Metal-Containing Monomers Based on Copper and Zinc Salts of Unsaturated Acids and Pendent 4-phenyl-2,2′:6′,2′′-terpyridine Ligands: Synthesis, Characterization and Thermal Properties

2020 ◽  
Vol 869 ◽  
pp. 119-128
Author(s):  
Rose K. Baimuratova ◽  
Gulzhian I. Dzhardimalieva ◽  
Vladimir A. Zhinzhilo ◽  
Kamila A. Kydralieva ◽  
Igor E. Uflyand
Keyword(s):  
Analytical Techniques ◽  
Dicarboxylic Acids ◽  
Gravimetric Analysis ◽  
Nmr Spectrum ◽  
Monocarboxylic Acids ◽  
Gaseous Products ◽  
Copper And Zinc ◽  
Zinc Salts ◽  
Terpyridine Ligands ◽  
First Time

Metal-containing monomers based on maleates of copper and zinc, cinnamate of copper and acrylate of zinc with 4-phenyl-2,2′:6′,2′′-terpyridine ligand were prepared for the first time and characterized using a number of analytical techniques including infrared spectroscopy, elemental analysis and thermal gravimetric analysis. According to the results of the thermal analysis, the coordination mixed-ligand complexes based on zinc salts are more stable than copper one both in the case of monocarboxylic acids and dicarboxylic acids. The first stage of polymerization according to results of mass spectra of gaseous products is initiated in accordance with the Borodin–Hunsdiecker mechanism: the initial decarboxylation leads to the formation of carboxy biradicals, which, in turn, cause the polymerization and the formation of polymers. In this paper we also describe facile two-step Kröhnke-type synthesis of 4′-phenyl-2,2′:6′,2′′-terpyridine from 2-acetylpyridine and its NMR spectrum.

scholarly journals Valorization of sugarcane bagasse by chemical pretreatment and enzyme mediated deconstruction

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Vihang S. Thite ◽  
Anuradha S. Nerurkar
Keyword(s):  
Cell Wall ◽  
Sugarcane Bagasse ◽  
Structural Changes ◽  
Enzymatic Saccharification ◽  
Dry Weight ◽  
Gravimetric Analysis ◽  
Chemical Pretreatment ◽  
Cell Wall Degrading Enzymes ◽  
First Time ◽  
Soluble Components

Abstract After chemical pretreatment, improved amenability of agrowaste biomass for enzymatic saccharification needs an understanding of the effect exerted by pretreatments on biomass for enzymatic deconstruction. In present studies, NaOH, NH4OH and H2SO4 pretreatments effectively changed visible morphology imparting distinct fibrous appearance to sugarcane bagasse (SCB). Filtrate analysis after NaOH, NH4OH and H2SO4 pretreatments yielded release of soluble reducing sugars (SRS) in range of ~0.17–0.44%, ~0.38–0.75% and ~2.9–8.4% respectively. Gravimetric analysis of pretreated SCB (PSCB) biomass also revealed dry weight loss in range of ~25.8–44.8%, ~11.1–16.0% and ~28.3–38.0% by the three pretreatments in the same order. Release of soluble components other than SRS, majorly reported to be soluble lignins, were observed highest for NaOH followed by H2SO4 and NH4OH pretreatments. Decrease or absence of peaks attributed to lignin and loosened fibrous appearance of biomass during FTIR and SEM studies respectively further corroborated with our observations of lignin removal. Application of commercial cellulase increased raw SCB saccharification from 1.93% to 38.84%, 25.56% and 9.61% after NaOH, H2SO4 and NH4OH pretreatments. Structural changes brought by cell wall degrading enzymes were first time shown visually confirming the cell wall disintegration under brightfield, darkfield and fluorescence microscopy. The microscopic evidence and saccharification results proved that the chemical treatment valorized the SCB by making it amenable for enzymatic saccharification.

scholarly journals Kinetical Study, Thermo-Mechanical Characteristics and Recyclability of Epoxidized Camelina Oil Cured with Antagonist Structure (Aliphatic/Aromatic) or Functionality (Acid/Amine) Hardeners

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2503
Author(s):  
Chiara Di Mauro ◽  
Aratz Genua ◽  
Alice Mija
Keyword(s):  
Disulfide Bonds ◽  
Mechanical Characteristics ◽  
Dicarboxylic Acids ◽  
Thermomechanical Properties ◽  
Chemical Recycling ◽  
Camelina Oil ◽  
Ft Ir ◽  
Tan Δ ◽  
The Individual ◽  
First Time

In an attempt to prepare sustainable epoxy thermosets, this study introduces for the first time the idea to use antagonist structures (aromatic/aliphatic) or functionalities (acid/amine) as hardeners to produce reprocessable resins based on epoxidized camelina oil (ECMO). Two kinds of mixtures were tested: one combines aromatic/aliphatic dicarboxylic acids: 2,2′-dithiodibenzoic acid (DTBA) and 3,3′-dithiodipropionic acid (DTDA); another is the combination of two aromatic structures with acid/amine functionality: DTBA and 4-aminophenyl disulfide (4-AFD). DSC and FT-IR analyses were used as methods to analyze the curing reaction of ECMO with the hardeners. It was found that the thermosets obtained with the dual crosslinked mechanism needed reduced curing temperatures and reprocessing protocols compared to the individual crosslinked thermosets. Thanks to the contribution of disulfide bonds in the network topology, the obtained thermosets showed recycling ability. The final thermomechanical properties of the virgin and mechanical reprocessed materials were analyzed by DMA and TGA. The obtained thermosets range from elastomeric to rigid materials. As an example, the ECMO/DTBA704-AFD30 virgin or reprocessed thermosets have tan δ values reaching 82–83 °C. The study also investigates the chemical recycling and the solvent resistance of these vitrimer-like materials.

scholarly journals Homopiperazine (Hexahydro-1,4-diazepine)

Molbank ◽  
10.3390/m1200 ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. M1200
Author(s):  
R. Alan Aitken ◽  
Dheirya K. Sonecha ◽  
Alexandra M. Z. Slawin
Keyword(s):  
13C Nmr ◽  
Title Compound ◽  
Coupling Constants ◽  
15N Nmr ◽  
Time Data ◽  
Nmr Spectrum ◽  
X Ray ◽  
First Time

The X-ray structure of the title compound has been determined for the first time. Data on its 1H–13C-NMR coupling constants and 15N-NMR spectrum are also given.

scholarly journals Novel Preparation of Noncovalent Modified GO Using RAFT Polymerization to Reinforce the Performance of Waterborne Epoxy Coatings

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 348 ◽  
Author(s):  
Baolei Liu ◽  
Mingqian Wang ◽  
Ying Liang ◽  
Zhicheng Zhang ◽  
Guohong Ren ◽  
...  
Keyword(s):  
Raft Polymerization ◽  
Salt Spray ◽  
Thermo Gravimetric Analysis ◽  
Analytical Techniques ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Block Polymer ◽  
Reversible Addition ◽  
Waterborne Epoxy ◽  
And Performance

This work launches the first-ever report on the fabrication of waterborne epoxy-graphene oxide (GO) coatings (WEGC) using a block polymer as a dispersant of GO, wherein the block polymer was synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization of acrylic acid and oligo(ethylene glycol) methyl ether methacrylate A number of analytical techniques, such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermo gravimetric analysis (TGA), and salt spray tests, were utilized to explore the morphology and performance of the WEGC. It was confirmed that POEGMA950-b-PAA attached to the GO nanosheets, increasing the integral space of the sheets. Modified GO (MGO) layers were well-dispersed in the epoxy matrix through the formation of a GO-dispersant-epoxy ternary molecular structure. Furthermore, the presence of MGO substantially influenced the thermal properties, mechanical properties, and anticorrosion performance of the WEGC. TGA, salt spray tests, and pull-off testsshowed that 0.5 wt.% MGO content achieved the greatest improvement in the evaluated properties.

Sphere-like CoS with nanostructures as peroxidase mimics for colorimetric determination of H2O2 and mercury ions

RSC Advances ◽  
2016 ◽  
Vol 6 (71) ◽  
pp. 66963-66970 ◽  
Author(s):  
Haiguan Yang ◽  
Junqi Zha ◽  
Peng Zhang ◽  
Yuhao Xiong ◽  
Linjing Su ◽  
...  
Keyword(s):  
Solvothermal Method ◽  
Analytical Techniques ◽  
Colorimetric Determination ◽  
Mercury Ions ◽  
Peroxidase Mimics ◽  
First Time ◽  
Facile Solvothermal Method

CoS, which was prepared using a facile solvothermal method, and characterized using various analytical techniques, was demonstrated for the first time to exhibit intrinsic peroxidase-like activity.

Characterization of Novel Solid Dispersions of Moringa oleifera Leaf Powder Using Thermo-Analytical Techniques

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2230
Author(s):  
Nontsikelelo Noxolo Tafu ◽  
Victoria A. Jideani
Keyword(s):  
Solid Dispersion ◽  
Moringa Oleifera ◽  
Solid Dispersions ◽  
Intermolecular Hydrogen Bond ◽  
Thermo Gravimetric Analysis ◽  
Analytical Techniques ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Hydrogen Bond Interactions ◽  
Leaf Powder

Moringa oleifera leaf powder (MOLP) has been identified as the most important functional ingredient owing to its rich nutritional profile and healthy effects. The solubility and functional properties of this ingredient can be enhanced through solid dispersion technology. This study aimed to investigate the effects of polyethylene glycols (PEGs) 4000 and 6000 as hydrophilic carriers and solid dispersion techniques (freeze-drying, melting, solvent evaporation, and microwave irradiation) on the crystallinity and thermal stability of solid-dispersed Moringa oleifera leaf powders (SDMOLPs). SDMOLPs were dully characterized using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The PXRD results revealed that the solid dispersions were partially amorphous with strong diffraction peaks at 2θ values of 19° and 23°. The calorimetric and thermogravimetric curves showed that PEGs conferred greater stability on the dispersions. The FTIR studyrevealed the existence of strong intermolecular hydrogen bond interactions between MOLP and PEG functional groups. MOLP solid dispersions may be useful in functional foods and beverages and nutraceutical formulations.

scholarly journals Fractionation of Birch Wood by Integrating Alkaline-Acid Treatments and Hydrogenation in Ethanol over a Bifunctional Ruthenium Catalyst

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1362
Author(s):  
Boris N. Kuznetsov ◽  
Sergey V. Baryshnikov ◽  
Angelina V. Miroshnikova ◽  
Aleksandr S. Kazachenko ◽  
Yuriy N. Malyar ◽  
...  
Keyword(s):  
Microcrystalline Cellulose ◽  
Catalytic Hydrogenation ◽  
Liquid Product ◽  
Gel Permeation Chromatography ◽  
Ruthenium Catalyst ◽  
Birch Wood ◽  
Gaseous Products ◽  
Liquid Products ◽  
First Time

For the first time, the fractionation of birch wood into microcrystalline cellulose, xylose and methoxyphenols is suggested based on the integration of alkali-acid pretreatments and hydrogenation in ethanol over a bifunctional Ru/C catalyst. It is established that removal of hemicelluloses during pretreatments of birch wood influences the yields of the liquid, gaseous and solid products of the non-catalytic and catalytic hydrogenation of pretreated samples in ethanol at 225 °C. The bifunctional Ru/carbon catalyst affects in different ways the conversion and yields of products of hydrogenation of the initial and acid- and alkali-pretreated birch wood. The most noticeable influence is characteristic of the hydrogenation of the acid-pretreated wood, where in contrast to the non-catalytic hydrogenation, the wood conversion and the yields of liquid products increase but the yields of the solid and gaseous products decrease. GC-MS, gel permeation chromatography and elemental analysis were used for characterization of the liquid product composition. The molecular mass distribution of the liquid products of hydrogenation of the initial and pretreated wood shifts towards the low-molecular range in the presence of the catalyst. From the GC-MS data, the contents of monomer compounds, predominantly 4-propylsyringol and 4-propanolsyringol, increase in the presence of the ruthenium catalyst. The solid products of catalytic hydrogenation of the pretreated wood contain up to 95 wt% of cellulose with the structure, similar to that of microcrystalline cellulose.

scholarly journals Non-Isothermal Sublimation Kinetics of 2,4,6-Trinitrotoluene (TNT) Nanofilms

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1163 ◽  
Author(s):  
Walid Hikal ◽  
Brandon Weeks
Keyword(s):  
Activation Energy ◽  
Analytical Techniques ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Absorbance Spectroscopy ◽  
Calculated Activation Energy ◽  
Sublimation Kinetics ◽  
Sublimation Rates ◽  
First Time ◽  
Kinetics Of

Non-isothermal sublimation kinetics of low-volatile materials is more favorable over isothermal data when time is a crucial factor to be considered, especially in the subject of detecting explosives. In this article, we report on the in-situ measurements of the sublimation activation energy for 2,4,6-trinitrotoluene (TNT) continuous nanofilms in air using rising-temperature UV-Vis absorbance spectroscopy at different heating rates. The TNT films were prepared by the spin coating deposition technique. For the first time, the most widely used procedure to determine sublimation rates using thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) was followed in this work using UV-Vis absorbance spectroscopy. The sublimation kinetics were analyzed using three well-established calculating techniques. The non-isothermal based activation energy values using the Ozawa, Flynn–Wall, and Kissinger models were 105.9 ± 1.4 kJ mol−1, 102.1 ± 2.7 kJ mol−1, and 105.8 ± 1.6 kJ mol−1, respectively. The calculated activation energy agreed well with our previously reported isothermally-measured value for TNT nanofilms using UV-Vis absorbance spectroscopy. The results show that the well-established non-isothermal analytical techniques can be successfully applied at a nanoscale to determine sublimation kinetics using absorbance spectroscopy.

scholarly journals Synthesis of calcium-phosphate and chitosan bioceramics for bone regeneration

2001 ◽  
Vol 73 (4) ◽  
pp. 525-532 ◽  
Author(s):  
MELLATIE R. FINISIE ◽  
ATCHE JOSUÉ ◽  
VALFREDO T. FÁVERE ◽  
MAURO C. M. LARANJEIRA
Keyword(s):  
Bone Regeneration ◽  
Solid Phase ◽  
Thermo Gravimetric Analysis ◽  
Analytical Techniques ◽  
Bone Substitutes ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Beneficial Effects ◽  
Fourier Transformed Infrared Spectroscopy

Bioceramic composites were obtained from chitosan and hydroxyapatite pastes synthesized at physiological temperature according to two different syntheses approaches. Usual analytical techniques (X-ray diffraction analysis, Fourier transformed infrared spectroscopy, Thermo gravimetric analysis, Scanning electron microscopy, X-ray dispersive energy analysis and Porosimetry) were employed to characterize the resulting material. The aim of this investigation was to study the bioceramic properties of the pastes with non-decaying behavior from chitosan-hydroxyapatite composites. Chitosan, which also forms a water-insoluble gel in the presence of calcium ions, and has been reported to have pharmacologically beneficial effects on osteoconductivity, was added to the solid phase of the hydroxyapatite powder. The properties exhibited by the chitosan-hydroxyapatite composites were characteristic of bioceramics applied as bone substitutes. Hydroxyapatite contents ranging from 85 to 98% (w/w) resulted in suitable bioceramic composites for bone regeneration, since they showed a non-decaying behavior, good mechanical properties and suitable pore sizes.

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