A catalyst for selective hydrogenation synthesis of 2-ethylhexanal and its application method

Abstract

The present invention provides a catalyst for synthesizing 2-ethylhexanal by selective hydrogenation and its application method, the catalyst composition is as follows (based on 100% of the total weight of the catalyst): (a) 1-40% nickel oxide; (b) 0.5-20% cobalt oxide, zinc oxide, copper oxide or zirconium oxide in one or more transition metal oxides; (c) 0.1-10% selected from one or more rare earth metal oxides in Ce, La, Sm; (d) 0.01-7% selected from one or two oxides in P, B; (e) the rest is silicon oxide and / or aluminum oxide. The catalyst of the present invention uses non-precious metal nickel as an active component, and the addition of transition metal elements is beneficial to improve the selectivity of hydrogenation of carbon-carbon double bonds; At the same time, the addition of rare earth metal elements can improve the dispersion of Ni on the carrier, thereby improving the activity and stability of the catalyst. The catalyst of the present invention has the advantages of high raw material conversion rate and product selectivity and long catalyst life, and can be applied to the industrial production of 2-ethylhexanal.

Description

Technical Field

[0001] The invention belongs to the technical field of selective hydrogenation, and particularly relates to a catalyst for synthesizing 2-ethylhexanal through selective hydrogenation of 2-ethylhexenal and an application method thereof. Background Art

[0002] 2-Ethylhexanal, also known as isooctylaldehyde, is mainly used as a fragrance and a raw material for synthesizing other compounds. For example, it is used to synthesize 2-ethylhexanoic acid (also known as isooctyl acid), which is widely used in the fields of medicine, fragrances, dyes, fungicides, cosmetics, resins, plastics, etc. In addition, isooctyl acid can be used to prepare isooctyl salts, which are used as driers. Compared with traditional cyclopentyl salt driers, isooctyl salt driers have obvious performance advantages and are gradually replacing cyclopentyl salt driers, with a growing demand.

[0003] At present, 2-ethylhexanal is mainly prepared by selective hydrogenation of 2-ethylhexanal. Most of the Pd-based catalysts are used in industry, and the yield can reach about 97%. However, the precious metal Pd is expensive and has high requirements for raw materials, which leads to high production costs. In recent years, more research has focused on the field of hydrogenation catalysts using non-precious metals such as Ni and other metals. For example, patent GB1102796A discloses a Ni / diatomaceous earth catalyst, which uses sulfide to poison part of the Ni catalyst to improve the selectivity of saturated aldehydes. At 225°C and normal pressure, the yield of 2-ethylhexanal is 96%, but the reaction is a gas phase hydrogenation reaction with a high reaction temperature, and the raw materials are prone to cracking and other side reactions. Patent US4018831A uses a Ni-based catalyst prepared by coprecipitation method, and at 120°C and 3.4MPa, the conversion rate of 2-ethylhexanal is 88%, and the selectivity of 2-ethylhexanal is 94%. CN114471618A discloses a sulfur-doped carbon-supported Ni-based catalyst, which has a 2-ethylhexanal conversion rate of 72.1% and a product selectivity of 89.1% at 70°C and 10MPa. The above non-precious metal-based 2-ethylhexanal selective hydrogenation catalysts have the disadvantages of high reaction pressure and high reaction temperature, and the 2-ethylhexanal yields of these catalysts are all low. Summary of the invention

[0004] The object of the present invention is to provide a selective hydrogenation catalyst with low cost and high 2-ethylhexanal yield and an application method thereof. The prepared catalyst has the characteristics of high specific surface area and good dispersion of active components, and achieves high conversion rate of raw material 2-ethylhexanal and high selectivity of 2-ethylhexanal under mild liquid phase hydrogenation conditions.

[0005] The present invention achieves the above object through the following technical scheme: a catalyst for selective hydrogenation synthesis of 2-ethylhexanal and its application method, based on 100% of the total weight of the catalyst, comprising the following components:

[0006] (a) 1 to 40% nickel oxide;

[0007] (b) 0.5-20% of one or more transition metal oxides selected from the group consisting of cobalt oxide, zinc oxide, copper oxide and zirconium oxide;

[0008] (c) 0.1-10% of one or more rare earth metal oxides selected from Ce, La, and Sm;

[0009] (d) 0.01-7% of one or two non-metallic oxides selected from P and B;

[0010] (e) The remainder is silicon oxide and / or aluminum oxide.

[0011] The catalyst of the present invention has a specific surface area of ​​150 to 400 m 2 / g.

[0012] The precursor of the catalyst active component Ni is selected from nickel nitrate, basic nickel carbonate, nickel chloride or nickel acetate; the precursor of the active component Co, Zn, Cu or Zr is selected from the corresponding sulfate, hydrochloride, nitrate or organic acid salt thereof.

[0013] The present invention also provides a method for applying the catalyst for selective hydrogenation synthesis of 2-ethylhexanal. The method adopts the catalyst of the present invention, takes 2-ethylhexanal and a solvent as raw materials, and reacts with H2 to obtain a hydrogenation product; the hydrogenation product is then subjected to removal of light and heavy impurities to obtain high-purity 2-ethylhexanal.

[0014] The solvent is selected from methanol, ethanol, n-butanol, cyclohexanol, 2-ethylhexanol or 2-ethylhexanal, preferably 2-ethylhexanal; the mixing ratio of the solvent to the raw material 2-ethylhexenal is (by mass) 0.5-50.

[0015] The selective hydrogenation reactor can be designed as a bubbling bed, trickle bed or fixed bed reactor.

[0016] The reaction pressure of the selective hydrogenation reaction is 0.5-5.0 MPa, the reaction temperature is 30-300°C, the ratio of hydrogen to raw material is (molar) 1.01-20, and the raw material volume space velocity is 0.1-20.0 h -1 .

[0017] The catalyst of the present invention uses Ni as an active component, which significantly reduces the production cost of the catalyst; at the same time, the catalyst of the present invention adds Co, Zn, Cu or Zr transition metal elements, which is conducive to improving the selectivity of carbon-carbon double bond hydrogenation and reducing the generation of by-products. In addition, the present invention obtains a carrier with suitable acidity and specific surface area by adding non-metallic elements such as P and B and a small amount of rare earth metal elements to the carrier, wherein the addition of rare earth elements is conducive to improving the dispersion of Ni on the carrier, thereby increasing the number of active centers of the catalyst, extending the service life of the catalyst and improving the conversion rate of the raw material.

[0018] The present invention is further described below by way of examples, but they are not intended to limit the scope of the present invention. DETAILED DESCRIPTION

[0019] Example 1

[0020] First, 300 g of pseudo-boehmite, 12 g of sesbania powder and 30 g of carbon black were weighed and mixed evenly, and then 300 g of an aqueous solution containing 6.6 g of silica sol (40% by mass), 4.3 g of phosphoric acid (85% by mass), 26.3 g of lanthanum nitrate, 15 g of cerium nitrate and 12 g of nitric acid (65% by mass) was added, kneaded and squeezed into The catalyst was prepared into a clover strip, dried at 110°C for 12 hours, and calcined at 650°C for 5 hours to obtain carrier Z1. Then, 3.2 g of cobalt nitrate was weighed and dissolved in 10 g of water, and the above cobalt nitrate solution was mixed with 148 g of nickel nitrate solution (14% Ni) to form an impregnation solution. Finally, carrier Z1 was impregnated in the impregnation solution for 12 hours, dried at 120°C, and calcined at 450°C for 6 hours to obtain catalyst C1. The catalyst composition and physicochemical properties are shown in Table 1, where the content of each component is based on the total weight of the catalyst.

[0021] Example 2

[0022] First, 300 g of pseudo-boehmite, 12 g of sesbania powder and 20 g of carbon black were weighed and mixed evenly, and then 300 g of an aqueous solution containing 36.2 g of silica sol (mass fraction 40%), 5.88 g of phosphoric acid (85% mass concentration), 12.86 g of boric acid, 20.6 g of cerium nitrate, 14 g of samarium nitrate and 10 g of nitric acid (65% mass concentration) was added, kneaded and squeezed into The catalyst was prepared into a clover strip, dried at 110°C for 12h, and calcined at 850°C for 5h to obtain the carrier Z2. Then, 84.2g of zinc nitrate was weighed and dissolved in 100g of water, and the zinc nitrate solution was mixed with 406.5g of nickel acetate solution (14% Ni) to form an impregnation solution. Finally, the carrier Z2 was impregnated in the impregnation solution for 12h, dried at 120°C, and calcined at 500°C for 6h to obtain the catalyst C2. The catalyst composition and physicochemical properties are shown in Table 1, where the content of each component is based on the total weight of the catalyst.

[0023] Example 3

[0024] First, 300 g of aluminum oxide, 10 g of sesbania powder and 25 g of carbon black were weighed and mixed evenly, and then 300 g of an aqueous solution containing 59.1 g of silica sol (40% by mass), 59 g of lanthanum nitrate, 5.7 g of samarium nitrate and 13 g of nitric acid (65% by mass) was added, kneaded and squeezed into The catalyst was prepared into a clover strip, dried at 110°C for 12h, and calcined at 680°C for 5h to obtain the carrier Z3. Then, 153.8g of cobalt chloride was weighed and dissolved in 150g of water, and the above cobalt chloride solution was mixed with 1328g of nickel acetate solution (14% Ni) to form an impregnation solution. Finally, the carrier Z3 was impregnated in the impregnation solution for 12h, dried at 120°C, and calcined at 400°C for 6h to obtain the catalyst C3. The catalyst composition and physicochemical properties are shown in Table 1, where the content of each component is based on the total weight of the catalyst.

[0025] Example 4

[0026] First, 300 g of pseudo-boehmite, 15 g of sesbania powder and 25 g of carbon black were weighed and mixed evenly, and then 300 g of an aqueous solution containing 13.4 g of phosphoric acid (85% mass concentration), 2.7 g of lanthanum nitrate and 3 g of nitric acid (65% mass concentration) was added, kneaded and squeezed into The catalyst was prepared into a clover strip, dried at 110°C for 12 hours, and calcined at 650°C for 5 hours to obtain the carrier Z4. Then, 31.9 g of zinc nitrate was weighed and dissolved in 30 g of water, and the zinc nitrate solution was mixed with 231.1 g of nickel nitrate solution (14% Ni) to form an impregnation solution. Finally, the carrier Z4 was impregnated in the impregnation solution for 12 hours, dried at 110°C, and calcined at 500°C for 6 hours to obtain the catalyst C4. The catalyst composition and physicochemical properties are shown in Table 1, where the content of each component is based on the total weight of the catalyst.

[0027] Example 5

[0028] First, 300 g of alumina, 12 g of sesbania powder and 20 g of carbon black were weighed and mixed evenly, and then 300 g of an aqueous solution containing 38.4 g of silica sol (40% by mass), 48.5 g of cerium nitrate, 9.9 g of samarium nitrate and 14 g of nitric acid (65% by mass) was added, kneaded and squeezed into The catalyst was prepared into a clover strip, dried at 110°C for 12 hours, and calcined at 700°C for 5 hours to obtain the carrier Z5. Then, 177.5 g of cobalt chloride was weighed and dissolved in 200 g of water, and the above cobalt chloride solution was mixed with 862.5 g of nickel nitrate solution (14% Ni) to form an impregnation solution. Finally, the carrier Z5 was impregnated in the impregnation solution for 12 hours, dried at 120°C, and calcined at 450°C for 6 hours to obtain the catalyst C5. The catalyst composition and physicochemical properties are shown in Table 1, where the content of each component is based on the total weight of the catalyst.

[0029] Example 6

[0030] First, 300 g of pseudo-boehmite, 12 g of sesbania powder and 30 g of carbon black were weighed and mixed evenly, and then 300 g of an aqueous solution containing 17.2 g of silica sol (40% by mass), 11.2 g of phosphoric acid (85% by mass), 34.33 g of lanthanum nitrate and 5 g of nitric acid (65% by mass) was added, kneaded and squeezed into The catalyst was prepared into a clover strip, dried at 110°C for 12 hours, and calcined at 650°C for 5 hours to obtain the carrier Z6. Then, 84g of cobalt nitrate was weighed and dissolved in 80g of water, and the above cobalt nitrate solution was mixed with 386.5g of nickel nitrate solution (14% Ni) to form an impregnation solution. Finally, the carrier Z6 was impregnated in the impregnation solution for 12 hours, dried at 120°C, and calcined at 480°C for 6 hours to obtain the catalyst C6. The catalyst composition and physicochemical properties are shown in Table 1, where the content of each component is based on the total weight of the catalyst.

[0031] Comparative Example 1

[0032] The catalyst D1 without transition metal was prepared by the same preparation steps and conditions as the carrier and catalyst in Example 6. The composition and physicochemical properties of the catalyst are shown in Table 1, wherein the content of each component is based on the total weight of the catalyst.

[0033] Comparative Example 2

[0034] Catalyst D2 free of rare earth metals was prepared by the same preparation steps and conditions as those for the carrier and catalyst in Example 6. The composition and physicochemical properties of the catalyst are shown in Table 1, wherein the content of each component is based on the total weight of the catalyst.

[0035] Table 1 Catalyst composition and physicochemical properties

[0036]

[0037] The catalyst samples C1, C2, C3, C4, C5, C6, D1 and D2 obtained in Examples 1-6 and Comparative Examples 1-2 were respectively placed in a bubbling bed reactor, and the performance of the catalyst selective hydrogenation was evaluated using 2-ethylhexenal as a raw material.

[0038] The catalyst was activated with hydrogen before use. The catalyst evaluation conditions were:

[0039] Reaction temperature: 80°C;

[0040] Reaction pressure: 2.0MPa;

[0041] Catalyst loading: 100g;

[0042] Hydrogen / 2-ethylhexenal (mole): 5.

[0043] The catalyst hydrogenation activity and selectivity are shown in Table 2.

[0044] Table 2 Catalyst hydrogenation activity and selectivity

[0045]

[0046] It can be concluded from Table 2 that the catalyst of the present invention has excellent selective hydrogenation performance, the conversion rate of the raw material 2-ethylhexanal is greater than 99.5%, and the selectivity of the product 2-ethylhexanal is greater than 99%.

Claims

1. A catalyst for selective hydrogenation synthesis of 2-ethylhexanal, comprising the following components based on 100% of the total weight of the catalyst: (a) 10-40% nickel oxide; (b) 0.5-20% of one or two transition metal oxides selected from cobalt oxide and zinc oxide; (c) 0.5-10% of one or more rare earth metal oxides selected from Ce, La, and Sm; (d) 1-3% of one or two non-metallic oxides selected from P and B; (e) The remainder is silicon oxide or aluminum oxide.

2. The catalyst according to claim 1, characterized in that The catalyst has a specific surface area of ​​150 to 400 m 2 / g.

3. The catalyst according to claim 1, characterized in that The precursor of the active component Ni is selected from nickel nitrate, basic nickel carbonate, nickel chloride or nickel acetate; the precursor of the active component Co or Zn is selected from the corresponding sulfate, hydrochloride, nitrate or organic acid salt thereof.

4. A method for using a catalyst for selective hydrogenation to synthesize 2-ethylhexanal, characterized in that The catalyst described in claims 1 to 3 is used, 2-ethylhexanal and a solvent are used as raw materials, and reacted with H2 to obtain a hydrogenation product; the hydrogenation product is then subjected to removal of light and heavy impurities to obtain high-purity 2-ethylhexanal.

5. The catalyst application method according to claim 4, characterized in that The solvent is selected from methanol, ethanol, n-butanol, cyclohexanol, 2-ethylhexanol or 2-ethylhexanal, and the mixing ratio of the solvent to the raw material 2-ethylhexenal is (mass ratio) 0.5-50.

6. The catalyst application method according to claim 4, characterized in that The selective hydrogenation reactor can be designed as a bubbling bed, trickle bed or fixed bed reactor.

7. The catalyst application method according to claim 4, characterized in that The reaction pressure of the selective hydrogenation reaction is 0.5-5.0 MPa, the reaction temperature is 30-300°C, the ratio of hydrogen to raw material (molar ratio) is 1.01-20, and the raw material volume space velocity is 0.1-20.0 h -1 .

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