Theoretical Exploration of 2,2’-Bipyridines as Electro-Active Compounds in Flow Batteries

2019 ◽  
Author(s):  
Mariano Sánchez-Castellanos ◽  
Martha M. Flores-Leonar ◽  
Zaahel Mata-Pinzón ◽  
Humberto G. Laguna ◽  
Karl García-Ruiz ◽  
...  
Keyword(s):  
Redox Potential ◽  
Active Material ◽  
Chemical Properties ◽  
Small Subset ◽  
Solubility In Water ◽  
Protonation Reaction ◽  
Redox Active ◽  
Physico Chemical ◽  
Pka Value ◽  
Flow Batteries

Compounds from the 2,2’-bipyridine molecular family were investigated for use as redox-active materials in organic flow batteries. For 156 2,2’-bipyridine derivatives reported in the academic literature, we calculated the redox potential, the pKa for the first protonation reaction, and the solubility in aqueous solutions. Using experimental data on a small subset of derivatives, we were able to calibrate our calculations. We find that functionalization with electron-withdrawing groups leads to an increase of the redox potential and to an increase of the molecular acidity (as expressed in a reduction of the pKa value for the first protonation step). Furthermore, calculations of solubility in water indicate that some of the studied derivatives have adequate solubility for flow battery applications. Based on an analysis of the physico-chemical properties of the 156 studied compounds, we down-select five molecules with carbonyl- and nitro-based functional groups, whose parameters are especially promising for potential application as negative redox-active material inorganic flow batteries.

Theoretical Exploration of 2,2’-Bipyridines as Electro-Active Compounds in Flow Batteries

2019 ◽  
Author(s):  
Mariano Sánchez-Castellanos ◽  
Martha M. Flores-Leonar ◽  
Zaahel Mata-Pinzón ◽  
Humberto G. Laguna ◽  
Karl García-Ruiz ◽  
...  
Keyword(s):  
Redox Potential ◽  
Active Material ◽  
Chemical Properties ◽  
Small Subset ◽  
Solubility In Water ◽  
Protonation Reaction ◽  
Redox Active ◽  
Physico Chemical ◽  
Pka Value ◽  
Flow Batteries

Compounds from the 2,2’-bipyridine molecular family were investigated for use as redox-active materials in organic flow batteries. For 156 2,2’-bipyridine derivatives reported in the academic literature, we calculated the redox potential, the pKa for the first protonation reaction, and the solubility in aqueous solutions. Using experimental data on a small subset of derivatives, we were able to calibrate our calculations. We find that functionalization with electron-withdrawing groups leads to an increase of the redox potential and to an increase of the molecular acidity (as expressed in a reduction of the pKa value for the first protonation step). Furthermore, calculations of solubility in water indicate that some of the studied derivatives have adequate solubility for flow battery applications. Based on an analysis of the physico-chemical properties of the 156 studied compounds, we down-select five molecules with carbonyl- and nitro-based functional groups, whose parameters are especially promising for potential application as negative redox-active material inorganic flow batteries.

TEMPO/Phenazine Combi-Molecule: A Redox-Active Material for Symmetric Aqueous Redox-Flow Batteries

2016 ◽  
Vol 1 (5) ◽  
pp. 976-980 ◽  
Author(s):  
Jan Winsberg ◽  
Christian Stolze ◽  
Simon Muench ◽  
Ferenc Liedl ◽  
Martin D. Hager ◽  
...  
Keyword(s):  
Active Material ◽  
Redox Flow Batteries ◽  
Redox Active ◽  
Flow Batteries

scholarly journals Karakterisasi sifat fisiko kimia pati bengkuang (Pachirrhyzus erosus) dan pati ganyong (Canna edulis Kerr) modifikasi [Characteristization on physico-chemical properties of modified canna (Canna edulis Kerr.) and jicama (Pachirrhyzus erosus) starches]

2021 ◽  
Vol 26 (1) ◽  
pp. 25
Author(s):  
Sri Haryani Anwar ◽  
Yeni Chandra Dewi ◽  
Novi Safriani
Keyword(s):  
Chemical Properties ◽  
National Standard ◽  
Chemical Modifications ◽  
Solubility In Water ◽  
Food Industries ◽  
Swelling Power ◽  
Physico Chemical ◽  
Moisture Treatment ◽  
Modified Starches ◽  
Physical And Chemical

Modification of native starch is needed mainly to increase its solubility in water thus broaden its application in food industries. On the other hand, modification of canna and jicama starches have rarely been applied. Physical and chemical modifications of starches are conducted to modify starch characteristics. The research aimed to investigate the physico-chemical properties of canna and jicama starches that had been modified chemically and physically. Chemical modifications which were conducted included modification via substitution with Octenyl Succinate Anhydride (OSA) and hydrolysis using hydrochloric acid (HCl), while physical modification was conducted via the Heat Moisture Treatment (HMT). The starch physico-chemical characteristics evaluated were degree of acid (DA), swelling power, degree of substitution (DS), moisture, ash, fat, and fiber contents. The analysis results showed that moisture, ash, fat, and fiber contents of native canna and jicama starches were not significantly different from those of modified ones. The result also revealed that the type of starches and modification methods increased the swelling power significantly (P≤0,05). The DS of modified canna dan jicama starches were 0.0246% and 0.0176%, respectively. While the DA of modified canna and jicama starches were 0.14% and 0.18%, respectively. This DA values of modified starches by HCL hydrolysis had meet the Indonesian National Standard (SNI 01-2593-1992) which is maximum of 5% for food application.Keywords: canna starch, jicama starch, HMT modification, modified starch, OSA modification 

Blatter Radicals as Bipolar Materials for Symmetric Redox-Flow Batteries

2021 ◽  
Author(s):  
Jelte Steen ◽  
Jules Nuismer ◽  
Vytautas Eiva ◽  
Albert Wiglema ◽  
Nicolas Daub ◽  
...  
Keyword(s):  
Active Material ◽  
Chemical Degradation ◽  
Limiting Factors ◽  
Redox Potentials ◽  
X Ray Crystallography ◽  
Redox Flow Batteries ◽  
Redox Active ◽  
Flow Batteries ◽  
The Stability ◽  
Bipolar Electrochemistry

Redox-active organic molecules are promising charge-storage materials for redox-flow batteries (RFBs), but material crossover between posolyte/negolyte and chemical degradation are limiting factors in the performance of all-organic RFBs. We demonstrate that the bipolar electrochemistry of 1,2,4-benzotriazin-4-yl (Blatter) radicals allows construction of batteries with symmetric electrolyte composition. Cyclic voltammetry shows that these radicals retain reversible bipolar electrochemistry also in the presence of water. The redox potentials of derivatives with a C(3)-CF3 substituent are least affected by water and, moreover, these compounds show >90% capacity retention after charge/discharge cycling in a static H-cell for seven days (ca. 100 cycles). Testing these materials in a flow regime at 0.1 M concentration of active material confirmed the high cycling stability under conditions relevant for RFB operation, and demonstrated that polarity inversion in a symmetric flow battery may be used to rebalance the cell. Chemical synthesis provides insight in the nature of the charged species by spectroscopy and (for the oxidized state) X-ray crystallography. The stability of these compounds in all three states of charge highlights the potential for application in symmetric organic redox-flow batteries.

scholarly journals The physico-chemical properties of 2-methoxyphenoxyacetates of Mn(II), Co(II), Ni(II) and Cu(II)

2018 ◽  
Vol 35 (2) ◽  
pp. 89
Author(s):  
W. Ferenc ◽  
M. Bernat ◽  
J. Sarzyński
Keyword(s):  
Magnetic Moments ◽  
Chemical Properties ◽  
Intermediate Formation ◽  
Bidentate Ligands ◽  
X Ray Diffraction ◽  
Solubility In Water ◽  
Physico Chemical ◽  
One Step ◽  
Thermogravimetric Studies ◽  
Ligand Fields

The complexes of 2-methoxyhenoxyacetates of Mn(II), Co(II), Ni(II) and  Cu(II)with the general formula: M(C9H9O4)3·4H2O, where M(II) = Mn, Co, Ni and Cu have been synthesized and characterized by elemental analysis, IR spectroscopy, magnetic and thermogravimetric studies and also X-ray diffraction measurements. The complexes have colours typical for M(II) ions (Mn(II) - a pale pink, Co(II) - pink, Ni(II) - green, and Cu(II) – blue). The carboxylate group binds as monodentate and bidentate ligands. On heating to 1273K in air thecomplexes decompose in the same way. At first, they dehydrate in one step to anhydrous salts, that next decompose to the oxides of respective metals with the intermediate formation of the oxycarbonates. Their solubility in water at 293K is of the order of 10-5 mol·dm-3. The magnetic moments of analysed complexes were determined in the range of 76-303K. The results reveal them to be high-spin complexes of weak ligand fields.

Improvement of aquatic pollutant partition coefficient correlations using 1D molecular descriptors — chlorobenzene case study

2013 ◽  
Vol 67 (2) ◽  
Author(s):  
Cristina Maria ◽  
Carmen Tociu ◽  
Gheorghe Maria
Keyword(s):  
Partition Coefficients ◽  
Molecular Descriptors ◽  
Chemical Properties ◽  
Structural Features ◽  
Algebraic Models ◽  
Aromatic Rings ◽  
Solubility In Water ◽  
Physico Chemical ◽  
Environmental Compartments

AbstractPartition coefficients between environmental compartments are essential parameters in any predictive models on pollutants’ fate in various emission scenarios. When sufficient experimental data are not available, empirical algebraic models are capable of predicting the pollutant partitioning characteristics based on bulk physico-chemical properties or various molecular structural features. When the use of sophisticated rules based on detailed 2D–3D molecular descriptors is not available as a quick option, inexpensive, simple correlations based solely on octanol-1-ol (octanol)-water partition coefficients (K ow) are extensively employed. The present study investigates enhancing the adequacy of such hydrophobicity-based models by adding simple 1D descriptors, readily identifiable by inspecting the substance structure (i.e. the number of chlorine atoms bound to aromatic rings, or the number of aromatic 5- or 6-atom rings, etc.), in addition to the pollutant’s solubility in water. Exemplification is made for predicting the water-biota (fish)-sediment partition coefficients for chlorobenzenes (CBz).

Decoration of specific sites on freeze-fractured membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 140-141
Author(s):  
H. Gross ◽  
H. Moor
Keyword(s):  
Pure Water ◽  
Freeze Fracture ◽  
Chemical Properties ◽  
Surface Forces ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Physico Chemical ◽  
Water Of Hydration ◽  
Small Container ◽  
Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

Physico-Chemical Properties of Recombinant Desulphatohirudin

1990 ◽  
Vol 63 (03) ◽  
pp. 499-504 ◽  
Author(s):  
A Electricwala ◽  
L Irons ◽  
R Wait ◽  
R J G Carr ◽  
R J Ling ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Chemical Properties ◽  
Alpha Helix ◽  
Apparent Molecular Weight ◽  
Correlation Spectroscopy ◽  
Nmr Studies ◽  
Recombinant Hirudin ◽  
Physico Chemical ◽  
Recombinant Molecule

SummaryPhysico-chemical properties of recombinant desulphatohirudin expressed in yeast (CIBA GEIGY code No. CGP 39393) were reinvestigated. As previously reported for natural hirudin, the recombinant molecule exhibited abnormal behaviour by gel filtration with an apparent molecular weight greater than that based on the primary structure. However, molecular weight estimation by SDS gel electrophoresis, FAB-mass spectrometry and Photon Correlation Spectroscopy were in agreement with the theoretical molecular weight, with little suggestion of dimer or aggregate formation. Circular dichroism studies of the recombinant molecule show similar spectra at different pH values but are markedly different from that reported by Konno et al. (13) for a natural hirudin-variant. Our CD studies indicate the presence of about 60% beta sheet and the absence of alpha helix in the secondary structure of recombinant hirudin, in agreement with the conformation determined by NMR studies (17)

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