Method for preparing aviation oil precursor by catalytic depolymerization of alkali lignin in ethanol-water solvent through cooperation of Pd/C catalyst and alkali catalyst

Abstract

The invention discloses a method for preparing an aviation oil precursor by catalytic depolymerization of alkali lignin in an ethanol-water solvent through cooperation of a Pd / C catalyst and an alkali catalyst. The method comprises the following steps: taking alkali lignin as a raw material, adding an ethanol-water two-phase solvent into the raw material as a reaction solvent, respectively adding the Pd / C catalyst and a NaOH catalyst for depolymerization reaction, and after the reaction is finished, obtaining the aviation oil precursor. According to the method, alkali lignin is efficiently depolymerized through a reaction system of Pd / C, the NaOH catalyst and the ethanol-water two-phase solvent to prepare the aviation oil precursor, wherein the NaOH homogeneous alkali catalyst overcomes the problem that the yield of monocyclic aromatic compounds is low due to mutual competition of hydrodeoxygenation and hydrogenolysis bond breaking of a carbon-based metal catalyst; and the Pd / C catalyst has the hydrogenation activity Pd metal center, such that the heavy polymerization aggravation problem when the NaOH is adopted as the catalyst can be inhibited; the selectivity and the yield of the alkali lignin converted into the monocyclic aromatic compound can be improved by using the reaction system, the product complexity can be reduced, and the efficient depolymerization of the alkali lignin can be achieved to prepare the monocyclic aromatic compound.

Description

technical field [0001] The invention relates to the technical field of biomass energy utilization, in particular to a method for preparing aviation oil precursors by catalytically depolymerizing alkali lignin with a Pd / C catalyst in cooperation with an alkali catalyst in an ethanol-water solvent. Background technique [0002] Lignin is a biomass resource second only to cellulose in nature, and it is a renewable macromolecular polymer. C-C bonds or C-O-C bonds in its structure are broken to obtain aromatic products, and bulk aromatic compounds can be obtained through functional group modification and modification, or liquid fuels can be prepared through hydrodeoxygenation, so it has great potential. Alkali lignin is the main component of black liquor in the alkaline pulping process, which has the characteristics of large output, complex structure and difficult depolymerization. It is difficult to realize its resource utilization with the current technology, and if it is dire...

AI Technical Summary

Problems solved by technology

The method prepares aviation fuel precursor by efficiently depolymerizing alkali lignin through the reaction system of carbon-based metal-homogeneous base synergistic catalyst and ethanol-water two-phase solvent, wherein the homogeneous base (NaOH) in the catalyst overcomes the carbon-based metal catalyst The competition between hydrodeoxygenation and hydrogenolysis leads to the problem of low yield of monocyclic aromatic compounds. At the same time, the hydrogenation active Pd metal center of Pd / C catalyst suppresses the disadvantage of intensified repolymerization when NaOH is used as a catalyst, and improves lignin production. The selectivity and yield of conversion to single-ring aromatics reduces the complexity of the product to solve the problem that the existing reaction system is difficult to achieve efficient depolymerization of alkali lignin to produce single-ring aromatics

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