Carriers and methods for making same, catalysts and methods for making and using same, and methods for hydrogenating methyl acrylate

Abstract

The application relates to the field of catalysts, and discloses a carrier and a preparation method thereof, a catalyst and a preparation method and application thereof, and a method for hydrogenation of methyl acrylate. The carrier comprises M-SiO2; the carrier further comprises an additive Y, the Y comprises P elements and / or B elements; and the M comprises one or more of Zr elements, Ti elements and Al elements. The catalyst containing the carrier of the application can be directly used in a product containing methyl acrylate to prepare methyl propionate through a hydrogenation reaction. In a long-term operation process of the hydrogenation process, the carrier in the catalyst can maintain a good morphology and catalyst activity, has good water resistance and heat resistance, and realizes a good catalyst effect.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to a support and its preparation method, a catalyst and its preparation method and application, and a method for hydrogenating methyl acrylate. Background Technology

[0002] Methyl propionate is an important chemical raw material that can be used as a solvent for coatings, nitrocellulose, varnishes, fragrances and flavorings. It can also be used as an intermediate in organic synthesis. Recent studies have also reported a process for synthesizing methyl methacrylate, a monomer for plexiglass, from methyl propionate in the gas phase.

[0003] Methyl acrylate contains one C=C double bond and one C=O double bond. During the hydrogenation reaction of methyl acrylate, the C=C double bond and the C=O double bond may undergo hydrogenation simultaneously, leading to a decrease in the selectivity of methyl propionate. Currently, using silica as a support in the process can improve the selectivity of methyl propionate. However, silica-supported catalysts are only suitable for feed systems with high purity methyl acrylate. When methyl acrylate contains moisture or other components, the catalyst activity will decrease during long-term operation of the hydrogenation process.

[0004] CN111905745A discloses a nickel-based catalyst for the hydrogenation reaction of methyl acrylate. The catalyst has high hydrogenation activity, but the catalyst support is alumina and the methyl acrylate raw material does not contain other raw materials. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing catalysts used in the hydrogenation of methyl acrylate to methyl propionate, which have poor water resistance and stability, and to provide a new catalyst for the hydrogenation of methyl acrylate and its preparation method.

[0006] In existing processes, to better comply with green production processes, formaldehyde and methyl acetate are generally condensed in the presence of methanol to synthesize methyl acrylate. The resulting product containing methyl acrylate contains product water and methyl acrylate, raw materials formaldehyde and methyl acetate, and methanol. When using methyl acrylate to produce methyl propionate by hydrogenation, it is necessary to first separate methyl acrylate from the product containing methyl acrylate, and then perform hydrogenation to obtain the product containing methyl propionate.

[0007] Currently, the process for synthesizing methyl acrylate using the condensation reaction of formaldehyde and methyl acetate has a low yield, typically 5-20%. Separating the methyl acrylate-containing product requires significant energy consumption. To address this energy issue, the inventors directly introduce the methyl acrylate-containing product from the reaction of formaldehyde and methyl acetate into a hydrogenation reaction without separation. In the hydrogenation reaction, to improve the selectivity of formaldehyde propionate, a catalyst with a silica support is generally used as the hydrogenation catalyst for methyl acrylate. However, during long-term operation of the hydrogenation process, the inventors discovered that the silica-supported catalyst exhibits collapse defects. Analysis revealed that other components in the methyl acrylate-containing product, especially water and methanol, affect the activity of the silica.

[0008] Based on the above findings, the first aspect of the present invention provides a support for a methyl acrylate hydrogenation catalyst, the support comprising M-SiO2; wherein the support further contains an auxiliary agent Y, Y comprising P and / or B elements; M comprising one or more of Zr, Ti, and Al elements.

[0009] A second aspect of the present invention provides a method for preparing the support for the above-mentioned methyl acrylate hydrogenation catalyst, the method comprising:

[0010] (1) The silicon source and the Y source are brought into contact for the first time, then the pH is adjusted to 1-6, and then the first drying and first calcination are carried out to obtain SiO2-1;

[0011] (2) A precursor solution containing element M and a precipitant are subjected to a precipitation reaction in a solution containing SiO2-1, followed by filtration, washing, and a second drying to obtain SiO2-2;

[0012] (3) SiO2-2 is shaped and then optionally dried and calcined to obtain the support for the hydrogenation catalyst of methyl acrylate.

[0013] A third aspect of the present invention provides a methyl acrylate hydrogenation catalyst, wherein the catalyst comprises the above-mentioned support for the methyl acrylate hydrogenation catalyst and an active component.

[0014] The fourth aspect of this invention provides a method for preparing the above-mentioned methyl acrylate hydrogenation catalyst, the method comprising:

[0015] S1 performs a heat pretreatment on the carrier;

[0016] S2 is prepared by contacting a solution containing the precursor of the active component with a pretreated support under acidic conditions, followed by filtration and washing to obtain a catalyst semi-finished product, and then azeotropic dehydration and calcination to obtain the catalyst.

[0017] The fifth aspect of the present invention provides the application of the above-mentioned methyl acrylate hydrogenation catalyst in the hydrogenation of methyl acrylate-containing feedstocks.

[0018] The sixth aspect of the present invention provides a method for hydrogenating methyl acrylate, the method comprising: hydrogenating a methyl acrylate-containing raw material in the presence of the above-described catalyst.

[0019] Through the above technical solution, the catalyst containing the support of the present invention can be directly used to prepare a product containing methyl propionate by hydrogenation of a product containing methyl acrylate synthesized by the condensation reaction of formaldehyde and methyl acetate in the presence of methanol. During the long-term operation of the hydrogenation process, the support in the catalyst can maintain a good morphology and catalyst activity, and has good water resistance and heat resistance, thus achieving a good catalyst effect. Detailed Implementation

[0020] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0021] The first aspect of the present invention provides a support for a hydrogenation catalyst of methyl acrylate, the support comprising M-SiO2; wherein the support further contains an auxiliary agent Y, Y comprising P and / or B elements; M comprising one or more of Zr, Ti, and Al elements.

[0022] In this invention, M-SiO2 refers to the complete formation of M-OH hydroxyl structures on SiO2; M / SiO2 refers to the presence of effective component M on the SiO2 support.

[0023] In this invention, the catalyst prepared using the support of this invention can be directly used in the hydrogenation reaction of products containing methyl acrylate to prepare methyl propionate. During the long-term operation of the hydrogenation process, the support in the catalyst can maintain a good morphology and catalyst activity, and has good water resistance and heat resistance, thus achieving a good catalytic effect.

[0024] According to the present invention, the content of Y in the support is not particularly required as long as the purpose of the present invention can be achieved. In some preferred embodiments, the content of Y is 0.01-1 wt% (e.g., 0.01 wt%, 0.02 wt%, 0.05 wt%, 0.1 wt%, 0.3 wt%, 0.4 wt%, 0.6 wt%, 0.8 wt%, or 1 wt%) based on the total mass of M-SiO2, preferably 0.02-0.8 wt%. Using the aforementioned embodiments can further increase the hydrothermal stability of the support, while simultaneously increasing the reactivity of the catalyst containing the support of the present invention.

[0025] According to the present invention, in some preferred embodiments, the content of M, based on the total mass of M-SiO2, is 0.01-5 wt% (e.g., 0.01 wt%, 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, or 5 wt%), preferably 0.1-4 wt%. Using the aforementioned embodiments, the water resistance and heat resistance of the carrier can be further increased.

[0026] According to the present invention, in some preferred embodiments, M includes at least two of Zr, Ti, and Al. Using the foregoing embodiments, the support of the present invention exhibits better stability in the hydrogenation reaction of methyl acrylate.

[0027] According to the present invention, it is understood that M includes at least two of the elements Zr, Ti, and Al, and any combination of two can be selected, with no particular limitation on their proportion. In some more preferred embodiments, when M is at least two different elements, the mass content of any one element is not less than 20%. By adopting the aforementioned embodiments, the stability of the support in the hydrogenation reaction of methyl acrylate can be further increased, and the catalyst containing the support of the aforementioned embodiments has better catalytic activity.

[0028] A second aspect of the present invention provides a method for preparing the support for the above-mentioned methyl acrylate hydrogenation catalyst, the method comprising:

[0029] (1) The silicon source and the Y source are brought into contact for the first time, then the pH is adjusted to 1-6, and then the first drying and first calcination are carried out to obtain SiO2-1;

[0030] (2) A precursor solution containing element M and a precipitant are subjected to a precipitation reaction in a solution containing SiO2-1, followed by filtration, washing, and a second drying to obtain SiO2-2;

[0031] (3) SiO2-2 is shaped and then optionally dried and calcined to obtain the support for the hydrogenation catalyst of methyl acrylate.

[0032] According to the present invention, it is understood that the Y source is a phosphorus source and / or a boron source; the M element includes one or more of the elements Zr, Ti, and Al.

[0033] In this invention, there is no particular limitation on the specific type of phosphorus source. Any compound that can provide phosphoric acid (P) is acceptable, including but not limited to phosphoric acid, ammonium phosphate, and ammonium dihydrogen phosphate.

[0034] According to the present invention, it is understood that "precursor solution containing element M" refers to a precursor solution containing element M obtained by mixing at least one of the precursors of Zr, Ti, and Al with a solvent. The concentration of the solution is not particularly limited, as long as it can completely dissolve the precursor of element M. The type of solvent in the precursor solution containing element M is not particularly limited, as long as it can dissolve the precursor of element M. In the present invention, the solvent in the precursor solution containing element M is water. The precursor of element M can be selected from nitrates, chlorides, etc. of element M.

[0035] In this invention, there is no particular limitation on the specific type of boron source; any compound that can provide element B is acceptable, including but not limited to boric acid and ammonium hydrogen borate.

[0036] According to the present invention, the pH adjustment in step (1) can be made using a pH adjuster, including but not limited to nitric acid.

[0037] According to some preferred embodiments of the present invention, in step (2), the precursor solution containing element M and the precipitant are fed in parallel into a solution containing SiO2-1 for precipitation reaction, followed by filtration and washing to obtain SiO2-2. Using the aforementioned embodiments can better increase the hydrothermal stability of the support.

[0038] In this invention, the solution containing SiO2-1 refers to the solution obtained by mixing SiO2-1 with a solvent. The amount of solvent is not particularly limited, as long as the amount of solvent can cover the SiO2-1. The type of solvent is not particularly limited, including but not limited to water.

[0039] According to some preferred embodiments of the present invention, the precipitant is selected from at least one of potassium carbonate solution, sodium bicarbonate solution, potassium bicarbonate solution, sodium hydroxide solution, potassium hydroxide solution, ammonium bicarbonate solution, urea solution and ammonia water, preferably ammonia water.

[0040] According to some preferred embodiments of the present invention, in step (2), the conditions of the precipitation reaction include controlling the pH at the precipitation endpoint to be 6-8.

[0041] According to the present invention, it is understood that there is no special limitation on the flow rate when the precursor solution containing element M and the precipitant flow in parallel, as long as the pH of the precipitation endpoint is 6-8, that is, the pH of the overall mixture when the precursor solution containing element M and the precipitant are mixed with the SiO2-1 solution is 6-8. The present invention will not elaborate further on this.

[0042] According to some preferred embodiments of the present invention, in step (2), the conditions for the precipitation reaction include: precipitation temperature of 50-90°C and precipitation time of 3-6 h.

[0043] In this invention, the precipitation time is calculated from the time the precursor solution containing element M and the precipitant are completely added.

[0044] In this invention, the filtration and washing in step (2) is a conventional technique in the art. For example, the filter cake obtained after filtration is washed with water until neutral to obtain SiO2-2.

[0045] In this invention, in step (1), in order to better mix the silicon source and the Y source, the first contact is a dynamic contact, that is, when contacting, operations such as stirring can be used to increase the uniformity of the mixing.

[0046] In this invention, the first drying in step (1) can be carried out by conventional drying methods in the art. Since the silica sol contains a lot of water, the first drying is carried out by evaporation. For example, when carrying out the first drying, the water is first evaporated at 80-90°C and then dried at 100-120°C for 2-10 hours.

[0047] According to the present invention, in some embodiments, the conditions for the first calcination in step (1) include: a calcination temperature of 300-700°C and a calcination time of 2-15 hours.

[0048] In this invention, the second drying method in step (2) is not particularly limited, and any drying method in the art is acceptable, such as drying at 100-130°C for 5-15 hours.

[0049] According to the present invention, there are no special restrictions on the shape formed in step (3), and it can be selected as needed. In order to better reduce the packing density when the carrier is used, a clover shape or a five-leaf clover shape can be selected. The clover shape is used as an example to illustrate the advantages of the present invention, but the present invention is not limited thereto.

[0050] According to the present invention, in some embodiments, the conditions for the third drying in step (3) include: a drying temperature of 50-150°C and a drying time of 2-30 hours.

[0051] According to the present invention, in some embodiments, the conditions for the third calcination in step (3) include: calcination temperature of 300-700℃; and calcination time of 2-10h.

[0052] According to some embodiments of the present invention, the silicon source includes at least one of tetraethyl orthosilicate, methyltrimethoxysilane solution, and silica sol.

[0053] According to some preferred embodiments of the present invention, the silicon source is silica sol.

[0054] According to the present invention, it is understood that the silica sol is a sol solution obtained by dispersing silica in water. As long as the purpose of the present invention can be achieved, the content of silica in the silica sol is not particularly limited. In some embodiments, the content of silica in the silica sol is 20-40 wt%.

[0055] According to some preferred embodiments of the present invention, the surface area of ​​silica in the silica sol is 100-400 m². 2 / g.

[0056] According to the present invention, in step (3), the molding method can be selected as needed. In some embodiments, in step (3), SiO2-2 is mixed with a molding agent for molding.

[0057] According to the present invention, in some embodiments, in step (3), the amount of the molding agent is 0.01-10 wt% of the mass of SiO2-2.

[0058] In this invention, the type of forming agent is not specifically limited, and any material that helps SiO2-2 to form is applicable to the system of this invention, including but not limited to guar gum powder.

[0059] A third aspect of the present invention provides a methyl acrylate hydrogenation catalyst, wherein the catalyst comprises the above-mentioned support for the methyl acrylate hydrogenation catalyst and an active component.

[0060] According to the present invention, the content of the active component in the catalyst can be selected as needed. In some embodiments, the content of the active component is 0.01-1 wt% based on the total mass of the catalyst.

[0061] According to the present invention, there are no special limitations on the type of active component as long as the purpose of the present invention is achieved. In some preferred embodiments, the active component includes Pd.

[0062] In this invention, the catalyst containing the carrier of this invention has better water resistance and stability in the hydrogenation reaction of methyl acrylate.

[0063] The fourth aspect of this invention provides a method for preparing the above-mentioned methyl acrylate hydrogenation catalyst, the method comprising:

[0064] S1 performs a heat pretreatment on the carrier;

[0065] S2 is prepared by contacting a solution containing the precursor of the active component with a pretreated support under acidic conditions, followed by filtration and washing to obtain a catalyst semi-finished product, and then azeotropic dehydration and calcination to obtain the catalyst.

[0066] According to the present invention, in some embodiments, the active component precursor includes a Pd source.

[0067] In this invention, the catalyst prepared not only has good catalytic activity in the hydrogenation of methyl acrylate, but also maintains good activity during long-term operation of the hydrogenation reaction.

[0068] According to the present invention, in some embodiments, the pretreatment conditions in step S1 include: a temperature of 100-180°C and a time of 2-10 hours.

[0069] In this invention, there is no limitation on the concentration of the solution containing the active component precursor, as long as a homogeneous solution of the active component precursor can be formed.

[0070] In this invention, there are no special restrictions on the specific type of active component precursor, as long as the active component can be provided, such as Pd source being PdCl2; there are also no special restrictions on the solvent in the solution containing the active component precursor, including but not limited to water.

[0071] According to the present invention, in step S2, as long as the pH of the solution containing the active component precursor can be adjusted to 2-6, there is no particular limitation on the specific type of pH adjuster. In some embodiments, the pH adjuster is selected from one or more of acetic acid, citric acid, phosphoric acid and hydrochloric acid, preferably acetic acid.

[0072] According to the present invention, the contact method in step S2 is not particularly limited as long as the purpose of the present invention can be achieved. In some preferred embodiments, the contact method in step S2 is excessive impregnation.

[0073] According to the present invention, in step S2, filtration and washing refers to repeatedly performing steps such as filtration and washing to wash the filter cake obtained by filtration until it is neutral to obtain a catalyst semi-finished product.

[0074] According to some preferred embodiments of the present invention, in step S2, the azeotropic dehydration method includes: mixing the catalyst semi-finished product with toluene for azeotropic dehydration, followed by filtration and nitrogen blowing to remove the solvent. Using the aforementioned embodiments, the dispersibility of the active component in the catalyst can be better increased, while further increasing the catalyst's activity and thermal stability.

[0075] According to some preferred embodiments of the present invention, the conditions for azeotropic dehydration include: a dehydration temperature of 80-200°C and a dehydration time of 3-8 hours.

[0076] According to some preferred embodiments of the present invention, in step S2, the calcination conditions include: a calcination temperature of 500-900°C and a calcination time of 2-10 hours.

[0077] The fifth aspect of the present invention provides the application of the above-mentioned methyl acrylate hydrogenation catalyst in the hydrogenation of methyl acrylate-containing feedstocks.

[0078] According to some preferred embodiments of the present invention, the methyl acrylate-containing raw material contains: 0.1-3 wt% free water, 1-10 wt% formaldehyde, 5-20 wt% methyl acrylate, 4-40 wt% methanol, and the balance being methyl acetate.

[0079] The catalyst of this invention can be used in methyl acrylate feedstocks containing water and other components such as formaldehyde, and the catalyst maintains better stability in the presence of water and other components.

[0080] The sixth aspect of the present invention provides a method for hydrogenating methyl acrylate, the method comprising: hydrogenating a methyl acrylate-containing raw material in the presence of the above-mentioned catalyst.

[0081] According to some preferred embodiments of the present invention, the methyl acrylate-containing raw material contains: 0.1-3 wt% free water, 1-10 wt% formaldehyde, 5-20 wt% methyl acrylate, 4-40 wt% methanol, and the balance being methyl acetate.

[0082] According to some preferred embodiments of the present invention, the conditions for the hydrogenation reaction include: a reaction temperature of 100-200°C and a pressure of 0.1-1 MPa.

[0083] According to some preferred embodiments of the present invention, the conditions for the hydrogenation reaction include: a hydrogen flow rate of 10-300 ml / min and a feed flow rate of 0.01-2 ml / min.

[0084] The present invention will be described in detail below through embodiments.

[0085] Example 1

[0086] Preparation of methyl acrylate hydrogenation catalyst:

[0087] Weigh out silica sol (silica content 30%, surface area 200m²). 2 900g of silicon dioxide (based on elemental P content, the amount used is 0.6wt% of silicon dioxide) was added and mixed. Nitric acid was added to adjust the pH to 4. The mixture was then stirred continuously at a drying temperature of 80℃ to evaporate the water. After drying at a drying temperature of 110℃ for 6 hours, it was calcined (calcination temperature of 600℃ for 4 hours) to obtain SiO2-1.

[0088] ZrO(NO3)2 (based on elemental Zr, with Zr accounting for 2 wt% of SiO2-1) and Ti(NO3)4 (based on elemental Ti, with Ti accounting for 1.2 wt% of SiO2-1) were used as precursors, and water was used to prepare a precursor solution. SiO2-1 was mixed with water (the amount of water covered the SiO2-1) to obtain a solution containing SiO2-1. The precursor solution and ammonia water as precipitant were flowed in parallel into a reactor containing the solution containing SiO2-1 to carry out a precipitation reaction. The pH value at the endpoint was controlled to be 7.5. The precipitation reaction was carried out at 60℃ for 5 hours. After that, the mixture was filtered, washed, and finally dried at 110℃ for 8 hours to obtain SiO2-2.

[0089] Weigh 150g of SiO2-2 and 3g of guar gum powder, mix them and shape them into a clover shape, then dry them at 80℃ for 10h, and then calcine them at 600℃ for 6h to obtain the support (Zr-Ti-SiO2).

[0090] The support was treated at 150℃ for 6 hours to obtain a pretreated support; a PdCl2 impregnation solution was prepared using deionized water, and acetic acid was added to adjust the pH to 4.5. The impregnation solution was then mixed with the pretreated support for over-impregnation for 4 hours. The mixture was then filtered and washed to obtain a catalyst semi-finished product.

[0091] The catalyst semi-finished product was mixed with toluene and subjected to azeotropic dehydration, then filtered, and then the solvent was removed by blowing under a nitrogen atmosphere. Finally, it was calcined at 600℃ for 5 hours to obtain the methyl acrylate hydrogenation catalyst (Pd content of 0.5wt%).

[0092] Hydrogenation of methyl acrylate:

[0093] 10 ml of methyl acrylate hydrogenation catalyst was loaded into a fixed-bed reactor (16 mm inner diameter, 1500 mm length). The raw material contained 2 wt% free water, 5 wt% formaldehyde, 15 wt% methyl acrylate, 25 wt% methanol, and the balance methyl acetate. The hydrogenation reaction was carried out under the following conditions: reaction temperature 120℃, hydrogen as carrier gas, flow rate 150 ml / min, and raw material flow rate 0.1 ml / min.

[0094] On day 1 of the reaction, the conversion rate of methyl acrylate was 99% and the selectivity of methyl propionate was 99%; after 25 days, the conversion rate of methyl acrylate was 99% and the selectivity of methyl propionate was 99%.

[0095] Example 2

[0096] Preparation of methyl acrylate hydrogenation catalyst:

[0097] Weigh out silica sol (silica content 30%, surface area 200m²). 2 900g of silicon dioxide (calculated as elemental B, amount is 0.5wt% of silicon dioxide) was added and mixed. Nitric acid was added to adjust the pH to 4. The mixture was then stirred continuously at a drying temperature of 80℃ to evaporate the water. After drying at a drying temperature of 110℃ for 6 hours, it was calcined (calcination temperature of 600℃, calcination time of 4 hours) to obtain SiO2-1.

[0098] Al(NO3)3 (based on elemental Al, with Al accounting for 1.6 wt% of SiO2-1) and Ti(NO3)4 (based on elemental Ti, with Ti accounting for 1.4 wt% of SiO2-1) were used as precursors, and water was used to prepare a precursor solution. SiO2-1 was mixed with water (the amount of water covered the SiO2-1) to obtain a solution containing SiO2-1. The precursor solution and ammonia water as precipitant were flowed in parallel into a reactor containing the solution containing SiO2-1 to carry out a precipitation reaction. The pH value at the endpoint was controlled to be 8. The precipitation reaction was carried out at 70°C for 4 hours. After that, the solution was filtered, washed, and finally dried at 110°C for 8 hours to obtain SiO2-2.

[0099] Weigh 150g of SiO2-2 and 3g of guar gum powder, mix them and shape them into a clover shape, then dry them at 80℃ for 10h, and then calcine them at 700℃ for 5h to obtain the support (Al-Ti-SiO2).

[0100] The support was treated at 170℃ for 4 hours to obtain the pretreated support; PdCl2 impregnation solution was prepared using deionized water, acetic acid was added to adjust the pH to 4, and then the impregnation solution was mixed with the pretreated support for over-impregnation for 5 hours. After filtration and washing, the catalyst semi-finished product was obtained.

[0101] The catalyst semi-finished product was mixed with toluene and subjected to azeotropic dehydration, then filtered, and then the solvent was removed by blowing under a nitrogen atmosphere. Finally, it was calcined at 550℃ for 65h to obtain the methyl acrylate hydrogenation catalyst (Pd content of 0.5wt%).

[0102] Hydrogenation of methyl acrylate:

[0103] 10 ml of methyl acrylate hydrogenation catalyst was loaded into a fixed-bed reactor (16 mm inner diameter, 1500 mm long). The raw material (containing 2 wt% free water, 5 wt% formaldehyde, 15 wt% methyl acrylate, 25 wt% methanol, and the balance being methyl acetate) was subjected to hydrogenation reaction. The hydrogenation reaction conditions were: reaction temperature 120℃, hydrogen as carrier gas, flow rate 150 ml / min, and raw material flow rate 0.1 ml / min.

[0104] On day 1 of the reaction, the conversion rate of methyl acrylate was 99% and the selectivity of methyl propionate was 99%; after 25 days, the conversion rate of methyl acrylate was 99% and the selectivity of methyl propionate was 99%.

[0105] Example 3

[0106] Preparation of methyl acrylate hydrogenation catalyst:

[0107] Weigh out silica sol (silica content 30%, surface area 200m²). 2 900g of silicon dioxide (based on elemental P content, the amount used is 0.6wt% of silicon dioxide) was added and mixed. Nitric acid was added to adjust the pH to 4. The mixture was then stirred continuously at a drying temperature of 80℃ to evaporate the water. After drying at a drying temperature of 110℃ for 6 hours, it was calcined (calcination temperature of 650℃ for 4 hours) to obtain SiO2-1.

[0108] ZrO(NO3)2 (based on elemental Zr, with Zr content equal to 1.2 wt% of SiO2-1) and Al(NO3)3 (based on elemental Al, with Al content equal to 1 wt% of SiO2-1) were used as precursors and prepared into a precursor solution using water. SiO2-1 was mixed with water (the amount of water completely covered the SiO2-1) to obtain a solution containing SiO2-1. The precursor solution and ammonia water as precipitant were flowed in parallel into a reactor containing the SiO2-1 solution for precipitation reaction. The pH value at the endpoint was controlled to be 8. The precipitation reaction was carried out at 70°C for 4 hours. After filtration, washing, and finally drying at 110°C for 10 hours, SiO2-2 was obtained.

[0109] Weigh 150g of SiO2-2 and 3g of guar gum powder, mix them and shape them into a clover shape. Then dry them at 80℃ for 10h and calcine them at 600℃ for 6h to obtain the support (Zr-Al-SiO2).

[0110] The support was treated at 150℃ for 6 hours to obtain a pretreated support; a PdCl2 impregnation solution was prepared using deionized water, acetic acid was added to adjust the pH to 5, and then the impregnation solution was mixed with the pretreated support for over-impregnation for 4 hours. After filtration and washing, a catalyst semi-finished product was obtained.

[0111] The catalyst semi-finished product was mixed with toluene and subjected to azeotropic dehydration, then filtered, and then the solvent was removed by blowing under a nitrogen atmosphere. Finally, it was calcined at 650℃ for 5 hours to obtain the methyl acrylate hydrogenation catalyst (Pd content of 0.5wt%).

[0112] Hydrogenation of methyl acrylate:

[0113] 10 ml of methyl acrylate hydrogenation catalyst was loaded into a fixed-bed reactor (16 mm inner diameter, 1500 mm length). The raw material contained 2 wt% free water, 5 wt% formaldehyde, 15 wt% methyl acrylate, 25 wt% methanol, and the balance methyl acetate. The hydrogenation reaction was carried out under the following conditions: reaction temperature 120℃, hydrogen as carrier gas, flow rate 150 ml / min, and raw material flow rate 0.1 ml / min.

[0114] On day 1 of the reaction, the conversion rate of methyl acrylate was 99% and the selectivity of methyl propionate was 99%; after 25 days, the conversion rate of methyl acrylate was 99% and the selectivity of methyl propionate was 99%.

[0115] Example 4

[0116] The method according to Example 1 differs in that:

[0117] Preparation of precursor solution: ZrO(NO3)2 (based on Zr element, the amount of Zr is 3.2 wt% of SiO2-1) was used as the precursor and water was used to prepare the precursor solution. The final carrier (Zr-SiO2) was the same as in Example 1.

[0118] The method for hydrogenating methyl acrylate is the same as in Example 1;

[0119] On day 1 of the reaction, the conversion rate of methyl acrylate was 99% and the selectivity of methyl propionate was 99%; after 25 days, the conversion rate of methyl acrylate was 96.8% and the selectivity of methyl propionate was 98%.

[0120] Example 5

[0121] The method according to Example 1 differs in that:

[0122] Preparation of precursor solution: Ti(NO3)4 (based on Ti element, the amount of Ti is 3.2t% of SiO2-1) was used as the precursor, and water was used to prepare the precursor solution. The final carrier (Ti-SiO2) was the same as in Example 1.

[0123] The method for hydrogenating methyl acrylate is the same as in Example 1;

[0124] On day 1 of the reaction, the conversion rate of methyl acrylate was 99% and the selectivity of methyl propionate was 99%; after 20 days, the conversion rate of methyl acrylate was 96.9% and the selectivity of methyl propionate was 98%.

[0125] Example 6

[0126] The method according to Example 1 differs in that:

[0127] The catalyst semi-finished product was not subjected to azeotropic dehydration, but was directly calcined at 600°C for 5 hours to finally obtain the methyl acrylate hydrogenation catalyst (Pd content 0.5 wt%); the rest was the same as in Example 1.

[0128] The method for hydrogenating methyl acrylate is the same as in Example 1;

[0129] On day 1 of the reaction, the conversion rate of methyl acrylate was 98% and the selectivity of methyl propionate was 99%; after 20 days, the conversion rate of methyl acrylate was 97.8% and the selectivity of methyl propionate was 99%.

[0130] Example 7

[0131] The method according to Example 1 differs in that:

[0132] The support was treated at 150°C for 6 hours to obtain a pretreated support; a PdCl2 impregnation solution was prepared using deionized water, and then the impregnation solution was mixed with the pretreated support for over-impregnation for 4 hours. After filtration and washing, a catalyst semi-finished product was obtained; the rest was the same as in Example 1.

[0133] The method for hydrogenating methyl acrylate is the same as in Example 1;

[0134] On day 1 of the reaction, the conversion rate of methyl acrylate was 99% and the selectivity of methyl propionate was 99%; after 20 days, the conversion rate of methyl acrylate was 98.4% and the selectivity of methyl propionate was 98.3%.

[0135] Comparative Example 1

[0136] The method according to Example 1 differs in that:

[0137] Weigh 900g of silica sol, add nitric acid to adjust the pH to 4, and then stir continuously at a drying temperature of 80℃ to evaporate the water. Then dry at a drying temperature of 110℃ for 6 hours, and then calcine (calcine temperature of 650℃, calcine time of 4 hours) to obtain SiO2-1; the rest is the same as in Example 1.

[0138] The method for hydrogenating methyl acrylate is the same as in Example 1;

[0139] On day 1 of the reaction, the conversion rate of methyl acrylate was 99% and the selectivity of methyl propionate was 99%; after 20 days, the conversion rate of methyl acrylate was 95.7% and the selectivity of methyl propionate was 99%.

[0140] Comparative Example 2

[0141] Preparation of methyl acrylate hydrogenation catalyst:

[0142] Weigh out silica sol (silica content 30%, surface area 200m²). 2 900g of silicon dioxide (based on elemental P content, the amount used is 0.6wt% of silicon dioxide) was added and mixed. Nitric acid was added to adjust the pH to 4. The mixture was then stirred continuously at a drying temperature of 80℃ to evaporate the water. After drying at a drying temperature of 110℃ for 6 hours, it was calcined (calcination temperature of 600℃ for 4 hours) to obtain SiO2-1.

[0143] ZrO(NO3)2 (based on Zr element, the amount of Zr is 2 wt% of SiO2-1) and Ti(NO3)4 (based on Ti element, the amount of Ti is 1.2 wt% of SiO2-1) were used as precursors. They were prepared into a precursor solution with water and loaded onto SiO2-1 by an equal volume impregnation method. After impregnation, the solution was filtered, washed, and finally dried at 110℃ for 10 h to obtain SiO2-2.

[0144] Weigh 150g of SiO2-2 and 3g of guar gum powder, mix them and shape them into a clover shape. Then dry them at 80℃ for 10h and calcine them at 600℃ for 6h to obtain the support (Zr-Ti / SiO2).

[0145] The support was treated at 150℃ for 6 hours to obtain a pretreated support; a PdCl2 impregnation solution was prepared using deionized water, acetic acid was added to adjust the pH to 4, and then the impregnation solution was mixed with the pretreated support for over-impregnation for 4 hours. After filtration and washing, a catalyst semi-finished product was obtained.

[0146] The catalyst semi-finished product was mixed with toluene and subjected to azeotropic dehydration, then filtered, and then the solvent was removed by blowing under a nitrogen atmosphere. Finally, it was calcined at 600℃ for 5 hours to obtain the methyl acrylate hydrogenation catalyst (Pd content of 0.5wt%).

[0147] The method for hydrogenating methyl acrylate is the same as in Example 1;

[0148] On day 1 of the reaction, the conversion rate of methyl acrylate was 99% and the selectivity of methyl propionate was 99%; after 20 days, the conversion rate of methyl acrylate was 96.2% and the selectivity of methyl propionate was 98%.

[0149] Comparative Example 3

[0150] Preparation of methyl acrylate hydrogenation catalyst:

[0151] Weigh out silica sol (silica content 30%, surface area 200m²). 2 900g of silicon dioxide (based on elemental P content, the amount used is 0.6wt% of silicon dioxide) was added and mixed. Nitric acid was added to adjust the pH to 4. The mixture was then stirred continuously at a drying temperature of 80℃ to evaporate the water. After drying at a drying temperature of 110℃ for 6 hours, it was calcined (calcination temperature of 600℃ for 4 hours) to obtain SiO2-1.

[0152] Weigh 150g of SiO2-1 and 3g of guar gum powder, mix them and shape them into a clover shape, then dry them at 80℃ for 10h, and then calcine them at 600℃ for 6h to obtain the carrier (SiO2).

[0153] The support was treated at 150℃ for 6 hours to obtain a pretreated support; a PdCl2 impregnation solution was prepared using deionized water, acetic acid was added to adjust the pH to 4, and then the impregnation solution was mixed with the pretreated support for over-impregnation for 4 hours. After filtration and washing, a catalyst semi-finished product was obtained.

[0154] The catalyst semi-finished product was mixed with toluene and subjected to azeotropic dehydration, then filtered, and then the solvent was removed by blowing under a nitrogen atmosphere. Finally, it was calcined at 600℃ for 5 hours to obtain the methyl acrylate hydrogenation catalyst (Pd content of 0.5wt%).

[0155] The method for hydrogenating methyl acrylate is the same as in Example 1;

[0156] On day 1 of the reaction, the conversion rate of methyl acrylate was 99% and the selectivity of methyl propionate was 99%; after 20 days, the conversion rate of methyl acrylate was 99% and the selectivity of methyl propionate was 99%.

[0157] On day 1 of the reaction, the conversion rate of methyl acrylate was 99% and the selectivity of methyl propionate was 99%; after 20 days, the conversion rate of methyl acrylate was 95% and the selectivity of methyl propionate was 98%.

[0158] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a support for a methyl acrylate hydrogenation catalyst, characterized in that, The preparation method includes: (1) The silicon source and the Y source are brought into contact for the first time, then the pH is adjusted to 1-6, and then the first drying and first calcination are carried out to obtain SiO2-1; (2) The precursor solution containing element M and the precipitant are fed into a solution containing SiO2-1 in parallel to carry out the precipitation reaction. After filtration, washing and second drying, SiO2-2 is obtained. (3) The SiO2-2 is shaped, then dried and calcined to obtain the support for the hydrogenation catalyst of methyl acrylate; The support comprises M-SiO2; wherein the support further contains an auxiliary agent Y, which includes P and / or B elements; M includes at least two of Zr, Ti, and Al elements; The content of Y, based on the total mass of M-SiO2, is 0.01-1 wt%; The content of M is 0.01-5 wt% based on the total mass of M-SiO2.

2. The preparation method according to claim 1, wherein, The content of Y, based on the total mass of M-SiO2, is 0.02-0.8 wt%; and / or The content of M is 0.1-4 wt% based on the total mass of M-SiO2.

3. The preparation method according to claim 1, wherein, The precipitant is selected from at least one of potassium carbonate solution, sodium bicarbonate solution, potassium bicarbonate solution, sodium hydroxide solution, potassium hydroxide solution, ammonium bicarbonate solution, urea solution, and ammonia water; And / or, In step (1), the conditions for the first roasting include: a roasting temperature of 300-700℃; a roasting time of 2-15h; and / or In step (3), the conditions for the third calcination include: a calcination temperature of 300-700℃; a calcination time of 2-20h; and / or The silicon source includes at least one of tetraethyl orthosilicate, methyltrimethoxysilane solution, and silica sol; and / or In step (3), SiO2-2 is mixed with a molding agent to form a mold.

4. The preparation method according to claim 3, wherein, The precipitant is ammonia; and / or The conditions for the precipitation reaction include: controlling the pH at the precipitation endpoint to be 6-8; and / or The precipitation temperature is 50-90℃; the precipitation time is 3-6 hours. and / or The silicon source is silica sol; and / or The amount of the molding agent is 0.01-10 wt% of the mass of SiO2-2.

5. The preparation method according to claim 4, wherein, The specific surface area of ​​silicon dioxide in the silica sol is 100-400 m². 2 / g.

6. A methyl acrylate hydrogenation catalyst, characterized in that, The catalyst comprises an active component and a support for the hydrogenation catalyst of methyl acrylate prepared by any one of claims 1-5, wherein the active component comprises Pd.

7. The methyl acrylate hydrogenation catalyst according to claim 6, wherein, The content of active components is 0.01-1 wt% based on the total mass of the catalyst.

8. A method for preparing the methyl acrylate hydrogenation catalyst according to claim 6 or 7, characterized in that, The preparation method includes: S1 The carrier is pretreated by heating; S2 Under acidic conditions, a solution containing the precursor of the active component is contacted with a pretreated support, followed by filtration and washing to obtain a catalyst semi-finished product, which is then subjected to azeotropic dehydration and calcination to obtain the catalyst. The active component precursor includes a Pd source.

9. The preparation method according to claim 8, wherein, In step S1, the pretreatment conditions include: a temperature of 100-180℃; a time of 2-10 hours; and / or In step S2, a pH adjuster is added to the solution containing the active component precursor to adjust the pH to 2-6, and then it is contacted with the pretreated carrier; and / or In step S2, the contact method is excessive impregnation; and / or In step S2, the calcination conditions include: a calcination temperature of 500-900℃ and a calcination time of 2-10 hours; and / or In step S2, the azeotropic dehydration method includes: mixing the catalyst semi-finished product with toluene for azeotropic dehydration, followed by filtration and nitrogen blowing to remove the solvent.

10. The preparation method according to claim 9, wherein, The pH adjuster is selected from one or more of acetic acid, citric acid, nitric acid, and phosphoric acid; and / or The conditions for azeotropic dehydration include: a dehydration temperature of 80-200℃ and a dehydration time of 3-8 hours.

11. The preparation method according to claim 10, wherein, The pH adjuster is acetic acid.

12. The application of the methyl acrylate hydrogenation catalyst according to claim 6 or 7 in the hydrogenation of methyl acrylate-containing feedstocks.

13. The application according to claim 12, wherein, The raw material containing methyl acrylate contains: 0.1-3 wt% free water, 1-10 wt% formaldehyde, 5-20 wt% methyl acrylate, 4-40 wt% methanol, and the balance is methyl acetate.

14. A method for hydrogenating methyl acrylate, characterized in that, The method includes: hydrogenating a methyl acrylate-containing feedstock in the presence of the catalyst described in claim 6 or 7.

15. The method according to claim 14, wherein, The raw material containing methyl acrylate contains: 0.1-3 wt% free water, 1-10 wt% formaldehyde, 5-20 wt% methyl acrylate, 4-40% methanol, and the balance is methyl acetate.

16. The method of claim 14, wherein, The conditions for the hydrogenation reaction include: The reaction temperature is 100-200℃, and the reaction pressure is 0.1-1MPa; and / or The flow rate of hydrogen is 10-300 ml / min; the flow rate of the raw material is 0.01-2 ml / min.

17. The method according to claim 16, wherein, The conditions for the hydrogenation reaction include a reaction temperature of 110-150℃.