Search NASA⌕ Search

SEARCH · Search NASA

Results for “dichloromethane”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

66 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ti2HCSe4Cl16O5 by Materials Project

Ti2Se4O5Cl14CHCl2 is alpha iridium vanadium structured and crystallizes in the monoclinic Pc space group. The structure is zero-dimensional and consists of two dichloromethane molecules and two Ti2Se4O5Cl14 clusters. In each Ti2Se4O5Cl14 cluster, there are two inequivalent Ti+3.50+ sites. In the first Ti+3.50+ site, Ti+3.50+ is bonded to three O2- and three Cl1- atoms to form distorted corner-sharing TiCl3O3 octahedra. The corner-sharing octahedral tilt angles are 17°. There is one shorter (1.82 Å) and two longer (2.14 Å) Ti–O bond length. There are a spread of Ti–Cl bond distances ranging from 2.26–2.45 Å. In the second Ti+3.50+ site, Ti+3.50+ is bonded to three O2- and three Cl1- atoms to form distorted corner-sharing TiCl3O3 octahedra. The corner-sharing octahedral tilt angles are 17°. There are a spread of Ti–O bond distances ranging from 1.81–2.16 Å. There are a spread of Ti–Cl bond distances ranging from 2.26–2.45 Å. There are four inequivalent Se+3.50+ sites. In the first Se+3.50+ site, Se+3.50+ is bonded in a 1-coordinate geometry to one O2- and two Cl1- atoms. The Se–O bond length is 1.68 Å. Both Se–Cl bond lengths are 2.21 Å. In the second Se+3.50+ site, Se+3.50+ is bonded in a 1-coordinate geometry to one O2- and two Cl1- atoms. The Se–O bond length is 1.68 Å. Both Se–Cl bond lengths are 2.21 Å. In the third Se+3.50+ site, Se+3.50+ is bonded in a 1-coordinate geometry to one O2- and two Cl1- atoms. The Se–O bond length is 1.68 Å. There are one shorter (2.20 Å) and one longer (2.22 Å) Se–Cl bond lengths. In the fourth Se+3.50+ site, Se+3.50+ is bonded in a 1-coordinate geometry to one O2- and two Cl1- atoms. The Se–O bond length is 1.68 Å. There are one shorter (2.20 Å) and one longer (2.22 Å) Se–Cl bond lengths. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Ti+3.50+ and one Se+3.50+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one Ti+3.50+ and one Se+3.50+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one Ti+3.50+ and one Se+3.50+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ti+3.50+ and one Se+3.50+ atom. In the fifth O2- site, O2- is bonded in a linear geometry to two Ti+3.50+ atoms. There are fourteen inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Se+3.50+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Se+3.50+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Ti+3.50+ atom. In the fourth Cl1- site, Cl1- is bonded in a single-bond geometry to one Ti+3.50+ atom. In the fifth Cl1- site, Cl1- is bonded in a single-bond geometry to one Ti+3.50+ atom. In the sixth Cl1- site, Cl1- is bonded in a single-bond geometry to one Ti+3.50+ atom. In the seventh Cl1- site, Cl1- is bonded in a single-bond geometry to one Se+3.50+ atom. In the eighth Cl1- site, Cl1- is bonded in a single-bond geometry to one Se+3.50+ atom. In the ninth Cl1- site, Cl1- is bonded in a single-bond geometry to one Se+3.50+ atom. In the tenth Cl1- site, Cl1- is bonded in a single-bond geometry to one Se+3.50+ atom. In the eleventh Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Ti+3.50+ atom. In the twelfth Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Ti+3.50+ atom. In the thirteenth Cl1- site, Cl1- is bonded in a single-bond geometry to one Se+3.50+ atom. In the fourteenth Cl1- site, Cl1- is bonded in a single-bond geometry to one Se+3.50+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on C10S(Cl4O)3 by Materials Project

(CCl)8CCl2CSO3Cl2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of thirty-two chloromethane molecules, four dichloromethane molecules, and four CSO3Cl2 clusters. In each CSO3Cl2 cluster, C2+ is bonded in a bent 120 degrees geometry to one O2- and one Cl1- atom. The C–O bond length is 1.45 Å. The C–Cl bond length is 1.75 Å. S2- is bonded in a distorted tetrahedral geometry to three O2- and one Cl1- atom. There is two shorter (1.43 Å) and one longer (1.62 Å) S–O bond length. The S–Cl bond length is 2.04 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one S2- atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one C2+ and one S2- atom. In the third O2- site, O2- is bonded in a single-bond geometry to one S2- atom. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one S2- atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PH30Pt2C10I2NCl2 by Materials Project

Pt2C9PNH28I2CH2Cl2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four dichloromethane molecules and four Pt2C9PNH28I2 clusters. In each Pt2C9PNH28I2 cluster, there are two inequivalent Pt2- sites. In the first Pt2- site, Pt2- is bonded to three C+2.40-, one N3-, and two I1- atoms to form distorted PtC3I2N octahedra that share a cornercorner with one PC3N tetrahedra and a faceface with one PtC3I2N octahedra. There are one shorter (2.06 Å) and two longer (2.07 Å) Pt–C bond lengths. The Pt–N bond length is 2.37 Å. There are one shorter (2.84 Å) and one longer (2.86 Å) Pt–I bond lengths. In the second Pt2- site, Pt2- is bonded to three C+2.40-, one N3-, and two I1- atoms to form distorted PtC3I2N octahedra that share a cornercorner with one PC3N tetrahedra and a faceface with one PtC3I2N octahedra. There are one shorter (2.06 Å) and two longer (2.07 Å) Pt–C bond lengths. The Pt–N bond length is 2.36 Å. There are one shorter (2.83 Å) and one longer (2.86 Å) Pt–I bond lengths. There are nine inequivalent C+2.40- sites. In the first C+2.40- site, C+2.40- is bonded in a distorted trigonal non-coplanar geometry to one Pt2- and three H1+ atoms. There is one shorter (1.09 Å) and two longer (1.10 Å) C–H bond length. In the second C+2.40- site, C+2.40- is bonded in a distorted trigonal non-coplanar geometry to one Pt2- and three H1+ atoms. All C–H bond lengths are 1.10 Å. In the third C+2.40- site, C+2.40- is bonded in a distorted trigonal non-coplanar geometry to one Pt2- and three H1+ atoms. All C–H bond lengths are 1.10 Å. In the fourth C+2.40- site, C+2.40- is bonded in a distorted trigonal non-coplanar geometry to one Pt2- and three H1+ atoms. All C–H bond lengths are 1.10 Å. In the fifth C+2.40- site, C+2.40- is bonded in a distorted trigonal non-coplanar geometry to one Pt2- and three H1+ atoms. All C–H bond lengths are 1.10 Å. In the sixth C+2.40- site, C+2.40- is bonded in a distorted trigonal non-coplanar geometry to one Pt2- and three H1+ atoms. All C–H bond lengths are 1.10 Å. In the seventh C+2.40- site, C+2.40- is bonded to one P5+ and three H1+ atoms to form distorted corner-sharing CPH3 tetrahedra. The C–P bond length is 1.80 Å. There is one shorter (1.09 Å) and two longer (1.10 Å) C–H bond length. In the eighth C+2.40- site, C+2.40- is bonded to one P5+ and three H1+ atoms to form distorted corner-sharing CPH3 tetrahedra. The C–P bond length is 1.80 Å. All C–H bond lengths are 1.10 Å. In the ninth C+2.40- site, C+2.40- is bonded to one P5+ and three H1+ atoms to form distorted corner-sharing CPH3 tetrahedra. The C–P bond length is 1.80 Å. There is one shorter (1.09 Å) and two longer (1.10 Å) C–H bond length. P5+ is bonded to three C+2.40- and one N3- atom to form PC3N tetrahedra that share corners with two PtC3I2N octahedra. The corner-sharing octahedra tilt angles range from 53–55°. The P–N bond length is 1.65 Å. N3- is bonded in a 2-coordinate geometry to two Pt2-, one P5+, and one H1+ atom. The N–H bond length is 1.03 Å. There are twenty-eight inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the fourteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the fifteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the sixteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the seventeenth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the eighteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the nineteenth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the twentieth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the twenty-first H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the twenty-second H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the twenty-third H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the twenty-fourth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the twenty-fifth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the twenty-sixth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the twenty-seventh H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. In the twenty-eighth H1+ site, H1+ is bonded in a single-bond geometry to one C+2.40- atom. There are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a 2-coordinate geometry to two Pt2- atoms. In the second I1- site, I1- is bonded in a distorted L-shaped geometry to two Pt2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Chemical Recycling of Mixed Plastics and Valuable Metals in the Electronic Waste Using Solvent-Based Processing

Annually, 20-55 million tons of electronic waste (e-waste) is produced worldwide (5% of all municipal solid waste). Although e-waste embodies only 2% of America’s municipal waste, it accounts for a significantly larger proportion of the heavy metals and flame retardants present in the waste stream. Currently, less than 20% of all e-waste is recycled in the United States because the heterogeneity of the feedstock limits the opportunity for reuse in high value products and processing of the waste itself is often too costly to justify handling. To address this concern, the aims of this study are: 1) to identify the major plastic and metal compositions within electronic shredder residue (ESR), 2) to formulate solvents and processing conditions to separate 90% of the plastics targeted from consumer shred ESR, and 3) to develop a process design model to estimate the cost and energy efficiency of the proposed solvent-based processing. In this study, a pre-sorted heterogeneous ESR feedstock (one where aluminum, magnetic components, and hazardous battery materials removed by an e-waste recycling facility) was used, with the major compositions of the ESR characterized. It was found that 25 wt.% of the feedstock was composed of plastics, 6 wt.% rubber, 27 wt.% printed circuit boards, 23% wire, and the remainder metals and capacitors. Within the plastic portion, polystyrene (PS, 40 wt.%), acrylonitrile butadiene styrene (ABS, 25 wt.%), and styrene-acrylonitrile (SAN, 9wt.%) were identified to compose the majority of the screened plastics using Fourier transform infrared spectroscopy (FTIR). Next, selective solvents were screened using Hansen Solubility Parameter Theory (HSP) for dissolving PS and ABS. The pre-screening results show that methylene chloride (dichloromethane, DCM) and tetrahydrofuran (THF) are capable of dissolving the most PS and ABS, while methanol (MeOH) and ethylene glycol (EG) are capable of precipitating the most PS and ABS. These solvents were subsequently used to recover polymers and remove. flame retardants within the ESR feedstock. By optimizing the dissolution time and the solvents used, the highest polymer dissolution yield (99 wt.%%) was achieved using DCM for 48 hr. Both pre-screened anti-solvents (MeOH and EG) showed the highest polymer precipitation yield (71 wt.%). In terms of flame retardant removal rate, EG was found to have a high phosphorus-containing flame retardant removal rate (up to 98%). Characterization shows that the proposed solvent-based processing can preserve a high molecular weight fraction of the polymers and effectively remove flame retardants. Cost analysis indicates that the amount of the solvent/anti-solvent recovered after the reaction would play a critical role in reducing the operating costs. The energy analysis shows that the proposed solvent-based processes can save up to 60% of the embodied energy used to manufacture plastics used in electronics (PS and ABS were used for calculations). The results from this project prove the potential of solvent-based processing to produce secondary materials (plastics and metals) from e-waste for cross-industry reuse.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Comparing computational times for simulations when using PBPK model template and stand-alone implementations of PBPK models

Introduction We previously developed a PBPK model template that consists of a single model “superstructure” with equations and logic found in many physiologically based pharmacokinetic (PBPK) models. Using the template, one can implement PBPK models with different combinations of structures and features. Methods To identify factors that influence computational time required for PBPK model simulations, we conducted timing experiments using various implementations of PBPK models for dichloromethane and chloroform, including template and stand-alone implementations, and simulating four different exposure scenarios. For each experiment, we measured the required computational time and evaluated the impacts of including various model features (e.g., number of output variables calculated) and incorporating various design choices (e.g., different methods for estimating blood concentrations). Results We observed that model implementations that treat body weight and dependent quantities as constant (fixed) parameters can result in a 30% time savings compared with options that treat body weight and dependent quantities as time-varying. We also observed that decreasing the number of state variables by 36% in our PBPK model template led to a decrease of 20–35% in computational time. Other factors, such as the number of output variables, the method for implementing conditional statements, and the method for estimating blood concentrations, did not have large impacts on simulation time. In general, simulations with PBPK model template implementations of models required more time than simulations with stand-alone implementations, but the flexibility and (human) time savings in preparing and reviewing a model implemented using the PBPK model template may justify the increases in computational time requirements. Conclusion Our findings concerning how PBPK model design and implementation decisions impact computational speed can benefit anyone seeking to develop, improve, or apply a PBPK model, with or without the PBPK model template.

Bernstein, Amanda S.↗
DOE OSTI2023

Sequential Recovery of Critical Metals from Leached Liquor of Processed Spent Lithium-Ion Batteries

The processing and extraction of critical metals from black mass is important to battery recycling. Separation and recovery of critical metals (Co, Ni, Li, and Mn) from other metal impurities must yield purified metal salts, while avoiding substantial losses of critical metals. Solvent extraction in batch experiments were conducted using mixed metal sulphates obtained from the leach liquor obtained from spent and shredded lithium-ion batteries. Selective extraction of Mn 2+ , Fe 3+ , Al 3+ and Cu 2+ from simulated and real leached mixed metals solution was carried out using di-2-ethylhexylphophoric acid (D2EPHA) and Cyanex-272 at varying pH. Further experiments with the preferred extractant (D2EPHA) were performed under different conditions: changing the concentration of extractant, organic to aqueous ratio, and varying the diluents. At optimum conditions (40% v/v D2EPHA in kerosene, pH 2.5, O:A = 1:1, 25 °C, and 20 min), 85% Mn 2+ , 98% Al 3+ , 100% Fe 3+ , and 43% Cu 2+ were extracted with losses of only trace amounts (<5.0%) of Co 2+ , Ni 2+ , and Li + . The order of extraction efficiency for the diluents was found to be kerosene > Exxal-10 >>> dichloromethane (CH 2 Cl 2 ) > toluene. Four stages of stripping of metals loaded on D2EPHA were performed as co-extracted metal impurities were selectively stripped, and a purified MnSO 4 solution was produced. Spent extractant was regenerated after Fe 3+ and Al 3+ were completely stripped using 1.0 M oxalic acid (C 2 H 2 O 4 ).

25 ENERGY STORAGE↗
DOE OSTI2021

Sensing Techniques for Organochlorides through Intermolecular Interaction with Bicyclic Amidines

Toxic organochloride molecules are widely used in industry for various purposes. With their high volatility, the direct detection of organochlorides in environmental samples is challenging. Here, a new organochloride detection mechanism using 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) is introduced to simplify a sensing method with higher detection sensitivity. Three types of organochloride compounds-trichloroethylene (TCE), dichloromethane (DCM), and dichlorodiphenyltrichloroethane (DDT)—were targeted to understand DCM conjugation chemistry by using nuclear magnetic resonance (NMR) and liquid chromatography with a mass spectrometer (LC-MS). 13C-NMR spectra and LC-MS data indicated that DBN can be labeled on these organochloride compounds by chlorine–nitrogen interaction. Furthermore, to demonstrate the organochloride sensing capability, the labeling yield and limit of detection were determined by a colorimetric assay as well as micellar electrokinetic chromatography (MEKC). The interaction with DBN was most appreciable for TCE, among other organochlorides. TCE was detected at picomolar levels, which is two orders of magnitude lower than the maximum contaminant level set by the United States Environmental Protection Agency. MEKC, in conjunction with this DBN-labeling method, enables us to develop a field-deployable sensing platform for detecting toxic organochlorides with high sensitivity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Ultrathin Boron Growth onto Nanodiamond Surfaces via Electrophilic Boron Precursors

Diamond as a templating substrate is largely unexplored, and the unique properties of diamond, including its large bandgap, thermal conductance, and lack of cytotoxicity, makes it versatile in emergent technologies in medicine and quantum sensing. Surface termination of an inert diamond substrate and its chemical reactivity are key in generating new bonds for nucleation and growth of an overlayer material. Oxidized high-pressure high temperature (HPHT) nanodiamonds (NDs) are largely terminated by alcohols that act as nucleophiles to initiate covalent bond formation when an electrophilic reactant is available. In this work, we demonstrate a templated synthesis of ultrathin boron on ND surfaces using trigonal boron compounds. Boron trichloride (BCl 3 ), boron tribromide (BBr 3 ), and borane (BH 3 ) were found to react with ND substrates at room temperature in inert conditions. BBr 3 and BCl 3 were highly reactive with the diamond surface, and sheet-like structures were produced and verified with electron microscopy. Surface-sensitive spectroscopies were used to probe the molecular and atomic structure of the ND constructs’ surface, and quantification showed the boron shell was less than 1 nm thick after 1–24 h reactions. Observation of the reaction supports a self-terminating mechanism, similar to atomic layer deposition growth, and is likely due to the quenching of alcohols on the diamond surface. X-ray absorption spectroscopy revealed that boron-termination generated midgap electronic states that were originally predicted by density functional theory (DFT) several years ago. DFT also predicted a negative electron surface, which has yet to be confirmed experimentally here. The boron-diamond nanostructures were found to aggregate in dichloromethane and were dispersed in various solvents and characterized with dynamic light scattering for future cell imaging or cancer therapy applications using boron neutron capture therapy (BNCT). The unique templating mechanism based on nucleophilic alcohols and electrophilic trigonal precursors allows for covalent bond formation and will be of interest to researchers using diamond for quantum sensing, additive manufacturing, BNCT, and potentially as an electron emitter.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Chemical Recycling of Mixed Plastics in Electronic Waste Using Solvent-Based Processing

Currently, less than 20% of electronic waste (E-waste) produced in the U.S. is recycled. To improve the recycling rate of E-waste, the study aimed to: (1) identify the major plastics found within electronic shredder residue (ESR), (2) design solvents and processing conditions capable of separating out 90% of the plastic in ESR, and (3) estimate the energy efficiency of the solvent-based process developed. Preliminary screening showed 25 wt.% of the ESR was composed of plastics, with two polymers dominating the sorted plastic fraction—polystyrene (PS, 40 wt.%) and acrylonitrile butadiene styrene (ABS, 25 wt.%). Subsequently, solvents and anti-solvents were screened using Hansen Solubility Parameter Theory for PS, ABS, and ESR dissolution. The pre-screening results showed dichloromethane (DCM) and tetrahydrofuran (THF) as the most effective solvents for PS and ABS, with methanol (MeOH) and ethylene glycol (EG) as the most effective anti-solvents. By optimizing the dissolution time and the solvents used, the highest polymer dissolution yield (99 wt.%) was achieved using DCM for 48 h. Both MeOH and EG precipitated 71 wt.% of the polymer fraction of ESR. EG removed more phosphorus containing flame retardants (94 wt.%) than MeOH (69 wt.%). Energy analysis indicated that the solvent-based processes could save 25–60% of the embodied energy for PS and ABS. Characterization showed that the solvent-based processing could preserve the high molecular weight fraction of the polymers while removing flame retardants at the same time. The results from this study prove the potential of solvent-based processing to produce secondary plastic materials from E-waste for cross-industry reuse.

Anderson, Lester↗
DOE OSTI2020

Disulfonamide Ligands as f-Element Extractants from Alkaline High-Level Waste

Almost 100 million gallons of high level waste (HLW) has been generated from defense reprocessing programs to support nuclear weapons production. HLW is currently stored at the Hanford and Savannah River Sites (SRS) [1]. It contains radioactive components, such as {sup 137}Cs, {sup 99}Tc and {sup 90}Sr, as well as large amounts of non-radioactive species, including solvated cations and insoluble metal hydroxides. HLW has high concentration of soluble hydroxides ([OH{sup -}] = 2 M at SRS [2]), complexing inorganic anions ([NO{sub 3}{sup -}] ∼ 0.65 - 3.7 M at SRS [2]) and a high ionic strength. Even though the majority of actinide component in alkaline HLW is precipitated, studies of An(III) and Ln(III) complexation in highly alkaline solutions in the presence of high nitrate concentrations have showed that soluble nitrate complexes can be formed [3]. The current treatment of HLW at SRS currently consists of two processes: The Actinide Removal Process (ARP) and the Next-Generation Caustic-Side Solvent Extraction process (NG-CSSX). Strontium and actinides are removed by sorption on monosodium titanate through the Actinide Removal Process (ARP) commonly referred to as the alpha-strike step [4]. Then, cesium is selectively extracted from the alkaline media via the Caustic-Side Solvent Extraction (CSSX) process [5]. The CSSX solvent consists of a calix[4]arene-crown-6 extractant dissolved in an inert hydrocarbon matrix containing i) a solvent modifier (alkylphenoxy alcohol) which increases extractant solubility and prevents third phase formation, and ii) a suppressor (trioctylamine or guanidine) - that mitigates surfactant effects. The CSSX process removes {sup 137}Cs selectively and rapidly, yet the post- CSSX aqueous stream may still contain high amounts of An, thus requiring a second ARP treatment (referred to as 'alpha-finishing') for some tanks. Despite the success of the ARP process in removing Sr and An, it often represents the kinetic bottleneck of integrated processing, as it is slower than solvent extraction. Understanding the complexation of actinides by organic ligands that are compatible with the CSSX process could eventually lead to a combined caustic-side Cs/Sr/actinide extraction process with better economics due to a reduced amount of monosodium titanate and/or a shorter required contact time with titanate during ARP. This would ensure a low-activity waste (LAW) stream with no actinides without additional ARP processing post-CSSX. Disulfonamides were studied for extraction of Sm(III) from alkaline aqueous media of pH 10-14 into dichloromethane. Up to 82% of Sm(III) was extracted from solutions of pH 12.5 -13.5 and up to 84% from solutions of pH 10.5 - 11.5. These results show some resemblance with Am extraction results by calixarene ligands previously reported [10]. Kinetic studies demonstrated that even 5 min is enough to complete stripping, whereas extraction is time-limiting process and requires up to 20 h for efficient removal of Sm(III) from alkaline aqueous media. Determination of composition of complexes in solution after extraction by the equilibrium shift method showed a 1:1 Sm(III):dsa-2 complexation ratio for the extracted species.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Extraction of Ln(III) and An(III) from Alkaline Solutions by Sulfonamide Ligands and Analogs - 20216

As part of our effort to develop advanced separations involving combined extraction of cesium, strontium, and actinides from High-Level Waste (HLW) at the Savannah River Site, we are now reporting highly efficient extraction of Sm(III) from aqueous media of various alkalinity by dichloromethane solutions of several ligands, including tri-sulfonamides, o-mono-sulfonamido-phenols and o-phenylenediamine- derived disulfonamides. Distribution experiments and DFT calculations provide insights on the complexation of Samarium vs Americium by these ligands. Further optimization of these ligands for extraction into highly lipophilic solvents and application to HLW simulants are underway. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Dynamics of Product Branching from Radical Intermediates in Elementary Combustion Reactions (Final Technical Report)

While the total rate constant for many elementary reactions is well-characterized, understanding the product branching in complex reactions presents a formidable challenge. To gain an incisive probe of such reactions, our experiments investigate the dynamics of the product channels that arise from transient radical intermediates along the bimolecular reaction coordinates. Our recent published work uses the methodology developed in my group in the last fifteen years, using both imaging and scattering apparatuses. The experiments generate a particular isomeric form of an unstable radical intermediate along a bimolecular reaction coordinate and study the branching between the ensuing product channels of the energized radical as a function of its internal rotational and vibrational energy under collision-less conditions. The experiments use a combination of: 1) measurement of product velocity and angular distributions in a crossed laser-molecular beam apparatus, with electron bombardment detection in my lab in Chicago or 2) with tunable vacuum ultraviolet photoionization detection at Taiwan's National Synchrotron Radiation Research Center (NSRRC), and 3) velocity map imaging using state-selective REMPI and single photon VUV ionization of radical intermediates and reaction products. We also employ tunable VUV photoionization detection in our imaging apparatus, using difference frequency four-wave mixing to produce photoionization light tunable from 8 to 10.8 eV. This year of support funded our work to photolytically generate the radical intermediate important in the OH + propene reaction when OH adds to an end carbon. Our other major result this past year was on the photoionization detection of vinoxy radicals. Our experiments at the NSRRC definitively show that vinoxy dissociatively ionizes to both CH 3 + and HCO + , and establishes the absolute partial photoionization cross section of vinoxy to CH 3 + at 10.5 and 11.44 eV. This should allow experimentalists detecting vinoxy radicals produced in bimolecular reactions such as OH + propene to get good branching fractions to that product channel. Finally we initiated studies of the photodissociation of 1-bromo-2-chloroethane and 1,1-bromochloroethane at 193 nm at the NSRRC.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗