Method for preparing glyoxal by dehydrogenation of ethylene glycol
The preparation of glyoxal by catalytic dehydrogenation of ethylene glycol using a supported copper catalyst solves the problems of high energy consumption and environmental pollution in existing technologies, and achieves low-cost, highly selective preparation of glyoxal and generation of high-purity hydrogen.
Patent Information
- Application Number
- CN202510771219.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-10
- Publication Date
- 2025-10-21
AI Technical Summary
Existing methods for preparing glyoxal suffer from high energy consumption, high cost, numerous byproducts, poor product quality, and environmental pollution, leading to China's reliance on imports for high-quality glyoxal.
Glyoxal was prepared by catalytic dehydrogenation of ethylene glycol under liquid-phase conditions using a supported copper catalyst. The catalyst consisted of Cu as the active component and Mg, Ba, Mn, etc. as promoters. The support was a molecular sieve. The reaction was carried out in a fixed-bed reactor at a temperature of 150–240 °C and a pressure of 0.001–0.2 MPa, producing glyoxal and hydrogen.
A low-energy, low-cost, and highly safe glyoxal preparation process has been achieved. Glyoxal exhibits high selectivity, few byproducts, and produces high-purity hydrogen, making it environmentally friendly.
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Figure BDA0005443028010000031
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of glyoxal preparation, and more specifically relates to a method for preparing glyoxal by dehydrogenating ethylene glycol. Background Art
[0002] Glyoxal is a very important fine chemical product, widely used in pharmaceutical manufacturing, fragrance synthesis, paints and coatings, adhesives, and other aspects. Currently, the main glyoxal production processes are ethylene glycol vapor oxidation and acetaldehyde nitric acid oxidation. The ethylene glycol vapor catalytic oxidation method has high reaction temperature, high production cost, high reaction energy consumption, low glyoxal yield, and by-products such as formaldehyde and acid, resulting in poor product quality. The acetaldehyde nitric acid oxidation method produces a large amount of acetic acid as a by-product and also contains a small amount of nitric acid, which is difficult to separate and treat, and there are "three wastes" problems such as NOx pollution. Currently, most of the high-quality glyoxal on the domestic market relies on imports. Therefore, a new method for preparing glyoxal is urgently needed. Summary of the Invention
[0003] In order to overcome the shortcomings and deficiencies of existing methods for preparing glyoxal, the present invention aims to provide a method for preparing glyoxal by dehydrogenating ethylene glycol.
[0004] In order to achieve the above object, the present invention provides the following technical solutions:
[0005] In a first aspect, the present invention provides a method for preparing glyoxal by dehydrogenating ethylene glycol, comprising the following steps: catalytically dehydrogenating liquid ethylene glycol under the catalytic action of a supported copper catalyst at a reaction temperature of 150 to 240° C. and a reaction pressure of 0.001 to 0.2 MPa to produce glyoxal and hydrogen, wherein the supported copper catalyst comprises an active component Cu, an auxiliary agent, and a carrier, wherein the active component Cu accounts for 5 to 50% of the total mass of the catalyst, the auxiliary agent is at least one of Mg, Ba, Mn, Fe, Co, Ni, Zn, Cr, La, Ce, Pr, Sm, B, Zr, Ga, In, Nb, Re, Mo, Ti, and Br, and the auxiliary agent accounts for 0.1 to 15% of the total mass of the catalyst, and the carrier is a molecular sieve.
[0006] Based on the above technical solution, further, the active component Cu accounts for 10 to 35% of the total mass of the catalyst.
[0007] Based on the above technical solution, further, the auxiliary agent accounts for 1 to 10% of the total mass of the catalyst.
[0008] Based on the above technical solution, further, the molecular sieve is one of SBA-15, HZSM5 or MCM-41.
[0009] Based on the above technical solution, the preparation method of the supported copper catalyst further comprises the following steps: impregnating a soluble salt of Cu or its hydrate and an aqueous solution of a soluble salt of an additive or its hydrate onto a carrier, aging at 40-80°C for 5-24 hours, grinding into powder after drying, calcining at 400-600°C in an air atmosphere for 3-10 hours, and finally reducing at 200-300°C in a hydrogen atmosphere for 1-5 hours.
[0010] Based on the above technical solution, further, the impregnation is equal volume impregnation.
[0011] Based on the above technical solution, further, the soluble salt of Cu includes nitrate, sulfate and chloride of Cu, and the soluble salt of the additive includes nitrate, sulfate and chloride.
[0012] Based on the above technical solution, further, the reaction temperature is 200-220° C., and the reaction pressure is 0.001-0.02 MPa.
[0013] Based on the above technical solution, the catalytic dehydrogenation is further carried out in a fixed bed reactor, and the mass space velocity of ethylene glycol is 0.1 to 1.0 h -1 .
[0014] Compared with the prior art, the present invention has the following beneficial effects:
[0015] 1) The reaction process of ethylene glycol dehydrogenation to glyoxal in the present application is simple, is an endothermic reaction, has a relatively low reaction temperature, low energy consumption, and high reaction safety;
[0016] 2) The glyoxal of the present application has high selectivity and can produce high-purity hydrogen;
[0017] 3) The reaction of the present application produces less three wastes, and the method for preparing glyoxal by liquid-phase catalytic dehydrogenation of ethylene glycol is greener, energy-saving, low-cost, and has high industrial application value. DETAILED DESCRIPTION
[0018] The present invention is described in detail below with reference to the embodiments, but the embodiments of the present invention are not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments obtained without creative work all fall within the scope of protection of the present invention.
[0019] Example 1
[0020] An equal volume of an aqueous solution containing 0.1 mol of copper nitrate trihydrate and 0.01 mol of zinc nitrate hexahydrate was impregnated onto 20 g of SBA-15, aged at 50°C for 12 hours, dried at 120°C and ground, calcined at 500°C in an air atmosphere for 5 hours, and then reduced with >99.9% hydrogen at 250°C for 2 hours to obtain catalyst #1.
[0021] Example 2
[0022] An equal volume of an aqueous solution containing 0.1 mol of copper nitrate trihydrate and 0.01 mol of lanthanum nitrate hexahydrate was impregnated onto 20 g of SBA-15, aged at 50°C for 12 hours, dried at 120°C and ground, calcined at 500°C in an air atmosphere for 5 hours, and then reduced with >99.9% hydrogen at 250°C for 2 hours to obtain catalyst #2.
[0023] Example 3
[0024] An equal volume of an aqueous solution containing 0.1 mol of copper nitrate trihydrate and 0.01 mol of manganese nitrate tetrahydrate was impregnated onto 20 g of SBA-15, aged at 50°C for 12 hours, dried at 120°C and ground, calcined at 500°C in air atmosphere for 5 hours, and then reduced with >99.9% hydrogen at 250°C for 2 hours to obtain catalyst #3.
[0025] Example 4
[0026] An equal volume of an aqueous solution containing 0.1 mol of copper nitrate trihydrate and 0.01 mol of zinc nitrate hexahydrate was impregnated onto 20 g of HZSM5, aged at 50°C for 12 hours, dried at 120°C and ground, calcined at 500°C in an air atmosphere for 5 hours, and then reduced with >99.9% hydrogen at 250°C for 2 hours to obtain catalyst #4.
[0027] Examples 5-12
[0028] Catalysts 1#, 2#, 3#, and 4# prepared in Examples 1-4 were pressed into tablets (10 MPa) and crushed into 20-40 mesh particles, a total of 10 g, diluted with quartz sand at a ratio of 1:1 and loaded into a fixed-bed reactor. The catalysts were subjected to catalytic dehydrogenation of ethylene glycol to produce glyoxal under different reaction conditions (see Table 1 for specific conditions). After 5 hours of reaction, the reaction liquids were collected and the products were analyzed using an Agilent 7890B high-performance gas chromatograph, with quantification performed using an external standard method. Test conditions: a DB-WAX column, a hydrogen flame detector (FID), hydrogen as the carrier gas, constant mode, a split ratio of 100:1, and a column box temperature of 60°C (2 min), increased at 30°C / min to 220°C (held for 5 min).
[0029] Table 1. Reaction conditions and experimental results of ethylene glycol dehydrogenation to glyoxal
[0030]
[0031] As shown in Table 1, under the conditions of reaction temperature of 200-220°C, reaction pressure of 0.02 MPa and ethylene glycol feed rate of 0.05 mL / min, the ethylene glycol conversion rate can reach 99.8% and the glyoxal selectivity can reach 98.7%.
[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing glyoxal by dehydrogenating ethylene glycol, characterized in that: The method comprises the following steps: catalytically dehydrogenating liquid ethylene glycol to produce glyoxal and hydrogen under the catalytic action of a supported copper catalyst at a reaction temperature of 150-240° C. and a reaction pressure of 0.001-0.2 MPa. The supported copper catalyst comprises an active component Cu, an auxiliary agent and a carrier, wherein the active component Cu accounts for 5-50% of the total mass of the catalyst, the auxiliary agent is at least one of Mg, Ba, Mn, Fe, Co, Ni, Zn, Cr, La, Ce, Pr, Sm, B, Zr, Ga, In, Nb, Re, Mo, Ti and Br, and the auxiliary agent accounts for 0.1-15% of the total mass of the catalyst, and the carrier is a molecular sieve.
2. The method according to claim 1, characterized in that The active component Cu accounts for 10-35% of the total mass of the catalyst.
3. The method according to claim 1, characterized in that The auxiliary agent accounts for 1 to 10% of the total mass of the catalyst.
4. The method according to claim 1, wherein The molecular sieve is one of SBA-15, HZSM5 or MCM-41.
5. The method according to claim 1, wherein The preparation method of the supported copper catalyst comprises the following steps: impregnating a soluble salt of Cu or its hydrate and an aqueous solution of a soluble salt of an additive or its hydrate onto a carrier, aging at 40-80° C. for 5-24 hours, grinding into powder after drying, calcining at 400-600° C. in an air atmosphere for 3-10 hours, and finally reducing at 200-300° C. in a hydrogen atmosphere for 1-5 hours.
6. The method according to claim 5, characterized in that The impregnation is equal volume impregnation.
7. The method according to claim 5, characterized in that The soluble salts of Cu include nitrates, sulfates and chlorides of Cu, and the soluble salts of additives include nitrates, sulfates and chlorides of Cu.
8. The method according to claim 1, characterized in that The reaction temperature is 200-220°C, and the reaction pressure is 0.001-0.02 MPa.
9. The method according to claim 1, characterized in that The catalytic dehydrogenation is carried out in a fixed bed reactor, and the mass space velocity of ethylene glycol is 0.1 to 1.0 h -1 .