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CN-122010710-A - Method for preparing organic acid by catalyzing biomass pyrolysis through cobalt oxide

CN122010710ACN 122010710 ACN122010710 ACN 122010710ACN-122010710-A

Abstract

The application discloses a method for preparing organic acid by catalyzing biomass pyrolysis through cobalt oxide, which comprises the steps of placing a first mixture containing biomass raw materials, cobalt oxide and alkali metal hydroxide in an anaerobic atmosphere for pyrolysis to obtain a solid-phase organic acid salt mixture, dissolving the solid-phase organic acid salt mixture by water and carrying out solid-liquid separation to obtain filtrate A and filter residue B, mixing the filtrate A with ethanol and carrying out solid-liquid separation to obtain filter residue C and filter residue B, dissolving the filter residue C by water, acidizing and extracting, and extracting to obtain first organic acid and raffinate. The method for preparing the organic acid by catalyzing biomass pyrolysis through the cobalt oxide provides a high-efficiency, green and sustainable biomass conversion path, realizes high-selectivity synthesis of the organic acid through a cobalt oxide catalytic system, has multiple advantages of simple and convenient process, mild conditions, high resource utilization rate, environmental positive benefit and the like, and has important industrial application prospect and ecological value.

Inventors

  • WU KEJING
  • WANG ZEQI
  • LIU GUOJIE
  • LU HOUFANG
  • LIANG BIN

Assignees

  • 四川大学

Dates

Publication Date
20260512
Application Date
20260302

Claims (10)

  1. 1. A method for preparing organic acid by pyrolysis of biomass catalyzed by cobalt oxide, comprising: pyrolyzing a first mixture containing biomass raw materials, cobalt oxide and alkali metal hydroxide in an oxygen-free atmosphere to obtain a solid-phase organic acid salt mixture; Dissolving the solid-phase organic acid salt mixture by adopting water and carrying out solid-liquid separation to obtain filtrate A and filter residue B; Mixing the filtrate A with ethanol and performing solid-liquid separation to obtain filter residue C and filtrate B; Dissolving the filter residue C with water, acidifying and extracting to obtain a first organic acid and raffinate with main components of glycolic acid, and/or cooling and solid-liquid separating the filtrate B to obtain a filter residue D and a filtrate C, and acidifying and fractionating the filter residue D to obtain a third organic acid containing propionic acid.
  2. 2. The method for preparing organic acid by pyrolysis of cobalt oxide catalyzed biomass according to claim 1, wherein the cobalt oxide is at least one selected from CoO, co 3 O 4 ; And/or the mass ratio of the cobalt oxide to the biomass raw material is 0.05-0.15:1; and/or the biomass raw material is at least one selected from fructose, glucose, sucrose, cellobiose, cellulose, hemicellulose, starch and chitosan.
  3. 3. The method for preparing organic acid by pyrolysis of cobalt oxide catalyzed biomass according to claim 1, wherein the alkali metal hydroxide is selected from at least one of NaOH and KOH; And/or the mass ratio of the alkali metal hydroxide to the biomass raw material is 2.0-4.5:1; And/or the pyrolysis reaction temperature is 190-250 ℃ and the time is 20-90 min.
  4. 4. The method for preparing organic acid by pyrolysis of cobalt oxide catalyzed biomass according to claim 1, wherein the mass ratio of the solid phase organic acid salt mixture to water is 1:150-300; And/or further comprising the steps of sequentially carrying out acid washing, drying and calcining on the filter residue B to obtain regenerated cobalt oxide.
  5. 5. The method for preparing organic acid by pyrolysis of cobalt oxide catalyzed biomass according to claim 4, wherein the acid used for pickling the filter residue B is dilute nitric acid with a mass fraction of 1% -5%, and the pickling times are 2-3 times; and/or the drying temperature is 110-150 ℃; and/or roasting at 800-1000 ℃ for 1-3 hours.
  6. 6. The method for preparing organic acid by pyrolysis of cobalt oxide catalyzed biomass according to claim 1, wherein the volume ratio of filtrate A to ethanol is 1:2-3; and/or the mass ratio of water to filter residue C is 1:50-100; And/or the acidification comprises the step of adjusting the pH value of the aqueous solution of the filter residue C to 2-3 by using 2-10% of dilute sulfuric acid by mass fraction; and/or the extractant used for extraction is at least one selected from ethyl acetate, butyl acetate, toluene or butanone; And/or the volume ratio of the extractant to the acidified aqueous solution is 1:0.5-1.0, and the extraction times are 2-3.
  7. 7. The method for preparing organic acid by pyrolysis of cobalt oxide catalyzed biomass according to claim 1, further comprising adding a precipitator into the filtrate C, performing precipitation reaction and solid-liquid separation to obtain filter residue E and filtrate D, dissolving the filter residue E by acid liquor, performing solid-liquid separation to obtain filter residue F and filtrate E, and fractionating the filtrate E to obtain a second organic acid with succinic acid as a main component.
  8. 8. The method for preparing organic acid by pyrolysis of cobalt oxide catalyzed biomass according to claim 7, wherein the cooling temperature is 0-5 ℃; and/or the precipitant is selected from calcium hydroxide; and/or the mass ratio of the precipitant to the filtrate C is 1:50-100; And/or the precipitation reaction temperature is 50-80 ℃; And/or the acid liquor is dilute sulfuric acid with the mass fraction of 2-10%, and the mass ratio of the filter residue E to the acid liquor is 1:50-100.
  9. 9. The method for preparing organic acid by pyrolysis of cobalt oxide catalyzed biomass according to claim 1, further comprising carrying out causticization and solid-liquid separation on a mixed solution obtained by mixing raffinate and filter residue D in sequence to obtain filtrate F and filter residue G, combining filtrate F and filter residue D, evaporating and concentrating, and recovering to obtain alkali metal hydroxide.
  10. 10. The method for preparing organic acid by pyrolysis of cobalt oxide catalyzed biomass according to claim 9, wherein the causticizing step comprises mixing and reacting calcium hydroxide with the mixed solution according to a mass ratio of 1:30-80; And/or the causticizing reaction temperature is 50-80 ℃ and the causticizing reaction times are 2-3.

Description

Method for preparing organic acid by catalyzing biomass pyrolysis through cobalt oxide Technical Field The application relates to the technical field of biomass pyrolysis, in particular to a method for preparing organic acid by catalyzing biomass pyrolysis through cobalt oxide. Background With the advancement of the global "two carbon" strategy, the utilization of renewable biomass to produce high value-added chemicals is a critical path for maximizing their resource value. Biomass, the only renewable carbon resource in nature, is an ideal precursor for the preparation of oxygen-containing organic acids. Among them, glycolic acid and succinic acid are extremely important platform compounds, and market demand continues to increase. Currently, the production of organic acids is mainly dependent on petrochemical routes or biological fermentation processes. In the biological fermentation method, although the reaction condition is mild, the biological fermentation method has the challenges of long fermentation period, low substrate concentration, obvious product inhibition effect, sensitivity to mixed bacteria pollution and the like, and is difficult to realize large-scale continuous production. In recent years, chemical conversion methods have been attracting attention because of their high reaction rates and large throughput. Among other things, biomass alkali heat treatment techniques are capable of depolymerizing macromolecular biomass at relatively mild temperatures. Research shows that strong alkali (such as NaOH and KOH) can effectively reduce the reaction activation energy, promote the reactions of deprotonation, reverse aldol condensation and the like, generate lactic acid, formic acid, acetic acid and the like (refer to Esipovich A L, Zlobin S Y, Shirshin K K, et al. "Catalytic conversion of glycerol to lactic acid over Cu-based catalysts"[J]. Catalysts, 2024, 14(4): 231.）. Liu Guojie and the like in patent (CN 116654867A) to disclose a two-stage biomass alkali heat treatment hydrogen production method, and realize the efficient hydrogen production of cellulose at a lower temperature. In view of this, a process that is capable of producing high value organic acids from biomass as a feedstock, and maintaining the selectivity of the high value organic acids in the product, is particularly desirable. Disclosure of Invention The application aims to provide a method for preparing organic acid by catalyzing biomass pyrolysis through cobalt oxide, which is beneficial to improving the selectivity of high-value organic acid. The application is realized in the following way: In a first aspect, the application provides a method for preparing organic acid by pyrolysis of biomass catalyzed by cobalt oxide, comprising: pyrolyzing a first mixture containing biomass raw materials, cobalt oxide and alkali metal hydroxide in an oxygen-free atmosphere to obtain a solid-phase organic acid salt mixture; Dissolving the solid-phase organic acid salt mixture by adopting water and carrying out solid-liquid separation to obtain filtrate A and filter residue B; Mixing the filtrate A with ethanol and performing solid-liquid separation to obtain filter residue C and filtrate B; Dissolving the filter residue C with water, acidifying and extracting to obtain a first organic acid and raffinate with main components of glycolic acid, and/or cooling and solid-liquid separating the filtrate B to obtain a filter residue D and a filtrate C, and acidifying and fractionating the filter residue D to obtain a third organic acid containing propionic acid. In an alternative embodiment, the cobalt oxide is selected from at least one of CoO, co 3O4; And/or the mass ratio of the cobalt oxide to the biomass raw material is 0.05-0.15:1; and/or the biomass raw material is at least one selected from fructose, glucose, sucrose, cellobiose, cellulose, hemicellulose, starch and chitosan. In an alternative embodiment, the alkali metal hydroxide is selected from at least one of NaOH and KOH; And/or the mass ratio of the alkali metal hydroxide to the biomass raw material is 2.0-4.5:1; And/or the pyrolysis reaction temperature is 190-250 ℃ and the time is 20-90 min. In an alternative embodiment, the mass ratio of the solid phase organic acid salt mixture to water is 1:150-300; And/or further comprising the steps of sequentially carrying out acid washing, drying and calcining on the filter residue B to obtain regenerated cobalt oxide. In an alternative embodiment, the acid used for pickling the filter residue B is dilute nitric acid with the mass fraction of 1% -5%, and the pickling times are 2-3 times; and/or the drying temperature is 110-150 ℃; and/or roasting at 800-1000 ℃ for 1-3 hours. In an alternative embodiment, the volume ratio of the filtrate A to the ethanol is 1:2-3; and/or the mass ratio of water to filter residue C is 1:50-100; And/or the acidification comprises the step of adjusting the pH value of the aqueous solution of the filter residue C to