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CN-122010733-A - Green preparation method of ethyl pyruvate

CN122010733ACN 122010733 ACN122010733 ACN 122010733ACN-122010733-A

Abstract

The invention relates to a green preparation method of ethyl pyruvate. The method is characterized in that ethyl lactate is used as a raw material, continuous gas-liquid phase oxidation is carried out in a fixed bed in the presence of oxygen-containing gas, mn-Cu-Co ternary oxide is adopted to load a catalyst containing nitrogen porous carbon, air calcination and CO 2 atmosphere activation are matched, and the catalyst can be pretreated in ethyl lactate/carrier gas to regulate and control metal valence state and oxygen vacancy structure. Water, a trace amount of lactic acid amide, glycine and alanine, and optionally phytic acid/phytate and choline chloride are introduced into the raw material liquid to construct a weak coordination and hydrogen bond network to adjust the interface oxidizing property, and the fixed bed is provided with a double reaction area for sectional temperature control and oxygen supply along the logistics direction. The invention realizes high conversion of ethyl lactate and high selectivity of ethyl pyruvate under milder conditions, and has few byproducts and good catalyst stability.

Inventors

  • YE LANJIE
  • Cai Erna

Assignees

  • 湖北朗昕生化药业有限公司

Dates

Publication Date
20260512
Application Date
20260203

Claims (10)

  1. 1. The green preparation method of the ethyl pyruvate is characterized by comprising the following steps of: (1) Mixing raw material liquid containing 75-99% of ethyl lactate by mass fraction with oxygen-containing gas, and continuously feeding the mixture into a fixed bed reactor; (2) In the presence of a porous carrier catalyst with surface loaded with oxides of three metals of manganese, copper and cobalt, carrying out continuous gas-liquid phase contact reaction at 80-150 ℃ and 0.1-1.0 MPa to obtain a reaction product effluent containing ethyl pyruvate; (3) And separating the reaction product effluent to obtain a pyruvic acid ethyl ester product.
  2. 2. The green preparation method of ethyl pyruvate according to claim 1, wherein the raw material liquid in the step (1) further comprises 1-15% by mass of water and 0.01-1.0% by mass of a mixture of lactic acid amide and amino acid.
  3. 3. The green production method of ethyl pyruvate according to claim 2, wherein the amino acids are glycine and alanine, and the molar ratio of the total molar amount of lactic acid amide and amino acid to ethyl lactate is (1-10) x 10 -3 :1.
  4. 4. The green preparation method of ethyl pyruvate according to claim 1 or 2, wherein the raw material liquid in the step (1) further comprises 0.01-0.5% of a mixture of phytic acid and phytate, and 0.02-2% of choline chloride.
  5. 5. The green preparation method of ethyl pyruvate according to claim 4, wherein the molar ratio of phytic acid to choline chloride is 1:1.5-3.
  6. 6. The green production method of ethyl pyruvate according to claim 1, wherein the porous carrier catalyst of surface-supported manganese copper cobalt oxide used in step (2) is produced by: (a) Loading an inorganic salt precursor containing manganese, copper and cobalt on a porous carrier of a nitrogen-containing carbon material, drying, and calcining at 400-550 ℃ for 2-6 hours in an air atmosphere; (b) And (C) treating the calcined product obtained in the step (a) in a carbon dioxide atmosphere at 300-450 ℃ for 1-5 hours.
  7. 7. The green process for preparing ethyl pyruvate according to claim 6, wherein step (C) is carried out after step (b), wherein the catalyst obtained in step (b) is pretreated in a mixture of ethyl lactate and carrier gas at 150 to 250 ℃ for 1 to 4 hours.
  8. 8. The green preparation method of ethyl pyruvate according to claim 7, wherein the volume fraction ratio of ethyl lactate vapor to carrier gas in the mixed gas introduced in the step (c) is 1:3-1:15, the carrier gas consists of nitrogen and carbon dioxide, and the volume fraction of carbon dioxide in the carrier gas is 20% -80%.
  9. 9. The green preparation method of ethyl pyruvate according to claim 7, wherein the fixed bed reactor is provided with a first reaction zone and a second reaction zone in sequence along the material flow direction, the bed temperature of the first reaction zone is 80-110 ℃, the bed temperature of the second reaction zone is 110-150 ℃, the molar ratio of oxygen to ethyl lactate in the first reaction zone is controlled to be 0.2-0.8:1, and the total molar ratio of oxygen to ethyl lactate in the second reaction zone is controlled to be 0.6-1.5:1.
  10. 10. The green preparation method of ethyl pyruvate according to claim 1, wherein the porous carrier is a nitrogen-containing carbon material, and the molar ratio of manganese, copper and cobalt in the catalyst is 1:0.5-2.0:0.1-1.5.

Description

Green preparation method of ethyl pyruvate Technical Field The invention relates to the technical field of ethyl pyruvate preparation, in particular to a green preparation method of ethyl pyruvate. Background Ethyl pyruvate is an important fine chemical intermediate and can be used for synthesizing medical raw materials, pesticide compounds and other functional chemicals. In the prior art, the preparation route of the ethyl pyruvate is more, wherein the traditional tartaric acid dehydration decarboxylation method has gradually reduced application due to more steps, low atom utilization rate, high energy consumption and the like. With the development of the lactic acid industry chain, an oxidation route using lactic acid or lactate as a raw material is attracting attention, and is considered to have better raw material availability and process greenness. Patent CN1204108C discloses a method of catalytic oxidation by mixing ethyl lactate gas phase with air in the presence of a silver/silica gel catalyst at about 250-300 ℃. The method can avoid using a chlorinating agent or a strong oxidizing agent, but has higher reaction temperature, and ethyl lactate is easy to generate side reaction and coking under the high temperature condition, so that the equipment burden is large, and the long-period running stability is limited. Patent CN106928059a discloses a solution for liquid phase oxidation of ethyl lactate using a strong or halogenated oxidant. Although oxidation can occur at milder temperatures, the required oxidants are corrosive or toxic, can produce chlorine-containing or other difficult to handle byproducts, are environmentally friendly and safe, and are difficult to meet in a continuous, green industry. Therefore, the problem to be solved is how to simultaneously achieve high conversion rate, high selectivity and stability of catalytic performance of ethyl lactate under continuous gas-liquid phase reaction conditions. Disclosure of Invention The invention aims to overcome the problems in the prior art and provide a green preparation method of ethyl pyruvate, which enables the conversion process of ethyl lactate to ethyl pyruvate to be carried out in a milder temperature and pressure range under the condition of taking oxygen-containing gas as an oxidant and adopting a fixed bed continuous gas-liquid phase reaction, realizes higher conversion rate on the premise of improving the selectivity of ethyl pyruvate and keeps the performance stability of a catalytic system in the continuous operation process. In order to achieve the above purpose, the invention provides a green preparation method of ethyl pyruvate, which comprises the following steps: (1) Mixing raw material liquid containing 75-99% of ethyl lactate by mass fraction with oxygen-containing gas, and continuously feeding the mixture into a fixed bed reactor; (2) In the presence of a porous carrier catalyst with surface loaded with oxides of three metals of manganese, copper and cobalt, carrying out continuous gas-liquid phase contact reaction at 80-150 ℃ and 0.1-1.0 MPa to obtain a reaction product effluent containing ethyl pyruvate; (3) And separating the reaction product effluent to obtain a pyruvic acid ethyl ester product. Preferably, the porous carrier is a nitrogen-containing carbon material, and the molar ratio of manganese, copper and cobalt in the catalyst is 1:0.5-2.0:0.1-1.5. The invention adopts a solid catalyst with three metal oxides of manganese, copper and cobalt as active components, and loads the solid catalyst on a porous material containing nitrogen and carbon, and the selective oxidation of ethyl lactate to ethyl pyruvate is completed through gas-liquid continuous contact. By limiting the mole ratio of manganese, copper and cobalt, multivalent redox centers with stable oxygen vacancies can be formed on the surface of the carrier. Manganese provides the predominant reactive oxygen species therein, effecting reversible abstraction of hydroxyl ortho-hydrogen. Copper is used for regulating the number of oxygen vacancies and the electron density, so that the regeneration rate of surface oxygen atoms is improved. Cobalt participates in the intermetallic redox cycle, stabilizing the reaction path before the formation of excessive oxidation potential. If the copper content is low, the oxygen vacancy is insufficient to reduce the conversion rate, and if the copper or cobalt content is high, the surface oxidation capability is too strong to cause the rupture of carbon-carbon bonds, so that the ethyl pyruvate selectivity is obviously reduced. By limiting the proportion ranges of the three, oxidation-reduction conditions suitable for oxidizing the ethyl lactate are formed, so that the conversion rate and the selectivity are simultaneously at a better level. The nitrogen-containing carbon carrier has higher specific surface area and abundant micropore and mesopore structures. And stable coordination is formed between nitrogen-containing confi