Catalyst for preparing 2-ethylhexanol as well as preparation method and application of catalyst

Abstract

The invention provides a catalyst for preparing 2-ethylhexanol as well as a preparation method and application of the catalyst. The catalyst is prepared from the following components in percentage by weight: 28 to 38 percent of copper oxide, 45 to 60 percent of zinc oxide, 3 to 12 percent of magnesium oxide and 2 to 8 percent of Ca-beta molecular sieve. 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 and roasting to obtain an oxide, then mixing and grinding the oxide and a Ca-beta molecular sieve to obtain a crude product, and finally adding a forming aid into the crude product to obtain a finished product of the catalyst. The catalyst provided by the invention is proper in acid-base site proportion, good in active component copper species dispersion and the like, so that the catalyst has the advantages of high reaction activity, high target product selectivity, low unsaturated byproduct selectivity and the like.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, and in particular to a catalyst for preparing 2-ethylhexanol and a preparation method and application thereof. Background Art

[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 chromaticity is an important quality indicator of 2-ethylhexanol products and a difficulty in production control. The substance that affects the chromaticity of 2-ethylhexanol sulfuric acid is the by-product in the product - unsaturated substances. The performance of the catalyst directly affects the content and distribution of the by-products, and is the key to controlling the chromaticity of 2-ethylhexanol sulfuric acid and producing high-quality 2-ethylhexanol. However, none of the existing patents have paid attention to or targeted optimization of the content and distribution of key by-products.

[0003] In industrial production, 2-ethylhexanol is often prepared by gas-phase hydrogenation of isooctene aldehyde, and copper-based catalysts are mainly used for catalytic reaction. There are multiple side reactions in the gas-phase hydrogenation of isooctene aldehyde to prepare 2-ethylhexanol, and a variety of unsaturated byproducts are generated. In order to reduce the sulfuric acid color of 2-ethylhexanol and improve the quality of 2-ethylhexanol, the development of catalysts with high activity, high selectivity for 2-ethylhexanol, and low selectivity for unsaturated byproducts is the focus of this field.

[0004] Copper-based catalysts are used for the gas phase hydrogenation of isooctenal to prepare 2-ethylhexanol in many existing patents and documents. Chinese patent CN 105080549A discloses a catalyst for preparing 2-ethylhexanol by gas phase hydrogenation of octenal and a preparation method thereof. The catalyst is prepared by a step-by-step precipitation method, and a highly selective catalyst is prepared by adding a catalyst aid. The preparation method using step-by-step precipitation requires targeted adjustment of the formation conditions of each step of precipitation, and the reaction conditions required to be adjusted are relatively large. Another Chinese patent CN 104549304A discloses a catalyst for preparing octanol by gas phase hydrogenation of octenal and a preparation method thereof. The catalyst is prepared by a urea hydrothermal precipitation method, and an acid solution is also used to dissolve the waste contact body during the preparation. Therefore, the preparation method is prone to produce harmful gases such as ammonia and acidic waste gas. Summary of the invention

[0005] The present invention aims to provide a catalyst for preparing 2-ethylhexanol, a preparation method and an application thereof. The catalyst has a catalytic effect of high activity, high selectivity for 2-ethylhexanol and low selectivity for unsaturated byproducts, and the preparation method thereof has simple steps and produces no polluting products.

[0006] To achieve the above object, the present invention proposes the following technical solutions:

[0007] A catalyst for preparing 2-ethylhexanol comprises, by weight, 28wt%-38wt% of copper oxide, 45wt%-60wt% of zinc oxide, 3wt%-12wt% of magnesium oxide, and 2wt%-8wt% of Ca-β molecular sieve.

[0008] As a preferred technical solution 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: mixing a copper-zinc-magnesium mixed salt solution consisting of a copper salt solution, a zinc salt solution and a magnesium salt solution with an alkaline solution at a suitable temperature and pH to generate a precipitate, and then aging, filtering, washing, drying and roasting to obtain an oxide;

[0011] The volume ratio of the copper-zinc-magnesium mixed salt solution to the alkaline solution is adjusted according to the pH required for generating precipitation, 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;

[0012] Step 2: subjecting the H-β molecular sieve to ion exchange reaction in a calcium nitrate solution for 1 to 3 times, filtering, and calcining to obtain a Ca-β molecular sieve;

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

[0014] The mass fraction of the Ca-β molecular sieve in the crude product is 2wt%-8wt%, and the mass fraction of the molding aid in the catalyst is 1wt%-3wt%.

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

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

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

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

[0019] The temperature of the copper-zinc-magnesium mixed salt solution and the alkaline solution when mixed is 55°C-70°C and the pH is 7.0-9.5, and a precipitate is generated in a parallel flow precipitation manner.

[0020] As a preferred technical solution of the present invention, in the step 2, 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] As a preferred technical solution of the present invention, in the step 2, the temperature of each ion exchange reaction is 80° C., and the time of the ion exchange reaction is 3 hours.

[0022] As a preferred technical solution of the present invention, the grinding treatment in step 3 is ball milling, and the time of the ball milling is 12h-24h;

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

[0024] A use 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 contact reaction of isooctylaldehyde with hydrogen in gas phase to generate 2-ethylhexanol.

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

[0026] 1. The catalyst provided by the present invention has the characteristics of an acid 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, so that the catalyst has the advantages of high reaction activity, high selectivity of the target product, and low selectivity of unsaturated by-products;

[0027] 2. The catalyst of the present invention is simple to operate during preparation, has few restrictions on reaction conditions, and produces no harmful byproducts during the preparation process; magnesium ions will prompt the catalyst precursor to generate more green covellite, which can effectively promote the dispersion of the active component copper species; at the same time, the addition of magnesium elements can prompt the catalyst to form more weakly alkaline sites, so that the catalyst has a suitable acid-base site ratio;

[0028] 3. During 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, and can effectively adjust the acid-base site ratio of the catalyst;

[0029] 4. During the preparation process of the catalyst of the present invention, the oxide and the Ca-β molecular sieve are ball-milled and mixed, so that the metal element components and the Ca-β molecular sieve are fully contacted, thereby achieving a deep mixing effect;

[0030] 5. The catalyst of the present invention is applied to the catalytic reaction of preparing 2-ethylhexanol by gas-phase hydrogenation of isooctene aldehyde, which can not only ensure a high yield of the target product 2-ethylhexanol, but also reduce the content of unsaturated byproducts in the target product crude alcohol, thereby obtaining a 2-ethylhexanol product with low sulfuric acid chroma; at the same time, the catalyst has a wide adjustable range of reaction process conditions, making it universal and having a very wide range of industrial applications.

[0031] It should be appreciated that all combinations of the foregoing concepts, as well as additional concepts described in greater detail below, may be considered to be part of the inventive subject matter of the present disclosure, provided such concepts are not mutually inconsistent.

[0032] The foregoing and other aspects, embodiments and features of the present invention can be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the present invention, such as the features and / or beneficial effects of the exemplary embodiments, will be apparent from the following description or learned from the practice of the specific embodiments according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are not drawn to scale according to actual reference objects. In the accompanying drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For the sake of clarity, not every component is labeled in each figure. Now, embodiments of various aspects of the present invention will be described by way of example and with reference to the accompanying drawings, in which:

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

[0035] Figure 2This is the EDS distribution diagram of the copper species, an active component in the catalyst of the embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs.

[0037] The words "first", "second" and similar words used in the patent application specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular form of "a", "an" or "the" and similar words do not indicate a quantity limitation, but indicate the existence of at least one. Words such as "include" or "comprise" mean that the elements or objects appearing before "include" or "comprise" include the features, wholes, steps, operations, elements and / or components listed after "include" or "comprise", and do not exclude the existence or addition of one or more other features, wholes, steps, operations, elements, components and / or their collections. "Up", "down", "left", "right" and the like are only used 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, the chemicals or raw materials in the examples of the present invention were purchased through regular commercial channels.

[0039] The product of the hydrogenation reaction of the raw material isooctylaldehyde was detected by an Agilent 7890A gas chromatograph using an Agilent DB-Waxer capillary column.

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

[0041] Isooctylaldehyde conversion rate = (isooctylaldehyde mole number in feed - isooctylaldehyde mole number in output) ÷ isooctylaldehyde mole number in feed × 100%;

[0042] 2-ethylhexanol selectivity = mole number of 2-ethylhexanol in the output / (mole number of isooctylaldehyde in the feed - mole number of isooctylaldehyde in the output) × 100%;

[0043] Byproduct: 2-ethylhexanal and heavy component selectivity calculation method is the same as that of 2-ethylhexanol.

[0044] like Figure 1 As shown, an embodiment of the present invention provides a catalyst for preparing 2-ethylhexanol, wherein the catalyst comprises, by weight, 28wt%-38wt% of copper oxide, 45wt%-60wt% of zinc oxide, 3wt%-12wt% of magnesium oxide, and 2wt%-8wt% of Ca-β molecular sieve. The ratio of the acidic site to the basic site of the catalyst is 0.75-1.15:1, and the ratio of the acidic site to the basic site is appropriate. In addition, as Figure 2 As shown, the active component copper species in the catalyst (including copper oxide and copper ions in other forms) has excellent dispersibility, a large number and relatively uniform dispersion. The above characteristics make the catalyst have the advantages of high reaction activity, high selectivity of target products and low selectivity of unsaturated by-products; magnesium ions will cause the catalyst precursor to generate more green covetous zinc ore, which can effectively promote the dispersion of the active component copper species. At the same time, the addition of magnesium elements can cause the catalyst to form more weakly alkaline sites, so that the catalyst has a suitable acid-base site ratio; in addition, through the interaction between Ca-β molecular sieve and metal elements, the active component copper species is highly dispersed. At the same time, Ca-β molecular sieve has the properties of aluminum elements, silicon elements and calcium ions, which can effectively adjust the acid-base site ratio of the catalyst.

[0045] The embodiment of the present invention also provides a method for preparing a catalyst for preparing 2-ethylhexanol, the preparation method comprising the following steps:

[0046] Step 1: Weigh appropriate amounts of soluble copper salt, zinc salt and magnesium salt and dissolve them in deionized water to prepare a copper-zinc-magnesium mixed salt solution composed of a copper salt solution, a zinc salt solution and a magnesium salt solution; weigh appropriate amounts of alkali and dissolve them in deionized water to prepare an alkaline solution; mix the copper-zinc-magnesium mixed salt solution with the alkaline solution at a certain suitable temperature and pH value to generate a precipitate, age, filter, wash, dry and roast to obtain an oxide.

[0047] The volume ratio of the copper-zinc-magnesium mixed salt solution to the alkaline solution is adjusted according to the pH required for the formation of precipitation. Because the formation of metal ion precipitation requires the solution to be in a certain pH range, and the type of metal ions in the embodiment of the present invention has also been determined, the pH required for precipitation is a determined value, so in the actual operation process, the pH of the mixed solution is adjusted by adjusting and controlling the drop volume ratio of the above two solutions, so that the pH is kept in the required range and precipitation is continuously generated.

[0048] In an embodiment of the present invention, the copper salt solution is a mixed salt solution of any one or both of a copper nitrate solution and a copper acetate solution, the zinc salt solution is a mixed salt solution of any one or both of a zinc nitrate solution and a zinc acetate solution, and the magnesium salt solution is a mixed salt solution of any one or both of magnesium nitrate and magnesium acetate. The total amount of metal ions in the copper-zinc-magnesium mixed salt solution is 0.5mol / L-2mol / L, preferably 0.8mol / L-1.2mol / L. Wherein magnesium ions can cause the catalyst precursor to generate more green covellite, which can effectively promote the dispersion of the active component copper ions. At the same time, the addition of magnesium elements can cause the catalyst to form more weakly basic sites, so that the catalyst has a suitable acid-base site ratio.

[0049] In an embodiment of the present invention, the alkaline solution is any one of a sodium carbonate solution and a sodium bicarbonate solution or a mixed alkaline solution of the two. The molar concentration of the alkali molecules in the alkaline solution is 0.5 mol / L-2 mol / L, preferably 0.8 mol / L-1.2 mol / L.

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

[0051] In an embodiment of the present 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, and a stirring paddle is provided in the container. During the mixing process, the water bath is heated to keep the temperature of the mixed solution at 55°C-70°C, and the flow rate of the copper-zinc-magnesium mixed salt solution and the alkaline solution is controlled to maintain the pH value of the mixed solution at 7.0-9.5 during the precipitation process by controlling and adjusting the flow rate of the copper-zinc-magnesium mixed salt solution and the alkaline solution (when the molar concentration of the two substances is the same, it is equivalent to adjusting the dropwise volume of the two), so as to generate a precipitate in a parallel flow precipitation manner.

[0052] The aging temperature of the aging process is 60° C.-75° C., the aging time of the aging process is 20 min-50 min, and the preferred aging time is 25 min-35 min.

[0053] In the implementation of the present invention, the drying process refers to drying the obtained solid under certain drying temperature conditions, the drying temperature is 100° C., and the drying time is 12 hours.

[0054] In the implementation of the present invention, the oxide roasting process refers to the solid obtained after the oxide is roasted and dried at a certain roasting temperature, the roasting temperature is 350° C.-450° C., and the roasting time is 2 h-6 h.

[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, filter, and calcine to obtain Ca-β molecular sieve.

[0056] In an embodiment of the present 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 calcium nitrate solution is ten times more than the Ca-β molecular sieve, so that the Ca-β molecular sieve can be completely immersed in the calcium nitrate solution, so that the two can fully carry out ion exchange reaction.

[0057] In an embodiment of the present invention, the number of ion exchange reactions between the H-β molecular sieve and the calcium nitrate solution is 1-3 times. Specifically, taking three ion exchange reactions as an example, after the first ion exchange reaction is completed, the molecular sieve after the first ion exchange is filtered out, and then the molecular sieve after the first ion exchange is placed in an appropriate amount of re-formulated calcium nitrate solution again, and the second ion exchange reaction is carried out. After completion, the molecular sieve after the second ion exchange is filtered out, and then the molecular sieve after the second ion exchange is placed in an appropriate amount of re-formulated calcium nitrate solution again. After the ion exchange is completed, the molecular sieve after the third ion exchange is filtered out, followed by subsequent roasting treatment.

[0058] The ion exchange reaction was stirred with a stirring paddle to increase the speed of the ion exchange reaction and achieve full reaction. The temperature of each ion exchange reaction was 80° C., and the time of the ion exchange reaction was 3 hours.

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

[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, and mix an appropriate amount of the crude product with an appropriate amount of a molding aid to prepare a molded catalyst; the mass fraction of the Ca-β molecular sieve in the crude product is 2wt%-8wt%, and the rest is oxide; the mass fraction of the molding aid in the catalyst is 1wt%-3wt%, and the rest is oxide and Ca-β molecular sieve, and the molding aid is graphite, which is used to make the catalyst easy to mold and does not involve catalyst active components.

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

[0062] In the embodiment of the present invention, the grinding process in step 3 is performed by a ball mill, the oxide and the Ca-β molecular sieve are mixed and added to a ball milling jar, and then grinding balls are added to start ball milling. The ball milling time is 12h-24h; the diameter of the grinding balls used in the ball milling process is 5mm-20mm, and the rotation speed of the grinding balls is 400r / min-500r / min. By ball milling the oxide and the 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 the embodiment of the present invention, the shaped catalyst may be a tablet-type catalyst, which may be tableted using an existing tableting machine, and the specifications of the shaped catalyst may be selected according to actual needs.

[0064] The catalyst of the embodiment of the present invention has simple operation and few restrictions on reaction conditions during the preparation process, and no harmful by-products are generated during the preparation process.

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

[0066] The catalyst of the embodiment of the present invention is applied to the catalytic reaction of preparing 2-ethylhexanol by gas-phase hydrogenation of isooctene aldehyde, which can not only ensure a high yield of the target product 2-ethylhexanol, but also reduce the content of unsaturated byproducts in the target product crude alcohol, thereby obtaining a 2-ethylhexanol product with low sulfuric acid chroma; at the same time, the catalyst has a wide adjustable range of reaction process conditions, making it universal and having a very wide range of industrial applications.

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

[0068] In the embodiment of the present invention, the catalyst is first reduced and activated before the isooctenal gas phase is contacted 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, and the nitrogen volume space velocity is maintained at 300h -1 -600h -1 , keep the temperature constant for 1h-2h to remove the physical water adsorbed by the catalyst, then introduce a mixed gas of hydrogen and nitrogen to reduce the catalyst, and maintain the volume space velocity of the mixed gas at 300h -1 -600h -1, and the volume fraction of hydrogen does not exceed 10%; then, after reduction for 1 hour, gradually increase the hydrogen concentration to volume fractions of 10%, 20%, 30%, 50%, and 100%, respectively, and control the hot spot temperature of the catalyst bed during the reduction process not to exceed 230°C; finally, raise the temperature to 200°C-230°C and reduce in a full hydrogen atmosphere for 2h-4h to obtain an activated catalyst.

[0069] Example 1

[0070] Weigh 202.0g of zinc nitrate, 90.4g of copper nitrate, and 51.2g of magnesium nitrate, and dissolve them in 1250mL of deionized water to obtain a copper-zinc-magnesium mixed salt solution; weigh 196.1g of sodium carbonate and dissolve it in 1850mL of deionized water to obtain an alkaline solution; co-precipitate the copper-zinc-magnesium mixed salt solution and the alkaline solution in a 65°C water bath with stirring paddles, and control the pH of the mixed solution to be 9.0-9.2 during the precipitation process. After co-precipitation, age at 70°C for 30min, dry at 100°C for 12h after washing, and calcine at 400°C for 4h to obtain the oxide.

[0071] Weigh 23.6g of calcium nitrate and dissolve it in 100mL of deionized water to obtain a calcium nitrate solution. Weigh 10g of H-β molecular sieve and place it in the calcium nitrate solution. Perform ion exchange treatment for 3h in a water bath at 80℃ and stirring with a stirring paddle, and filter. Repeat the above process twice, and then calcine the obtained sample at 550℃ for 4h 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 of the ball mill, add grinding balls, adjust the speed of the grinding balls to 500r / min, and ball mill for 12h. The ball-milled catalyst and the additive are evenly mixed and formed into tablets using a tabletting machine to obtain a formed catalyst, wherein the ratio of acid sites to basic sites in the prepared catalyst is 1.14:1.

[0073] Example 2

[0074] Weigh 220.3g of zinc nitrate, 126.5g of copper nitrate, and 38.4g of magnesium nitrate, and dissolve them in 1450mL of deionized water to obtain a copper-zinc-magnesium mixed salt solution; weigh 165.1g of sodium carbonate and dissolve it in 1550mL of deionized water to obtain an alkaline solution; co-precipitate the copper-zinc-magnesium mixed salt solution and the alkaline solution in a 60°C water bath with stirring paddles, and control the pH of the mixed solution to be 7.3-7.5 during the precipitation process. After co-precipitation, age at 65°C for 30min, dry at 100°C for 12h after washing, and calcine at 350°C for 4h to obtain the oxide.

[0075] Weigh 23.6g of calcium nitrate and dissolve it in 100mL of deionized water to obtain a calcium nitrate solution. Weigh 10g of H-β molecular sieve and place it in the calcium nitrate solution. Perform ion exchange treatment for 3h in a water bath at 80℃ with stirring paddles, and filter. Repeat the above process twice, and then calcine the obtained sample at 550℃ for 4h 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 of the ball mill, add grinding balls, adjust the speed of the grinding balls to 500r / min, and ball mill for 16h. The ball-milled catalyst and the additive are evenly mixed and formed into tablets using a tabletting machine to obtain a formed catalyst, wherein the ratio of the number of acid sites to the number of basic sites in the prepared catalyst is 0.93:1.

[0077] Example 3

[0078] Weigh 233.6g of zinc nitrate, 119.3g of copper nitrate, and 38.4g of magnesium nitrate, and dissolve them in 1450mL of deionized water to obtain a copper-zinc-magnesium mixed salt solution; weigh 189.5g of sodium carbonate and dissolve it in 1800mL of deionized water to obtain an alkaline solution; co-precipitate the copper-zinc-magnesium mixed salt solution and the alkaline solution in a 60°C water bath with stirring paddles, and control the pH of the mixed solution to be 8.0-8.2 during the precipitation process. After co-precipitation, age at 65°C for 30min, dry at 100°C for 12h after washing, and calcine at 350°C for 4h to obtain the oxide.

[0079] The subsequent preparation process is consistent with Example 2. Finally, the ratio of the number of acid sites to basic sites in the prepared catalyst is 1.02:1, indicating that the number of acid sites and basic sites in the catalyst is almost the same, so that the acidity and alkalinity of the catalyst are suitable, with high activity, high selectivity of the target product and low selectivity of unsaturated by-products. As shown in Table 1, at this time, the conversion rate of isooctene aldehyde is the highest, and the selectivity of 2-ethylhexanol is the highest, and the selectivity of 2-ethylhexanal and the selectivity of heavy components are the lowest.

[0080] Example 4

[0081] Weigh 233.6g of zinc nitrate, 119.3g of copper nitrate, and 38.4g of magnesium nitrate, and dissolve them in 1450mL of deionized water to obtain a copper-zinc-magnesium mixed salt solution; weigh 189.5g of sodium carbonate and dissolve it in 1800mL of deionized water to obtain an alkaline solution; co-precipitate the copper-zinc-magnesium mixed salt solution and the alkaline solution in a 60°C water bath with stirring paddles, and control the pH of the mixed solution to be 8.5-8.7 during the precipitation process. After co-precipitation, age at 65°C for 30min, dry at 100°C for 12h after washing, and calcine at 350°C for 4h to obtain the oxide.

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

[0083] Example 5

[0084] Weigh 264.4g of zinc nitrate, 126.5g of copper nitrate, and 46.1g of magnesium nitrate, and dissolve them in 1600mL of deionized water to obtain a copper-zinc-magnesium mixed salt solution; weigh 229.0g of sodium carbonate and dissolve it in 2150mL of deionized water to obtain an alkaline solution; co-precipitate the copper-zinc-magnesium mixed salt solution and the alkaline solution in a 65°C water bath with stirring paddles, and control the pH of the mixed solution to be 8.0-8.2 during the precipitation process. After co-precipitation, age at 70°C for 30min, dry at 100°C for 12h after washing, and calcine at 350°C for 4h to obtain the oxide.

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

[0086] Weigh 100g of oxide and 3.0g of Ca-β molecular sieve, place them in the ball mill of the ball mill, add grinding balls, adjust the speed of the grinding balls to 450r / min, and ball mill for 20h. Mix the ball-milled catalyst and the additives evenly and use a tabletting machine to form a tablet to obtain a formed catalyst. Finally, the ratio of the number of acid sites to basic sites in the prepared catalyst is 0.90:1.

[0087] Experimental example

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

[0089] Catalyst reduction 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, and the nitrogen volume space velocity was maintained at 480 h -1 , keep the temperature constant for 2 hours to remove the physical water adsorbed by the catalyst. Then, a mixed gas of hydrogen and nitrogen is introduced to reduce the catalyst, the volume fraction of hydrogen is 2%, and after reduction for at least 1 hour, the concentration of hydrogen is gradually increased to 5%, 10%, 20%, 50%, and 100% by volume, and the hot spot temperature of the catalyst bed is controlled not to exceed 230°C during the reduction process; finally, the temperature is raised to 230°C and reduced for 2 hours in a full hydrogen atmosphere to obtain an activated catalyst.

[0090] Catalytic reaction evaluation: After the catalyst was reduced and activated, the isooctenal was gasified and mixed with H2 as the reaction raw material at an inlet temperature of 155°C and a reaction pressure of 0.4 MPa. The volumetric space velocity of the isooctenal liquid was controlled to be 0.4 h-1 , the molar ratio of H2 to isooctene aldehyde is 80: 1. Under this condition, isooctene aldehyde hydrogenation reaction is carried out to obtain a reaction product. The isooctene aldehyde conversion rate, 2-ethylhexanol selectivity, 2-ethylhexanal selectivity and heavy component selectivity are shown in Table 1 below.

[0091]

[0092]

[0093] As can be seen from Table 1, the CuZnMgOx&Ca-β catalyst provided by the present invention can obtain a catalytic effect of high isooctylaldehyde conversion, high 2-ethylhexanol selectivity, low unsaturated 2-ethylhexanal selectivity and low heavy component selectivity. As shown in Examples 3 and 4, especially when the number of acid sites and basic sites in the catalyst is almost close, the conversion rate of isooctylaldehyde is the highest, the selectivity of 2-ethylhexanol is the highest, and the selectivity of 2-ethylhexanal and the selectivity of heavy components are both low.

[0094] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A catalyst for preparing 2-ethylhexanol, characterized in that: The catalyst comprises, on a weight basis, 28 wt% to 38 wt% of copper oxide, 45 wt% to 60 wt% of zinc oxide, 3 wt% to 12 wt% of magnesium oxide, and 2 wt% to 8 wt% of Ca-β molecular sieve.

2. The catalyst for preparing 2-ethylhexanol according to claim 1, characterized in that The ratio of acidic sites to basic sites in the catalyst is 0.75-1.15:

1.

3. A method for preparing a catalyst for preparing 2-ethylhexanol as claimed in claim 1 or 2, characterized in that: The preparation method comprises the following steps: Step 1: mixing a copper-zinc-magnesium mixed salt solution consisting of a copper salt solution, a zinc salt solution and a magnesium salt solution with an alkaline solution at a suitable temperature and pH to generate a precipitate, and then aging, filtering, washing, drying and roasting to obtain an 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 alkali solution is 0.5 mol / L-2 mol / L; Step 2: subjecting the H-β molecular sieve to ion exchange reaction in a calcium nitrate solution for 1 to 3 times, filtering, and calcining to obtain a Ca-β molecular sieve; Step 3: mixing the oxide and the Ca-β molecular sieve and grinding them to obtain a crude product, and mixing the crude product with a molding aid to prepare the molded catalyst; Wherein, the mass fraction of the Ca-β molecular sieve in the crude product is 2wt%-8wt%.

4. The method for preparing a catalyst for preparing 2-ethylhexanol according to claim 3, characterized in that: The copper salt solution, zinc salt solution and magnesium salt solution are respectively any one of the corresponding nitrate solutions and acetate solutions or a mixed salt solution of two thereof, 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.

5. The method for preparing a catalyst for preparing 2-ethylhexanol according to claim 3, characterized in that: The alkaline solution is any one of a sodium carbonate solution and a sodium bicarbonate solution or a mixed alkaline solution of the two, and the molar concentration of the alkaline molecules in the alkaline solution is 0.8 mol / L-1.2 mol / L.

6. The method for preparing a catalyst for preparing 2-ethylhexanol according to claim 3, characterized in that: The total molar concentration of metal ions in the copper-zinc-magnesium mixed salt solution is kept the same as the molar concentration of alkali molecules in the alkali solution.

7. The method for preparing a catalyst for preparing 2-ethylhexanol according to claim 3, characterized in that: In the step 1, the copper-zinc-magnesium mixed salt solution consisting of a copper salt solution, a zinc salt solution and a magnesium salt solution is mixed with an alkaline solution at a suitable temperature and pH to generate a precipitate, comprising: The temperature of the copper-zinc-magnesium mixed salt solution and the alkaline solution when mixed is 55°C-70°C and the pH is 7.0-9.5, and a precipitate is generated in a parallel flow precipitation manner.

8. The method for preparing a catalyst for preparing 2-ethylhexanol by gas phase hydrogenation of isooctene aldehyde according to claim 3, characterized in that: In the step 2, 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.

9. The method for preparing a catalyst for preparing 2-ethylhexanol by gas phase hydrogenation of isooctene aldehyde according to claim 3, characterized in that: The grinding process in step 3 is ball milling, and the ball milling time is 12h-24h; The diameter of the grinding balls used in the ball milling process is 5mm-20mm, and the rotation speed of the grinding balls is 400r / min-500r / min.

10. Use of a catalyst for preparing 2-ethylhexanol as claimed in claim 1 or 2 or a catalyst prepared by the preparation method as claimed in any one of claims 3 to 9, characterized in that: The catalyst is used for the contact reaction of isooctyl aldehyde with hydrogen in gas phase to generate 2-ethylhexanol.

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