Catalyst for synthesizing ethanol from methyl acetate and preparation method thereof

Abstract

The invention provides a preparation method of a catalyst for synthesizing ethanol from methyl acetate, which comprises the following steps: mixing and stirring an SSZ-13 molecular sieve, an SBA-15 molecular sieve, absolute ethyl alcohol and an aqueous solution containing a Zn soluble compound according to a mass ratio of (100-50): 1 to obtain a suspension, aging, drying and calcining to prepare a ZnO / molecular sieve composite carrier; mixing and stirring the ZnO / molecular sieve composite carrier, absolute ethyl alcohol and an aqueous solution containing an Al soluble compound, and loading Al2O3 through a hydrothermal reaction to prepare an Al2O3 / ZnO / molecular sieve composite carrier; the preparation method comprises the following steps: preparing soluble salt precursors containing Cu, Mn, Co, Cr and In into a mixed solution; and dipping the Al2O3 / ZnO / molecular sieve composite carrier in the mixed solution, and then filtering, washing, drying and roasting. The method is simple in process, raw materials are easy to obtain and low in cost, industrial popularization and application are facilitated, and the novel catalyst with high activity and stability is obtained.

Description

Technical Field

[0001] The present invention relates to the field of ethanol production, and particularly to a catalyst for synthesizing ethanol from methyl acetate and a preparation method thereof. Background Art

[0002] Ethanol is one of the important bulk chemicals and is widely used in many fields such as energy, chemical industry, food, and medicine. Ethanol is a clean energy source. It can not only be used instead of traditional gasoline antiknock agents, but also be further processed into fuel ethanol to reduce the pollution caused by gasoline combustion. At present, the main methods for producing ethanol are grain fermentation method, ethylene hydration method, and coal chemical method. The grain fermentation method has prominent problems such as "competing with people for food and competing with food for land", and the production cost is relatively high. It needs national financial subsidies to survive. Therefore, enterprises have been constantly seeking a non-grain-based method for producing ethanol to replace it. The ethylene hydration method and the coal chemical method are alternative methods. However, the initial raw material of the ethylene hydration method is petroleum, which does not conform to the basic national condition of "rich in coal, poor in oil, and scarce in gas" in China. The coal chemical method first converts coal into syngas (mainly composed of carbon monoxide and hydrogen), and then synthesizes ethanol through steps such as methanol, dimethyl ether carbonylation, and hydrogenation. The main starting raw material of this method is coal, which is more in line with the basic national conditions of China. Therefore, with the continuous progress of technology, the application of the coal chemical method in ethanol production is becoming more and more extensive and attracting more and more attention. Hydrogenation of methyl acetate to produce ethanol is an important step in the indirect synthesis of ethanol from syngas. Especially for chemical enterprises mainly engaged in ester products, hydrogenating the esters produced from syngas in the long chain of this coal chemical method to produce ethanol not only facilitates flexible adjustment of production capacity layout, but also can conveniently enrich product types.

[0003] The key factor affecting the economic benefits of ester (methyl acetate) chemical enterprises in adjusting the production of ethanol is the hydrogenation catalyst. Among them, copper-based catalysts are a type of hydrogenation reduction catalysts with relatively high comprehensive cost performance reported at present, with low price and simple preparation process. However, the existing copper-based catalysts mostly have problems such as copper migration and aggregation leading to catalyst deactivation and short service life, and there is still room for further improvement in ethanol selectivity and conversion rate. Moreover, the formulations and preparation processes of excellent catalysts on the market are basically kept confidential, which is not conducive to technology upgrading and promotion cooperation.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a preparation method of a catalyst for synthesizing ethanol from methyl acetate. This method has the advantages of low cost and easy industrialization, and the obtained catalyst has high activity, good stability, and is not easily deactivated.

[0006] An embodiment of the present invention provides a preparation method of a catalyst for synthesizing ethanol from methyl acetate, comprising the following steps: Step 1, mixing and stirring SSZ-13 molecular sieve, SBA-15 molecular sieve with absolute ethanol and an aqueous solution of a Zn-soluble compound in a mass ratio of (100~50):1 to obtain a suspension, followed by aging, drying, and calcination to prepare a ZnO / molecular sieve composite support; Step 2, mixing and stirring the ZnO / molecular sieve composite support with absolute ethanol and an aqueous solution of an Al-soluble compound, and loading Al through a hydrothermal reaction 2 O 3 to prepare an Al 2 O 3 / ZnO / molecular sieve composite support; Step 3, preparing a mixed solution from soluble salt precursors containing Cu, Mn, Co, Cr, and In; Step 4, impregnating the Al 2 O 3 / ZnO / molecular sieve composite support into the mixed solution obtained in Step 3, followed by filtration, washing, drying, and calcination to obtain the product.

[0007] As a mode, in Step 1, the mass ratio of absolute ethanol to the total mass of SSZ-13 molecular sieve and SBA-15 molecular sieve is (15~70):1.

[0008] As a mode, in the Al 2 O 3 / ZnO / molecular sieve composite support, by mass percentage, Al 2 O 3 is 6%-20%, ZnO is 4%-10%, and the molecular sieve is 70%-90%.

[0009] As a mode, in Step 2, the mass ratio of ZnO / molecular sieve to absolute ethanol is 1:(25~80).

[0010] As a mode, the loading amounts of Cu, Mn, Co, Cr, and In and the mass ratio of the Al 2 O 3 / ZnO / molecular sieve composite support are (0.3-0.8), (0.2-0.5), (0.01-0.1), (0.02-0.2), and (0.01-0.05) respectively.

[0011] As a mode, in Step 1, aging for 12~30h, drying at 100-130°C, and calcining at 350-800°C for 1-4h.

[0012] As a mode, in step 2, the temperature of the hydrothermal reaction is 80 - 120 °C, and the time is 9 - 15 h.

[0013] As a mode, the calcination temperature in step 4 is 480 - 900 °C, and the time is 4 - 12 h.

[0014] The present invention also provides a catalyst for synthesizing ethanol from methyl acetate, which is obtained by the preparation method described in any one of the above.

[0015] The present invention further provides a method for synthesizing ethanol from methyl acetate, wherein methyl acetate, methanol and H 2 The raw materials are put in a molar ratio of 100:(5 - 30):(500 - 1200), and under the action of the catalyst of the present invention, ethanol is prepared by reacting in an H 2 atmosphere.

[0016] The present invention has the following advantages: 1. The present invention discloses a preparation method of a novel catalyst with high activity and stability, which has simple process, easily available raw materials and low cost, is conducive to industrial promotion and use, and is also convenient for the upgrading and iteration of the technology in the industry.

[0017] 2. The catalyst prepared by the present invention has excellent methyl acetate conversion rate and ethanol selectivity, and still shows stability after continuous operation for 300 h, which is conducive to extending the service life, reducing the time cost of the factory for stopping production to replace the catalyst, and improving economic benefits.

[0018] 3. The preparation method of the present invention uses SSZ-13 molecular sieve and SBA-15 molecular sieve to compound Al 2 O 3 and ZnO in a mass ratio of (100 - 50):1, which not only ensures the catalytic activity of the catalyst, but also effectively controls the cost and improves the enterprise benefits.

[0019] 4. The ethanol synthesis method of the present invention realizes the conversion and utilization of the surplus methanol raw materials in the factory area through the cooperation of the catalyst and the process steps, and improves the resource utilization efficiency and economic benefits. Specific embodiments

[0020] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] For each soluble salt precursor containing Cu, Mn, Co, Cr, and In used in the following examples, commercially available reagents can be adopted, as long as the dosages of Cu, Mn, Co, Cr, and In meet the conditions of the present invention.

[0022] Example 1 A preparation method of a catalyst for synthesizing ethanol from methyl acetate, comprising the following steps: Step 1: Mix and stir SSZ-13 molecular sieve, SBA-15 molecular sieve, absolute ethanol, and an aqueous solution of a soluble Zn compound in a mass ratio of 100:1 to obtain a suspension; after aging for 30 h, drying at 130 °C, and calcining at 350 °C for 4 h, a ZnO / molecular sieve composite support is prepared; wherein, the mass ratio of absolute ethanol to the total mass of SSZ-13 molecular sieve and SBA-15 molecular sieve is 70:1; Step 2: Mix and stir the ZnO / molecular sieve composite support and absolute ethanol in a mass ratio of 1:80 with an aqueous solution of a soluble Al compound, and carry out a hydrothermal reaction at 120 °C for 9 h to load Al 2 O 3 to prepare an Al 2 O 3 / ZnO / molecular sieve composite support, wherein, by mass percentage, Al 2 O 3 is 20%, ZnO is 10%, and the molecular sieve is 70%; Step 3: Prepare a mixed solution from each soluble salt precursor containing Cu, Mn, Co, Cr, and In; the loading amounts of Cu, Mn, Co, Cr, and In and the mass ratio of the Al 2 O 3 / ZnO / molecular sieve composite support are 0.8, 0.5, 0.01, 0.02, and 0.05 respectively; Step 4: Immerse the Al 2 O 3 / ZnO / molecular sieve composite support in the mixed solution obtained in Step 3, then filter, wash, dry, and calcine at 480 °C for 12 h to obtain the product.

[0023] Example 2 A preparation method of a catalyst for synthesizing ethanol from methyl acetate, comprising the following steps: Step 1: Mix and stir SSZ-13 molecular sieve, SBA-15 molecular sieve, absolute ethanol, and an aqueous solution of a soluble Zn compound in a mass ratio of 50:1 to obtain a suspension; after aging for 12 h, drying at 100 °C, and calcining at 800 °C for 1 h, a ZnO / molecular sieve composite support is prepared; wherein, the mass ratio of absolute ethanol to the total mass of SSZ-13 molecular sieve and SBA-15 molecular sieve is 15:1; Step 2: Mix the ZnO / molecular sieve composite support and absolute ethanol in a mass ratio of 1:25 with an aqueous solution of an Al-soluble compound, stir, and hydrothermally react at 80 °C for 15 h to load Al 2 O 3 to obtain an Al 2 O 3 / ZnO / molecular sieve composite support, where, by mass percentage, Al 2 O 3 is 6%, ZnO is 4%, and the molecular sieve is 90%; Step 3: Prepare a mixed solution from the soluble salt precursors of Cu, Mn, Co, Cr, and In; the loading amounts of Cu, Mn, Co, Cr, and In and the mass ratio of the Al 2 O 3 / ZnO / molecular sieve composite support are 0.3, 0.2, 0.1, 0.2, and 0.01 respectively; Step 4: Immerse the Al 2 O 3 / ZnO / molecular sieve composite support in the mixed solution obtained in Step 3, then filter, wash, dry, and calcine at 900 °C for 4 h to obtain the product.

[0024] Example 3 A preparation method of a catalyst for synthesizing ethanol from methyl acetate, comprising the following steps: Step 1: Mix the SSZ-13 molecular sieve and SBA-15 molecular sieve in a mass ratio of 70:1 with absolute ethanol and an aqueous solution of a Zn-soluble compound, stir to obtain a suspension; after aging for 16 h, drying at 110 °C, and calcining at 500 °C for 3 h, a ZnO / molecular sieve composite support is prepared; wherein, the mass ratio of absolute ethanol to the total mass of the SSZ-13 molecular sieve and SBA-15 molecular sieve is 40:1; Step 2: Mix the ZnO / molecular sieve composite support and absolute ethanol in a mass ratio of 1:40 with an aqueous solution of an Al-soluble compound, stir, and hydrothermally react at 90 °C for 14 h to load Al 2 O 3 to obtain an Al 2 O 3 / ZnO / molecular sieve composite support, where, by mass percentage, Al 2 O 3 is 10%, ZnO is 6%, and the molecular sieve is 84%; Step 3: Prepare a mixed solution from the soluble salt precursors of Cu, Mn, Co, Cr, and In; the loading amounts of Cu, Mn, Co, Cr, and In and the mass ratio of the Al 2 O 3The mass ratios of the / ZnO / molecular sieve composite carriers are 0.5, 0.3, 0.04, 0.05, and 0.02 respectively; Step 4, immerse the Al 2 O 3 / ZnO / molecular sieve composite carrier in the mixed solution obtained in Step 3, then filter, wash, dry, and calcine at 600 °C for 8 h to obtain the product.

[0025] Example 4 A preparation method of a catalyst for synthesizing ethanol from methyl acetate, comprising the following steps: Step 1, mix and stir SSZ-13 molecular sieve, SBA-15 molecular sieve according to a mass ratio of 80:1 with absolute ethanol and an aqueous solution of a Zn-soluble compound to obtain a suspension; after aging for 20 h, drying at 120 °C, and calcining at 600 °C for 1.5 h, a ZnO / molecular sieve composite carrier is prepared; wherein, the mass ratio of absolute ethanol to the total mass of SSZ-13 molecular sieve and SBA-15 molecular sieve is 50:1; Step 2, mix and stir the ZnO / molecular sieve composite carrier and absolute ethanol according to a mass ratio of 1:60 with an aqueous solution of an Al-soluble compound, and perform a hydrothermal reaction at 85 °C for 12 h to load Al 2 O 3 to prepare an Al 2 O 3 / ZnO / molecular sieve composite carrier, wherein, by mass percentage, Al 2 O 3 is 15%, ZnO is 5%, and the molecular sieve is 80%; Step 3, prepare a mixed solution from soluble salt precursors of Cu, Mn, Co, Cr, and In; the loading amounts of Cu, Mn, Co, Cr, and In and the mass ratio of the Al 2 O 3 / ZnO / molecular sieve composite carrier are 0.4, 0.3, 0.02, 0.1, and 0.03 respectively; Step 4, immerse the Al 2 O 3 / ZnO / molecular sieve composite carrier in the mixed solution obtained in Step 3, then filter, wash, dry, and calcine at 500 °C for 10 h to obtain the product.

[0026] Example 5 A preparation method of a catalyst for synthesizing ethanol from methyl acetate, comprising the following steps: Step 1: Mix and stir SSZ-13 molecular sieve, SBA-15 molecular sieve, absolute ethanol, and an aqueous solution of a Zn-soluble compound in a mass ratio of 90:1 to obtain a suspension; after aging for 18 h, drying at 125 °C, and calcining at 750 °C for 2.5 h, a ZnO / molecular sieve composite support is prepared; wherein, the mass ratio of absolute ethanol to the total mass of SSZ-13 molecular sieve and SBA-15 molecular sieve is 60:1; Step 2: Mix and stir the ZnO / molecular sieve composite support and absolute ethanol in a mass ratio of 1:75 with an aqueous solution of an Al-soluble compound, and perform a hydrothermal reaction at 100 °C for 10 h to load Al 2 O 3 to prepare an Al 2 O 3 / ZnO / molecular sieve composite support, wherein, by mass percentage, Al 2 O 3 is 20%, ZnO is 5%, and the molecular sieve is 75%; Step 3: Prepare a mixed solution from soluble salt precursors of Cu, Mn, Co, Cr, and In; the loading amounts of Cu, Mn, Co, Cr, and In and the mass ratio of the Al 2 O 3 / ZnO / molecular sieve composite support are 0.7, 0.5, 0.08, 0.1, and 0.03 respectively; Step 4: Immerse the Al 2 O 3 / ZnO / molecular sieve composite support in the mixed solution obtained in Step 3, then filter, wash, dry, and calcine at 650 °C for 9 h to obtain the product.

[0027] Comparative Example 1 The difference from Example 1 is that in Step 1, SSZ-13 molecular sieve and SBA-15 molecular sieve are put in a mass ratio of 110:1, and the others remain the same.

[0028] Comparative Example 2 The difference from Example 1 is that a Zn-soluble compound is not used, the support does not contain ZnO, and the corresponding amount of ZnO in Example 1 is converted to an equal amount of Al 2 O 3 , and the others remain the same. Specifically as follows: Step 1: Mix and stir SSZ-13 molecular sieve, SBA-15 molecular sieve, and absolute ethanol in a mass ratio of 100:1 to obtain a suspension; after aging for 30 h, drying at 130 °C, and calcining at 350 °C for 4 h, a molecular sieve composite support is prepared; wherein, the mass ratio of absolute ethanol to the total mass of SSZ-13 molecular sieve and SBA-15 molecular sieve is 70:1; Step 2: Mix the molecular sieve composite support and absolute ethanol in a mass ratio of 1:80 with an aqueous solution of an Al-soluble compound, and stir. Conduct hydrothermal reaction at 120 °C for 9 h to load Al 2 O 3 , and prepare an Al 2 O 3 / molecular sieve composite support, wherein, by mass percentage, Al 2 O 3 is 30%, and the molecular sieve is 70%; Step 3: Prepare a mixed solution from the soluble salt precursors containing Cu, Mn, Co, Cr, and In; the loading amounts of Cu, Mn, Co, Cr, and In and the mass ratio of the Al 2 O 3 / molecular sieve composite support are 0.8, 0.5, 0.01, 0.02, and 0.05 respectively; Step 4: Immerse the Al 2 O 3 / molecular sieve composite support in the mixed solution obtained in Step 3, then filter, wash, dry, and calcine at 480 °C for 12 h to obtain the product.

[0029] Application Example 1 Load the catalysts of the above Examples 1-5 and Comparative Examples 1-2 into the reaction tube, reduce them in pure H 2 at 300 °C for 4 h, and after reduction, cool to 100-110 °C in an H 2 atmosphere, pressurize to 1.2 MPa, heat and vaporize methyl acetate (MA), mix it with H 2 , and then enter a fixed-bed reactor equipped with the catalyst. Keep the molar ratios of the component gases in the feed, MA(g) / methanol(g) / H 2 , to be 100 / 5 / 500 (Group A), 100 / 15 / 850 (Group B), and 100 / 30 / 1200 (Group C) respectively, and the mass space velocity of methyl acetate is 0.7 h -1 . Then raise the temperature to 235 °C and conduct the reaction for 2.5 h.

[0030] Use an Agilent 7890A gas chromatograph, with an FID detector and an Rtx-5 capillary column, to online detect and analyze the composition of the tail gas, and obtain the conversion rate of methyl acetate and the selectivity of ethanol, as shown in Table 1.

[0031] Table 1 Examples 1-5 in Table 1 are Examples 1-5, and Dui 1-2 are Comparative Examples 1-2.

[0032] Under the above conditions, after continuous operation for 300 hours, the changes in the conversion rate and selectivity of the catalyst are not significant, and the catalyst performance is stable. Specifically, as shown in Table 2.

[0033] Table 2 Although the embodiments disclosed in the present invention are as above, the above content is only an embodiment adopted for the convenience of understanding the present invention and is not intended to limit the present invention. Any person skilled in the art within the scope of the present invention can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention. However, the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A method for preparing a catalyst for synthesizing ethanol from methyl acetate, characterized in that: The steps include: Step 1, mixing SSZ-13 molecular sieve and SBA-15 molecular sieve with anhydrous ethanol and an aqueous solution containing a Zn-soluble compound in a mass ratio of (100-50):1 to obtain a suspension, and preparing a ZnO / molecular sieve composite carrier through aging, drying and calcining; Step 2, mixing the ZnO / molecular sieve composite carrier with anhydrous ethanol and an aqueous solution containing an Al-soluble compound, and loading Al2O3 through a hydrothermal reaction to prepare an Al2O3 / ZnO / molecular sieve composite carrier; Step 3, preparing a mixed solution of soluble salt precursors containing Cu, Mn, Co, Cr and In; Step 4, impregnating the Al2O3 / ZnO / molecular sieve composite carrier into the mixed solution obtained in step 3, and then filtering, washing, drying and calcining to obtain the composite carrier.

2. The method for preparing a catalyst for synthesizing ethanol from methyl acetate according to claim 1, characterized in that: In step 1, the ratio of the mass of anhydrous ethanol to the total mass of the SSZ-13 molecular sieve and the SBA-15 molecular sieve is (15-70):

1.

3. The method for preparing a catalyst for synthesizing ethanol from methyl acetate according to claim 1, characterized in that: In the Al2O3 / ZnO / molecular sieve composite carrier, by mass percentage, Al2O3 is 6%-20%, ZnO is 4%-10%, and molecular sieve is 70%-90%.

4. The method for preparing a catalyst for synthesizing ethanol from methyl acetate according to claim 1, characterized in that: In step 2, the mass ratio of ZnO / molecular sieve to anhydrous ethanol is 1:(25-80).

5. The method for preparing a catalyst for synthesizing ethanol from methyl acetate according to claim 1, characterized in that: The ratios of the loading amounts of Cu, Mn, Co, Cr and In to the mass of the Al2O3 / ZnO / molecular sieve composite carrier are (0.3-0.8), (0.2-0.5), (0.01-0.1), (0.02-0.2) and (0.01-0.05), respectively.

6. The method for preparing a catalyst for synthesizing ethanol from methyl acetate according to claim 1, characterized in that: In step 1, the mixture is aged for 12 to 30 hours, dried at 100 to 130° C., and then calcined at 350 to 800° C. for 1 to 4 hours.

7. The method for preparing a catalyst for synthesizing ethanol from methyl acetate according to claim 1, characterized in that: In step 2, the temperature of the hydrothermal reaction is 80-120° C. and the time is 9-15 h.

8. The method for preparing a catalyst for synthesizing ethanol from methyl acetate according to claim 1, characterized in that: The calcination temperature of step 4 is 480-900°C and the calcination time is 4-12h.

9. A catalyst for synthesizing ethanol from methyl acetate, characterized in that: Obtained according to the preparation method according to any one of claims 1 to 8.

10. A method for synthesizing ethanol from methyl acetate, characterized in that: Methyl acetate, methanol and H2 are added in a molar ratio of 100:(5-30):(500-1200) and react in a H2 atmosphere under the action of the catalyst described in claim 9 to prepare ethanol.

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