Catalyst for synthesizing isobutanol, preparation method and application thereof
By preparing catalysts with ZrO2-SiO2 composite support and ZnCrOx support combined with CuO active components, the problems of harsh reaction conditions and low selectivity of isobutanol in the synthesis of isobutanol from syngas were solved, realizing efficient and low-energy-consumption isobutanol synthesis, which is suitable for industrial application.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF COAL CHEM CHINESE ACAD OF SCI
- Filing Date
- 2026-03-10
- Publication Date
- 2026-06-26
AI Technical Summary
Existing catalysts require harsh reaction conditions in the synthesis of isobutanol from syngas, have low selectivity for isobutanol, and consume high energy to separate alcohol products, making industrialization difficult.
A ZrO2-SiO2 composite support was prepared by alkaline reflux method. Combined with ZnCrOx support and CuO active component, and with the addition of alkali metal promoters K or Cs, a catalyst was prepared by co-precipitation and impregnation methods to form active centers that couple CHxO with non-dissociated adsorbed CO, thereby promoting the formation of isobutanol.
Isobutanol was synthesized efficiently at lower temperatures and pressures. Methanol and isobutanol accounted for more than 96% of the total alcohols in the alcohol products, with other alcohols being less abundant. The subsequent separation process had low energy consumption, with a CO conversion rate of up to 63.8% and an isobutanol selectivity of 47.6%, demonstrating industrialization potential.
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Figure CN122273531A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of catalysts for chemical products, and relates to a catalyst for synthesizing isobutanol from synthesis gas, a preparation method and application thereof. BACKGROUND
[0002] In addition to being used as a basic organic chemical raw material to synthesize chemicals, isobutanol is also used to produce synthetic rubber, artificial musk, fruit essence, synthetic drug intermediates and rare earth purification agents, and has good market application prospects. Isobutanol can be used as a gasoline additive to reduce PM2.5 emissions when mixed with diesel; as aviation fuel, it can reduce the risk of fuel price fluctuations, and was listed in the oil additive directory by the US Environmental Protection Agency in 2010, and has potential market. With the rapid growth of demand for butyl rubber, the demand for high-purity isobutene is increasing year by year, and coal-to-isobutanol (non-petroleum route) technology is expected to give birth to a new production route for high-purity isobutene, reducing the dependence of isobutene production on petroleum resources.
[0003] In industry, isobutanol is mainly derived from by-products in the synthesis of butanol / octanol from propylene carbonylation, and the yield is low. With the increasing depletion of petroleum resources, it is necessary to research and develop new raw materials and new processes for the preparation of isobutanol. In existing research, there are mainly two catalyst systems for isobutanol as the target product starting from synthesis gas: modified methanol catalyst system (high-temperature high-pressure ZnCr catalyst and low-temperature low-pressure CuZnAl catalyst) and ZrO2-based catalyst system.
[0004] An Wei et al. (Fuel Chemistry, 1994, 22 (1): 63-69) used ZnCr as a catalyst, at 10.0 MPa, H2 / CO=1.9, 5000h -1 , 400℃, the selectivity of isobutanol was 10.36%, and the selectivity of methanol+isobutanol was 89.19%. Cheng Shuyan et al. (Natural Gas Chemical Industry-C1 Chemistry and Chemical Industry, 2018, 43 (2): 14-18) used CuZnAl as a catalyst, at 4.0 MPa, H 2 / CO=2, 2000h -1 , 320℃, the selectivity of isobutanol was 15.54%, and the selectivity of methanol+isobutanol was 86.53%.
[0005] European Patent (EP0208102A2) used a catalyst composed of ZrO2-CeO2-Pd-alkali metal / alkaline earth metal to increase the content of isobutanol in the synthesis of alcohol from synthesis gas. Under the conditions of a reaction temperature of 420℃, a pressure of 25 MPa, and a space velocity of 13600h -1 , the content of isobutanol in the liquid product was 40.4%, and the content of methanol+isobutanol was 84.3%.
[0006] Chinese patent CN105080545 A discloses a catalyst for the hydrogenation of CO to isobutanol. This catalyst primarily consists of zirconium, copper, silicon, and aluminum, and operates at a reaction temperature of 360°C and a reaction pressure of 6.0 MPa. 2 / CO=2, air velocity 5000 h -1 Under the specific process conditions, the CO conversion rate reached a maximum of 46.4%, the isobutanol selectivity reached a maximum of 36.7%, and the methanol + isobutanol selectivity reached 93.8%.
[0007] Chinese patent CN106311267A discloses a catalyst for the synthesis of isobutanol from syngas, its preparation method, and its application. The catalyst is prepared by a co-precipitation method, and its components are CuO, ZrO2, MnO2, NiO, and Fe2O3, with oxides of alkali metals and noble metals added as promoters. The reaction is carried out at a temperature of 400℃, a pressure of 6MPa, and a syngas space velocity of 8000h⁻¹. -1 Under the reaction conditions, the proportions of methanol and isobutanol in the liquid phase product are higher than 85%, and the proportion of isobutanol is higher than 29%.
[0008] Chinese patent CN102029166 A relates to a catalyst for producing low-carbon mixed alcohols from syngas. This catalyst is prepared using a co-precipitation method, wherein the precursors of Zr, Mn, and Cu are all nitrates. The addition of starch during preparation increases the specific surface area of the catalyst, effectively improving the dispersion of the oxides, preventing sintering, and significantly enhancing the catalyst's stability. This catalyst operates under mild reaction conditions, with C... 2+ The selectivity for alcohols can be greater than 36 wt%, the selectivity for isobutanol can be greater than 25 wt%, the selectivity for hydrocarbons (mainly methane) can be less than 4 wt%, and the selectivity for methanol + isobutanol can reach up to 85.6%.
[0009] Chinese patent CN112657506A discloses a method for preparing a catalyst for the synthesis of isobutanol from syngas. The catalyst is mainly composed of oxides of Mn, Zn, and Zr. An alkali metal stabilizer is added during the preparation process, followed by impregnation of Cu and Pd salts onto a support. A lubricant and water are added, and the catalyst is then pressed into tablets to obtain the catalyst. The catalyst is used for the synthesis of isobutanol from syngas, exhibiting good isobutanol selectivity, good catalyst stability, and mild reaction conditions. The product contains up to 40% isobutanol, with a 26.3% CO conversion rate and an 82.4% total alcohol selectivity, including over 10% of other alcohols besides methanol and isobutanol.
[0010] Chinese patent CN106540680A discloses a catalyst for the synthesis of isobutanol from syngas and its uses; the catalyst has the general molecular formula Zn. a B b C c D d O xWherein, B is selected from at least one element in Group IA of the periodic table, C is selected from at least one element in Group VIB of the periodic table, and D is selected from at least one lanthanide metal. This catalyst is used in reactions at 400℃ and 10.0 MPa, with H... 2 / CO=1, air velocity 10000 h / h -1 Under the specific process conditions, the molar content of isobutanol in the alcohol can reach up to 40% or more, and the selectivity of methanol + isobutanol can reach up to 70.7%.
[0011] In summary, existing technologies employ relatively harsh reaction conditions for ZnCr catalysts: above 400℃ and pressure greater than 10MPa. Modified low-temperature methanol synthesis catalysts, compared to high-temperature catalysts, exhibit milder reaction conditions: 270–360℃ and 6–8MPa. The products are primarily methanol and isobutanol, but the carbon monoxide conversion rate is low, and the isobutanol selectivity is also low. While zirconium-based catalysts primarily produce methanol and isobutanol as alcohol products, the ZrO2 crystal structure is easily altered, resulting in poor stability. Furthermore, in currently developed catalyst systems, the methanol + isobutanol selectivity for total alcohols is generally below 90%, with higher contents of other alcohols such as ethanol and propanol. This leads to high energy consumption for subsequent product separation, hindering industrial-scale application. Summary of the Invention
[0012] To overcome the above shortcomings, the present invention provides a catalyst with mild reaction conditions and high selectivity for isobutanol. The present invention also provides a method for preparing the catalyst and its application in the synthesis of isobutanol from syngas.
[0013] The catalyst provided by this invention has small and uniform particle size and a simple preparation process. First, a ZrO2-SiO2 composite support is prepared using an alkaline reflux method. This support has a large specific surface area and is rich in -OH groups. These groups not only serve as active centers for dispersing and anchoring the active component Cu, but also activate CO to form CH4. x O species (active C1 intermediate in isobutanol formation); ZnCrO x The composite support contains a large number of non-stoichiometric ZnCr spinel structures with abundant oxygen vacancies, providing rich active sites for the non-dissociative adsorption of CO (another active C1 intermediate in the formation of isobutanol); the introduction of Cu can achieve adsorption activation of H2 and CO at a lower temperature, and then provide H and CO to the composite support through the overflow effect; the introduction of alkali metals K or Cs can enhance the basicity of the catalyst surface, providing basic sites for the condensation reaction in the formation of isobutanol. x O couples with non-dissociated adsorbed CO to form a C2 intermediate. This C2 intermediate, catalyzed by a basic site, then reacts with CH4. x O species undergoes a continuous condensation reaction to form isobutanol.
[0014] This invention provides a catalyst for the synthesis of isobutanol from syngas, comprising a composite support, an active component Cu oxide, and an alkali metal oxide auxiliary.
[0015] In this invention, the carrier is preferably a high specific surface area ZrO2-SiO2 carrier and a ZnCrO2 carrier. x A mixture of carriers; the active component is preferably CuO; the alkali metal auxiliaries are either K2O or Cs2O.
[0016] The weight percentages of each component of the catalyst are as follows: ZrO2-SiO2 composite support: 28.69%~37.70%; ZnCrO x Composite carrier: 53.80%~65.54%; Active component CuO: 2.95%~6.13%; Alkali metal oxide additives: 2.58%~5.87%; The Si / Zr molar ratio in the ZrO2-SiO2 composite support is 0.04~0.21:1; ZnCrO x The Zn / Cr molar ratio in the composite carrier is 0.5~1.0:1.
[0017] This invention provides a method for preparing the catalyst for the synthesis of isobutanol from syngas, comprising the following steps: (1) Using zirconium salt and silicon source as raw materials, a high specific surface area ZrO2-SiO2 composite carrier was prepared in an alkaline solution by alkaline reflux method; (2) ZnCrO was prepared by co-precipitation using zinc salt, chromium salt, and alkali as raw materials. x Composite carrier; (3) The composite support ZrO2-SiO2 (A) and ZnCrO x The composite support (B) was mixed at a mass ratio of 0.44~0.70 and then ball-milled. Cu was introduced into the mixed support by impregnation. After impregnation, drying and calcination, the catalyst precursor was obtained. (4) K or Cs is introduced into the catalyst precursor by impregnation, and the catalyst is obtained by impregnation, drying and calcination.
[0018] The specific preparation process of step (1) is as follows: Zirconium salt and silicon source are dissolved in deionized water to prepare a cationic aqueous solution with a Si / Zr molar ratio of 0.04~0.21:1. An alkaline reagent is added dropwise under stirring to induce precipitation. After precipitation, the mother liquor is transferred to a polytetrafluoroethylene flask for reflux. After reflux, the solution is filtered, and the filter cake is washed until neutral. The filtered cake is then dried and calcined to obtain the ZrO2-SiO2 composite support. The alkaline reagent is ethylenediamine or a 25% (mass concentration) ammonia solution. The specific preparation process of step (2) is as follows: Zinc salt and chromium salt are mixed and dissolved in deionized water to prepare a metal salt aqueous solution with a Zn / Cr molar ratio of 0.5~1.0:1; alkali is dissolved in deionized water to prepare an alkaline solution; the metal salt solution and alkaline solution are simultaneously added dropwise to a beaker for precipitation using a co-precipitation method; after precipitation, the solution is aged and then filtered; the resulting filter cake is dried and calcined to obtain ZnCrO. x Composite carrier.
[0019] Preferably, the zirconium salt in step (1) is zirconium nitrate dihydrate or zirconium oxychloride octahydrate, the silicon source is tetraethyl orthosilicate or sodium silicate, and the alkaline solution is ethylenediamine or 25% (wt%) ammonia. The total concentration of cations in the cation aqueous solution is 0.02~0.1 mol / L; Preferably, the precipitation temperature in step (1) is 30~60℃, the precipitation pH is 8~11, the reflux temperature is 80~100℃, and the reflux time is preferably 1~6 days.
[0020] After the precipitate from step (1) is refluxed, it is washed with deionized water until neutral, and then dried and calcined in sequence.
[0021] Preferably, the drying temperature in step (1) is 80~120℃ and the drying time is 4~8h; the calcination temperature is 350~550℃ and the calcination time is 4~10h.
[0022] Preferably, the zinc salt in step (2) is zinc nitrate hexahydrate or zinc acetate, the chromium salt is chromium nitrate nonahydrate or chromium acetate, and the alkali is ammonium carbonate; In step (2), the total concentration of metal ions in the salt solution is 0.05~0.15 mol / L; in step (2), the concentration of NH4+ in the alkaline solution is... + The concentration is 0.1~0.3 mol / L.
[0023] Preferably, the precipitation temperature in step (2) is 30~80℃, the pH of the precipitation is 8~12, and the aging time is 2~6h; The precipitate after aging in step (2) is filtered, and then the filter cake is dried and roasted in sequence.
[0024] Preferably, the drying temperature in step (2) is 80~120℃ and the drying time is 4~8h; the calcination temperature is 350~550℃ and the calcination time is 4~10h.
[0025] Preferably, after ball milling and mixing the composite carriers A and B in step (3), the Zr / Zn molar ratio is 0.82; Preferably, in step (3), Cu is added to the carrier in the form of a copper salt, which is preferably copper nitrate trihydrate or copper acetate monohydrate; the solvent used to dissolve the copper precursor is one of ammonia, ethanol, water or ethylene glycol; the concentration of copper ions is preferably 0.05~0.15 mol / L. Preferably, the immersion temperature in step (3) is 30~70℃ and the immersion time is 3~7h; The composite carrier after impregnation in step (3) is subjected to ultrasonic evaporation and drying in sequence, and then calcined. The ultrasonic evaporation frequency in step (3) is 20~100kHz, and the ultrasonic evaporation time is 4~8h; the drying temperature is 80~120℃, and the drying time is 4~8h; the calcination temperature is 400~600℃, and the calcination time is preferably 5~10h.
[0026] In step (4), when adding K, the K precursor is either potassium nitrate or potassium hydroxide; the concentration is 0.08~0.16 mol / L; the K / Zr molar ratio is preferably 0.21~0.42:1; In step (4), when adding Cs, the Cs precursor is either cesium nitrate or cesium carbonate; the concentration is 0.08~0.16 mol / L; the Cs / Zr molar ratio is 0.04~0.08:1; In step (4), when adding K or Cs elements, the impregnation solvent is water or ethanol.
[0027] Preferably, the immersion temperature in step (4) is 30~70℃ and the immersion time is 3~7h.
[0028] The catalyst precursor C, after impregnation in step (4), is subjected to ultrasonic evaporation and drying in sequence, and then calcined.
[0029] Preferably, the ultrasonic drying frequency in step (4) is 20~100kHz, the ultrasonic drying time is 4~8h, the drying temperature is 80~120℃, the drying time is 4~8h, the calcination temperature is 400~600℃, and the calcination time is 5~10h.
[0030] The present invention provides a catalyst obtained by the above preparation method.
[0031] This invention also provides the application of the above-mentioned catalyst in the direct preparation of isobutanol from syngas.
[0032] The specific application process is as follows: First, the catalyst is reduced by introducing H2 / N2 reducing gas into a fixed-bed reactor containing the catalyst, setting the temperature to 250~400℃ and the space velocity to 500~2000h. -1 After reduction at atmospheric pressure for 2-6 hours, syngas is introduced for catalytic reaction. The catalytic reaction process is as follows: the molar ratio of feed gas H2 / CO is 1:1-3:1, the reaction temperature is 300-360℃, the reaction pressure is 4.0-7.0 MPa, and the syngas space velocity is 2000-7000 h⁻¹. -1 Catalyst performance was evaluated under these conditions.
[0033] In the above applications, the volume ratio of H2 to N2 in the reducing gas is 10~30:100.
[0034] The beneficial effects of this invention are: (1) This invention provides a catalyst and its preparation method. After precipitation of an aqueous solution containing zirconium salt and silicon precursor, the catalyst is subjected to high-temperature reflux, filtration, washing, drying, and calcination to obtain a composite support ZrO2-SiO2; after precipitation of an aqueous solution containing zinc salt and chromium salt, the catalyst is subjected to filtration, drying, and calcination to obtain a composite support ZnCrO2. x The composite support ZrO2-SiO2 and ZnCrO x The catalyst precursor is obtained by ball milling and mixing, followed by impregnation with a copper salt solution, drying, and calcination. The catalyst precursor is then mixed with a K or Cs solution, impregnated, dried, and calcined to obtain the catalyst. This invention proposes a method for preparing catalysts using non-precious metals as active components, which features a simple process and low production costs and equipment investment.
[0035] (2) The catalyst provided by the present invention can synthesize isobutanol with high efficiency at lower reaction temperature and pressure. Methanol and isobutanol are the main alcohol products, accounting for more than 96% of the total alcohols, while other alcohols are less. The subsequent separation energy consumption is low. When the catalyst of the present invention is applied to the direct synthesis of isobutanol from catalytic synthesis gas, the CO conversion rate can reach up to 63.8%, and the selectivity of isobutanol in the product can reach up to 47.6%, which is more promising for industrial application. Attached Figure Description
[0036] Figure 1 The XRD patterns of the composite support ZrO2-SiO2 (A) in Examples 1 and 4 are shown. Figure 2 The IR spectra of the composite support ZrO2-SiO2 (A) in Examples 1 and 4 are shown. Figure 3 TEM images of the catalysts in Examples 1 and 4; Figure 4 The in-situ infrared diffuse reflectance spectra are for Comparative Examples 1, 2, 3 and Example 4. Detailed Implementation
[0037] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention. Example 1
[0038] 26.15 g of zirconium oxychloride octahydrate and 0.69 g of tetraethyl orthosilicate were dissolved in deionized water to prepare an aqueous solution with a total cation concentration of 0.02 mol / L and a Si / Zr molar ratio of 0.04. Ethylenediamine solution was added dropwise under stirring to induce precipitation at 30 °C. After precipitation, the pH of the mother liquor was 8. The mother liquor was transferred to a polytetrafluoroethylene flask for reflux at 80 °C for one day. After reflux, the solution was filtered, the filter cake was washed until neutral, dried at 80 °C for 4 hours, and then calcined at 350 °C for 4 hours to obtain the composite carrier ZrO2-SiO2(A) with a specific surface area of 398 m². 2 g -1 ; 29.60 g of zinc nitrate hexahydrate and 80.03 g of chromium nitrate nonahydrate were mixed and dissolved in deionized water to prepare an aqueous solution of the metal salt with a total metal ion concentration of 0.05 mol / L and a Zn / Cr molar ratio of 0.5. 47.95 g of ammonium carbonate was dissolved in deionized water to prepare an NH4+ solution. + A 0.1 mol / L alkaline solution was prepared by co-precipitation, in which the metal salt solution and the alkaline solution were simultaneously added dropwise to a beaker. The precipitation temperature was 30℃ and the pH of the precipitation was 10. After precipitation, the solution was aged for 2 hours and then filtered. The resulting filter cake was dried at 80℃ for 4 hours and then calcined at 350℃ for 4 hours to obtain composite carrier B. Composite supports A and B were ball-milled and mixed to obtain a mixed support. Then, 3.19 g of copper nitrate trihydrate was weighed and dissolved in 25% ammonia water to prepare an aqueous solution with a Cu ion concentration of 0.05 mol / L. This solution was added to the mixed support and impregnated at 30°C for 3 h. Then, it was ultrasonically dried at a frequency of 20 Hz and dried at 100°C for 6 h. After drying, it was calcined at 550°C for 6 h to obtain catalyst precursor C. 1.07 g of potassium nitrate was dissolved in deionized water to prepare a solution with a metal ion concentration of 0.09 mol / L. Catalyst precursor C was added to this solution and impregnated at 30 °C for 3 h. Then, it was ultrasonically evaporated at a frequency of 20 Hz, dried at 80 °C for 6 h, and calcined at 600 °C for 5 h to obtain the catalyst. The mass percentages of each component were: ZrO2, 28.14%; SiO2, 0.56%; ZnO, 22.78%; Cr2O3, 42.76%; CuO, 2.95%; K2O, 2.81%.
[0039] H2 and N2 reducing gases (H2 to N2 volume ratio of 20:100) were introduced into a fixed-bed reactor containing a catalyst, and the temperature was set at 250℃ and the space velocity was 1000 h⁻¹. -1 After reduction at atmospheric pressure for 2 hours, syngas was introduced, and the reaction was carried out at H2 / CO (molar ratio) = 1, 300℃, 6.0MPa, for 2000 hours. -1 Catalyst performance was evaluated under the following conditions. CO conversion (mol%) was 50.2%, and the selectivity (Cmol) for hydrocarbons, CO2, and alcohols were 40.4%, 18.8%, and 40.8%, respectively. The alcohol products included methanol, ethanol, propanol, isobutanol, and C... 4+ The alcohol distributions (Cmol) were 56.6%, 0.5%, 1.2%, 40.9%, and 0.8%, respectively, and the selectivity for methanol + isobutanol was 97.5%.
[0040] The Cmol mentioned above represents "carbon moles", meaning that the product composition is expressed as the percentage of carbon moles in each product. Example 2
[0041] 21.69 g of zirconium oxynitrate dihydrate and 1.22 g of sodium silicate were dissolved in deionized water to prepare an aqueous solution with a total cation concentration of 0.03 mol / L and a Si / Zr molar ratio of 0.12. A 25% ammonia solution was added dropwise under stirring to induce precipitation at 50 °C. After precipitation, the pH of the mother liquor was 11. The mother liquor was transferred to a polytetrafluoroethylene flask for reflux at 85 °C for 2 days. After reflux, the solution was filtered, the filter cake was washed until neutral, dried at 110 °C for 8 hours, and then calcined at 450 °C for 6 hours to obtain composite carrier A with a specific surface area of 415 m². 2 g -1 ; Mix 18.26 g of zinc acetate and 42.21 g of chromium acetate, dissolve in deionized water to prepare an aqueous solution of the metal salt with a total metal ion concentration of 0.1 mol / L and a Zn / Cr molar ratio of 0.54. Dissolve 45.67 g of ammonium carbonate in deionized water to prepare an NH4+ solution. + A 0.14 mol / L alkaline solution was prepared by co-precipitation, in which the metal salt solution and the alkaline solution were simultaneously added dropwise to a beaker. The precipitation temperature was 60℃ and the pH of the precipitation was 8. After precipitation, the solution was aged for 4 hours and then filtered. The resulting filter cake was dried at 100℃ for 8 hours and then calcined at 550℃ for 6 hours to obtain composite carrier B. Composite supports A and B were ball-milled and mixed to obtain a mixed support. Then, 3.01 g of copper acetate was weighed and dissolved in anhydrous ethanol to prepare a solution with a Cu ion concentration of 0.06 mol / L. This solution was added to the mixed support and impregnated at 40 °C for 4 h. Then, the solution was ultrasonically dried at a frequency of 40 Hz and dried at 100 °C for 5 h. After drying, the solution was calcined at 500 °C for 10 h to obtain catalyst precursor C. 0.71 g of potassium hydroxide was dissolved in anhydrous ethanol to prepare a solution with a metal ion concentration of 0.08 mol / L. Catalyst precursor C was added to this solution and impregnated at 40 °C for 4 h. Then, it was ultrasonically evaporated at a frequency of 40 Hz, dried at 100 °C for 5 h, and calcined at 500 °C for 10 h to obtain the catalyst. The mass percentages of each component were: ZrO2, 28.48%; SiO2, 1.71%; ZnO, 23.08%; Cr2O3, 39.89%; CuO, 3.42%; K2O, 3.42%.
[0042] H2 and N2 reducing gases (H2 to N2 volume ratio of 20:100) were introduced into a fixed-bed reactor containing a catalyst, and the temperature was set at 300℃ and the space velocity at 500 h⁻¹. -1 After reduction at atmospheric pressure for 6 hours, syngas was introduced, and the reaction was carried out at H2 / CO (molar ratio) = 2, 320℃, 7.0 MPa, for 3000 hours. -1 Catalyst performance was evaluated under the following conditions. CO conversion (mol%) was 54.4%, and the selectivity (Cmol) for hydrocarbons, CO2, and alcohols were 38.6%, 19.1%, and 42.3%, respectively. The alcohol products included methanol, ethanol, propanol, isobutanol, and C... 4+ The alcohol distributions (Cmol) were 54.6%, 0.8%, 1.1%, 42.9%, and 0.6%, respectively, with a methanol + isobutanol selectivity of 97.5%. Example 3
[0043] 26.15 g of zirconium oxychloride octahydrate and 0.61 g of sodium silicate were dissolved in deionized water to prepare an aqueous solution with a total cation concentration of 0.05 mol / L and a Si / Zr molar ratio of 0.06. A 25% ammonia solution was added dropwise under stirring to induce precipitation at 60 °C. After precipitation, the pH of the mother liquor was 8.5. The mother liquor was transferred to a polytetrafluoroethylene flask for reflux at 90 °C for 3 days. After reflux, the solution was filtered, the filter cake was washed until neutral, dried at 120 °C for 6 hours, and then calcined at 550 °C for 8 hours to obtain composite carrier A with a specific surface area of 423 m². 2 g -1 ; Mix 18.26 g of zinc acetate and 63.19 g of chromium nitrate nonahydrate, dissolve in deionized water to prepare a metal salt aqueous solution with a total metal ion concentration of 0.15 mol / L and a Zn / Cr molar ratio of 0.63. Dissolve 41.88 g of ammonium carbonate in deionized water to prepare an NH4+ solution. + A 0.18 mol / L alkaline solution was prepared by co-precipitation, in which the metal salt solution and the alkaline solution were simultaneously added dropwise to a beaker. The precipitation temperature was 80℃ and the pH of the precipitation was 12. After precipitation, the solution was aged for 6 hours and then filtered. The resulting filter cake was dried at 110℃ for 6 hours and then calcined at 450℃ for 8 hours to obtain composite carrier B. Composite supports A and B were ball-milled and mixed to obtain a mixed support. Then, 4.25g of copper nitrate trihydrate was weighed and dissolved in deionized water to prepare an aqueous solution with a Cu ion concentration of 0.14mol / L. This solution was added to the mixed support and impregnated at 50℃ for 4h. Then, it was ultrasonically dried at a frequency of 50Hz and dried at 120℃ for 8h. After drying, it was calcined at 400℃ for 6h to obtain catalyst precursor C. 1.00 g of cesium nitrate was dissolved in deionized water to prepare a solution with a metal ion concentration of 0.1 mol / L. Catalyst precursor C was added to this solution and impregnated at 50 °C for 4 h. Then, it was ultrasonically evaporated at a frequency of 50 Hz, dried at 120 °C for 8 h, and calcined at 400 °C for 6 h to obtain the catalyst. The mass percentages of the components were: ZrO2, 30.09%; SiO2, 0.90%; ZnO, 24.37%; Cr2O3, 36.10%; CuO, 4.21%; Cs2O, 4.33%.
[0044] H2 and N2 reducing gases (H2 to N2 volume ratio of 10:100) were introduced into a fixed-bed reactor containing a catalyst, and the temperature was set at 350℃ and the space velocity at 800 h⁻¹. -1 After reduction at atmospheric pressure for 5 hours, syngas was introduced, and the reaction was carried out at H2 / CO (molar ratio) = 1.5, 330℃, 5.0 MPa, for 3000 hours. -1 Catalyst performance was evaluated under the following conditions. CO conversion (mol%) was 56.4%, and the selectivity (Cmol) for hydrocarbons, CO2, and alcohols were 32.1%, 20.3%, and 47.6%, respectively. The alcohol products included methanol, ethanol, propanol, isobutanol, and C... 4+ The alcohol distributions (Cmol) were 57.0%, 1.0%, 1.3%, 40.3%, and 0.4%, respectively, with a methanol + isobutanol selectivity of 97.3%. Example 4
[0045] 26.15 g of zirconium oxychloride octahydrate and 0.81 g of sodium silicate were dissolved in deionized water to prepare an aqueous solution with a total cation concentration of 0.04 mol / L and a Si / Zr molar ratio of 0.08. A 25% ammonia solution was added dropwise under stirring to induce precipitation at 40°C. After precipitation, the pH of the mother liquor was 9. The mother liquor was transferred to a polytetrafluoroethylene flask for reflux at 95°C for 4 days. After reflux, the solution was filtered, the filter cake was washed until neutral, dried at 90°C for 5 hours, and then calcined at 500°C for 10 hours to obtain composite carrier A with a specific surface area of 462 m². 2 g -1 ; 29.60 g of zinc nitrate hexahydrate and 30.15 g of chromium acetate were mixed and dissolved in deionized water to prepare an aqueous solution of the metal salt with a total metal ion concentration of 0.12 mol / L and a Zn / Cr molar ratio of 0.76. 38.09 g of ammonium carbonate was dissolved in deionized water to prepare an NH4+ solution. + A 0.2 mol / L alkaline solution was prepared by co-precipitation, in which the metal salt solution and the alkaline solution were simultaneously added dropwise to a beaker. The precipitation temperature was 70℃ and the pH of the precipitation was 11. After precipitation, the solution was aged for 5 hours and then filtered. The resulting filter cake was dried at 120℃ for 7 hours and then calcined at 400℃ for 10 hours to obtain composite carrier B. Composite supports A and B were ball-milled and mixed to obtain a mixed support. Then, 4.40 g of copper nitrate trihydrate was weighed and dissolved in ethylene glycol to prepare an aqueous solution with a Cu ion concentration of 0.12 mol / L. This solution was added to the mixed support and impregnated at 60 °C for 3 h. Then, the solution was ultrasonically dried at a frequency of 40 Hz and dried at 100 °C for 5 h. After drying, the solution was calcined at 550 °C for 5 h to obtain catalyst precursor C. 1.72 g of potassium nitrate was dissolved in deionized water to prepare a solution with a metal ion concentration of 0.12 mol / L. Catalyst precursor C was added to this solution and impregnated at 60 °C for 3 h. Then, it was ultrasonically evaporated at a frequency of 40 Hz, dried at 100 °C for 5 h, and calcined at 550 °C for 5 h to obtain the catalyst. The mass percentages of the components were: ZrO2, 31.69%; SiO2, 1.27%; ZnO, 25.67%; Cr2O3, 31.70%; CuO, 4.60%; K2O, 5.07%.
[0046] H2 and N2 reducing gases (H2 to N2 volume ratio of 20:100) were introduced into a fixed-bed reactor containing a catalyst, and the temperature was set at 320℃ and the space velocity was 1200 h⁻¹. -1 After reduction at atmospheric pressure for 4 hours, syngas was introduced, and the reaction was carried out at an H2 / CO (molar ratio) of 2, 340℃, 5.0 MPa, for 5000 hours. -1Catalyst performance was evaluated under the following conditions. CO conversion (mol%) was 63.8%, and the selectivity (Cmol) for hydrocarbons, CO2, and alcohols were 28.1%, 15.2%, and 56.7%, respectively. The alcohol products included methanol, ethanol, propanol, isobutanol, and C... 4+ The alcohol distributions (Cmol) were 51.1%, 0.4%, 0.8%, 47.6%, and 0.1%, respectively, with a methanol + isobutanol selectivity of 98.7%. Example 5
[0047] 21.69 g of zirconium oxynitrate dihydrate and 0.69 g of tetraethyl orthosilicate were dissolved in deionized water to prepare an aqueous solution with a total cation concentration of 0.1 mol / L and a Si / Zr molar ratio of 0.04. Ethylenediamine solution was added dropwise under stirring to induce precipitation at 30 °C. After precipitation, the pH of the mother liquor was 8. The mother liquor was transferred to a polytetrafluoroethylene flask for reflux at 100 °C for 6 days. After reflux, the solution was filtered, the filter cake was washed until neutral, dried at 100 °C for 7 hours, and then calcined at 400 °C for 6 hours to obtain composite carrier A with a specific surface area of 423 m². 2 g -1 ; Mix 29.60 g of zinc nitrate hexahydrate and 55.29 g of chromium acetate, dissolve in deionized water to prepare an aqueous solution of the metal salt with a total metal ion concentration of 0.08 mol / L and a Zn / Cr molar ratio of 0.72. Dissolve 39.04 g of ammonium carbonate in deionized water to prepare an NH4+ solution. + A 0.25 mol / L alkaline solution was prepared by co-precipitation, in which the metal salt solution and the alkaline solution were simultaneously added dropwise to a beaker. The precipitation temperature was 40℃ and the pH of the precipitation was 9. After precipitation, the solution was aged for 4 hours and then filtered. The resulting filter cake was dried at 100℃ for 5 hours and then calcined at 500℃ for 8 hours to obtain composite carrier B. Composite supports A and B were ball-milled and mixed to obtain a mixed support. Then, 3.76 g of copper acetate was weighed and dissolved in 25% ammonia water to prepare an aqueous solution with a Cu ion concentration of 0.08 mol / L. This solution was added to the mixed support and impregnated at 70℃ for 6 h. Then, it was ultrasonically dried at a frequency of 40 Hz and dried at 110℃ for 4 h. After drying, it was calcined at 600℃ for 5 h to obtain catalyst precursor C. 2.19 g of cesium carbonate was weighed and dissolved in deionized water to prepare a solution with a metal ion concentration of 0.14 mol / L. Catalyst precursor C was added to this solution and impregnated at 70 °C for 6 h. Then, it was ultrasonically evaporated at a frequency of 40 Hz, dried at 110 °C for 4 h, and calcined at 600 °C for 5 h to obtain the catalyst. The mass percentages of each component were: ZrO2, 31.07%; SiO2, 0.62%; ZnO, 25.16%; Cr2O3, 32.62%; CuO, 4.66%; Cs2O, 5.87%.
[0048] H2 and N2 reducing gases (H2 to N2 volume ratio of 10:100) were introduced into a fixed-bed reactor containing a catalyst, and the temperature was set at 400℃ and the space velocity at 1000 h⁻¹. -1 After reduction at atmospheric pressure for 4 hours, syngas was introduced, and the reaction was carried out at H2 / CO (molar ratio) = 1, 350℃, 3.0MPa, for 7000 hours. -1 Catalyst performance was evaluated under the following conditions. CO conversion (mol%) was 52.8%, and the selectivity (Cmol) for hydrocarbons, CO2, and alcohols were 15.7%, 16.3%, and 68.0%, respectively. The alcohol products included methanol, ethanol, propanol, isobutanol, and C... 4+ The alcohol distributions (Cmol) were 58.0%, 0.9%, 1.5%, 38.9%, and 0.7%, respectively, with a methanol + isobutanol selectivity of 96.9%. Example 6
[0049] 26.15 g of zirconium oxychloride octahydrate and 0.81 g of sodium silicate were dissolved in deionized water to prepare an aqueous solution with a total cation concentration of 0.08 mol / L and a Si / Zr molar ratio of 0.08. Ethylenediamine solution was added dropwise under stirring to induce precipitation at 30 °C. After precipitation, the pH of the mother liquor was 8. The mother liquor was transferred to a polytetrafluoroethylene flask for reflux at 98 °C for 2 days. After reflux, the solution was filtered, the filter cake was washed until neutral, dried at 110 °C for 5 h, and then calcined at 450 °C for 8 h to obtain composite carrier A with a specific surface area of 445 m². 2 g -1 ; Mix 18.26 g of zinc acetate and 66.34 g of chromium nitrate nonahydrate, dissolve in deionized water to prepare an aqueous solution of the metal salt with a total metal ion concentration of 0.06 mol / L and a Zn / Cr molar ratio of 0.60. Dissolve 43.02 g of ammonium carbonate in deionized water to prepare an NH4+ solution. +A 0.3 mol / L alkaline solution was prepared by co-precipitation, in which the metal salt solution and the alkaline solution were simultaneously added dropwise to a beaker. The precipitation temperature was 50℃ and the pH of the precipitation was 10. After precipitation, the solution was aged for 3 hours and then filtered. The resulting filter cake was dried at 110℃ for 4 hours and then calcined at 380℃ for 5 hours to obtain composite carrier B. Composite supports A and B were ball-milled and mixed to obtain a mixed support. Then, 4.02 g of copper acetate was weighed and dissolved in anhydrous ethanol to prepare an aqueous solution with a Cu ion concentration of 0.06 mol / L. This solution was added to the mixed support and impregnated at 50 °C for 5 h. Then, the solution was ultrasonically dried at a frequency of 30 Hz and dried at 90 °C for 5 h. After drying, the solution was calcined at 500 °C for 9 h to obtain catalyst precursor C. 1.24 g of cesium nitrate was dissolved in anhydrous ethanol to prepare a solution with a metal ion concentration of 0.16 mol / L. Catalyst precursor C was added to this solution and impregnated at 50 °C for 5 h. Then, it was ultrasonically evaporated at a frequency of 30 Hz, dried at 90 °C for 6 h, and calcined at 500 °C for 9 h to obtain the catalyst. The mass percentages of the components were: ZrO2, 28.98%; SiO2, 1.16%; ZnO, 23.48%; Cr2O3, 36.52%; CuO, 4.64%; Cs2O, 5.22%.
[0050] H2 and N2 reducing gases (H2 to N2 volume ratio of 20:100) were introduced into a fixed-bed reactor containing a catalyst, and the temperature was set at 350℃ and the space velocity at 800 h⁻¹. -1 After reduction at atmospheric pressure for 4 hours, syngas was introduced, and the reaction was carried out at an H2 / CO (molar ratio) of 2.5, 360℃, 3.0 MPa, for 3000 hours. -1 Catalyst performance was evaluated under the following conditions. CO conversion (mol%) was 56.0%, and the selectivity (Cmol) for hydrocarbons, CO2, and alcohols were 30.9%, 18.9%, and 50.2%, respectively. The alcohol products included methanol, ethanol, propanol, isobutanol, and C... 4+ The alcohol distributions (Cmol) were 58.2%, 0.6%, 1.4%, 39.6%, and 0.2%, respectively, with a methanol + isobutanol selectivity of 97.8%. Example 7
[0051] 26.15 g of zirconium oxychloride octahydrate and 1.73 g of tetraethyl orthosilicate were dissolved in deionized water to prepare an aqueous solution with a total cation concentration of 0.06 mol / L and a Si / Zr molar ratio of 0.1. Ethylenediamine solution was added dropwise under stirring to induce precipitation at 50 °C. After precipitation, the pH of the mother liquor was 10. The mother liquor was then transferred to a polytetrafluoroethylene flask for reflux at 96 °C for 3 days. After reflux, the solution was filtered, the filter cake was washed until neutral, dried at 120 °C for 8 hours, and then calcined at 450 °C for 8 hours to obtain composite carrier A with a specific surface area of 450 m². 2 g -1 ; Mix 18.26 g of zinc acetate and 25.63 g of chromium acetate, dissolve in deionized water to prepare an aqueous solution of the metal salt with a total metal ion concentration of 0.1 mol / L and a Zn / Cr molar ratio of 0.89. Dissolve 35.24 g of ammonium carbonate in deionized water to prepare an NH4+ solution. + A 0.28 mol / L alkaline solution was prepared by co-precipitation, in which the metal salt solution and the alkaline solution were simultaneously added dropwise to a beaker. The precipitation temperature was 60℃ and the pH of the precipitation was 12. After precipitation, the solution was aged for 4 hours and then filtered. The resulting filter cake was dried at 120℃ for 8 hours and then calcined at 480℃ for 4 hours to obtain composite carrier B. Composite supports A and B were ball-milled and mixed to obtain a mixed support. Then, 4.52 g of copper acetate was weighed and dissolved in deionized water to prepare an aqueous solution with a Cu ion concentration of 0.1 mol / L. This solution was added to the mixed support and impregnated at 40 °C for 4 h. Then, it was ultrasonically dried at a frequency of 100 Hz and dried at 100 °C for 6 h. After drying, it was calcined at 400 °C for 6 h to obtain catalyst precursor C. 0.68 g of cesium nitrate was dissolved in anhydrous ethanol to prepare a solution with a metal ion concentration of 0.1 mol / L. Catalyst precursor C was added to this solution and impregnated at 40 °C for 4 h. Then, it was ultrasonically evaporated at a frequency of 100 Hz, dried at 100 °C for 6 h, and calcined at 400 °C for 6 h to obtain the catalyst. The mass percentages of the components were: ZrO2, 33.47%; SiO2, 1.67%; ZnO, 27.11%; Cr2O3, 28.45%; CuO, 6.02%; Cs2O, 3.28%.
[0052] H2 and N2 reducing gases (H2 to N2 volume ratio of 30:100) were introduced into a fixed-bed reactor containing a catalyst, and the temperature was set at 260℃ and the space velocity at 2000 h⁻¹. -1 After reduction at atmospheric pressure for 6 hours, syngas was introduced, and the reaction was carried out at H2 / CO (molar ratio) = 3, 340℃, 3.0 MPa, for 3000 hours. -1Catalyst performance was evaluated under the following conditions. CO conversion (mol%) was 51.3%, and the selectivity (Cmol) for hydrocarbons, CO2, and alcohols were 34.8%, 16.5%, and 48.7%, respectively. The alcohol products included methanol, ethanol, propanol, isobutanol, and C... 4+ The alcohol distributions (Cmol) were 56.1%, 1.0%, 1.1%, 41.5%, and 0.3%, respectively, with a methanol + isobutanol selectivity of 97.6%. Example 8
[0053] 21.69 g of zirconium oxynitrate dihydrate and 2.08 g of tetraethyl orthosilicate were dissolved in deionized water to prepare an aqueous solution with a total cation concentration of 0.06 mol / L and a Si / Zr molar ratio of 0.1. 25% ammonia solution was added dropwise under stirring to induce precipitation at 40°C. After precipitation, the pH of the mother liquor was 9. The mother liquor was transferred to a polytetrafluoroethylene flask for reflux at 88°C for 2 days. After reflux, the solution was filtered, the filter cake was washed until neutral, dried at 120°C for 8 hours, and then calcined at 450°C for 6 hours to obtain composite carrier A with a specific surface area of 420 m². 2 g -1 ; Mix 29.60 g of zinc nitrate hexahydrate and 28.94 g of chromium acetate, dissolve in deionized water to prepare an aqueous solution of the metal salt with a total metal ion concentration of 0.14 mol / L and a Zn / Cr molar ratio of 0.79. Dissolve 37.33 g of ammonium carbonate in deionized water to prepare an NH4+ solution. + A 0.16 mol / L alkaline solution was prepared by co-precipitation, in which the metal salt solution and the alkaline solution were simultaneously added dropwise to a beaker. The precipitation temperature was 80℃ and the pH of the precipitation was 12. After precipitation, the solution was aged for 4 hours and then filtered. The resulting filter cake was dried at 120℃ for 4 hours and then calcined at 500℃ for 6 hours to obtain composite carrier B. Composite supports A and B were ball-milled and mixed to obtain a mixed support. Then, 5.77 g of copper nitrate trihydrate was weighed and dissolved in ethylene glycol to prepare an aqueous solution with a Cu ion concentration of 0.14 mol / L. This solution was added to the mixed support and impregnated at 50 °C for 5 h. Then, it was ultrasonically dried at a frequency of 100 Hz and dried at 110 °C for 4 h. After drying, it was calcined at 450 °C for 9 h to obtain catalyst precursor C. 0.48 g of potassium hydroxide was dissolved in deionized water to prepare a solution with a metal ion concentration of 0.09 mol / L. Catalyst precursor C was added to this solution and impregnated at 50 °C for 5 h. Then, it was ultrasonically evaporated at a frequency of 100 Hz, dried at 110 °C for 3 h, and calcined at 450 °C for 8 h to obtain the catalyst. The mass percentages of the components were: ZrO2, 32.25%; SiO2, 1.94%; ZnO, 26.13%; Cr2O3, 30.97%; CuO, 6.13%; K2O, 2.58%.
[0054] H2 and N2 reducing gases (H2 to N2 volume ratio of 10:100) were introduced into a fixed-bed reactor containing a catalyst, and the temperature was set at 350℃ and the space velocity at 700 h⁻¹. -1 After reduction at atmospheric pressure for 3 hours, syngas was introduced, and the reaction was carried out at an H2 / CO (molar ratio) of 2.5, 300℃, 4.0 MPa, for 6000 hours. -1 Catalyst performance was evaluated under the following conditions. CO conversion (mol%) was 54.1%, and the selectivity (Cmol) for hydrocarbons, CO2, and alcohols were 25.4%, 12.6%, and 62.0%, respectively. The alcohol products included methanol, ethanol, propanol, isobutanol, and C... 4+ The alcohol distributions (Cmol) were 52.0%, 0.6%, 1.3%, 45.6%, and 0.5%, respectively, with a methanol + isobutanol selectivity of 97.6%. Example 9
[0055] 26.15 g of zirconium oxychloride octahydrate and 2.77 g of tetraethyl orthosilicate were dissolved in deionized water to prepare an aqueous solution with a total cation concentration of 0.09 mol / L and a Si / Zr molar ratio of 0.16. Ethylenediamine solution was added dropwise under stirring to induce precipitation at 40 °C. After precipitation, the pH of the mother liquor was 10. The mother liquor was then transferred to a polytetrafluoroethylene flask for reflux at 95 °C for 4 days. After reflux, the solution was filtered, the filter cake was washed until neutral, dried at 110 °C for 6 hours, and then calcined at 500 °C for 9 hours to obtain composite carrier A with a specific surface area of 453 m². 2 g -1 ; Mix 29.60 g of zinc nitrate hexahydrate and 42.12 g of chromium nitrate nonahydrate, dissolve in deionized water to prepare an aqueous solution of the metal salt with a total metal ion concentration of 0.15 mol / L and a Zn / Cr molar ratio of 0.95. Dissolve 34.30 g of ammonium carbonate in deionized water to prepare an NH4+ solution. +A 0.26 mol / L alkaline solution was prepared by co-precipitation, in which the metal salt solution and the alkaline solution were simultaneously added dropwise to a beaker. The precipitation temperature was 60℃ and the pH of the precipitation was 11. After precipitation, the solution was aged for 6 hours and then filtered. The resulting filter cake was dried at 110℃ for 4 hours and then calcined at 550℃ for 6 hours to obtain composite carrier B. Composite supports A and B were ball-milled and mixed to obtain a mixed support. Then, 5.01 g of copper nitrate trihydrate was weighed and dissolved in anhydrous ethanol to prepare an aqueous solution with a Cu ion concentration of 0.15 mol / L. This solution was added to the mixed support and impregnated at 70 °C for 7 h. Then, the solution was ultrasonically dried at a frequency of 80 Hz and dried at 110 °C for 8 h. After drying, the solution was calcined at 600 °C for 5 h to obtain catalyst precursor C. 0.97 g of potassium nitrate was dissolved in deionized water to prepare a solution with a metal ion concentration of 0.08 mol / L. Catalyst precursor C was added to this solution and impregnated at 70 °C for 6 h. Then, it was ultrasonically evaporated at a frequency of 70 Hz, dried at 110 °C for 6 h, and calcined at 600 °C for 5 h to obtain the catalyst. The mass percentages of each component were: ZrO2, 33.96%; SiO2, 2.72%; ZnO, 27.50%; Cr2O3, 27.16%; CuO, 5.60%; K2O, 3.06%.
[0056] H2 and N2 reducing gases (H2 to N2 volume ratio of 20:100) were introduced into a fixed-bed reactor containing a catalyst, and the temperature was set at 360℃ and the space velocity at 500 h⁻¹. -1 After reduction at atmospheric pressure for 5 hours, syngas was introduced, and the reaction was carried out at an H2 / CO (molar ratio) of 2, 320℃, 5.0 MPa, for 4000 hours. -1 Catalyst performance was evaluated under the following conditions. CO conversion (mol%) was 53.7%, and the selectivity (Cmol) for hydrocarbons, CO2, and alcohols were 31.5%, 16.9%, and 51.6%, respectively. The alcohol products included methanol, ethanol, propanol, isobutanol, and C... 4+ The alcohol distributions (Cmol) were 49.8%, 1.1%, 1.5%, 46.9%, and 0.7%, respectively, and the selectivity for methanol + isobutanol was 96.7%. Example 10
[0057] 26.15 g of zirconium oxychloride octahydrate and 2.03 g of sodium silicate were dissolved in deionized water to prepare an aqueous solution with a total cation concentration of 0.06 mol / L and a Si / Zr molar ratio of 0.21. 25% ammonia solution was added dropwise under stirring to induce precipitation at 30°C. After precipitation, the pH of the mother liquor was 11. The mother liquor was transferred to a polytetrafluoroethylene flask for reflux at 100°C for 4 days. After reflux, the solution was filtered, the filter cake was washed until neutral, dried at 100°C for 6 hours, and then calcined at 500°C for 7 hours to obtain composite carrier A with a specific surface area of 395 m². 2 g -1 ; Mix 18.26 g of zinc acetate and 22.91 g of chromium acetate, dissolve in deionized water to prepare an aqueous solution of the metal salt with a total metal ion concentration of 0.05 mol / L and a Zn / Cr molar ratio of 1.0. Dissolve 33.54 g of ammonium carbonate in deionized water to prepare an NH4+ solution. + A 0.2 mol / L alkaline solution was prepared by co-precipitation, in which the metal salt solution and the alkaline solution were simultaneously added dropwise to a beaker. The precipitation temperature was 60℃ and the pH of the precipitation was 10. After precipitation, the solution was aged for 4 hours and then filtered. The resulting filter cake was dried at 100℃ for 4 hours and then calcined at 400℃ for 6 hours to obtain composite carrier B. Composite supports A and B were ball-milled and mixed to obtain a mixed support. Then, 3.21 g of copper acetate was weighed and dissolved in 25% ammonia water to prepare an aqueous solution with a Cu ion concentration of 0.12 mol / L. This solution was added to the mixed support and impregnated at 60 °C for 3 h. Then, it was ultrasonically dried at a frequency of 70 Hz and dried at 120 °C for 5 h. After drying, it was calcined at 400 °C for 8 h to obtain catalyst precursor C. 1.39 g of cesium carbonate was dissolved in deionized water to prepare a solution with a metal ion concentration of 0.06 mol / L. Catalyst precursor C was added to this solution and impregnated at 60 °C for 3 h. Then, it was ultrasonically evaporated at a frequency of 70 Hz, dried at 120 °C for 5 h, and calcined at 400 °C for 8 h to obtain the catalyst. The mass percentages of the components were: ZrO2, 34.26%; SiO2, 3.43%; ZnO, 27.76%; Cr2O3, 26.05%; CuO, 4.39%; Cs2O, 4.11%.
[0058] H2 and N2 reducing gases (H2 to N2 volume ratio of 20:100) were introduced into a fixed-bed reactor containing a catalyst, and the temperature was set at 280℃ and the space velocity at 600 h⁻¹. -1 After reduction at atmospheric pressure for 4 hours, syngas was introduced, and the reaction was carried out at an H2 / CO (molar ratio) of 2, 300℃, 4.0 MPa, for 5000 hours. -1Catalyst performance was evaluated under the following conditions. CO conversion (mol%) was 46.9%, and the selectivity (Cmol) for hydrocarbons, CO2, and alcohols were 28.8%, 14.2%, and 57.0%, respectively. The alcohol products included methanol, ethanol, propanol, isobutanol, and C... 4+ The alcohol distributions (Cmol) were 54.0%, 0.7%, 1.6%, 43.3%, and 0.4%, respectively, with a methanol + isobutanol selectivity of 97.3%.
[0059] Comparative Example 1
[0060] 26.15 g of zirconium oxychloride octahydrate and 2.03 g of sodium silicate were dissolved in deionized water to prepare an aqueous solution with a total cation concentration of 0.06 mol / L and a Si / Zr molar ratio of 0.21. 25% ammonia solution was added dropwise under stirring to induce precipitation at 30°C. After precipitation, the pH of the mother liquor was 10. The mother liquor was then transferred to a polytetrafluoroethylene flask for reflux at 90°C for 4 days. After reflux, the solution was filtered, the filter cake was washed until neutral, dried at 100°C for 4 hours, and then calcined at 500°C for 5 hours to obtain a ZrO2-SiO2 catalyst with a specific surface area of 398 m². 2 g -1 The mass percentages of each component are ZrO2, 90.91% and SiO2, 9.09%.
[0061] H2 and N2 reducing gases (H2 to N2 volume ratio of 20:100) were introduced into a fixed-bed reactor packed with ZrO2-SiO2 catalyst, and the temperature was set at 280℃ and the space velocity at 600 h⁻¹. -1 After reduction at atmospheric pressure for 4 hours, syngas was introduced, and the reaction was carried out at an H2 / CO (molar ratio) of 2, 340℃, 4.0 MPa, for 5000 hours. -1 Catalyst performance was evaluated under the following conditions. CO conversion (mol%) was 11.2%, and the selectivity (Cmol, where Cmol represents "carbon moles," i.e., product composition expressed as the percentage of carbon moles in each product) for hydrocarbons, CO2, and alcohols were 38.4%, 35.1%, and 15.3%, respectively. Among the alcohol products, methanol, ethanol, propanol, isobutanol, and C... 4+ The alcohol distributions (Cmol) were 96.7%, 1.2%, 0.4%, 1.3%, and 0.4%, respectively. Although the selectivity of methanol + isobutanol reached 98%, the selectivity of isobutanol was only 1.3%, with methanol being the main product.
[0062] Comparative Example 2
[0063] Mix 18.26 g of zinc acetate and 22.91 g of chromium acetate, dissolve in deionized water to prepare an aqueous solution of the metal salt with a total metal ion concentration of 0.05 mol / L and a Zn / Cr molar ratio of 1.0. Dissolve 33.54 g of ammonium carbonate in deionized water to prepare an NH4+ solution. + A 0.2 mol / L alkaline solution was used for precipitation by simultaneously adding the metal salt solution and the alkaline solution dropwise into a beaker using a co-precipitation method. The precipitation temperature was 60℃, the pH was 10, and the solution was aged for 4 hours after precipitation. The mixture was then filtered, and the resulting filter cake was dried at 100℃ for 4 hours and then calcined at 400℃ for 6 hours to obtain ZnCrO. x The catalyst has the following mass percentages: ZnO, 51.59%; Cr2O3, 48.41%.
[0064] H2 and N2 reducing gases (H2 to N2 volume ratio of 20:100) are passed into a container containing ZnCrO. x The catalyst was placed in a fixed-bed reactor at a temperature of 280°C and a space velocity of 600 h⁻¹. -1 After reduction at atmospheric pressure for 4 hours, syngas was introduced, and the reaction was carried out at an H2 / CO (molar ratio) of 2, 320℃, 4.0 MPa, for 5000 hours. -1 Catalyst performance was evaluated under the following conditions. CO conversion (mol%) = 14.5%, hydrocarbon, CO2, and alcohol product selectivity (Cmol, where Cmol represents "carbon molar," i.e., product composition expressed as the percentage of carbon molars in each product) were 36.5%, 25.3%, and 38.2%, respectively. Among the alcohol products, methanol, ethanol, propanol, isobutanol, and C... 4+ The distributions of alcohols (Cmol) were 87.8%, 0.8%, 0.5%, 9.6%, and 1.3%, respectively, with methanol being the main product.
[0065] Comparative Example 3 (Comparative Example without Alkali Metals) Following the experimental procedures in Comparative Examples 1 and 2, ZrO2-SiO2 and ZnCrO were prepared respectively. x The composite was then ball-milled to obtain a mixed support. 3.21 g of copper acetate was dissolved in 25% ammonia water to prepare an aqueous solution with a Cu ion concentration of 0.12 mol / L. This solution was added to the mixed support, and the mixture was impregnated at 60°C for 3 hours. Then, it was ultrasonically dried at 70 Hz, followed by drying at 120°C for 5 hours. After drying, it was calcined at 400°C for 8 hours to obtain Cu-ZrO2-SiO2-ZnCrO2. x The catalyst has the following mass percentages: ZrO2, 35.75%; SiO2, 3.57%; ZnO, 28.95%; Cr2O3, 27.16%; CuO, 4.57%.
[0066] Reducing gases H2 and N2 (H2 to N2 volume ratio of 20:100) are passed into a container filled with Cu-ZrO2-SiO2-ZnCrO x The catalyst was placed in a fixed-bed reactor at a temperature of 280°C and a space velocity of 600 h⁻¹. -1 After reduction at atmospheric pressure for 4 hours, syngas was introduced, and the reaction was carried out at an H2 / CO (molar ratio) of 2, 360℃, 4.0 MPa, for 5000 hours. -1 Catalyst performance was evaluated under the following conditions. CO conversion (mol%) was 45.9%, and the selectivity (Cmol, where Cmol represents "carbon moles," i.e., product composition expressed as the percentage of carbon moles in each product) for hydrocarbons, CO2, and alcohols were 62.1%, 29.3%, and 8.6%, respectively. Among the alcohol products, methanol, ethanol, propanol, isobutanol, and C... 4+ The alcohol distributions (Cmol) were 64.5%, 20.4%, 10.6%, 3.9%, and 0.6%, respectively, and the products were mainly straight-chain mixed alcohols.
[0067] Figure 1 The XRD patterns of the composite support ZrO2-SiO2 (A) in Examples 1 and 4 are shown. Figure 2 The XRD spectra of the composite support ZrO2-SiO2 (A) in Examples 1 and 4 are shown. The XRD spectra show that the composite support exhibits high XRD activity at 30°C. o and 50 o The presence of broadened diffraction peaks on both sides indicates that ZrO2 has an amorphous structure and small particle size, resulting in low crystallinity and broadened diffraction peaks. No diffraction peaks were observed for SiO2 in the spectrum, indicating that SiO2 also has a small particle size. The IR spectrum shows a peak at 3732 cm⁻¹. -1 and 3488 cm -1 The infrared characteristic peak at the location is attributed to the hydroxyl groups (-OH) on the surface of composite support A. As can be seen from the figure, the surface of the composite support contains abundant hydroxyl groups.
[0068] Figure 3 The images show TEM images of the catalysts in Examples 1 and 4; the left image represents Example 1, and the right image represents Example 4. As can be seen from the images, both catalysts have relatively small particle sizes, approximately 5 nm, indicating that the catalysts prepared using the method of this invention have small particle sizes and large specific surface areas, which facilitates the dispersion of the active components and thus promotes the catalytic performance of the catalyst.
[0069] Figure 4 The images show the in-situ infrared diffuse reflectance spectra of Comparative Examples 1, 2, 3, and Example 4. As can be seen from the figures, at the same temperature (200...),... o C) After adsorbing H2 and CO, compare at 1600 cm⁻¹ -1The characteristic adsorption peaks on the left and right show that the peak intensity of C1 intermediates formed on the catalyst surface in Comparative Examples 1 and 2 is low and the content is small. However, in Comparative Examples 3 and 4, after the addition of the active component Cu, a large number of C1 intermediates were formed on the catalyst surface, indicating that the introduction of the active component Cu can promote the activation of H2 and CO.
[0070] As can be seen from the above 10 examples and 3 comparative examples, the catalyst of the present invention is inexpensive, and at a relatively low temperature, the CO conversion rate is up to 63.8%. Methanol and isobutanol are the main alcohol products, accounting for more than 96% of the total alcohols. The selectivity of isobutanol in the alcohol products is up to 47.6% (the lowest is 38.9%, which is significantly better than the data of the comparative examples). Other alcohols are less abundant, the subsequent separation process is simple, and the energy consumption is low.
[0071] The above embodiments of the present invention do not describe all details exhaustively, nor do they limit the present invention to the embodiments described above. Various changes, modifications, substitutions, and variations made by those skilled in the art to these embodiments without departing from the principles and spirit of the present invention should be included within the scope of protection of the present invention.
Claims
1. A catalyst for the synthesis of isobutanol from syngas, characterized in that, It is composed of a composite carrier, an active component of Cu oxide, and an alkali metal oxide additive; the carrier is a high specific surface area ZrO2-SiO2 carrier and ZnCrO x A mixture of carriers; the active component is CuO; the alkali metal auxiliaries are either K2O or Cs2O; the weight percentages of each component are as follows: ZrO2-SiO2 composite support: 28.69%~37.70%; ZnCrO x Composite carrier: 53.80%~65.54%; Active component CuO: 2.95%~6.13%; Alkali metal oxide additives: 2.58%~5.87%.
2. The catalyst for the synthesis of isobutanol from syngas according to claim 1, characterized in that, The Si / Zr molar ratio in the ZrO2-SiO2 composite support is 0.04~0.21:1; ZnCrO x The Zn / Cr molar ratio in the composite carrier is 0.5~1.0:
1.
3. A method for preparing a catalyst for the synthesis of isobutanol from syngas as described in claim 1 or 2, characterized in that... Includes the following steps: (1) Using zirconium salt and silicon source as raw materials, a high specific surface area ZrO2-SiO2 composite carrier was prepared in an alkaline solution by alkaline reflux method; (2) ZnCrO was prepared by co-precipitation using zinc salt, chromium salt, and alkali as raw materials. x Composite carrier; (3) The composite support ZrO2-SiO2 and the composite support ZnCrO x After mixing at a mass ratio of 0.44~0.70, the mixture is ball-milled. Cu is introduced into the mixed support by impregnation. After impregnation, drying and calcination, the catalyst precursor is obtained. (4) K or Cs is introduced into the catalyst precursor by impregnation, and the catalyst is obtained by impregnation, drying and calcination.
4. The method for preparing the catalyst for the synthesis of isobutanol from syngas according to claim 3, characterized in that, The specific preparation process of step (1) is as follows: dissolve zirconium salt and silicon source in deionized water to prepare a cationic aqueous solution with a Si / Zr molar ratio of 0.04~0.21:1; add alkaline reagent dropwise under stirring to precipitate, and after precipitation, transfer the mother liquor to a polytetrafluoroethylene flask for reflux. After reflux, filter the solution, wash the filter cake until neutral, and dry and calcine to obtain ZrO2-SiO2 composite carrier; the alkaline reagent is ethylenediamine or a 25% ammonia aqueous solution.
5. The method for preparing the catalyst for the synthesis of isobutanol from syngas according to claim 4, characterized in that, The zirconium salt is zirconium nitrate dihydrate or zirconium oxychloride octahydrate, and the silicon source is tetraethyl orthosilicate or sodium silicate; the total concentration of cations in the cationic aqueous solution is 0.02~0.1 mol / L; The precipitation temperature in step (1) is 30~60℃, the precipitation pH is 8~11; the reflux temperature is 80~100℃, and the reflux time is preferably 1~6 days; The drying temperature in step (1) is 80~120℃ and the drying time is 4~8h; the calcination temperature is 350~550℃ and the calcination time is 4~10h.
6. The method for preparing the catalyst for the synthesis of isobutanol from syngas according to claim 3, characterized in that, The specific preparation process of step (2) is as follows: Zinc salt and chromium salt are mixed and dissolved in deionized water to prepare a metal salt aqueous solution with a Zn / Cr molar ratio of 0.5~1.0:1; alkali is dissolved in deionized water to prepare an alkaline solution; the metal salt solution and alkaline solution are simultaneously added dropwise to a beaker for precipitation using a co-precipitation method; after precipitation, the solution is aged and then filtered; the resulting filter cake is dried and calcined to obtain ZnCrO. x Composite carrier.
7. The method for preparing the catalyst for the synthesis of isobutanol from syngas according to claim 6, characterized in that, The zinc salt is zinc nitrate hexahydrate or zinc acetate, and the chromium salt is chromium nitrate nonahydrate or chromium acetate; the total concentration of metal ions in the salt solution is 0.05~0.15 mol / L; The alkali is ammonium carbonate; the alkali solution contains NH4. + The concentration is 0.1~0.3 mol / L; The precipitation temperature is 30~80℃, the precipitation pH is 8~12, and the aging time is 2~6h; The drying temperature is 80~120℃, and the drying time is 4~8h; the calcination temperature is 350~550℃, and the calcination time is 4~10h.
8. The method for preparing the catalyst for the synthesis of isobutanol from syngas according to claim 3, characterized in that, The composite support ZrO2-SiO2 and the composite support ZnCrO2 mentioned in step (3) x After ball milling and mixing, the Zr / Zn molar ratio was 0.82; Step (3) Cu is added to the carrier in the form of copper salt, wherein the copper salt is copper nitrate trihydrate or copper acetate monohydrate; the solvent used to dissolve the copper salt is one of ammonia, ethanol, water or ethylene glycol; the concentration of copper ions is 0.05~0.15mol / L; The immersion temperature is 30~70℃, and the immersion time is 3~7h; The composite carrier after impregnation is subjected to ultrasonic evaporation and drying in sequence, and then calcined; the frequency of ultrasonic evaporation is 20~100kHz, and the time of ultrasonic evaporation is 4~8h; the temperature of drying is 80~120℃, and the time of drying is 4~8h; the temperature of calcination is 400~600℃, and the time of calcination is 5~10h.
9. The method for preparing the catalyst for the synthesis of isobutanol from syngas according to claim 3, characterized in that, In step (4), when adding K, the K precursor is either potassium nitrate or potassium hydroxide; the concentration is 0.08~0.16 mol / L; the K / Zr molar ratio is preferably 0.21~0.42:1; When Cs is added, the Cs precursor is either cesium nitrate or cesium carbonate; the concentration is 0.08~0.16 mol / L; the Cs / Zr molar ratio is 0.04~0.08:1; When adding K or Cs elements, the impregnation solvent is water or ethanol; the impregnation temperature is 30~70℃, and the impregnation time is 3~7h; The catalyst precursor C after impregnation is subjected to ultrasonic evaporation and drying in sequence, and then calcined; the frequency of ultrasonic evaporation is 20~100kHz, and the time of ultrasonic evaporation is 4~8h; the drying temperature is 80~120℃, and the drying time is 4~8h; the calcination temperature is 400~600℃, and the calcination time is 5~10h.
10. The application of the catalyst for the synthesis of isobutanol according to claim 1 or 2 in the direct preparation of isobutanol from syngas, characterized in that, The specific application process is as follows: First, the catalyst is reduced by introducing H2 / N2 reducing gas into a fixed-bed reactor containing the catalyst, setting the temperature to 250~400℃ and the space velocity to 500~2000h. -1 After reduction at atmospheric pressure for 2-6 hours, syngas is introduced for catalytic reaction. The catalytic reaction process is as follows: the molar ratio of H2 / CO in the feed gas is 1:1-3:1, the reaction temperature is 300-360℃, the reaction pressure is 4.0-7.0 MPa, and the syngas space velocity is 2000-7000 h⁻¹. -1 Catalyst performance was evaluated under these conditions.