A catalyst for preparing 2-ethylhexanol and a preparation method and application thereof

Abstract

The application provides a catalyst for preparing 2-ethylhexanol and a preparation method and application thereof, the catalyst comprises 28wt%-38wt% of copper oxide, 45wt%-60wt% of zinc oxide, 3wt%-12wt% of magnesium oxide and 2wt%-8wt% of Ca-beta molecular sieve on a weight basis; the preparation method of the catalyst comprises the following steps: mixing a copper-zinc-magnesium mixed salt solution with an alkali solution to generate a precipitate, aging, filtering, washing, drying, calcining to prepare an oxide, then mixing and grinding the oxide with Ca-beta molecular sieve to prepare a crude product, and finally adding a molding aid into the crude product to prepare a catalyst finished product. The catalyst provided by the application has the advantages of high reaction activity, high selectivity of a target product and low selectivity of unsaturated by-products due to appropriate acid-base site ratio and good dispersion of copper species of an active component.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to a catalyst for preparing 2-ethylhexanol, its preparation method, and its application. Background Technology

[0002] 2-Ethylhexanol, also known as octanol, is an important organic chemical product, mainly used in the production of plasticizers such as dioctyl terephthalate, dioctyl phthalate, and dioctyl adipate. Sulfuric acid color is a crucial quality indicator for 2-ethylhexanol and a challenge in production control. The substances affecting the sulfuric acid color of 2-ethylhexanol are byproducts—unsaturated compounds. The performance of the catalyst directly affects the content and distribution of these byproducts, which is key to controlling the sulfuric acid color of 2-ethylhexanol and producing high-quality 2-ethylhexanol. However, existing patents have not addressed or optimized the content and distribution of these key byproducts.

[0003] In industrial production, isooctenealdehyde is often used for gas-phase hydrogenation to prepare 2-ethylhexanol, primarily employing copper-based catalysts. However, this reaction involves several side reactions, generating various unsaturated byproducts. Therefore, developing highly active catalysts with high selectivity for 2-ethylhexanol and low selectivity for unsaturated byproducts is a key focus in this field to reduce the sulfuric acid color of 2-ethylhexanol and improve its quality.

[0004] Copper-based catalysts for the gas-phase hydrogenation of isooctenal to 2-ethylhexanol are documented in numerous existing patents and literature. Chinese patent CN 105080549A discloses a catalyst and its preparation method for the gas-phase hydrogenation of octenal to 2-ethylhexanol. This catalyst is prepared via stepwise precipitation and a highly selective catalyst is achieved by adding catalyst promoters. However, this stepwise precipitation method requires precise adjustment of the precipitation conditions for each step, resulting in numerous regulated reaction conditions. Another Chinese patent, CN 104549304A, discloses a catalyst and its preparation method for the gas-phase hydrogenation of octenal to octanol, using a urea hydrothermal precipitation method. During the preparation process, acid is used to dissolve the waste catalyst; therefore, this method easily generates harmful gases such as ammonia and acidic waste gases. Summary of the Invention

[0005] The present invention aims to provide a catalyst for the preparation of 2-ethylhexanol, its preparation method, and its application. The catalyst has high activity, high selectivity for 2-ethylhexanol, and low selectivity for unsaturated byproducts. Its preparation method is simple and produces no polluting products.

[0006] To achieve the above objectives, the present invention proposes the following technical solution:

[0007] A catalyst for the preparation of 2-ethylhexanol, said catalyst comprising, on a weight basis, 28 wt%-38 wt% copper oxide, 45 wt%-60 wt% zinc oxide, 3 wt%-12 wt% magnesium oxide, and 2 wt%-8 wt% Ca-β molecular sieve.

[0008] As a preferred embodiment of the present invention, the ratio of acidic sites to basic sites in the catalyst is 0.75-1.15:1.

[0009] The present invention also provides a method for preparing a catalyst for preparing 2-ethylhexanol, the method comprising the following steps:

[0010] Step 1: A copper-zinc-magnesium mixed salt solution, consisting of copper salt solution, zinc salt solution and magnesium salt solution, is mixed with an alkaline solution at a suitable temperature and pH to generate a precipitate. After aging, filtration, washing, drying and calcination, the oxide is obtained.

[0011] The volume ratio of the copper-zinc-magnesium mixed salt solution to the alkaline solution is adjusted according to the pH required for precipitation. The total molar concentration of metal ions in the copper-zinc-magnesium mixed salt solution is 0.5 mol / L to 2 mol / L, and the molar concentration of alkaline molecules in the alkaline solution is 0.5 mol / L to 2 mol / L.

[0012] Step 2: The H-β molecular sieve is subjected to 1-3 ion exchange reactions in calcium nitrate solution, and after filtration and calcination, Ca-β molecular sieve is obtained.

[0013] Step 3: The oxide and the Ca-β molecular sieve are mixed and ground to obtain a crude product. The crude product is then mixed with a molding aid to form a molded catalyst.

[0014] The crude product contains 2wt%-8wt% of Ca-β molecular sieve, and the catalyst contains 1wt%-3wt% of the forming aid.

[0015] As a preferred embodiment of the present invention, the copper salt solution, zinc salt solution and magnesium salt solution are any one or a mixture of two of their corresponding nitrate solutions and acetate solutions, and the total molar concentration of metal ions in the copper-zinc-magnesium mixed salt solution is 0.8 mol / L-1.2 mol / L.

[0016] As a preferred embodiment of the present invention, the alkaline solution is any one or a mixture of two of sodium carbonate solution and sodium bicarbonate solution, and the molar concentration of alkaline molecules in the alkaline solution is preferably 0.8 mol / L-1.2 mol / L.

[0017] As a preferred embodiment of the present invention, the total molar concentration of metal ions in the copper-zinc-magnesium mixed salt solution is the same as the molar concentration of alkali molecules in the alkaline solution.

[0018] As a preferred embodiment of the present invention, the copper-zinc-magnesium mixed salt solution, composed of copper salt solution, zinc salt solution and magnesium salt solution, is mixed with an alkaline solution at a suitable temperature and pH to generate a precipitate, comprising:

[0019] When a copper-zinc-magnesium mixed salt solution is mixed with an alkaline solution, the temperature is 55℃-70℃ and the pH is 7.0-9.5, and a precipitate is formed by co-current precipitation.

[0020] In a preferred embodiment of the present invention, in step two, the mass ratio of the calcium nitrate solution to the Ca-β molecular sieve is 10:1, and the concentration of the calcium nitrate solution is 1 mol / L.

[0021] In a preferred embodiment of the present invention, in step two, the temperature of each ion exchange reaction is 80°C and the reaction time is 3 hours.

[0022] As a preferred embodiment of the present invention, the grinding process in step three is ball milling, and the ball milling time is 12h-24h.

[0023] The grinding balls used in the ball milling process have a diameter of 5mm-20mm and a rotation speed of 400r / min-500r / min.

[0024] Application of a catalyst for the preparation of 2-ethylhexanol as described above, or a catalyst prepared by the method described above, wherein the catalyst is used for the gas-phase reaction of isooctenealdehyde with hydrogen to produce 2-ethylhexanol.

[0025] The catalyst for preparing 2-ethylhexanol, its preparation method, and its application provided by the technical solution of the present invention have at least the following advantages compared with the prior art:

[0026] 1. The catalyst provided by the present invention has the characteristics of an acidic site to basic site ratio of 0.75-1.15:1, an appropriate acid-base site ratio, and good dispersion of the active component copper species, which makes the catalyst have the advantages of high reaction activity, high selectivity for target product and low selectivity for unsaturated by-products.

[0027] 2. The catalyst of the present invention is simple to operate and has few restrictions on reaction conditions during preparation. No harmful by-products are generated during the preparation process. Magnesium ions will promote the formation of more green copper zinc ore in the catalyst precursor, which can effectively promote the dispersion of copper species of active component. At the same time, the addition of magnesium can promote the formation of more weakly basic sites in the catalyst, so that the catalyst has a suitable acid-base site ratio.

[0028] 3. In the preparation process of the catalyst of the present invention, Ca-β molecular sieve is also added. Through the interaction between Ca-β molecular sieve and metal elements, the active component copper ions are highly dispersed. At the same time, Ca-β molecular sieve has the properties of aluminum, silicon and calcium ions, which can effectively adjust the acid-base site ratio of the catalyst.

[0029] 4. In the preparation process of the catalyst of the present invention, the oxide and Ca-β molecular sieve are ball-milled and mixed, which can make the metal element components fully contact the Ca-β molecular sieve and achieve the effect of deep mixing.

[0030] 5. When the catalyst of the present invention is applied to the gas-phase hydrogenation of isooctene aldehyde to prepare 2-ethylhexanol, it can not only ensure a high yield of the target product 2-ethylhexanol, but also reduce the content of unsaturated byproducts in the crude alcohol of the target product, thereby obtaining a 2-ethylhexanol product with low sulfuric acid color. At the same time, the reaction process conditions of the catalyst are adjustable over a wide range, making it universal and with a very wide range of industrial applications.

[0031] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other.

[0032] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0033] The accompanying drawings are not drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings, wherein:

[0034] Figure 1 This is an enlarged structural diagram of the catalyst according to an embodiment of the present invention;

[0035] Figure 2This is an EDS distribution diagram of copper species, the active component, in the catalyst of this invention. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below 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 described embodiments of the present invention without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art.

[0037] The terms "first," "second," and similar words used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "comprising" or "including" indicate that the element or object preceding "comprising" encompasses the features, wholes, steps, operations, elements, and / or components listed following "comprising" or "including," and do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or collections thereof. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0038] Unless otherwise specified, all chemicals or raw materials used in the embodiments of this invention were purchased through legitimate commercial channels.

[0039] The products of the hydrogenation reaction of the raw material isooctene aldehyde were detected using an Agilent 7890A gas chromatograph with an Agilent DB-Waxer capillary column.

[0040] The conversion rate and selectivity calculation formulas in this embodiment of the invention are as follows:

[0041] Isooctene conversion rate = (moles of isooctene in feed - moles of isooctene in discharge) ÷ moles of isooctene in feed × 100%;

[0042] 2-Ethylhexanol selectivity = (moles of 2-ethylhexanol in the discharge) / (moles of isoocteneal in the feed - moles of isoocteneal in the discharge) × 100%;

[0043] The selection methods for byproducts 2-ethylhexanal and heavy components are the same as those for 2-ethylhexanol.

[0044] like Figure 1 As shown, this embodiment of the invention provides a catalyst for preparing 2-ethylhexanol, the catalyst comprising, by weight, 28wt%-38wt% copper oxide, 45wt%-60wt% zinc oxide, 3wt%-12wt% magnesium oxide, and 2wt%-8wt% Ca-β molecular sieve. The ratio of acidic sites to basic sites in the catalyst is 0.75-1.15:1, which is an appropriate acid-base ratio. Furthermore, as... Figure 2 As shown, the active copper species (including copper oxide and copper ions in other forms) in the catalyst exhibit excellent dispersion, are abundant, and are relatively uniformly dispersed. These characteristics result in advantages such as high reactivity, high selectivity for the target product, and low selectivity for unsaturated byproducts. Magnesium ions promote the formation of more chalcopyrite in the catalyst precursor, effectively enhancing the dispersion of the active copper species. Furthermore, the addition of magnesium promotes the formation of more weakly basic sites on the catalyst, resulting in a suitable acid-base site ratio. In addition, the interaction between the Ca-β molecular sieve and the metal elements promotes the high dispersion of the active copper species. The Ca-β molecular sieve also possesses properties similar to aluminum, silicon, and calcium ions, effectively regulating the acid-base site ratio of the catalyst.

[0045] This invention also provides a method for preparing a catalyst for preparing 2-ethylhexanol, the method comprising the following steps:

[0046] Step 1: Weigh appropriate amounts of soluble copper, zinc, and magnesium salts and dissolve them in deionized water to prepare a copper-zinc-magnesium mixed salt solution. Weigh appropriate amounts of alkali and dissolve them in deionized water to prepare an alkali solution. Mix the copper-zinc-magnesium mixed salt solution and the alkali solution at a suitable temperature and pH to generate a precipitate. After aging, filtering, washing, drying, and calcining, the oxide is obtained.

[0047] The volume ratio of the copper-zinc-magnesium mixed salt solution to the alkaline solution is adjusted according to the pH required for precipitate formation. Since the precipitation of metal ions requires the solution to be within a certain pH range, and the types of metal ions are already determined in this embodiment, the required pH for precipitation is a fixed value. Therefore, in actual operation, the pH of the mixed solution is adjusted by controlling the volume ratio of the two solutions added, keeping the pH within the required range and continuously generating precipitate.

[0048] In this embodiment of the invention, the copper salt solution is a mixture of one or two of copper nitrate solution and copper acetate solution; the zinc salt solution is a mixture of one or two of zinc nitrate solution and zinc acetate solution; and the magnesium salt solution is a mixture of one or two of magnesium nitrate solution and magnesium acetate solution. The total molar concentration of metal ions in the copper-zinc-magnesium mixed salt solution is 0.5 mol / L-2 mol / L, preferably 0.8 mol / L-1.2 mol / L. Magnesium ions promote the formation of more green copper-zinc ore in the catalyst precursor, effectively promoting the dispersion of the active component copper ions. Simultaneously, the addition of magnesium promotes the formation of more weakly basic sites on the catalyst, resulting in a suitable acid-base site ratio.

[0049] In this embodiment of the invention, the alkaline solution is any one or a mixture of two of sodium carbonate and sodium bicarbonate solutions. The molar concentration of the alkaline molecules in the alkaline solution is 0.5 mol / L to 2 mol / L, preferably 0.8 mol / L to 1.2 mol / L.

[0050] In this embodiment of the invention, the total molar concentration of metal ions in the copper-zinc-magnesium mixed salt solution may be the same as or different from the molar concentration of alkali molecules in the alkaline solution; preferably, they are the same or substantially the same, so that it is easier to control the volume ratio of the two solutions when they are mixed and added dropwise, and thus easier to adjust the pH of the solution.

[0051] In this embodiment of the invention, when the copper-zinc-magnesium mixed salt solution is mixed with the alkaline solution, a clean and dry container is placed in a water bath with a stirring paddle inside. During the mixing process, the water bath is heated to maintain the temperature of the mixed solution at 55°C-70°C. The pH of the mixed solution is maintained at 7.0-9.5 during precipitation by controlling and adjusting the flow rates of the copper-zinc-magnesium mixed salt solution and the alkaline solution (equivalent to adjusting the drop volume of the two solutions when their molar concentrations are the same), so that the precipitate is generated in a co-current precipitation manner.

[0052] The aging temperature during the aging process is 60℃-75℃, and the aging time is 20min-50min, with the preferred aging time being 25min-35min.

[0053] In this invention, the drying process refers to drying the solid obtained under certain drying temperature conditions, with the drying temperature being 100°C and the drying time being 12 hours.

[0054] In this invention, the oxide calcination process refers to the solid obtained after the oxide is calcined and dried at a certain calcination temperature of 350℃-450℃ and the calcination time of 2h-6h.

[0055] Step 2: Weigh an appropriate amount of H-β molecular sieve and add it to an appropriate amount of calcium nitrate solution for ion exchange. After filtration and calcination, Ca-β molecular sieve is obtained.

[0056] In this embodiment of the invention, the mass ratio of the calcium nitrate solution to the Ca-β molecular sieve is 10:1, the concentration of the calcium nitrate solution is 1 mol / L, and the amount of calcium nitrate solution is ten times greater than that of the Ca-β molecular sieve, so that the Ca-β molecular sieve can be completely immersed in the calcium nitrate solution, thereby allowing the two to fully carry out the ion exchange reaction.

[0057] In this embodiment of the invention, the H-β molecular sieve undergoes ion exchange reactions with calcium nitrate solution 1-3 times. Specifically, taking 3 ion exchange reactions as an example, after the first ion exchange reaction, the molecular sieve after the first ion exchange is filtered out. Then, the molecular sieve after the first ion exchange is placed again in an appropriate amount of freshly prepared calcium nitrate solution for the second ion exchange reaction. After the second ion exchange is completed, the molecular sieve after the second ion exchange is filtered out. Then, the molecular sieve after the second ion exchange is placed again in an appropriate amount of freshly prepared calcium nitrate solution for the third ion exchange. This is followed by subsequent calcination treatment.

[0058] During the ion exchange reaction, a stirrer was used to accelerate the reaction and ensure complete reaction. The temperature for each ion exchange reaction was 80℃, and the reaction time was 3 hours.

[0059] In this invention, the molecular sieve calcination process refers to the solid obtained after the molecular sieve is calcined and dried at a certain calcination temperature of 550°C and the calcination time is 4-6 hours.

[0060] Step 3: Weigh an appropriate amount of the oxide and an appropriate amount of the Ca-β molecular sieve, mix them, and grind them to obtain a crude product. Mix an appropriate amount of the crude product with an appropriate amount of molding aid to prepare a molded catalyst. The mass fraction of Ca-β molecular sieve in the crude product is 2wt%-8wt%, and the remainder is oxide. The mass fraction of the molding aid in the catalyst is 1wt%-3wt%, and the remainder is oxide and Ca-β molecular sieve. The molding aid is graphite, which is used to make the catalyst easier to mold and does not involve the active components of the catalyst.

[0061] In this embodiment of the invention, the interaction between Ca-β molecular sieve and metal elements promotes the high dispersion of copper species as the active component. At the same time, Ca-β molecular sieve has the properties of aluminum, silicon and calcium ions, which can effectively adjust the acid-base site ratio of the catalyst.

[0062] In this embodiment of the invention, the grinding process in step three is performed using a ball mill. The oxide and Ca-β molecular sieve are mixed and added to a ball mill jar, then grinding balls are added to begin ball milling. The ball milling time is 12-24 hours; the diameter of the grinding balls used is 5mm-20mm, and the rotation speed of the grinding balls is 400-500 r / min. By ball milling the oxide and Ca-β molecular sieve, the metal element components can be fully contacted with the Ca-β molecular sieve, achieving a deep mixing effect.

[0063] In this embodiment of the invention, the formed catalyst can be a flake catalyst, which can be formed using an existing flake forming machine. The specifications of the formed catalyst can be selected according to actual needs.

[0064] The catalyst of this invention is simple to prepare, has few restrictions on reaction conditions, and produces no harmful byproducts.

[0065] The present invention also provides an application of the catalyst for preparing 2-ethylhexanol as described above or the catalyst prepared by the preparation method as described above, wherein the catalyst is used for the gas-phase reaction of isooctenealdehyde with hydrogen to generate 2-ethylhexanol.

[0066] The catalyst of this invention is applied to the gas-phase hydrogenation of isooctene aldehyde to prepare 2-ethylhexanol. It can not only ensure a high yield of the target product 2-ethylhexanol, but also reduce the content of unsaturated byproducts in the crude alcohol, thereby obtaining a 2-ethylhexanol product with low sulfuric acid color. At the same time, the reaction process conditions of this catalyst are adjustable over a wide range, making it universal and with a very wide range of industrial applications.

[0067] In this embodiment of the invention, the reaction temperature for the gas-phase reaction of isoocteneal with hydrogen is 150℃-170℃, and the reaction pressure is 0.4MPa-0.6MPa; the molar ratio of H2 to isoocteneal is (50-100):1; and the liquid hourly space velocity of isoocteneal is 0.3h. -1 -0.6h -1 .

[0068] In this embodiment of the invention, the catalyst is first reduced and activated before being used in the gas-phase reaction of isoocteneal with hydrogen to generate 2-ethylhexanol. The catalyst is placed in a fixed-bed reactor, and the reactor temperature is raised to 170°C under a nitrogen atmosphere, while maintaining a nitrogen volume hourly space velocity of 300 h⁻¹. -1 -600h -1 The catalyst is kept at a constant temperature for 1-2 hours to remove the physical water adsorbed on it. Then, a mixture of hydrogen and nitrogen gas is introduced to reduce the catalyst, maintaining the volume hourly space velocity (VHSV) of the mixture at 300 h⁻¹. -1 -600h -1The hydrogen concentration is increased to 10% by volume, and the hydrogen volume fraction is not more than 10%. After reduction for 1 hour, the hydrogen concentration is gradually increased to 10%, 20%, 30%, 50%, and 100% by volume, respectively, while controlling the hot spot temperature of the catalyst bed to not exceed 230℃ during the reduction process. Finally, the temperature is raised to 200℃-230℃ and reduced in a full hydrogen atmosphere for 2-4 hours to obtain the activated catalyst.

[0069] Example 1

[0070] 202.0 g of zinc nitrate, 90.4 g of copper nitrate, and 51.2 g of magnesium nitrate were weighed and dissolved in 1250 mL of deionized water to obtain a copper-zinc-magnesium mixed salt solution. 196.1 g of sodium carbonate was weighed and dissolved in 1850 mL of deionized water to obtain an alkaline solution. The copper-zinc-magnesium mixed salt solution and the alkaline solution were co-precipitated under a 65°C water bath with stirring. The pH of the mixed solution was controlled at 9.0-9.2 during precipitation. After co-precipitation, the solution was aged at 70°C for 30 min, washed, dried at 100°C for 12 h, and calcined at 400°C for 4 h to obtain the oxide.

[0071] Weigh 23.6 g of calcium nitrate and dissolve it in 100 mL of deionized water to obtain a calcium nitrate solution. Weigh 10 g of H-β molecular sieve and place it in the calcium nitrate solution. Perform ion exchange treatment for 3 h under 80 °C water bath conditions with stirring paddle, and then filter. Repeat the above process twice. After that, calcine the obtained sample at 550 °C for 4 h to obtain Ca-β molecular sieve.

[0072] Weigh 90g of oxide and 4.5g of Ca-β molecular sieve, place them in the ball mill jar, add grinding balls, adjust the grinding ball speed to 500 r / min, and ball mill for 12 h. Mix the ball-milled catalyst with the additives evenly, and then use a tableting machine to form tablets to obtain the formed catalyst. The ratio of acidic sites to basic sites in the obtained catalyst is 1.14:1.

[0073] Example 2

[0074] 220.3 g of zinc nitrate, 126.5 g of copper nitrate, and 38.4 g of magnesium nitrate were weighed and dissolved in 1450 mL of deionized water to obtain a copper-zinc-magnesium mixed salt solution. 165.1 g of sodium carbonate was weighed and dissolved in 1550 mL of deionized water to obtain an alkaline solution. The copper-zinc-magnesium mixed salt solution and the alkaline solution were co-precipitated under a 60°C water bath with stirring. The pH of the mixed solution was controlled at 7.3-7.5 during precipitation. After co-precipitation, the solution was aged at 65°C for 30 min, washed, dried at 100°C for 12 h, and calcined at 350°C for 4 h to obtain the oxide.

[0075] Weigh 23.6 g of calcium nitrate and dissolve it in 100 mL of deionized water to obtain a calcium nitrate solution. Weigh 10 g of H-β molecular sieve and place it in the calcium nitrate solution. Treat the solution with ion exchange at 80 °C in a water bath with stirring for 3 h, then filter. Repeat the above process twice. After that, calcine the obtained sample at 550 °C for 4 h to obtain Ca-β molecular sieve.

[0076] Weigh 100g of oxide and 4.5g of Ca-β molecular sieve, place them in the ball mill jar, add grinding balls, adjust the grinding ball speed to 500r / min, and ball mill for 16h. Mix the ball-milled catalyst with the additives evenly, and then use a tableting machine to form tablets to obtain the formed catalyst. The ratio of acidic sites to basic sites in the obtained catalyst is 0.93:1.

[0077] Example 3

[0078] 233.6 g of zinc nitrate, 119.3 g of copper nitrate, and 38.4 g of magnesium nitrate were weighed and dissolved in 1450 mL of deionized water to obtain a copper-zinc-magnesium mixed salt solution. 189.5 g of sodium carbonate was weighed and dissolved in 1800 mL of deionized water to obtain an alkaline solution. The copper-zinc-magnesium mixed salt solution and the alkaline solution were co-precipitated under a 60°C water bath with stirring, maintaining the pH of the mixed solution at 8.0-8.2 during precipitation. After co-precipitation, the solution was aged at 65°C for 30 min, washed, dried at 100°C for 12 h, and calcined at 350°C for 4 h to obtain the oxide.

[0079] The subsequent preparation process remained consistent with Example 2. Finally, the ratio of acidic to basic sites in the obtained catalyst was 1.02:1, indicating that the number of acidic and basic sites in the catalyst was almost equal, resulting in a suitable pH level, high activity, high selectivity for the target product, and low selectivity for unsaturated byproducts. As shown in Table 1, this yielded the highest conversion rate of isoocteneal, the highest selectivity for 2-ethylhexanol, and the lowest selectivity for both 2-ethylhexanol and the heavy component.

[0080] Example 4

[0081] 233.6 g of zinc nitrate, 119.3 g of copper nitrate, and 38.4 g of magnesium nitrate were weighed and dissolved in 1450 mL of deionized water to obtain a copper-zinc-magnesium mixed salt solution. 189.5 g of sodium carbonate was weighed and dissolved in 1800 mL of deionized water to obtain an alkaline solution. The copper-zinc-magnesium mixed salt solution and the alkaline solution were co-precipitated under a 60°C water bath with stirring, maintaining the pH of the mixed solution at 8.5-8.7 during precipitation. After co-precipitation, the solution was aged at 65°C for 30 min, washed, dried at 100°C for 12 h, and calcined at 350°C for 4 h to obtain the oxide.

[0082] The subsequent preparation process remained consistent with that of Example 2. Finally, the ratio of acidic sites to basic sites in the obtained catalyst was 1.05:1, as shown in Table 1. At this point, the conversion rate of isooctenealdehyde was high, the selectivity of 2-ethylhexanol was high, and the selectivity of 2-ethylhexanol and the selectivity of heavy components were both low.

[0083] Example 5

[0084] 264.4 g of zinc nitrate, 126.5 g of copper nitrate, and 46.1 g of magnesium nitrate were weighed and dissolved in 1600 mL of deionized water to obtain a copper-zinc-magnesium mixed salt solution. 229.0 g of sodium carbonate was weighed and dissolved in 2150 mL of deionized water to obtain an alkaline solution. The copper-zinc-magnesium mixed salt solution and the alkaline solution were co-precipitated under a 65°C water bath with stirring. The pH of the mixed solution was controlled at 8.0-8.2 during precipitation. After co-precipitation, the solution was aged at 70°C for 30 min, washed, dried at 100°C for 12 h, and calcined at 350°C for 4 h to obtain the oxide.

[0085] The molecular sieve ion exchange process is consistent with that in Example 1.

[0086] 100g of oxide and 3.0g of Ca-β molecular sieve were weighed and placed in the ball mill jar. Grinding balls were added, and the grinding speed was adjusted to 450 r / min. The mixture was ball-milled for 20 h. The ball-milled catalyst was then mixed evenly with the additives and shaped into tablets using a tableting machine to obtain the shaped catalyst. Finally, the ratio of acidic sites to basic sites in the obtained catalyst was 0.90:1.

[0087] Experimental Example

[0088] The reaction performance of the catalysts prepared in Examples 1-5 above was investigated under the following conditions.

[0089] Catalyst reduction and activation: The formed catalyst was loaded into a fixed-bed reactor with a catalyst loading of 50 mL. First, the reactor temperature was raised to 170 °C under a nitrogen atmosphere, maintaining a nitrogen volume hourly space velocity (VHSV) of 480 h⁻¹. -1 The catalyst was kept at a constant temperature for 2 hours to remove adsorbed physical water. Then, a mixture of hydrogen and nitrogen was introduced to reduce the catalyst, with a hydrogen volume fraction of 2%. After reduction for at least 1 hour, the hydrogen concentration was gradually increased to 5%, 10%, 20%, 50%, and 100% by volume, while controlling the hot spot temperature of the catalyst bed to not exceed 230°C during the reduction process. Finally, the temperature was raised to 230°C and reduced for 2 hours in a full hydrogen atmosphere to obtain the activated catalyst.

[0090] Catalytic reaction evaluation: After catalyst reduction and activation, isooctene aldehyde was vaporized and mixed with H2 as reactants under the conditions of inlet temperature 155℃ and reaction pressure 0.4MPa, and the liquid hourly space velocity of isooctene aldehyde was controlled at 0.4h.-1 The molar ratio of H2 to isoocteneal was 80:1. Under these conditions, the hydrogenation reaction of isoocteneal was carried out to obtain the reaction product. The conversion rate of isoocteneal, the selectivity of 2-ethylhexanol, the selectivity of 2-ethylhexanol, and the selectivity of the heavy components are detailed in Table 1 below.

[0091]

[0092]

[0093] As shown in Table 1, the CuZnMgOx&Ca-β catalyst provided by this invention exhibits high isooctaldehyde conversion, high 2-ethylhexanol selectivity, low selectivity for the unsaturated compound 2-ethylhexanol, and low selectivity for the heavy components. As demonstrated in Examples 3 and 4, the highest isooctaldehyde conversion and 2-ethylhexanol selectivity are observed, particularly when the number of acidic and basic sites in the catalyst is nearly equal, while the selectivity for 2-ethylhexanol and the heavy components are both relatively low.

[0094] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A catalyst for the gas-phase hydrogenation of isoocteneal to prepare 2-ethylhexanol, characterized in that, The catalyst comprises, on a weight basis, 28wt%-38wt% copper oxide, 45wt%-60wt% zinc oxide, 3wt%-12wt% magnesium oxide, and 2wt%-8wt% Ca-β molecular sieve. The method for preparing the catalyst includes: co-precipitating a copper-zinc-magnesium mixed salt solution with an alkaline solution to prepare a copper-zinc-magnesium oxide; impregnating an H-β molecular sieve in a calcium nitrate solution to carry out an ion exchange reaction to prepare a Ca-β molecular sieve; mixing the copper-zinc-magnesium oxide with the Ca-β molecular sieve and then grinding it to obtain a crude product; and mixing the crude product with a molding aid to prepare the shaped catalyst. The ratio of acidic sites to basic sites in the catalyst is 0.75-1.15:1, which enables the catalyst to exhibit high selectivity for 2-ethylhexanol in the product and low selectivity for the byproduct 2-ethylhexanol when used in the hydrogenation reaction of isooctenealdehyde.

2. A method for preparing the catalyst for the gas-phase hydrogenation of isoocteneal to 2-ethylhexanol as described in claim 1, characterized in that, The preparation method includes the following steps: Step 1: A mixed salt solution of copper, zinc, and magnesium salts, consisting of copper, zinc, and magnesium salts, is mixed with an alkaline solution at a suitable temperature and pH to form a precipitate. The precipitate is then aged, filtered, washed, dried, and calcined to obtain the oxide. The total molar concentration of metal ions in the copper-zinc-magnesium mixed salt solution is 0.5 mol / L-2 mol / L, and the molar concentration of alkali molecules in the alkaline solution is 0.5 mol / L-2 mol / L. Step 2: The H-β molecular sieve is subjected to 1-3 ion exchange reactions in calcium nitrate solution, and after filtration and calcination, Ca-β molecular sieve is obtained. Step 3: The oxide is mixed with the Ca-β molecular sieve and then ground to obtain a crude product. The crude product is then mixed with a molding aid to form the shaped catalyst. The mass fraction of Ca-β molecular sieve in the crude product is 2wt%-8wt%.

3. The method for preparing the catalyst for the gas-phase hydrogenation of isoocteneal to 2-ethylhexanol according to claim 2, characterized in that, The copper salt solution, zinc salt solution, and magnesium salt solution are any one or a mixture of two of their corresponding nitrate and acetate solutions, respectively, and the total molar concentration of metal ions in the copper-zinc-magnesium mixed salt solution is 0.8 mol / L-1.2 mol / L.

4. The method for preparing the catalyst for the gas-phase hydrogenation of isoocteneal to 2-ethylhexanol according to claim 2, characterized in that, The alkaline solution is any one or a mixture of two of sodium carbonate and sodium bicarbonate solutions, and the molar concentration of alkaline molecules in the alkaline solution is 0.8 mol / L-1.2 mol / L.

5. The method for preparing the catalyst for the gas-phase hydrogenation of isoocteneal to 2-ethylhexanol according to claim 2, characterized in that, The total molar concentration of metal ions in the copper-zinc-magnesium mixed salt solution is the same as the molar concentration of alkali molecules in the alkaline solution.

6. The method for preparing the catalyst for the gas-phase hydrogenation of isoocteneal to 2-ethylhexanol according to claim 2, characterized in that, In step one, the copper-zinc-magnesium mixed salt solution, composed of copper salt solution, zinc salt solution, and magnesium salt solution, is mixed with an alkaline solution at a suitable temperature and pH to generate a precipitate, including: When a copper-zinc-magnesium mixed salt solution is mixed with an alkaline solution, the temperature is 55℃-70℃ and the pH is 7.0-9.5, and a precipitate is formed by co-current precipitation.

7. The method for preparing the catalyst for the gas-phase hydrogenation of isoocteneal to 2-ethylhexanol according to claim 2, characterized in that, In step two, the mass ratio of the calcium nitrate solution to the Ca-β molecular sieve is 10:1, and the concentration of the calcium nitrate solution is 1 mol / L.

8. The method for preparing the catalyst for the gas-phase hydrogenation of isoocteneal to 2-ethylhexanol according to claim 2, characterized in that, The grinding process in step three is ball milling, and the ball milling time is 12h-24h. The grinding balls used in the ball milling process have a diameter of 5mm-20mm and a rotation speed of 400r / min-500r / min.

9. The application of a catalyst for the gas-phase hydrogenation of isoocteneal to 2-ethylhexanol as described in claim 1, or a catalyst prepared by any one of the preparation methods described in 2-8, characterized in that, The catalyst is used for the gas-phase contact reaction of isooctenealdehyde with hydrogen. Among them, the conversion rate of isoocteneal was the highest at 99.97%; The selected 2-ethylhexanol had the highest selectivity of 99.7%, while the selected 2-ethylhexanal had the highest selectivity of only 0.25%.

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