker, dissolving the platinum chloride with 40mL of deionized water at room temperature, and stirring for 1 h;
(2) adding 0.2g of dopamine into the mixed solution in the step (1), putting a beaker into the mixed solution at 35 ℃, and stirring for 3 hours;
(3) drying 5g of SBA-15 in an oven at 120 ℃ overnight, removing water, adding 0.5g of SBA-15 into the solution in the step (2), stirring for 30min, adding 8mL of ammonia water to adjust the pH value of 9, and stirring for 12h at 35 ℃;
(4) centrifuging the solid collected in the step (3), washing the solid to be neutral by deionized water, washing the solid by absolute ethyl alcohol, and carrying out vacuum drying at 65 ℃ overnight;
(5) and (3) putting the dried product in the step (4) into a tube furnace for hydrogen: nitrogen gas 3: calcining at 700 ℃ for 3h at the gas flow rate of 40mL/min under the atmosphere of 7, wherein the heating rate is 5 ℃/min, and cooling to obtain Pt/[email protected] NC;
adding 0.2g of Pt/[email protected] NC catalyst into a fixed bed reactor, filling inert quartz sand into a reaction tube, carrying out hydrogenation reaction at 150 ℃ and 2.4MPa for 1h, diluting 5.6g of dibutyl phthalate by 112g of n-decane during the reaction to prepare a raw material solution, wherein the feeding rate is 0.2 mL/min. The conversion by gas chromatography was 98.2% and the selectivity was 96.9%.
Comparative example 1
A preparation method of a core-shell structure monatomic alloy catalyst comprises the following steps:
(1) weighing 0.03g of platinum chloride and 0.02g of potassium permanganate, adding the platinum chloride and the potassium permanganate into a 50mL beaker, dissolving the platinum chloride and the potassium permanganate with 40mL of deionized water at room temperature, and stirring for 1 h;
(2) adding 0.2g of dopamine into the mixed solution in the step (1), putting a beaker into the mixed solution at 35 ℃, and stirring for 3 hours;
(3) centrifuging the solid collected in the step (2), washing the solid with deionized water to be neutral, washing the solid with absolute ethyl alcohol, and carrying out vacuum drying at 65 ℃ overnight;
(4) and (3) putting the dried product in the step (3) into a tube furnace for hydrogen: nitrogen gas 3: calcining at 700 ℃ for 3h at the gas flow rate of 40mL/min under the atmosphere of 7 at the temperature rise rate of 5 ℃/min, and cooling to obtain PtMn @ NC;
adding 0.2g of PtMn @ NC catalyst into a fixed bed reactor, filling inert quartz sand into a reaction tube, carrying out hydrogenation reaction at 150 ℃ and 2.4MPa for 1h, diluting 5.6g of dibutyl phthalate by 112g of n-decane during the reaction to prepare a raw material solution, wherein the feeding rate is 0.2 mL/min. The conversion by gas chromatography was 93.9% and the selectivity was 94.2%.
Comparative example 2
A preparation method of a core-shell structure monatomic alloy catalyst comprises the following steps:
(1) weighing 0.03g of platinum chloride and 0.02g of potassium permanganate, adding into a beaker, dissolving with 0.5mL of deionized water at room temperature, and carrying out ultrasonic treatment for 10 min;
(2) drying 5g of SBA-15 in an oven at 120 ℃ overnight, removing water, taking 0.5g of SBA-15, dropwise adding SBA-15 into the solution in the step (1), and soaking overnight;
(3) and (3) putting the dried product in the step (2) into a tube furnace for hydrogen: nitrogen gas 3: calcining at 700 ℃ for 3h at the gas flow rate of 40mL/min under the atmosphere of 7 at the temperature rise rate of 5 ℃/min, and cooling to obtain PtMn/SBA-15;
adding 0.2g of PtMn/SBA-15 catalyst into a fixed bed reactor, filling inert quartz sand into a reaction tube, carrying out hydrogenation reaction at 150 ℃ and 2.4MPa for 1h, diluting 5.6g of dibutyl phthalate by 112g of n-decane during the reaction to prepare a raw material solution, wherein the feeding rate is 0.2 mL/min. The conversion by gas chromatography was 86.1% and the selectivity was 92.9%.
Comparative example 3
A preparation method of a core-shell structure monatomic alloy catalyst comprises the following steps:
(1) weighing 0.03g of platinum chloride and 0.02g of potassium permanganate, adding the platinum chloride and the potassium permanganate into a 50mL beaker, dissolving the platinum chloride and the potassium permanganate with 40mL of deionized water at room temperature, and stirring for 1 h;
(2) adding 0.2g of dopamine solid particles into the mixed solution in the step (1), and placing a beaker at 35 ℃ to stir for 3 hours;
(3) drying 5g of SBA-15 in an oven at 120 ℃ overnight, removing water, adding 0.5g of SBA-15 into the solution in the step (2), stirring for 30min, adding 8mL of ammonia water to adjust the pH value of 9, and stirring for 12h at 35 ℃;
(4) centrifuging the solid collected in the step (3), washing the solid to be neutral by deionized water, washing the solid by absolute ethyl alcohol, and carrying out vacuum drying at 65 ℃ overnight;
(5) and (3) putting the dried product in the step (4) into a tube furnace for hydrogen: nitrogen gas 3: calcining at 700 ℃ for 3h at the gas flow rate of 40mL/min under the atmosphere of 7, wherein the heating rate is 5 ℃/min, and cooling to obtain PtMn/[email protected] NC;
adding 0.2g of PtMn/[email protected] NC catalyst into a fixed bed reactor, filling inert quartz sand into a reaction tube, carrying out hydrogenation reaction at 120 ℃ and 2.4MPa for 1h, diluting 5.6g of dibutyl phthalate by 112g of n-decane during the reaction to prepare a raw material solution, wherein the feeding rate is 0.2 mL/min. The conversion by gas chromatography was 93.1% and the selectivity was 96.8%.
Comparative example 4
A preparation method of a core-shell structure monatomic alloy catalyst comprises the following steps:
(1) weighing 0.03g of platinum chloride and 0.02g of potassium permanganate, adding the platinum chloride and the potassium permanganate into a 50mL beaker, dissolving the platinum chloride and the potassium permanganate with 40mL of deionized water at room temperature, and stirring for 1 h;
(2) adding 0.2g of dopamine solid particles into the mixed solution in the step (1), and placing a beaker at 35 ℃ to stir for 3 hours;
(3) drying 5g of SBA-15 in an oven at 120 ℃ overnight, removing water, adding 0.5g of SBA-15 into the solution in the step (2), stirring for 30min, adding 8mL of ammonia water to adjust the pH value of 9, and stirring for 12h at 35 ℃;
(4) centrifuging the solid collected in the step (3), washing the solid to be neutral by deionized water, washing the solid by absolute ethyl alcohol, and carrying out vacuum drying at 65 ℃ overnight;
(5) and (3) putting the dried product in the step (4) into a tube furnace for hydrogen: nitrogen gas 3: calcining at 700 ℃ for 3h at the gas flow rate of 40mL/min under the atmosphere of 7, wherein the heating rate is 5 ℃/min, and cooling to obtain PtMn/[email protected] NC;
adding 0.2g of PtMn/[email protected] NC catalyst into a fixed bed reactor, filling inert quartz sand into a reaction tube, carrying out hydrogenation reaction at 150 ℃ and 3MPa for 1h, diluting 5.6g of dibutyl phthalate by 112g of n-decane during the reaction to prepare a raw material solution, wherein the feeding rate is 0.2 mL/min. The conversion by gas chromatography was 98.9% and the selectivity was 89.6%.
The difference between example 1 and example 2 is that no metal Mn is added in example 2, which shows that the metal Mn has bimetallic synergy between Pt atoms in the catalytic reaction process, and effectively improves the conversion rate of the reaction and the selectivity of the product.
Comparative example 1 compared to example 1 in which no SBA-15 was added during the catalyst preparation, the catalyst conversion and selectivity decreased, with a greater decrease in selectivity, indicating that the addition of SBA-15 serves as part of the selectivity enhancement. Comparative example 2 does not form a nitrogen-doped carbon coating layer as compared to example 1, resulting in a decrease in catalyst conversion and selectivity, indicating that the coordination environment of nitrogen-doped carbon has a synergistic effect on the monatomic alloy, which is beneficial to increase of the conversion rate of the reaction.
The present invention is not limited to the above-described embodiments, and any obvious improvements, substitutions or modifications can be made by those skilled in the art without departing from the spirit of the present invention.