A catalyst composition and use thereof

Abstract

This invention discloses a catalyst composition and its application, comprising a supported metal salt catalyst and a palladium-on-carbon catalyst, wherein the loading of the metal salt is 10%-30%, and the metal salt includes zinc salt and / or cobalt salt; by mass, the supported metal salt catalyst comprises 90-95 parts, and the palladium-on-carbon catalyst comprises 5-10 parts. The catalyst composition provided by this invention includes a supported metal salt catalyst, reducing the amount of palladium-on-carbon catalyst used, significantly reducing the cost of the catalyst. Furthermore, when used in aldol condensation-catalyst hydrogenation type reactions, it exhibits high selectivity for the target end product and can accelerate the reaction process, thus shortening the reaction time.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, and in particular to a catalyst composition and its application. Background Technology

[0002] Aldol condensation is an important type of addition reaction that can be used to elongate carbon-carbon chains. In particular, the addition product can be catalytically hydrogenated to form ketones with extended carbon chains. Examples include the synthesis of MIAK from acetone and isobutyraldehyde, MIBK from acetone, MAK from acetone and n-butyraldehyde, and MIPK from butanone and formaldehyde aqueous solution. Aldol condensation is typically carried out under acidic or alkaline conditions, while catalytic hydrogenation is performed in the presence of noble metals such as palladium. Especially when aldol condensation and catalytic hydrogenation are separated into two steps, the separation of aldol condensation intermediates is involved. Even in a one-step method, the amount of noble metal required for catalytic hydrogenation is large, leading to high synthesis costs. Even with subsequent catalyst recovery, the cost remains high considering losses. Furthermore, for aldol condensation-catalytic hydrogenation reaction systems using acid or alkaline condensation reagents and noble metals as hydrogenation catalysts, the selectivity of the target final product needs further improvement. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a catalyst composition and its application, wherein the catalyst composition includes a supported metal salt catalyst, which is low in cost and, when applied to aldol condensation-catalyst hydrogenation type reaction, exhibits high selectivity for the target product, can accelerate the reaction process, and shorten the reaction time.

[0004] To address the aforementioned technical problems, the first aspect of this invention provides a catalyst composition comprising: Supported metal salt catalysts, wherein the metal salt loading is 10%-30%, and the metal salts include zinc salts and cobalt salts; Palladium on carbon catalyst; By mass, 90-95 parts of supported metal salt catalyst and 5-10 parts of palladium on carbon catalyst.

[0005] In this invention, the supported metal salt catalyst, together with the palladium-on-carbon catalyst, primarily functions as a catalyst for hydrogenation, significantly reducing the amount of palladium-on-carbon catalyst required. Since the cost of the supported metal catalyst is far lower than that of precious metals such as palladium, the cost of catalyst use can be significantly reduced, thereby contributing to lower synthesis costs. Simultaneously, when the supported metal salt catalyst preferably uses zinc salts (such as zinc chloride) and / or cobalt salts (such as cobalt chloride), it also has a certain catalytic dehydration effect in the aldol condensation reaction, working with condensing agents such as acids or bases to promote the aldol condensation reaction process and shorten the reaction time. The catalyst composition provided by this invention significantly reduces the amount of precious metal catalyst required and helps to shorten the reaction time, while also exhibiting high selectivity for the target final product. In the supported metal salt catalyst of this invention, the support is preferably a porous material such as diatomaceous earth or molecular sieves, more preferably diatomaceous earth. It should be noted that when using the catalyst composition of this invention, the supported metal salt catalyst and the palladium-on-carbon catalyst can be directly added to the reaction system in parts by weight, without the need for physical or chemical compounding operations. The method of use is simple, widely applicable, and suitable for industrial applications.

[0006] In one specific embodiment, the supported metal salt catalyst is obtained by the following method: S1, Carrier pretreatment; S2. The carrier treated in S1 is impregnated with a metal salt solution. After impregnation, the carrier is aged and dried in sequence to obtain the precursor. S3. The precursor obtained from S2 is calcined in an inert atmosphere. After calcination, it is cooled to room temperature and then powdered to obtain a supported metal salt catalyst.

[0007] Preferably, the carrier in S1 is diatomaceous earth, and the pretreatment includes acid washing, water washing, and drying, followed by powdering for later use. The impregnation treatment in S2 uses an equal-volume impregnation method; the aging time is 12-24 hours; and the drying temperature is 105℃-120℃. The calcination temperature in S3 is 350-450℃, and the calcination time is 2-6 hours, wherein the calcination heating rate is 1.5-2.5℃ / min.

[0008] In this specific embodiment, when diatomaceous earth is preferably used as the carrier, the pretreatment includes acid washing to remove soluble impurities such as carbonates and iron and aluminum oxides, using dilute nitric acid as an example; water washing to remove residual acid, followed by washing until neutral, and drying at a temperature of, for example, 100°C-110°C. After complete drying, purified diatomaceous earth is obtained. Powdering is achieved, for example, by grinding, and preferably the powder passes through a 40-60 mesh sieve. The pretreatment of other carriers may differ from that of diatomaceous earth, but carriers treated according to the pretreatment methods for carriers in the prior art are all applicable to this invention.

[0009] In this specific embodiment, equal-volume impregnation refers to determining the volume of the metal salt solution (preferably water) based on the water absorption rate (pore volume) of the support. By controlling the volume of the metal salt solution to be equal to or slightly smaller than the pore volume of the support, the support can completely absorb the metal salt solution, thus achieving controllable metal salt loading and uniform metal salt distribution. The impregnation method, for example, involves slowly adding a metal salt solution prepared according to the total pore volume of the support dropwise to the support. After half of the solution has been added, it forms a uniform paste. The mixture is then left to stand with the container sealed to allow for aging. This allows the metal salt solution to fully diffuse and disperse evenly within the pores of the support. After aging, the solution is dried to remove the metal salt solvent. Once completely dry, a precursor for the supported metal salt catalyst is obtained. The precursor is calcined, for example, in a muffle furnace under an inert atmosphere, such as by introducing inert gases like nitrogen or argon. Calcination yields an activated supported metal salt catalyst. Powdering is achieved, for example, by grinding, preferably with the powder passing through a 40-60 mesh sieve.

[0010] To address the aforementioned technical problems, a second aspect of the present invention is to provide the application of the aforementioned catalyst composition in aldol condensation-catalytic hydrogenation reactions.

[0011] In this invention, the catalyst composition is a combination of 90-95 parts by weight of a supported metal salt catalyst and 5-10 parts by weight of a palladium-on-carbon catalyst. It is suitable for reaction systems involving aldol condensation and catalytic hydrogenation, where an acid or base is used as the condensing agent. It is preferably applied in a one-step synthesis process. When using the catalyst composition, it only needs to be added to the reaction system according to the specified weight; no chemical or physical compounding of the catalyst composition is required. The method of use is simple and highly versatile. It is preferably applicable to the synthesis of MIAK from acetone and isobutyraldehyde, the synthesis of MIBK from acetone, the synthesis of MAK from acetone and n-butyraldehyde, and the synthesis of MIPK from butanone and formaldehyde aqueous solution.

[0012] In this invention, although the catalyst composition mainly plays the role of catalytic hydrogenation, when the metal salt in the supported metal salt catalyst is preferably zinc salt and / or cobalt salt, it also plays the role of catalytic dehydration. Together with the acid or base condensing agent, it plays the role of promoting aldol condensation reaction, which is beneficial to promoting the reaction process and shortening the reaction time. Moreover, selecting an appropriate metal loading amount is also beneficial to improving the selectivity of the target end product.

[0013] In one specific embodiment, the catalyst composition is added at 1%-3% of the total mass of the reactants participating in the aldol condensation reaction. For example, in the synthesis of MIAK using acetone and isobutyraldehyde as raw materials, the total mass of the catalyst is 1%-3% of the total mass of acetone and isobutyraldehyde. Understandably, when the catalyst composition of the present invention is applied to the aldol condensation-catalytic hydrogenation reaction, since the amount of palladium catalyst on carbon added does not exceed 10% of the total catalyst composition, and the amount of catalyst composition added is 1%-3% of the total mass of the reactants participating in the aldol condensation reaction, the amount of palladium catalyst used is significantly reduced, thereby helping to reduce synthesis costs. Attached Figure Description

[0014] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is the spectrum of experimental group 1 in Embodiment 2 of the present invention; Figure 2 This is the spectrum of experimental group 2 in Embodiment 2 of the present invention; Figure 3 This is the spectrum of experimental group 3 in Embodiment 2 of the present invention; Figure 4 This is the spectrum of experimental group 4 in Embodiment 2 of the present invention; Figure 5 This is a comparative spectrum of the present invention. Detailed Implementation

[0016] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0017] Example 1: Preparation of Supported Metal Salt Catalysts S1. Mix diatomaceous earth (commercially available) with 37.8% nitric acid and stir at 60-80℃ for 2-4 hours. Then, under vacuum filtration, wash with deionized water until the filtrate is neutral. Place the filter cake in a 105℃ oven to dry for 12 hours. After drying, grind it for later use. S2. The water absorption rate of the diatomaceous earth obtained in S1 was determined. Based on the water absorption rate of the diatomaceous earth, the required mass of diatomaceous earth, and the loading of the metal salt, the required amount of zinc chloride and solvent water were calculated. A zinc chloride aqueous solution was prepared and slowly added dropwise to the diatomaceous earth while continuously stirring until the system became a uniform paste. After sealing with plastic wrap, the mixture was allowed to age at room temperature for 24 hours. After aging, the mixture was transferred to an oven and dried at a temperature range of 105℃-120℃ for 12 hours to obtain the supported metal salt catalyst precursor. S3. Place the supported metal salt catalyst precursor into a crucible, place it in a muffle furnace, and heat it to 400℃ at a rate of 2℃ / min under a nitrogen atmosphere. Calcinate it at this temperature for 3 hours. After calcination, allow it to cool naturally to room temperature, remove it, and grind it through a 50-mesh sieve to obtain the ZnCl2 / diatomite catalyst (supported metal salt catalyst).

[0018] Example 2: Application of the catalyst composition in aldol condensation-catalytic hydrogenation reactions 1. Materials: Acetone is commercially available. Isobutyraldehyde is commercially available. The catalyst composition includes a supported metal catalyst and a palladium-on-carbon catalyst, wherein the supported metal catalyst comprises 4.52 parts by mass and the palladium-on-carbon catalyst comprises 0.4 parts by mass. The supported metal catalyst is prepared by the method of Example 1, with metal salt loadings of 10%, 20%, and 30%, respectively. The palladium-on-carbon catalyst is commercially available. It should be noted that the catalyst composition in the embodiments of the present invention does not limit whether the components (supported metal catalyst and palladium-on-carbon catalyst) are in a mixed state. They can be in a mixed state or an unmixed state. When added to the reaction vessel, they can be added together after mixing or added separately. The catalyst composition is relative to the catalytic effect. Regardless of whether the components of the catalyst composition are added to the reaction vessel sequentially or simultaneously (and when added simultaneously, regardless of whether they are in a mixed state or an unmixed state), they are in an effective catalytic state during the reaction process.

[0019] Alkaline solution is obtained by dissolving sodium hydroxide in deionized water, with a mass concentration of 3%. 2. Reaction vessel: 1L hydrogenation reactor.

[0020] Experimental Group 1: 174g acetone, 72g isobutyraldehyde, 4.92g catalyst composition, and 20g alkaline water were added to a reaction vessel. The supported metal catalyst contained 10% zinc chloride. Stirring was started (1000 r / min), and the reaction was carried out at 70℃ and 1 MPa for 3.5 h. Samples were taken for analysis, and the gas chromatogram is shown below. Figure 1 As shown, MIAK is at 7.271 min, with a selectivity of 82.36%.

[0021] Experimental Group 2: 174g acetone, 72g isobutyraldehyde, 4.92g catalyst composition, and 20g alkaline water were added to a reaction vessel. The supported metal catalyst contained 20% zinc chloride. Stirring was started (1000 r / min), and the reaction was carried out at 70℃ and 1 MPa for 3 hours. Samples were taken for analysis, and the gas chromatogram is shown below. Figure 2 As shown, MIAK is at 7.436 min, with a selectivity of 99.44%.

[0022] Experimental Group 3: 246g of acetone, 4.92g of catalyst composition, and 20g of alkaline water were added to a reaction vessel. The supported metal catalyst contained 20% zinc chloride. Stirring was started (1000 r / min), and the reaction was carried out at 70℃ and 1 MPa for 3 hours. Samples were taken for analysis, and the gas chromatogram is shown below. Figure 3 As shown, the MIBK is located at 5.401 min, with a selectivity of 99.05%.

[0023] Experimental Group 4: 174g acetone, 72g isobutyraldehyde, 4.92g catalyst composition, and 20g alkaline water were added to a reaction vessel. The supported metal catalyst contained 30% zinc chloride. Stirring was started (1000 r / min), and the reaction was carried out at 70℃ and 1 MPa for 3 hours. Samples were taken for analysis, and the gas chromatogram is shown below. Figure 4 As shown, MIAK is at 7.287 min, with a selectivity of 75.05%.

[0024] Comparative Example The difference from experimental group 1 in Example 2 is that the catalyst was palladium on carbon only, and the amount added was 4.92g. The gas chromatogram is shown below. Figure 5 As shown, MIAK was observed at 7.536 min, with a selectivity of 98.67%. The relevant conditions and product selectivity results for experimental groups 1-4 in Example 2 and the comparative examples are shown in Table 1. Experimental group 1 4.52 / 0.452g 0.4g 3.5h / 82.36% Experimental group 2 4.52 / 0.904g 0.4g 3h / 99.44% Experimental group 3 4.52 / 0.904g 0.4g 3h 99.05% / Experimental group 4 4.52 / 1.352g 0.4g 3h / 75.05% Comparative Example 0 / 0 4.92g 3.5h / 98.67% The reaction results of experimental groups 1, 2 and 4 in Example 2 show that the loading of metal salt in the supported metal catalyst has a significant impact on the selectivity of the product. When the loading of metal salt reaches 30%, the product selectivity is poor and it is not suitable for industrial application. Therefore, it is preferable that the loading is less than 30%, and more preferably, the loading of metal salt is 20%.

[0025] Meanwhile, in Examples 2, although the experimental groups 1-4 and the comparative examples showed higher product selectivity, the amount of palladium-on-carbon catalyst required was 12.3 times that in Examples 2 because no supported metal catalyst was used. Compared with experimental group 2 in Examples 2, the product selectivity was lower and the reaction time was longer. It can be seen that the catalyst composition provided by the present invention can significantly reduce the amount of palladium-on-carbon catalyst used, save catalyst costs, and improve product selectivity, save reaction time, and improve reaction efficiency by reasonably adjusting the content of metal salt in the supported metal catalyst.

[0026] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A catalyst composition characterized in that, include: Supported metal salt catalysts, wherein the metal salt loading is 10%-30%, and the metal salts include zinc salts and cobalt salts; Palladium on carbon catalyst; By mass, 90-95 parts of supported metal salt catalyst and 5-10 parts of palladium on carbon catalyst.

2. The catalyst composition of claim 1, wherein, Supported metal salt catalysts are obtained by the following method: S1, Carrier pretreatment; S2. The carrier treated in S1 is impregnated with a metal salt solution. After impregnation, the carrier is aged and dried in sequence to obtain the precursor. S3. The precursor obtained from S2 is calcined in an inert atmosphere. After calcination, it is cooled to room temperature and then powdered to obtain a supported metal salt catalyst.

3. The catalyst composition of claim 2, wherein, The carrier in S1 is diatomaceous earth, and the pretreatment includes acid washing, water washing and drying, after which it is powdered for later use.

4. The catalyst composition of claim 2, wherein The impregnation treatment in S2 adopts the equal-volume impregnation method; The aging time is 12-24 hours; The drying temperature is 105℃-120℃.

5. The catalyst composition of claim 2, wherein The calcination temperature in S3 is 350-450℃, and the calcination time is 2-6h.

6. The catalyst composition of claim 5, wherein The heating rate for calcination is 1.5-2.5℃ / min.

7. The use of a catalyst composition according to any one of claims 1-6 in aldol condensation-catalytic hydrogenation reactions.

8. The application as described in claim 7, characterized in that, The amount of catalyst composition added is 1%-3% of the total mass of the reactants participating in the aldol condensation reaction.

9. The application as described in claim 7, characterized in that, Aldol condensation-catalytic hydrogenation reactions include: MIAK was synthesized from acetone and isobutyraldehyde. MIBK was synthesized using acetone as a raw material; MAK was synthesized from acetone and n-butyraldehyde. MIPK was synthesized using butanone and formaldehyde aqueous solution as raw materials.

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