Catalytic conversion of cellulose to liquid hydrocarbon fuels by progressive removal of oxygen to facilitate separation processes and achieve high selectivities
Inventors
Dumesic, James A. • Ruiz, Juan Carlos Serrano • West, Ryan M.
Assignees
Publication Number
US-9067903-B2
Publication Date
2015-06-30
Expiration Date
2029-06-23
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
Described is a method to make liquid chemicals. The method includes deconstructing cellulose to yield a product mixture comprising levulinic acid and formic acid, converting the levulinic acid to γ-valerolactone, and converting the γ-valerolactone to pentanoic acid. Alternatively, the γ-valerolactone can be converted to a mixture of n-butenes. The pentanoic acid can be decarboxylated yield 1-butene or ketonized to yield 5-nonanone. The 5-nonanone can be hydrodeoxygenated to yield nonane, or 5-nonanone can be reduced to yield 5-nonanol. The 5-nonanol can be dehydrated to yield nonene, which can be dimerized to yield a mixture of C9 and C18 olefins, which can be hydrogenated to yield a mixture of alkanes.
Core Innovation
The invention describes a cascading catalytic method for converting cellulose, preferably derived from biomass, into valuable liquid hydrocarbons and chemical intermediates such as pentanoic acid and 5-nonanone, which can be further transformed into liquid fuels. The method comprises several steps including deconstructing cellulose to produce a mixture containing levulinic acid and formic acid, converting levulinic acid to γ-valerolactone (GVL), and subsequently converting GVL to pentanoic acid. Pentanoic acid can be further converted to 5-nonanone via ketonization, which is useful as a solvent and fuel additive. The 5-nonanone can be further upgraded to fuels such as nonane or to other intermediates via hydrogenation, dehydration, and oligomerization steps.
A key aspect of the method is utilizing hydrophobic intermediates such as GVL and pentanoic acid that spontaneously separate or can be efficiently extracted from the aqueous acidic reaction media, thereby significantly simplifying purification and reducing costly separation steps. The use of sulfuric acid or other mineral acids for cellulose deconstruction is integral to the process, with strategies described for partial removal or recycling of the acid during conversion steps to maintain catalyst performance. The method further includes balancing hydrogen produced from decomposition of formic acid in situ for the reduction steps, optimizing reaction conditions, and integrating with biomass gasification or pyrolysis for full utilization of biomass fractions.
Claims Coverage
The patent includes multiple independent claims focusing on methods for converting glucose to γ-valerolactone and pentanoic acid, involving acid-catalyzed hydrolysis and successive catalytic conversions.
Method for converting glucose to γ-valerolactone
A method comprising (a) hydrolyzing glucose in an aqueous, acid-catalyzed reaction to yield levulinic acid and formic acid; (b) converting formic acid within the mixture to H2 and CO2 without separating levulinic and formic acid; and (c) reducing levulinic acid to γ-valerolactone using the H2 produced in step (b).
Method for converting glucose to pentanoic acid
A method comprising the steps of hydrolyzing glucose to form levulinic acid and formic acid, converting formic acid to H2 and CO2 without separation, reducing levulinic acid to γ-valerolactone, and subsequently reducing γ-valerolactone to pentanoic acid using a catalyst comprising transition metals (including Nb and Pd) in the presence of hydrogen.
Use of mineral acids in glucose hydrolysis and in situ catalytic conversions
Methods where glucose hydrolysis is performed by reaction with mineral acids such as sulfuric acid, and steps of converting formic acid to hydrogen and reducing levulinic acid to γ-valerolactone are conducted in the presence of said mineral acid, with further steps to remove mineral acid from γ-valerolactone to enable recycling to glucose hydrolysis.
The claims cover methods of sequentially converting glucose via acid-catalyzed hydrolysis and catalytic reductions to valuable intermediates such as γ-valerolactone and pentanoic acid, utilizing catalysts comprising various metals and integrating the use and recycling of mineral acids to optimize process efficiency.
Stated Advantages
The method eliminates many purification and complex separation steps by producing hydrophobic intermediates that spontaneously separate or can be easily extracted from the aqueous acidic media.
The catalytic steps effectively operate in the presence of mineral acids, enabling recycling of acid and minimizing catalyst poisoning and process costs.
Extraction of γ-valerolactone into ethyl acetate significantly reduces energy requirements for separation compared to direct evaporation of aqueous solutions.
The cascading process minimizes capital costs and allows for regional processing of biomass to reduce transportation costs, enhancing economic feasibility.
The method achieves high yields (approximately 90%) and carbon selectivities for pentanoic acid and other intermediates, with efficient conversion of cellulose components.
Documented Applications
Conversion of cellulose-derived glucose to liquid transportation fuels including jet and Diesel fuels via intermediates such as pentanoic acid, 5-nonanone, nonane, and nonene.
Production of valuable chemical intermediates such as 1-butene for polymer industries by decarboxylation of pentanoic acid.
Use of 5-nonanone as a solvent and fuel additive.
Integration with biomass gasification to provide hydrogen and syngas for supporting the catalytic processes and for combined heat and power generation.
Production of branched and linear olefins and alkanes for use as fuel additives in gasoline, jet, and Diesel fuels.
Interested in licensing this patent?