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Results for “dehydration”
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Role of Water on Zeolite-Catalyzed Dehydration of Polyalcohols and EVOH Polymer
Not provided.
Direct Brønsted Acid-Catalyzed Dehydration of Glucose to HMF in Methyl Isobutyl Ketone
Not provided.
Structure and Function of a Dehydrating Condensation Domain in Nonribosomal Peptide Biosynthesis
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A Priori Design of Dual-Atom Alloy Sites and Experimental Demonstration of Ethanol Dehydrogenation and Dehydration on PtCrAg
Not Available
Electric Field’s Dueling Effects through Dehydration and Ion Separation in Driving NaCl Nucleation at Charged Nanoconfined Interfaces
Investigating nucleation in charged nanoconfined environments under electric fields is crucial for many scientific and engineering applications. Here we study the nucleation of NaCl from aqueous solution near charged surfaces using machine-learning-augmented enhanced sampling molecular dynamics simulations. Our simulations successfully drive phase transitions between the liquid and solid phases of NaCl. The solid phase is stabilized under electric fields, particularly at an intermediate surface charge density. We examine which physical characteristics drive the nucleation of NaCl from aqueous solutions and find that the removal of solvent water from Cl– at the solid precursor surface plays a more critical role than the accumulation of ions. Our simulations reveal the competing effects of electric fields on nucleation processes: they facilitate the removal of water, promoting nucleation, but also promote the separation of ion pairs, thereby hindering nucleation. Here, this work provides a framework for studying nucleation processes in nanoconfined environments under electric fields and provides physical insights for the design of electrochemistry materials.
Dehydration synthesis and crystal structure of terbium oxychloride, TbOCl
Terbium oxychloride, TbOCl, was synthesized via a simple heat-treatment of TbCl3·6H2O. The structure was determined using X-ray powder diffraction (XRD) data. The TbOCl compound crystallizes within the tetragonal P4/nmm space group, and its crystal structure is composed of alternating layers of (TbO)n and n Cl- anions. The unit cell parameters, volume, and density were compared to the literature data of other isostructural rare-earth oxychlorides in the P4/nmm space group and showed a good agreement when fitted to the calculated trendlines.
Heat capacity and thermodynamic functions of partially dehydrated sodium and zinc zeolite A (LTA)
Zeolite A (LTA) is an industrially important zeolite that exhibits sorption-induced framework flexibility, the thermodynamics of which are poorly understood. In this work, we report heat capacity measurements on zinc and sodium zeolite A from 1.8 to 300 K and compare the heat capacity of water in sodium zeolite A with that of water in other zeolites. The heat capacity of zeolitic water varies significantly depending on the hydration level and identity of the host zeolite, and more tightly bound water exhibits strong inflections in its heat capacity curve. This suggests a combination of effects, including differences in water-framework binding strength and hydration-dependent flexibility transitions. We also report fits of the heat capacity data using theoretical functions, and we report values for $C_{P,m}^°$,$Δ_0^TS_m^°$,$Δ_0^TH_m^°$, and $Φ_m^°$ from 0 to 300 K. These results contribute to a systematic thermodynamic understanding of the effects of cation exchange, guest molecule confinement, and sorbate-dependent flexibility transitions in zeolites.
Water transport pathway in clay interlayer upon dehydration [Slides]
Smectite (e.g., Montmorillonite): phyllosilicate minerals found in bentonites. Bentonites have been considered as key backfill barrier materials in deep geological nuclear waste repository concepts. Swelling/shrinking of montmorillonite (MMT) occurs with increasing/decreasing relative humidity. Our research question is, "Microscopically, how does the hydration/dehydration process occur?"
Water transport pathway in clay interlayer upon dehydration [Slides]
Smectite (e.g., Montmorillonite): phyllosilicate minerals found in bentonites. Bentonites have been considered as key backfill barrier materials in deep geological nuclear waste repository concepts. Swelling/shrinking of montmorillonite (MMT) occurs with increasing/decreasing relative humidity. Microscopically, how does the hydration/dehydration process occur?
Transport-mechanical-chemical coupling effects during clay dehydration .
Abstract not provided.
Chemo-mechanical effects and moisture transport during clay dehydration.
Abstract not provided.
Production of bio-diesel blend stocks via acid-catalyzed dehydration of ethanol oligomerization products
Ethanol is the most widely produced biofuel in the world. Gasoline demand is projected to decrease in the next 20 years largely due to an increase in electric vehicles. Diesel fuel demand is projected to continue to increase. Long-chain mono C10+ ethers have high cetane numbers and appropriate physical properties to be blended at high levels into petroleum diesel fuel. A techno-economic analysis shows that the ethers can be produced at prices similar to biodiesel. In our presentation we will show the catalytic chemistry involved in our ethanol to diesel approach, the engine and physical measurements of the produced diesel-range ethers, and a summary of the techno-economic analysis.
“CY1” Chondrites Produced by Impact Dehydration of the CI Chondrite Parent Body
The recently proposed Yamato-type (CY) chondrites share significant similarities with CI chondrites and Ryugu. We present major and trace elemental, Re–Os, and mass-independent Ti, Cr, and Fe isotope data for seven CY chondrites. The elemental data along with isotopic compositions reveal two distinct lithologies, here designated as CY1 and CY2, potentially originating from two different parent bodies. Although sharing similarities with CM chondrites, CY2 chondrites have distinct Cr isotope compositions, arguing against a close genetic relationship. The CY1 lithology exhibits elemental abundances similar to CI chondrites/Ryugu as well as Fe, Ti, and Cr isotope compositions that closely overlap with those of CI chondrites/Ryugu. This suggests that CI chondrites, CY1 chondrites, and Ryugu accreted in the same region of the solar system and may even originate from the same parent body. In fact, we find that the reduced water content and certain volatile element abundances alongside increased sulfide content and mass-dependent O isotope enrichments observed in CY1 compared to CI chondrites could be attributed to an impact-induced heating event on the CI parent body. This impact likely disrupted the CI parent body, resulting in the ejection of both CI and CY1 lithologies. Furthermore, given that there are presently only five known CI meteorite specimens, the close chemical composition between CY1 and CI chondrites substantially expands the data set for comparisons and referrals to the bulk solar system composition for nonvolatile elements. Finally, we propose that the “CY1” chondrites could be called “CI1T,” while the designation “CY” chondrites could be restricted to “CY2” samples.
Integrated process for direct saccharification and dehydration of intact biomass to furfurals
A method of converting a lignocellulosic biomass to monosaccharides, and optionally further converting the monosaccharides to one or both of furfural and HMF, includes contacting the biomass with a reactive liquid phase comprising LiBr, H 2 SO 4 , and water, wherein H 2 SO 4 preferably constitutes at most 1.0 wt %, more preferably at most 0.5 wt %, and most preferably at most 0.1 wt % of the reactive liquid phase, and water preferably constitutes at most at most 60 wt %, more preferably at most 50 wt %, and most preferably at most 30 wt % of the reactive liquid phase.
Water transport early in the dehydration process can be by advection in the interlayer.
Abstract not provided.
Dehydration of Scandium for RERecycling and Synthesis of Nano Materials.
Abstract not provided.