scholarly journals A Bioinspired Molybdenum Catalyst for Aqueous Perchlorate Reduction

2020 ◽  
Author(s):  
Changxu Ren ◽  
peng yang ◽  
Jiaonan Sun ◽  
Eric Bi ◽  
Jacob Palmer ◽  
...  
Keyword(s):  
Sodium Molybdate ◽  
Carbon Support ◽  
Molar Ratio ◽  
Oxygen Atom Transfer ◽  
Turnover Number ◽  
Molybdenum Catalyst ◽  
Nitrogen Ligand ◽  
Perchlorate Reduction ◽  
Harsh Conditions

<p>The detection of perchlorate (ClO<sub>4</sub><sup>−</sup>) on and beyond Earth requires ClO<sub>4</sub><sup>−</sup> reduction technologies to support water purification and space exploration. However, the reduction of ClO<sub>4</sub><sup>−</sup> usually entails either harsh conditions or multi-component enzymatic processes. We developed a heterogeneous Mo−Pd/C catalyst from sodium molybdate to reduce aqueous ClO<sub>4</sub><sup>−</sup> into Cl<sup>−</sup> with 1 atm H<sub>2</sub> at room temperature. Upon hydrogenation by H<sub>2</sub>/Pd, the reduced Mo oxide species and a bidentate nitrogen ligand (1:1 molar ratio) are transformed <i>in situ</i> into oligomeric Mo sites on the carbon support. The turnover number and frequency for oxygen atom transfer from ClO<sub>x</sub><sup>−</sup> substrates reached 3850 and 165 h<sup>−1</sup> on each Mo site. This simple bioinspired design yielded a robust water-compatible catalyst for the removal and utilization of ClO<sub>4</sub><sup>−</sup>.</p>

scholarly journals A Bioinspired Molybdenum Catalyst for Aqueous Perchlorate Reduction

2020 ◽  
Author(s):  
Changxu Ren ◽  
peng yang ◽  
Jiaonan Sun ◽  
Eric Bi ◽  
Jacob Palmer ◽  
...  
Keyword(s):  
Sodium Molybdate ◽  
Carbon Support ◽  
Molar Ratio ◽  
Oxygen Atom Transfer ◽  
Turnover Number ◽  
Molybdenum Catalyst ◽  
Nitrogen Ligand ◽  
Perchlorate Reduction ◽  
Harsh Conditions

<p>The detection of perchlorate (ClO<sub>4</sub><sup>−</sup>) on and beyond Earth requires ClO<sub>4</sub><sup>−</sup> reduction technologies to support water purification and space exploration. However, the reduction of ClO<sub>4</sub><sup>−</sup> usually entails either harsh conditions or multi-component enzymatic processes. We developed a heterogeneous Mo−Pd/C catalyst from sodium molybdate to reduce aqueous ClO<sub>4</sub><sup>−</sup> into Cl<sup>−</sup> with 1 atm H<sub>2</sub> at room temperature. Upon hydrogenation by H<sub>2</sub>/Pd, the reduced Mo oxide species and a bidentate nitrogen ligand (1:1 molar ratio) are transformed <i>in situ</i> into oligomeric Mo sites on the carbon support. The turnover number and frequency for oxygen atom transfer from ClO<sub>x</sub><sup>−</sup> substrates reached 3850 and 165 h<sup>−1</sup> on each Mo site. This simple bioinspired design yielded a robust water-compatible catalyst for the removal and utilization of ClO<sub>4</sub><sup>−</sup>.</p>

A Mild and Simple Method for Making MIDA Boronates

2020 ◽  
Author(s):  
Aidan Kelly ◽  
Peng-Jui (Ruby) Chen ◽  
Jenna Klubnick ◽  
Daniel J. Blair ◽  
Martin D. Burke
Keyword(s):  
Organic Synthesis ◽  
Boronic Acids ◽  
Simple Method ◽  
Direct Preparation ◽  
Synthesis Procedure ◽  
Harsh Conditions

<div> <div> <div> <p>Existing methods for making MIDA boronates require harsh conditions and complex procedures to achieve dehydration. Here we disclose that a pre-dried form of MIDA, MIDA anhydride, acts as both a source of the MIDA ligand and an in situ desiccant to enable a mild and simple MIDA boronate synthesis procedure. This method expands the range of sensitive boronic acids that can be converted into their MIDA boronate counterparts. Further utilizing unique properties of MIDA boronates, we have developed a MIDA Boronate Maker Kit which enables the direct preparation and purification of MIDA boronates from boronic acids using only heating and centrifuge equipment that is widely available in labs that do not specialize in organic synthesis. </p> </div> </div> </div>

scholarly journals In Situ Thermal-Stage Fitted-STEM Characterization of Spherical-Shaped Co/MoS2 Nanoparticles for Conversion of Heavy Crude Oils

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1239
Author(s):  
Manuel Ramos ◽  
Félix Galindo-Hernández ◽  
Brenda Torres ◽  
José Manuel Domínguez-Esquivel ◽  
Martin Heilmaier
Keyword(s):  
Molybdenum Disulfide ◽  
Sodium Molybdate ◽  
Interlayer Spacing ◽  
Scanning Transmission Electron Microscope ◽  
Interplanar Distance ◽  
Scanning Transmission ◽  
Heavy Crude ◽  
C 50 ◽  
Nano Catalysts

We report the thermal stability of spherically shaped cobalt-promoted molybdenum disulfide (Co/MoS2) nano-catalysts from in-situ heating under electron irradiation in the scanning transmission electron microscope (STEM) from room temperature to 550 °C ± 50 °C with aid of Fusion® holder (Protochip©, Inc.). The catalytic nanoparticles were synthesized via a hydrothermal method using sodium molybdate (Na2MoO4·2H2O) with thioacetamide (CH3CSNH2) and cobalt chloride (CoCl2) as promoter agent. The results indicate that the layered molybdenum disulfide structure with interplanar distance of ~0.62 nm remains stable even at temperatures of 550 °C, as observed in STEM mode. Subsequently, the samples were subjected to catalytic tests in a Robinson Mahoney Reactor using 30 g of Heavy Crude Oil (AGT-72) from the golden lane (Mexico’s east coast) at 50 atm using (ultrahigh purity) UHP hydrogen under 1000 rpm stirring at 350 °C for 8 h. It was found that there is no damage on the laminar stacking of Co/MoS2 with temperature, with interlayer spacing remaining at 0.62 nm; these sulfided catalytic materials led to aromatics rise of 22.65% and diminution of asphaltenes and resins by 15.87 and 3.53%, respectively.

scholarly journals Modified sodium molybdate as an efficient high yielding heterogeneous catalyst for biodiesel from Ghanaian indigenous Camelina sativa as a non-edible resource

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Mohammed Takase ◽  
Paul Kwame Essandoh ◽  
Rogers Kipkoech
Keyword(s):  
Reaction Time ◽  
Sodium Molybdate ◽  
Normal Pressure ◽  
Camelina Sativa ◽  
International Standards ◽  
Lewis Acidity ◽  
Molar Ratio ◽  
Solid Catalyst ◽  
Atmospheric Conditions ◽  
Heterogeneous Solid

AbstractSodium molybdate (Na2MoO4) has been synthesized and investigated as a heterogeneous solid catalyst for biodiesel from Camelina sativa seed oil. Transesterification reactions occurred under atmospheric conditions with relatively, low temperature short reaction time and normal pressure. The prepared catalyst was characterised by means of SEM, TGA, UV, XRD and FTIR. The properties of the biodiesel were compared with international standards. The transesterification reaction was very efficient with the optimum yield higher than 95% at methanol to oil molar ratio of 17:1, catalyst amount of 6%, reaction temperature of 60 °C and reaction time of 2.5 h. The molybdate complex had a high Lewis acidity and most certainly act as alcohol O–H bond leading to a transient species which has high nucleophilic character. The catalyst was easily recovered and after being washed for three times, showed capacity of recyclability for another catalytic reaction of five cycles with similar activity. The properties of the biodiesel were comparable to international standards.

scholarly journals Negligible degradation upon in situ voltage cycling of a PEMFC using an electrospun niobium-doped tin oxide supported Pt cathode

2015 ◽  
Vol 17 (26) ◽  
pp. 16970-16976 ◽  
Author(s):  
Iuliia Savych ◽  
Surya Subianto ◽  
Yannick Nabil ◽  
Sara Cavaliere ◽  
Deborah Jones ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Carbon Support ◽  
Mitigation Strategy ◽  
High Cell ◽  
Degradation Mechanisms ◽  
Niobium Doped

Pt/Nb–SnO2 loose-tubes constitute a mitigation strategy for two known degradation mechanisms in PEMFC: corrosion of the carbon support at the cathode, and dissolution of Pt at high cell voltages.

On the dimorphism of Pr6Mo10O39

2017 ◽  
Vol 72 (11) ◽  
pp. 765-774
Author(s):  
Daniel Rudolph ◽  
Sonja Laufer ◽  
Ingo Hartenbach
Keyword(s):  
Crystal Structure ◽  
Thermal Decomposition ◽  
Single Crystals ◽  
Main Product ◽  
Molar Ratio ◽  
Coordination Environment ◽  
Space Group ◽  
Coordination Numbers ◽  
Dense Modification

AbstractAttempts to synthesize Pr4Mo7O27 using Pr, Pr6O11 and MoO3 in a molar ratio of 8:6:77 led to a main product of scheelite-type Pr0.667[MoO4] and few single crystals of the triclinic A-type Pr6Mo10O39. The latter crystallizes in space group P1̅ (a=945.25(1), b=1058.49(2), c=1815.16(3) pm; α=104.149(1), β=95.220(1), γ=102.617(1)°, Z=2). Its crystal structure comprises six crystallographically independent Pr3+ cations, eight tetrahedral [MoO4]2− units, and one [Mo2O7]2− entity. The cations display coordination numbers of seven (1×) and eight (5×), while the [MoO4]2− tetrahedra are surrounded by five Pr3+ cations each. The [Mo2O7]2− anions exhibit a coordination environment of seven Pr3+ cations. The attempt to synthesize PrF[MoO4] using PrOF (from in situ thermal decomposition of PrF[CO3]) as reagent did not lead to the desired product but to monoclinic B-type Pr6Mo10O39. This slightly less dense modification compared to its triclinic analogue crystallizes in space group C2/c (a=1247.93(3), b=1989.68(6), c=1392.52 (4) pm, β=100.505(2)°, Z=4) with three crystallographically independent Pr3+ cations, four [MoO4]2− tetrahedra, and again one [Mo2O7]2− unit in the crystal structure. Thus, both Pr6Mo10O39 modifications are better described with the structured formula Pr6[MoO4]8[Mo2O7]. The coordination numbers around the Pr3+ cations are seven (1×) and eight (2×) while all four [MoO4]2− anions are again surrounded by five Pr3+ cations each. Six of the latter represent the coordination environment around the [Mo2O7]2− entities. Besides the thorough comparison of the crystal structures single crystal Raman spectra were recorded for both Pr6Mo10O39 phases.

scholarly journals STUDY OF THE PROCESS OF OXIDATIVE DESULFURIZATION OF DIESEL FUEL IN THE PRESENCE OF CO-CATALYSTS

2021 ◽  
pp. 88-96
Author(s):  
D. Muktaly ◽  
◽  
Zh.K. Myltykbaeva ◽  
M.B. Smaiyl ◽  
◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Transition Metals ◽  
Diesel Fuel ◽  
Oxidation Process ◽  
Oxidative Desulfurization ◽  
Sodium Molybdate ◽  
Molar Ratio ◽  
Petrochemical Plant ◽  
Continuous Growth ◽  
Diesel Fractions

Continuous growth in consumption of oil in the world, as well as ever-increasing quality requirements stimulate the search for new scientific and technological solutions to directionally affect the characteristics of petroleum products, including their chemical composition. The advantages of oxidative desulfurization before hydrotreating are the absence of the need to use hydrogen, as well as small capital and energy costs, since the method does not require high temperatures and pressures. The purpose of this work was to study the oxidation process of diesel fuel and to search for the optimal mode of oxidative desulfurization of diesel fuel in the presence of transition metals salts with the addition of mineral acids. The object of the study is a straight-run diesel fraction of the Pavlodar Petrochemical Plant with boiling temperatures of 180-350°C. The oxidation process was carried out with hydrogen peroxide in the presence of salts of the transition metals molybdenum, vanadium and tungsten. The article defined the basic physico-chemical characteristics of straight-run and desulfurized diesel fractions. The optimal catalyst (Na2MoO4) was selected at a molar ratio of metal to sulfur of 1:100 for the oxidation process of straight-run diesel fractions. As a result of oxidative desulfurization of diesel fuel in the presence of sodium molybdenum perox complexes, the total sulfur content decreased by 42.9%, and with the addition of sulfuric acid by 56.5%. An increase in the cetane index from 56.3 to 58.6 was revealed in the presence of sodium molybdate with the addition of sulfuric acid.

Analysis of the World's First Polymer Injectivity Test in a Carbonate Reservoir Under Extreme Harsh Conditions in ADNOC's Reservoirs

2021 ◽  
Author(s):  
Juan Manuel Leon ◽  
Shehadeh K. Masalmeh ◽  
Siqing Xu ◽  
Ali M. AlSumaiti ◽  
Ahmed A. BinAmro ◽  
...  
Keyword(s):  
High Temperature ◽  
Laboratory Experiments ◽  
High Salinity ◽  
Laboratory Data ◽  
Injection Pressure ◽  
Carbonate Reservoir ◽  
Experimental Program ◽  
Full Field ◽  
Harsh Conditions

Abstract Assessing polymer injectivity for EOR field applications is highly important and challenging. An excessive injectivity reduction during and after polymer injection may potentially affect the well integrity and recovery efficiency and consequently, injection strategy and the economics of the polymer projects. Moreover, well conditions such as skin, completion configuration, and injection water quality can significantly impact polymer injectivity. Additionally, the presence of fractures or micro-fractures may govern injection pressure. In contrast, historic field applications have shown that polymer injectivity is in general better than expected from simulations or laboratory data. In the laboratory experiments, the polymer injectivity has been evaluated by injection of significant amounts of pore volumes of polymer at relevant well-injection rates. In addition, several experiments were performed to measure the complex in-situ rheology expected to dominate the flow near the wellbore This paper presents the analysis of the the world's first polymer injectivity test (PIT) conducted in a high temperature and high salinity (HTHS) carbonate reservoir in Abu Dhabi as part of a comprehensive de-risking program for a new polymer-based EOR scheme proposed by ADNOC for these challenging carbonate reservoirs (see Masalmeh et. al., 2014). The de-risking program includes an extensive laboratory experimental program and field injectivity test to ensure that the identified polymer can be injected and propagated in the target formation before multi-well pilot and full-field implementation stages. Experimental laboratory data and the field injectivity test results are presented in earlier publications (Masalmeh et. al., 2019; Rachapudi et. al., 2020) and references therein. This PIT is the world's first polymer injectivity test in a carbonate reservoir under such harsh conditions of high salinity, high content of divalent ions and high temperature. In addition, the polymer used during the test has never been field-tested before. Therefore, the results of the PIT interpretation will help to de-risk the suitable polymer for the future inter-well pilot for the new proposed EOR Polymer-based scheme and it is a game-changer to unlock several opportunities for different Chemical EOR applications on full-field scale in other reservoirs with similar characteristics. A single well radial simulation model was built to integrate the surveillance data during PIT and the extensive laboratory experiments. Morever, multiple Pressure Fall Off Tests (PFOs) during the same periods were analyzed and intergaretd in the model.The study assessed the effect of polymer viscosity on mobility reduction, evaluated the polymer bank propagation, investigated the effect of the skin build-up, residual resistance factor (RRF) and shear effects on the well injectivity. Additionally, a comprehensive assisted history match method and robust simulation sensitivity analysis was implemented, thousands of sensitivity simulation runs were performed to capture several possible injection scenarios and validate laboratory parameters. The simulation study confirmed that the PIT could be interpreted using the laboratory-measured polymer parameters such as polymer bulk viscosity, in-situ rheology, RRF and adsorption.

scholarly journals Colorless and Transparent Copolyimides and Their Nanocomposites: Thermo-Optical Properties, Morphologies, and Gas Permeabilities

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 585 ◽  
Author(s):  
Hyeon Shin ◽  
Young-Je Kwark ◽  
Jin-Hae Chang
Keyword(s):  
Optical Properties ◽  
Coefficient Of Thermal Expansion ◽  
Amic Acid ◽  
Gas Permeation ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Thermal Imidization ◽  
Organically Modified ◽  
Permeation Properties

A series of linear aromatic copolyimides (Co-PIs) were synthesized by reacting 4,4′-biphthalic anhydride (BPA) with various molar contents of 2,2′-bis(trifluoromethyl)benzidine (TFB) and p-xylylenediamine (p-XDA) in N,N′-dimethylacetamide (DMAc). Co-PI films were fabricated by solution casting and thermal imidization with poly(amic acid) (PAA) on glass plates. The thermo-optical properties and gas permeabilities of Co-PI films composed of various molar ratios of p-XDA (0.2–1.0 relative to BPA) were investigated. Thermal properties were observed to deteriorate with increasing p-XDA concentration. However, oxygen-transmission rates (O2TRs) and optical transparencies improved with increasing p-XDA concentration. Co-PI hybrids with a 1:0.2:0.8 molar ratio of BPA:TFB:p-XDA and organically modified hectorite (STN) were prepared by the in situ intercalation method. The morphologies and the thermo-optical and gas permeation properties of the hybrids were examined as functions of STN loading (5–50 wt %). XRD and TEM revealed substantial increases in clay particle agglomeration in the Co-PI hybrid films as the clay loading was increased from 5 to 50 wt %. The coefficient of thermal expansion (CTE) and the O2TR of a Co-PI hybrid film were observed to improve with increasing STN concentration; however, its optical transparency decreased gradually with increasing STN concentration.

scholarly journals In situ nanofabrication of hybrid PEG-dendritic–inorganic nanoparticles and preliminary evaluation of their biocompatibility

Nanoscale ◽  
2015 ◽  
Vol 7 (9) ◽  
pp. 3933-3940 ◽  
Author(s):  
Ana Sousa-Herves ◽  
Christian Sánchez Espinel ◽  
Amir Fahmi ◽  
África González-Fernández ◽  
Eduardo Fernandez-Megia
Keyword(s):  
Block Copolymers ◽  
Inorganic Nanoparticles ◽  
Molar Ratio ◽  
Preliminary Evaluation

An in situ template fabrication of inorganic nanoparticles using carboxylated PEG-dendritic block copolymers of the GATG family is described as a function of the dendritic block generation, the metal (Au, CdSe) and metal molar ratio.

Sign in / Sign up

Export Citation Format

Share Document