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Hydroxide Catalysts for Lignin Depolymerization

National Renewable Energy Laboratory

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Technology Marketing Summary

Biofuels are a major component of a balanced international renewable energy portfolio. Most methods for producing biofuels have been focused on utilizing the cellulose or hemicellulose components of biomass. Lignin, a major component of woody biomass that represents rich organic molecules, is underutilized in current biomass production due to the lack of economic and technically feasible routes for lignin depolymerization. One way to deconstruct lignin is through base-catalyzed depolymerization (BCD) with sodium hydroxide or other soluble base materials. Typical BCD processes rely on an aqueous-phase basic media that requires substantial treatment to neutralize the resulting streams and adds significant costs to the overall production process. Due to the expensive process for lignin depolymerization, alternative technologies are needed to deconstruct lignin more economically.

Description

NREL researchers have developed a way to use nitrate-loaded hydrotalcite for lignin depolymerization to oxygenated aromatic compounds. Utilizing solid catalysts avoids the high cost of a liquid-phase, non-recyclable base, while also avoiding downstream processing steps, such as neutralization. For these solid base catalysts, layered double hydroxides (LDHs) can be used as recyclable, heterogeneous catalysts during BCD. This is advantageous because of LDHs’ ability to form metal hydroxides, to act as solid base catalysts in water and organic solvents in high temperatures, and to be used directly as a catalyst or as an active support in multifunctional catalysts. Additionally, the interlayer spacing of LDHs is tunable, which allows for a significant breadth and range of available chemistries and potential substrates. LDHs provide a more efficient way to deconstruct lignin, while avoiding expensive downstream processing steps.

Benefits
  • Reduces costs in biofuel production via effective lignin depolymerization
  • Avoids production of waste streams common to pulping processes
  • Versatility of layered double hydroxides
Applications and Industries
  • Lignin Deconstruction
  • Biofuel Production
  • Biomass Conversion
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
14-53DevelopmentAvailable06/27/201606/27/2016

Contact NREL About This Technology

To: Eric Payne<eric.payne@nrel.gov>