Preparation method of catalyst for liquid-phase hydrofining of crude octanol

Abstract

The invention discloses a preparation method of a catalyst for liquid-phase hydrofining of crude octanol, and the preparation method comprises the following steps: (1) mixing pretreated fly ash and pseudo-boehmite, adding deionized water and nitric acid, stirring until a colloid is formed, drying the colloid, mixing with kaolin, kneading, carrying out extrusion molding, drying and roasting to obtain a carrier; and (2) taking nickel salt, manganese salt and zinc salt as active components, taking calcium salt as an auxiliary component, dissolving the active components and the auxiliary component in deionized water to obtain a salt solution, adding n-hexane into the salt solution, uniformly stirring to prepare an impregnation liquid, putting the carrier into the impregnation liquid for impregnation, and then washing, drying and roasting to obtain the catalyst. The catalyst prepared by the method provided by the invention is mainly used in a crude octanol liquid phase hydrofining reaction process, and has high activity stability and selectivity.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts for the liquid-phase hydrogenation refining reaction of crude octanol, and particularly relates to a preparation method for a catalyst for the liquid-phase hydrogenation refining of crude octanol. Background Art

[0002] Butanol and octanol are important basic organic chemical raw materials. At present, the production methods of butanol and octanol in the world mainly use the low-pressure rhodium method to produce butyraldehyde, which is then condensed into octenal. Butyraldehyde and octenal are hydrogenated to obtain butanol and octanol. There are two types of hydrogenation processes: gas phase and liquid phase. At present, the product quality of the liquid-phase method is better than that of the gas-phase method. There are various types of liquid-phase hydrogenation catalysts in the world. The active component is basically Ni as the first choice, and the promoters are Cu, Cr, Mo, Mn, Co, Fe, K, Na, etc. The carrier is preferably SiO2, followed by Al2O3-Fe2O3 or ZrO2.

[0003] In China, the current production method of butanol and octanol is mainly the oxo process. The hydrogenation process used to have both gas-phase and liquid-phase processes. At present, the gas-phase method has basically added a liquid-phase supplementary hydrogenation process, that is, a refining process, to improve product quality. The 50,000-ton butanol and octanol / year device of Jilin Petrochemical Company uses a liquid-phase hydrogenation process, and the catalyst of BASF Company is used in this process. However, with the continuous increase in the price of imported catalysts, the production cost has been remaining high. Therefore, it is particularly urgent to develop a catalyst with low cost for the domestic market.

[0004] Patent CN99107761.X discloses a liquid-phase hydrogenation catalyst, its preparation method and application. The carrier of the catalyst is selected from SiO2 or diatomite, nickel is the first active component, and other active components are selected from cobalt, molybdenum, chromium, potassium; by weight percentage, the nickel content is 5-40; the content of cobalt and molybdenum is 0.2-5.0. The active components are supported on the SiO2 or diatomite carrier by impregnation or co-precipitation. The present invention can be used in the liquid-phase hydrogenation process for preparing saturated alcohols from saturated and unsaturated aldehydes. The preparation method of this catalyst is simple and the cost is low, but the activity and selectivity of this catalyst need to be improved.

[0005] Patent CN201610443254.X discloses an aldehyde hydrogenation catalyst and its preparation method. The catalyst is composed of a catalyst unit with a core-shell structure and a promoter. The shell layer of the catalyst unit is composed of NiO and SiO2, and the core layer is composed of Ni3Si2O5(OH)4. The preparation process includes: first, preparing nickel-silicon precipitate by precipitation method, then performing heat treatment by constant-temperature air-blowing drying and microwave heating furnace to obtain the catalyst unit, and finally mixing the catalyst unit with the promoter and performing shaping treatment to obtain the core-shell structure aldehyde liquid-phase hydrogenation catalyst. The selectivity of the catalyst prepared by this method is improved, but the stability of the catalyst prepared by this method still needs to be improved. Summary of the Invention

[0006] Aiming at the problems of high preparation cost, and the stability and selectivity to be improved of the catalyst used in the current hydrogenation reaction of refined liquid phase, the present invention provides a preparation method for a catalyst for liquid phase hydrogenation refining of crude octanol.

[0007] To solve the above technical problems, the present invention provides the following technical solutions: A preparation method for a catalyst for liquid phase hydrogenation refining of crude octanol, the preparation method comprising: (1) Mix the pretreated fly ash and pseudo-boehmite, then add deionized water and nitric acid, stir until a colloid is formed, dry the colloid and mix it with kaolin, and obtain a support after kneading, extrusion molding, drying and calcination; (2) Nickel salt, manganese salt and zinc salt are used as active components, and calcium salt is used as an auxiliary component. The active components and the auxiliary component are dissolved in deionized water to obtain a salt solution. Add n-hexane to the salt solution and stir evenly to prepare an impregnation solution. Immerse the support in the impregnation solution, and then obtain the catalyst after washing, drying and calcination.

[0008] Further, the method for pretreating fly ash is as follows: the fly ash is sieved to obtain fly ash with uniform particle size, then the fly ash, deionized water and N-methyldiethanolamine are mixed and placed in a hydrothermal reaction kettle. After the reaction is completed, it is filtered and dried to obtain the pretreated fly ash.

[0009] Further, the volume ratio of the N-methyldiethanolamine to the deionized water is 0.5:10.

[0010] Further, the hydrothermal reaction conditions are as follows: in a high-pressure reaction kettle with a polytetrafluoroethylene inner liner, react at 105 °C for 12 hours; After the hydrothermal reaction, wait for the reaction solution to cool to room temperature, filter to remove the supernatant, wash with deionized water, centrifuge to collect the precipitate, and dry the obtained precipitate.

[0011] Further, the mass ratio of the pretreated fly ash to the pseudo-boehmite is 1:5-10.

[0012] Further, the dosage of kaolin is 35-50 wt% of the mass of the colloid, preferably, the dosage of kaolin is 40 wt% of the mass of the colloid.

[0013] Further, the nickel salt, manganese salt, zinc salt and calcium salt are nitrates, and the molar ratio of the metals Ni, Mn, Zn, Ca in the nickel salt, manganese salt, zinc salt and calcium salt is 5:0.1-2:0.1-2:0.05; The volume of the n-hexane is 0.5-2% of the volume of the salt solution, preferably, the volume of the n-hexane is 1% of the volume of the salt solution.

[0014] Furthermore, the impregnation is over-volume impregnation, and the impregnation time is 10 - 15 hours. The calcination is carried out in a muffle furnace at 700 °C for 4 - 7 hours.

[0015] The crude octanol liquid-phase hydrogenation refining catalyst obtained by the preparation method of the crude octanol liquid-phase hydrogenation refining catalyst described above. The present invention has the following beneficial effects: 1. A preparation method of a catalyst for crude octanol liquid-phase hydrogenation refining provided by the present invention. The carrier of this catalyst is prepared using fly ash and pseudo-boehmite as raw materials. By pretreating the fly ash, the carrier has high stability and can still exhibit good activity after being used for 500 h, which can reduce the cost of the catalyst in the octanol preparation process to a certain extent and improve the overall efficiency of octanol synthesis.

[0016] 2. A preparation method of a catalyst for crude octanol liquid-phase hydrogenation refining provided by the present invention. By appropriately proportioning nickel salt, manganese salt, zinc salt, and calcium salt, the active component and promoter component of the catalyst are formed, so that the catalyst has good activity and selectivity.

[0017] 3. A preparation method of a catalyst for crude octanol liquid-phase hydrogenation refining provided by the present invention. During the preparation process of loading the active component and promoter component onto the carrier, n-hexane is added to the impregnation solution, and by controlling the addition amount of n-hexane, the activity of the catalyst is further improved.

[0018] 4. A preparation method of a catalyst for crude octanol liquid-phase hydrogenation refining provided by the present invention. The preparation method of the catalyst is easy to control, the preparation method is simple, and it is very suitable for industrial production. Specific Embodiments

[0019] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. The reagents and equipment used in the present invention are all known products or obtained by purchasing commercially available products.

[0020] Example 1 The fly ash passes through a 40-mesh sieve to obtain fly ash with uniform particle size. Then, the fly ash, deionized water, and N-methyldiethanolamine are mixed and placed in a high-pressure reaction kettle with a polytetrafluoroethylene inner liner. The volume ratio of N-methyldiethanolamine to deionized water is 0.5:10, and the fly ash is 40% of the mass of deionized water. The reaction conditions are 105 °C for 12 hours. After the reaction, wait for the reaction solution to cool to room temperature, filter to remove the supernatant, wash with deionized water, centrifuge to collect the precipitate, and dry the obtained precipitate at 110 °C for 12 hours to obtain pretreated fly ash.

[0021] (1) Mix the pretreated fly ash and pseudoboehmite, then add deionized water and nitric acid. The mass ratio of the pretreated fly ash to pseudoboehmite is 1:5. The amount of deionized water is 2.5 times the total mass of fly ash and pseudoboehmite. The concentration of nitric acid is 6 mol / L, which is used to adjust the final pH to 4.5, and then stir until a colloid is formed.

[0022] After drying the colloid, mix it with kaolin. The dosage of kaolin is 40wt% of the mass of the colloid. Then, after kneading and extruding into a clover shape, dry it at 120°C for 8 hours, and calcine it in a tube furnace under an air atmosphere at 650°C for 5 hours to obtain the support.

[0023] (2) Weigh the corresponding nitrates according to the molar ratio of metals Ni, Mn, Zn, and Ca in nickel salt, manganese salt, zinc salt, and calcium salt nitrates as 5:1:0.5:0.05, and dissolve them in deionized water to obtain a salt solution. Add n-hexane to the salt solution to prepare an impregnation solution. The volume of n-hexane is 0.5% of the volume of the salt solution. Immerse the support in the impregnation solution for volume impregnation for 12 hours, then wash it with deionized water, dry it in a vacuum drying oven at 100°C for 8 hours, and then calcine it in a muffle furnace under an air atmosphere at 700°C for 4 hours to obtain the catalyst.

[0024] Example 2 Pass the fly ash through a 40-mesh sieve to obtain fly ash with uniform particle size. Then, mix the fly ash, deionized water, and N-methyldiethanolamine and place them in a high-pressure reactor with a polytetrafluoroethylene inner liner. The volume ratio of N-methyldiethanolamine to deionized water is 0.5:10, and the fly ash is 40% of the mass of deionized water. The reaction conditions are 105°C for 12 hours. After the reaction, wait for the reaction solution to cool to room temperature, filter to remove the supernatant, wash it with deionized water, centrifuge to collect the precipitate, and dry the obtained precipitate at 110°C for 12 hours to obtain the pretreated fly ash.

[0025] (1) Mix the pretreated fly ash and pseudoboehmite, then add deionized water and nitric acid. The mass ratio of the pretreated fly ash to pseudoboehmite is 1:8. The amount of deionized water is 2.5 times the total mass of fly ash and pseudoboehmite. The concentration of nitric acid is 6 mol / L, which is used to adjust the final pH to 5.5, and then stir until a colloid is formed.

[0026] After drying the colloid, mix it with kaolin. The dosage of kaolin is 50wt% of the mass of the colloid. Then, after kneading and extruding into a clover shape, dry it at 120°C for 8 hours, and calcine it in a tube furnace under an air atmosphere at 650°C for 5 hours to obtain the support.

[0027] (2) Weigh the corresponding nitrates according to the molar ratio of metals Ni, Mn, Zn, and Ca in nickel nitrate, manganese nitrate, zinc nitrate, and calcium nitrate being 5:1:0.5:0.05, dissolve them in deionized water to obtain a salt solution, add n-hexane to the salt solution to prepare an impregnation solution, where the volume of n-hexane is 0.5% of the volume of the salt solution. Immerse the carrier in the impregnation solution for volume impregnation for 12 hours, then wash it with deionized water, dry it in a vacuum drying oven at 100 °C for 15 hours, and then calcine it in a muffle furnace in an air atmosphere at 700 °C for 4 hours to obtain the catalyst.

[0028] Example 3 The fly ash is sieved through a 40-mesh sieve to obtain fly ash with uniform particle size. Then, the fly ash, deionized water, and N-methyldiethanolamine are mixed and placed in a high-pressure reactor with a polytetrafluoroethylene inner lining. The volume ratio of N-methyldiethanolamine to deionized water is 0.5:10, and the fly ash is 40% of the mass of deionized water. The reaction conditions are 105 °C for 12 hours. After the reaction, wait for the reaction solution to cool to room temperature, filter to remove the supernatant, wash it with deionized water, centrifuge to collect the precipitate, and dry the obtained precipitate at 110 °C for 12 hours to obtain pretreated fly ash.

[0029] (1) Mix the pretreated fly ash and pseudoboehmite, then add deionized water and nitric acid. The mass ratio of the pretreated fly ash to pseudoboehmite is 1:10, the amount of deionized water is 2.5 times the total mass of the fly ash and pseudoboehmite, and the concentration of nitric acid is 6 mol / L, used to adjust the final pH to 4.5, and then stir until a colloid is formed.

[0030] Dry the colloid and mix it with kaolin. The dosage of kaolin is 40 wt% of the mass of the colloid. Then, after kneading and extruding into a clover shape, dry it at 120 °C for 8 hours, and calcine it in a tubular furnace in an air atmosphere at 650 °C for 5 hours to obtain the carrier.

[0031] (2) Weigh the corresponding nitrates according to the molar ratio of metals Ni, Mn, Zn, and Ca in nickel nitrate, manganese nitrate, zinc nitrate, and calcium nitrate being 5:2:2:0.05, dissolve them in deionized water to obtain a salt solution, add n-hexane to the salt solution to prepare an impregnation solution, where the volume of n-hexane is 1% of the volume of the salt solution. Immerse the carrier in the impregnation solution for volume impregnation for 10 hours, then wash it with deionized water, dry it in a vacuum drying oven at 100 °C for 8 hours, and then calcine it in a muffle furnace in an air atmosphere at 700 °C for 4 hours to obtain the catalyst.

[0032] Example 4 Fly ash is passed through a 40-mesh sieve to obtain fly ash with uniform particle size. Then, the fly ash, deionized water, and N-methyldiethanolamine are mixed and placed in a high-pressure reactor lined with polytetrafluoroethylene. The volume ratio of N-methyldiethanolamine to deionized water is 0.5:10, and the fly ash is 40% of the mass of deionized water. The reaction conditions are 105 °C for 12 hours. After the reaction, the reaction solution is cooled to room temperature, the supernatant is filtered off and washed with deionized water, and the precipitate is collected by centrifugation. The obtained precipitate is dried at 110 °C for 12 hours to obtain pretreated fly ash.

[0033] (1)The pretreated fly ash and pseudo-boehmite are mixed and then deionized water and nitric acid are added. The mass ratio of the pretreated fly ash to pseudo-boehmite is 1:5, the amount of deionized water is 2.5 times the total mass of fly ash and pseudo-boehmite, and the concentration of nitric acid is 6 mol / L, which is used to adjust the final pH to 5.5. Then, it is stirred until a colloid is formed.

[0034] The colloid is dried and then mixed with kaolin. The dosage of kaolin is 35 wt% of the mass of the colloid. After kneading and extruding into a clover shape, it is dried at 120 °C for 8 hours and then calcined in a tube furnace under an air atmosphere at 650 °C for 5 hours to obtain a support.

[0035] (2)The corresponding nitrates of nickel salt, manganese salt, zinc salt, and calcium salt are weighed according to the molar ratio of metals Ni, Mn, Zn, and Ca in the nitrates of 5:0.1:0.1:0.05, and they are dissolved in deionized water to obtain a salt solution. n-Hexane is added to the salt solution to prepare an impregnation solution. The volume of n-hexane is 1% of the volume of the salt solution. The support is placed in the impregnation solution and impregnated for 15 hours by volume. After washing with deionized water, it is dried in a vacuum drying oven at 100 °C for 8 hours, and then calcined in a muffle furnace under an air atmosphere at 700 °C for 7 hours to obtain a catalyst.

[0036] Comparative Example 1 Same as Example 1, except that the fly ash is not pretreated and is directly passed through a 40-mesh sieve and used for preparing the support.

[0037] Comparative Example 2 Same as Example 1, except that the mass ratio of the pretreated fly ash to pseudo-boehmite in step (1) is 0.5:5.

[0038] Comparative Example 3 Same as Example 1, except that the dosage of kaolin in step (1) is 20 wt% of the mass of the colloid.

[0039] Comparative Example 4 Same as Example 1, except that there is no calcium salt in step (2).

[0040] Comparative Example 5 Same as Example 1, except that in step (3), the volume of n-hexane in the impregnation solution is 5% of the volume of the salt solution.

[0041] Catalyst activity measurement method The prepared catalyst was reduced: the reduction medium was hydrogen, at a reduction temperature of 500 °C, the hydrogen space velocity was 6000 h -1 , and the reduction was carried out for 10 hours.

[0042] The reaction was carried out in a tubular reactor used in the laboratory. 50 mL of the crude octanol raw material liquid was measured and placed in the reactor. The ratio of 2-ethylhexenal to 2-ethylhexanol in the crude octanol raw material liquid was 1:4. 5 g of the catalyst was added. The reaction temperature was 110 °C, the reaction time was 5 h, the reaction pressure was 4.0 MPa, and the space velocity of the crude octanol raw material liquid was 1.1 h -1 . The detailed composition of the materials before and after was detected by gas phase analysis. The gas phase analysis instrument used a Shimadzu GC-1000 gas chromatograph in Japan to analyze and detect the component content in the sample, and the analysis method was the normalization method.

[0043] The specific detection results are shown in Table 1 below. Table 1 Experiment Conversion rate of 2-ethylhexenal Selectivity of 2-ethylhexanol Example 1 98.7% 99.3% Example 2 97.9% 99.5% Example 3 99.5% 99.8% Example 4 99.2% 99.3% Comparative Example 1 90.7% 95.2% Comparative Example 2 95.3% 94.6% Comparative Example 3 93.9% 91.8% Comparative Example 4 95.5% 83.2% Comparative Example 5 84.8% 93.1% It can be seen from the detection results in Table 1 above that since the metal salt is an important element that determines the final activity and selectivity of the catalyst, when no calcium salt is added as an additive, its selectivity decreases significantly, and the effect on the activity is not significant; when the n-hexane added in the impregnation solution exceeds a certain range, the activity of the catalyst decreases significantly.

[0044] In order to detect the stability of the catalyst, the specific test method is as follows. The prepared catalyst was evaluated for 500 hours of operation. The reaction conditions were the same as those in the catalyst activity measurement method. The composition of the hydrogenated material was analyzed by chromatography, and the detection results are shown in Table 2.

[0045] Table 2 Item Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 6 Conversion rate of 5h-2-ethylhexenal 98.7% 90.7% 95.3% 93.9% Conversion rate of 500h-2-ethylhexenal 97.1% 75.6% 85.1% 81.4% It can be seen from the data in Table 2 above that the catalyst prepared in Example 1 can still maintain a high activity after 500 h of use and has very good stability. While the fly ash was not pretreated, the activity decreased by 16.6% after 500 h. In addition, during the preparation process of the carrier, the mass ratio of fly ash to pseudo-boehmite, and the change in the amount of kaolin used will also have a relatively obvious impact on the stability of the catalyst.

Claims

1. A method for preparing a catalyst for liquid phase hydrogenation refining of crude octanol, characterized in that: The preparation method comprises: (1) pre-treated fly ash and pseudo-boehmite are mixed, deionized water and nitric acid are added, and the mixture is stirred until a colloid is formed. The colloid is dried and mixed with kaolin, and the carrier is obtained after kneading, extrusion molding, drying and roasting; (2) Nickel salt, manganese salt and zinc salt are used as active components, and calcium salt is used as an auxiliary component. The active components and auxiliary components are dissolved in deionized water to obtain a salt solution. n-hexane is added to the salt solution and stirred evenly to prepare an impregnation solution. The carrier is immersed in the impregnation solution and then washed, dried and calcined to obtain a catalyst.

2. The method for preparing a catalyst for liquid phase hydrogenation refining of crude octanol according to claim 1, characterized in that: The method for pretreating fly ash is as follows: the fly ash is sieved to obtain fly ash with uniform particle size, and then the fly ash, deionized water and N-methyldiethanolamine are mixed and placed in a hydrothermal reactor, and after the reaction is completed, the pretreated fly ash is filtered and dried to obtain the pretreated fly ash.

3. The method for preparing a catalyst for liquid phase hydrogenation refining of crude octanol according to claim 2, characterized in that: The volume ratio of the N-methyldiethanolamine to deionized water is 0.5:

10.

4. The method for preparing a catalyst for liquid phase hydrogenation refining of crude octanol according to claim 2, characterized in that: The hydrothermal reaction conditions were: in a polytetrafluoroethylene-lined autoclave, 105°C for 12 hours; After the hydrothermal reaction, the reaction solution is cooled to room temperature, the supernatant is removed by filtration, washed with deionized water, the precipitate is collected by centrifugation, and the obtained precipitate is dried.

5. The method for preparing a catalyst for liquid phase hydrogenation refining of crude octanol according to claim 1, characterized in that: The mass ratio of the pretreated fly ash to pseudo-boehmite is 1: 5-10.

6. The method for preparing a catalyst for liquid phase hydrogenation refining of crude octanol according to claim 1, characterized in that: The amount of kaolin used is 35-50wt% of the mass of the colloid. Preferably, the amount of kaolin used is 40wt% of the mass of the colloid.

7. The method for preparing a catalyst for liquid phase hydrogenation refining of crude octanol according to claim 1, characterized in that: The nickel salt, manganese salt, zinc salt and calcium salt are nitrates, and the molar ratio of metal Ni, Mn, Zn and Ca in the nickel salt, manganese salt, zinc salt and calcium salt is 5:0.1-2: 0.1-2:0.05; The volume of the n-hexane is 0.5-2% of the volume of the salt solution. Preferably, the volume of the n-hexane is 1% of the volume of the salt solution.

8. The method for preparing a catalyst for liquid phase hydrogenation refining of crude octanol according to claim 1, characterized in that: The impregnation is over volume impregnation, the impregnation time is 10-15 hours, and the calcination is calcined in a muffle furnace at 700° C. for 4-7 hours.

9. The crude octanol liquid phase hydrogenation refining catalyst prepared according to the preparation method for the crude octanol liquid phase hydrogenation refining catalyst according to any one of claims 1 to 8.