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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Ignition Delay Measurements of Four Component Model Gasolines Exploring the Impacts of Biofuels and Aromatics

This study explores the impacts of combinations of biofuel (ethanol, isobutanol and 2-methyl furan) and aromatic (toluene) compounds in a four component fuel blend, at fixed research octane number (RON) on ignition delay measured in an advanced fuel ignition delay analyzer (AFIDA 2805). Ignition delay measurements were performed over a range of temperatures from 400 to 725 °C (673 to 998 K) and two chamber pressures of 10 and 20 bar. The four component mixtures are compared to primary reference fuels at RON values of 90 and 100. The ignition delay measurements show that as the aromatic and biofuel concentrations increased, two stage ignition behavior was suppressed, at both initial chamber pressures. But both RON 100 (isooctane) and RON 90 reference fuels showed two stage ignition behavior, as did fuel mixtures with low biofuel and aromatic content. RON 90 fuels showed stronger two stage ignition behavior than RON 100 fuels, as expected. Depending on the type of biofuel in the mixture, the ignition delay at low chamber temperatures could be far greater than for the reference fuels. In particular, for the RON 100 mixtures at either 10 or 20 bar initial chamber pressure, the ignition delay at 400 °C (673 K) for the high level blend of 2-methyl furan and toluene (30 vol% of each) exhibited an ignition delay that was 10 times longer than for neat isooctane. The results show the strong non-linear octane blending response of these three biofuel compounds, especially in concert with the kinetic antagonism that toluene is known to display in mixtures with isooctane. These results have implications for the formulation of biofuel mixtures for spark ignition and advanced compression ignition engines, where this non-linear octane blending response could be exploited to improve knock resistance, or modulate the autoignition process.

2-methyl furan↗
DOE OSTI2020

Catalytic Activity of Ti-based MXenes for the Hydrogenation of Furfural

Here, we report on the catalytic activity of Ti-based MXenes (Ti 3 CNT z and Ti 3 C 2 T z ) for biomass transformation. MXenes were found to be active catalysts for the hydrogenation of furfural using either gaseous hydrogen or 2-propanol as solvent and hydrogen source. Both catalysts showed good activity in the conversion of furfural to furfuryl alcohol, with furfuryl ether as the main by-product. Stability tests indicated that Ti 3 CNT z is more stable than Ti 3 C 2 T z against deactivation. Ab initio calculations were used to examine the hydrogenation and etherification reactions pathways and their corresponding reaction energetics on the Ti 3 CNT z MXene. The results indicate that the hydrogenation of the carbonyl bond efficiently proceeds via the heterolytic activation of hydrogen over the metal-oxygen site pair followed by the addition of the proton and hydride to the C and O atoms of the carbonyl. The subsequent hydrogenation of the unsaturated furan ring via metal bound hydrogen, however, is calculated to be much more difficult. Protons bound to the oxygen of the MXene are acidic and can also catalyze the etherification of the resulting alcohols. Finally, the bifunctional acid-metal site pairs also selectively catalyze the hydrogenolysis of the furfuryl alcohol to form 2-methyl furan.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Investigation of O( 3 P) Initiated Oxidation Products of 2,3-Dimethylfuran Using Synchrotron Photoionization

Biofuels are an appealing alternative to augment conventional fossil fuels, given that traditional fossil fuels are finite in nature despite being the highest-consumed energy source. Furans have been studied as potential biofuels due to their renewability, high energy density, and ability to both blend with existing fossil fuels and serve as a stand-alone fuel. Although promising, more research efforts on the combustion of furan-based biofuels are needed. Here, in this study, the oxidation of 2,3-dimethylfuran (2,3-DMF) initiated by O( 3 P) was investigated using vacuum-ultraviolet synchrotron radiation from the Advanced Light Source at the Lawrence Berkeley National Laboratory. The reaction was studied at 550 K and 7 Torr. Major reaction products include 3-methyl-3-buten-2-one, 4,5-dimethyl-3(2H)-furanone, and 3-methyl-4-oxo-2(Z)-pentenal, with 3-methyl-3-buten-2-one being the most abundant.

CBS-QB3↗
DOE OSTI2023

Mechanism of furfural toxicity and metabolic strategies to engineer tolerance in microbial strains

Abstract Lignocellulosic biomass represents a carbon neutral cheap and versatile source of carbon which can be converted to biofuels. A pretreatment step is frequently used to make the lignocellulosic carbon bioavailable for microbial metabolism. Dilute acid pretreatment at high temperature and pressure is commonly utilized to efficiently solubilize the pentose fraction by hydrolyzing the hemicellulose fibers and the process results in formation of furans—furfural and 5-hydroxymethyl furfural—and other inhibitors which are detrimental to metabolism. The presence of inhibitors in the medium reduce productivity of microbial biocatalysts and result in increased production costs. Furfural is the key furan inhibitor which acts synergistically along with other inhibitors present in the hydrolysate. In this review, the mode of furfural toxicity on microbial metabolism and metabolic strategies to increase tolerance is discussed. Shared cellular targets between furfural and acetic acid are compared followed by discussing further strategies to engineer tolerance. Finally, the possibility to use furfural as a model inhibitor of dilute acid pretreated lignocellulosic hydrolysate is discussed. The furfural tolerant strains will harbor an efficient lignocellulosic carbon to pyruvate conversion mechanism in presence of stressors in the medium. The pyruvate can be channeled to any metabolite of interest by appropriate modulation of downstream pathway of interest. The aim of this review is to emphasize the use of hydrolysate as a carbon source for bioproduction of biofuels and other compounds of industrial importance.

5-hydroxymethyl furfural↗
DOE OSTI2025

Highly functional microspheres facilitating Diels–Alder network formation

Introducing particles to dynamic covalent networks is a common approach to improve their performance. However, network formation can be impacted by their size and functionality. The influence can be predicted by common theories for small molecular precursors, but it is unclear whether they are applicable to precursors bearing numerous reactive groups and micrometer-scale dimensions. In this work, an experimental study was undertaken using dynamic covalent networks formed by the Diels–Alder reaction between furan and maleimide groups. The gelation behavior of the Diels–Alder networks was studied using rheometry to track their network formation at 40 °C with varying maleimide-functionalized microsphere loading. The highly functional microspheres can interact with the furan precursor, aiding in the formation of the Diels–Alder networks. A 5 wt% microsphere sample can reduce the gelation time by 23% and facilitate network formation in an unbalanced stoichiometry near the critical composition to form a percolating network.

36 MATERIALS SCIENCE↗
DOE OSTI2020

2019 Results for Avian Monitoring of Inorganic and Organic Element Concentrations in Passerine Eggs and a Nestling Collected from Technical Area 16 Burn Grounds, Technical Area 36 Minie, and Technical Area 39 Point 6 at Los Alamos National Laboratory

In 2019, non-viable avian eggs and one nestling were opportunistically collected at Los Alamos National Laboratory (LANL) near open detonation sites located at Technical Area (TA) 16 burn grounds, TA-36 Minie, and TA-39 Point 6. These samples were evaluated for inorganic elements (mostly metals), polychlorinated biphenyls (PCBs), dioxins, and furans. A total of 26 western bluebird (Sialia mexicana) and five mountain bluebird (Sialia currucoides) egg samples and one non-viable ash-throated flycatcher (Myiarchus cinerascens) nestling were collected among the three locations of interest. Concentrations of inorganic elements observed in this study were compared with the regional statistical reference level (RSRL) which is the upper-level bounds of background concentrations (mean + three standard deviations = 99% confidence interval). Several inorganic elements were not detected in avian eggs and the majority of inorganic elements detected were below the RSRL. The few elements that exceeded the RSRL were below the lowest observable adverse effect level (LOAEL), when available. One nestling collected from TA-16 contained detectable concentrations of some dioxin and furan congeners. Octachlorodibenzodioxin-1,2,3,4,6,7,8,9 concentration exceeded the RSRL, but did not exceed the calculated tetrachlorodibenzodioxin-2,3,7,8 (TCDD) toxic equivalent LOAEL. PCBs were also detected in the nestling sample and were above the RSRL but below the LOAEL. These data suggest that inorganic and organic element concentrations in eggs and nestlings are not of ecological concern. More data are needed to make a robust assessment and to evaluate trends over time.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Soil Sample Plan in Support of the Site 300 Explosives Waste Treatment Facility Ecological Risk Assessment Pursuant to the Hazardous Waste Facility Permit, Part V, Special Condition #14 a-f. August 2020

The Department of Toxic Substances Control issued the Final Hazardous Waste Facility Permit to Lawrence Livermore National Laboratory, Site 300 in 2017. As part of the continual process to ensure waste treatment emissions are not impacting ecological receptors, LLNL analyzed soil samples in the vicinity of the Explosive Waste Treatment Facility (EWTF) Burn Units (i.e., Burn Cage and Burn Pan) and the Detonation Pad. Soil samples were analyzed by EPA Solid Waste 846 Methods for furans, explosives, metals, and semivolatile compounds. In all samples, furans, explosives, and semi-volatile organic compounds were not detected. Metals were detected at concentrations below background levels. This soil sample plan will sample the same four downwind areas of the Burn Units and the same downwind areas of the Detonation, as well as including four new sample locations. The four new locations will be located to the northeast and southwest of the Burn Units and Detonation (as shown in Figure 3). The constituents to be analyzed are in Tables 2 and 3. Perchlorate was not identified as a constituent of concern in the 2007 Soil Sampling Plan. However, for this plan, all soil samples will be analyzed for perchlorate. After completion of the sampling event, a soil sample report will be submitted to DTSC in accordance with requirements specified in the Hazardous Waste Facility Permit, Part V, Special Conditions 16 a-f. This proposed soil sampling plan will be fully implemented no later than one year after receiving DTSC approval, in accordance with the Hazardous Waste Facility Permit, Part V, Special Condition 15.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Soil Sample Workplan in Support of the Site 300 Explosives Waste Treatment Facility Ecological Risk Assessment Pursuant to the Hazardous Waste Facility Permit (Part V, Special Condition #14 a-f)

The Department of Toxic Substances Control issued the Final Hazardous Waste Facility Permit to Lawrence Livermore National Laboratory, Site 300 in 2017. As part of the continual process to ensure waste treatment emissions are not impacting ecological receptors, LLNL analyzed soil samples in the vicinity of the Explosive Waste Treatment Facility (EWTF) Burn Units (i.e., Burn Cage and Burn Pan) and the Detonation Pad. Soil samples were analyzed by EPA Solid Waste 846 Methods for furans, explosives, metals, and semi-volatile compounds. In all samples, furans, explosives, and semi-volatile organic compounds were not detected. Metals were detected at concentrations below background levels. This soil sample plan will sample the same four downwind areas of the Burn Units and the same downwind areas of the Detonation, as well as including four new sample locations. The four new locations will be located to the northeast and southwest of the Burn Units and Detonation (as shown in Figure 3). The constituents to be analyzed are in Tables 7 and 8. Perchlorate was not identified as a constituent of concern in the 2007 Soil Sampling Plan. However, for this plan, all soil samples will be analyzed for perchlorate. Nitrate and all CAM17 metals have been added to the sampling plan to comply with DTSC comments received in correspondence dated June 4, 2021. After completion of the sampling event, a soil sample report will be submitted to DTSC in accordance with requirements specified in the Hazardous Waste Facility Permit, Part V, Special Conditions 16 a-f. This proposed soil sampling plan will be fully implemented no later than one year after receiving DTSC approval, in accordance with the Hazardous Waste Facility Permit, Part V, Special Condition 15.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2022

2021 Results for Avian Monitoring of Inorganic and Organic Element Concentrations in Passerine Eggs and Nestlings Collected from Technical Area 16 Burn Grounds, Technical Area 36 Minie, and Technical Area 39 Point 6 at Los Alamos National Laboratory (Rev. 2)

In 2021, non-viable avian eggs and one nestling were opportunistically collected at Los Alamos National Laboratory (LANL) near open detonation sites located at Technical Area (TA) 16 burn grounds and TA-36 Minie. Similar to previous years, nestboxes were monitored at TA-39 Point 6, however, no avian samples were available for opportunistic collection. Samples were evaluated for inorganic elements (mostly metals), dioxins, and furans. One ash-throated flycatcher (Myiarchus cinerascens) egg sample was collected from TA-16 burn grounds. One ash-throated flycatcher and one mountain bluebird (Sialia currucoides) egg sample and one deceased western bluebird (Sialia mexicana) nestling sample were collected from TA-36 Minie. Concentrations of inorganic elements observed in this study were compared with the regional statistical reference level (RSRL) which is the upper-level bounds of background concentrations (mean + three standard deviations = 99% confidence interval). Several inorganic elements were not detected in avian eggs. Most inorganic elements detected were below the RSRL and all were the lowest observable adverse effect level (LOAEL), when available. The nestling collected from TA-36 did not contain detectable concentrations of dioxin or furan congeners. These data suggest that inorganic and organic element concentrations in eggs and nestlings are not of ecological concern. More data are needed to make a robust assessment and to evaluate trends over time.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1975

Reforming and decomposition of glucose in an aqueous phase

Exploratory experiments have been carried out to study the decomposition of glucose, a typical carbohydrate, in a high temperature-high pressure water reactor. The objective of the study was to examine the feasibility of such a process to decompose cellulosic waste materials in long-term space missions. At temperatures below the critical point of water, glucose decomposed to form liquid products and char. Little gas was noted with or without reforming catalysts present. The rate of the primary glucose reaction increased significantly with temperature. Partial identification of the liquid phase was made and the C:H:O ratios determined for both the liquid and solid products. One of the more interesting results from this study was the finding that when glucose was injected into a reactor held at the critical temperature (and pressure) of water, no solid products formed. Gas production increased, but the majority of the carbon was found in soluble furans (and furan derivatives). This significant result is now being investigated further.

Amin, S.↗
DOE OSTI2022

Phosphorus-containing solid catalysts and reactions catalyzed thereby, including synthesis of p-xylene

Methods and phosphorus-containing solid catalysts for catalyzing dehydration of cyclic ethers (e.g., furans, such as 2,5-dimethylfuran) and alcohols (e.g., ethanol and isopropanol). The alcohols and cyclic ethers may be derived from biomass. One example includes a tandem Diels-Alder cycloaddition and dehydration of biomass-derived 2,5-dimethyl-furan and ethylene to renewable p-xylene. The phosphorus-containing solid catalysts are also active and selective for dehydration of alcohols to alkenes.

Cho, Hong Je↗
DOE OSTI2026

Trace gases at TRACER ANC site

Speciated volatile organic compounds (VOCs) were measured using an Ionicon PTR-TOF 8000 from 20 June to 3 July 2022 at the TRACER ancillary (TRACER ANC) site in Guy, TX. The dataset is reported at 1-min time resolution. Mixing ratios (ppb) are provided for acetone, methanol, acetaldehyde, dimethyl sulfide (DMS), furan, isoprene, methyl vinyl ketone plus methyl ethyl ketone (MVK + MEK), terpenes, xylene, and trimethylbenzene. Instrument calibrations for these species were performed weekly using a certified gas standard.

acetaldehyde↗
NASA NTRS2026

Biobased Polybenzoxazine Derived from Furfurylamine and Piceol with Low Cure Temperature and Advanced Properties for Composite Matrices

A novel benzoxazine made from furfurylamine, paraformaldehyde, and piceol, Bz-FA-HA, is assessed for applications in fiber reinforced (FR) composites. Piceol is a biobased phenolic compound derived from the roots of Norwegian spruce trees and contains a methyl ketone group at the para position. Bz-FA-HA is a liquid at room temperature, has a viscosity of < 1 Pa.s at temperatures above 90 °C, and a Tonset of cure at 132 °C. The carbonyl is found to react with the furan ring, yielding a crosslinking reaction, when cured above 180 °C as indicated by differential scanning calorimetry and thermogravimetric analysis coupled with Fourier transform infrared spectroscopy. Poly(Bz-FA-HA) has a Tg > 350 °C, attributed to the crosslinking reaction. Furthermore, the storage modulus is > 3 GPa, regardless of cure temperature. Poly(Bz-FA-HA) has a char yield at 800 °C of 65.0 % (62.3 % at 1000 °C), and a Tonset of decomposition of 357 °C in nitrogen. The resulting carbon formed during pyrolysis shrinks during the carbonization reaction and scanning electron microscopy imaging shows a cross-section with micro cracks. The high processability, advanced mechanical properties, and exceptional char yield make it a promising candidate as the matrix for FR composites.

Benzoxazine↗
DOE OSTI2020

Respirator Cartridge Performance on Mixed Vapors from Hanford Tank Headspaces and Exhausters - 20427

Between 2016 and 2018, the Hanford Tank Operations Contractor - Washington River Protection Solutions (WRPS) - conducted a series of tests of air-purifying respirator (APR) chemical cartridges commonly used at Hanford tank farms to determine the period of time for which the cartridges would provide adequate performance when used in APRs and powered-air-purifying respirators (PAPRs) to protect workers when exposed to a mixture of vapors exiting tank headspaces. Although cartridge manufacturers provide service life estimating tools for individual chemical compounds, the projected performance of these cartridges on complex vapor mixtures is not available, and the adequacy of APRs for tank farm applications represents an important workforce concern. The Occupational Safety and Health Administration identifies cartridge testing as a valid approach for establishing cartridge service life. The primary function of the WRPS Cartridge Test Program was to obtain objective data to determine service lives for the APR and PAPR cartridges used at Hanford tank farms. WRPS contracted with Pacific Northwest National Laboratory to analyze the test data and offer an independent analysis of and recommendations based on respirator cartridge performance. A total of 28 APR and 10 PAPR cartridge tests were conducted between 2016 and 2018 on 12 different tank headspaces and tank farm exhauster slipstreams. Two APR cartridges from SCOTT (now 3M) and two PAPR cartridges from MSA Safety, Inc. and 3M were evaluated using a cartridge testing system specifically designed to measure and monitor test conditions and sample cartridge inlet and outlet vapor streams for important chemical compounds. Testing focused on analysis of approximately 61 tank vapor chemicals of potential concern (COPCs) that have been previously detected in tank vapors at levels above 10% of their occupational exposure limits (OELs). Each test was conducted over 16 hours of run time. Evidence of chemical breakthrough was assessed by comparing inlet and outlet COPC concentrations over the duration of each test. The breakthrough threshold was normally defined as exceeding 10% of the compounds OEL at the cartridge outlet. Ammonia breakthrough was observed in a majority of the cartridge tests and occurred earlier than breakthrough of any other chemical compound. Several other COPCs did exhibit breakthrough behavior, including mercury, 1,3-butadiene, furan, 2,5 dihydrofuran, and N-nitrosodimethylamine (NDMA), but only in a very limited number of cartridge tests and only after ammonia breakthrough had occurred. In addition, tests results suggest that breakthrough of some of these COPCs may have been affected by competition with and breakthrough of other non-COPC organics, such as ethanol and acetone, with substantially lower toxicological hazard. Comparison of cartridge manufacturers' service life estimates with the experimentally derived breakthrough times indicates that manufacturers' estimates are generally conservative, even in the presence of the complex mixed vapor streams experienced in these tests. With consideration of appropriate safety margins, these results provide valuable insights on cartridge performance to inform industrial hygiene professionals in establishing appropriate cartridge change-out schedules for APR and PAPR use in the Hanford tank farms. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

Vacancy Mediated Electrooxidation of 5‐Hydroxymethyl Furfuryl Using Defect Engineered Layered Double Hydroxide Electrocatalysts

Abstract Electrochemical biomass oxidation coupled with hydrogen evolution offers a promising route to generate value‐added chemicals and clean energy. The complex adsorption behavior of 5‐hydroxymethyl furfural (HMF) and hydroxyl ions (OH − ) on the electrocatalyst surface during HMF electrooxidation reaction (HMFOR) necessitates an in‐depth understanding of active sites available for adsorption. Herein, oxygen vacancy (V O ) defects are introduced in NiFe layered double hydroxide (LDH) using Ce dopants to manipulate electronic structure. Synchrotron‐based HE‐XRD and XAS indicate negligible V O in La‐doped NiFe while Ce doping leads to V O defects due to flexible Ce redox (Ce 3+ ↔ Ce 4+ ). The V O ‐rich Ce‐NiFe exhibits higher Faradic efficiency of ≈90% to produce 2,5‐furan dicarboxylic acid (FDCA), far greater than ≈60% for NiFe V O in Ce‐NiFe act as alternative active sites for OH − adsorption, hence reducing adsorption competition for the same metal sites. DFT calculation results corroborate experimental findings by showcasing that the presence of V O in Ce‐NiFe manipulates the adsorption energies and facilitates the chemical adsorption OH − in V O to improve HMFOR. In situ HE‐XRD derived pair distribution function coupled to RMC simulations confirm OH − trapping in V O and HMF adsorption on metal centers as evident by interlayer distance evolution. Taken together, this work showcases routes for dual‐site electrocatalyst design for improved biomass electrooxidation.

Chemistry↗
DOE OSTI2020

Protection Strategies Enable Selective Conversion of Biomass

Abstract Selective and economic conversion of lignocellulosic biomass components to bio‐based fuels and chemicals is the major goal of biorefineries, but low yields and selectivity for fuel precursors such as sugars, furanics, and lignin‐derived monomers pose significant disadvantages in process economics. In this Minireview we summarize the existing protection strategies used in biomass chemocatalytic conversion processes and focus the discussions on the mechanisms, challenges, and opportunities of each strategy. We introduce a concept of using analogous methods to manipulate biomass catalytic conversion pathways during the upgrading of carbohydrates to fuels and chemicals. This Minireview may provide new insights into the development of selective biorefining processes from a different perspective, expanding the options for selective conversion of biomass to fuels and chemicals.

Luo, Xiaolin↗
DOE OSTI2020

Protection Strategies Enable Selective Conversion of Biomass

Abstract Selective and economic conversion of lignocellulosic biomass components to bio‐based fuels and chemicals is the major goal of biorefineries, but low yields and selectivity for fuel precursors such as sugars, furanics, and lignin‐derived monomers pose significant disadvantages in process economics. In this Minireview we summarize the existing protection strategies used in biomass chemocatalytic conversion processes and focus the discussions on the mechanisms, challenges, and opportunities of each strategy. We introduce a concept of using analogous methods to manipulate biomass catalytic conversion pathways during the upgrading of carbohydrates to fuels and chemicals. This Minireview may provide new insights into the development of selective biorefining processes from a different perspective, expanding the options for selective conversion of biomass to fuels and chemicals.

Luo, Xiaolin↗