Thermal degradation and evolved gas analysis of epoxy (DGEBA)/novolac resin blends (ENB) during pyrolysis and combustion

The thermal degradation of epoxy (DGEBA) and phenol formaldehyde (novolac) resins blend was investigated by using thermogravimetric analysis (TGA) coupled with Fourier transform infrared spectroscopy and mass spectroscopy. The results of TGA revealed that the thermal degradation process can be subdivided into four stages: drying the sample, fast and second thermal decomposition, and further cracking process of the polymer. The total mass loss of 89.32 mass% at 950 °C is found during pyrolysis, while the polymer during the combustion almost finished at this temperature. The emissions of carbon dioxide, aliphatic hydrocarbons, carbon monoxide, etc., while aromatic products, are emitted at higher temperature during combustion and pyrolysis. It was observed that the intensities of CO₂, CO, H₂O, etc., were very high when compared with their intensities during pyrolysis, attributed to the oxidation of decomposition product.     

DyF3: An Efficient Electrocatalyst for N2 Fixation to NH3 under Ambient Conditions

NH₃ synthesis by the Haber–Bosch method is regarded as the dominant method in industry. Such a process is energy‐intensive, accompanied by a large amount of CO₂ emission. Electrocatalytic N₂ reduction is a sustainable avenue for NH₃ production at ambient conditions. However, it needs a catalyst to boost the N₂ reduction reaction. Here, we demonstrate that DyF₃ is an efficient electrocatalyst. In 0.1 m Na₂SO₄, DyF₃ attains a large NH₃ yield of 10.9 μg h^?1 mg^?1_cat. at ?0.45 V vs. the reversible hydrogen electrode, with the corresponding Faradaic efficiency of 8.8 %. Furthermore, this catalyst exhibits high electrochemical stability.     

Charge-Transfer Reaction of Chloranilic Acid with Crizotinib: Spectrophotometric Study,Computational Modeling and Use in Development of Microwell Assay for Crizotinib

The reaction of chloranilic acid (CA) with crizotinib (CZT); a novel drug used for treatment of non-small cell lung cancer) was investigated in different solvents of varying dielectric constants and polarity indices. The reaction resulted in the formation of a violet-colored product. Spectrophotometric investigations confirmed that the reaction proceeded through CT complex formation. The molar absorptivity of the CT complex produced was found to be linearly correlated with the dielectric constant and polarity index of the solvent. The association constant of the CA–CZT CT complex and the stoichiometric ratio of CA:CZT were determined. Computational molecular modeling for the CT complex between CA and CZT was conducted, the sites of interaction on CZT molecule were determined, and the mechanism of the reaction was postulated. The reaction was employed as a basis for the development of a novel 96-microwell assay for CZT. In this assay, the absorbances of the CA–CZT CT complex solutions were measured by a microwell-plate absorbance reader. The CZT limits of detection and quantitation are 8.8 and 26.4 μg·mL^?1, respectively. The assay was successfully applied to the analysis of CZT in its bulk form and capsules with good accuracy and precision. The assay described herein has great practical value as it has high throughput and consumes minimum volume of organic solvent, thus it reduces the exposures of the analysts to the toxic effects of organic solvents, and significantly reduces the analysis cost.     

Salt effects on reactivities of low-spin iron(II) complexes of diazabutadiene and Schiff base ligands

Salt effects on reactivity are reported for base hydrolysis of tris-ligand-iron(II) complexes of several diazabutadiene and Schiff base ligands in aqueous solutions of alkali metal halides and of tetraalkylammonium bromides. The observed patterns vary markedly with ligand nature, the trend paralleling ligand hydrophilicity. These patterns of salt effects on reactivity are compared with those for a variety of other inorganic substitution reactions.     

Kinetics of base hydrolysis of tris-(1,10-phenanthroline)iron(II) and of solvolysis of cis-dichlorobis(1,2-ethanediamine)cobalt(III) in water + diol mixtures

Rate constants for base hydrolysis of the tris-(1,10-phenanthroline)iron(II) cation and for solvolysis of the cis-dichlorobis(1,2-ethanediamine)cobalt(III) cation have been measured in binary aqueous mixtures containing 1,2-ethanediol, 1,2- or 1,4-butanediol, 1,2- or 1,6-hexanediol, 1-propanol, or t-butyl alcohol, at 298.2 K. Kinetics of base hydrolysis of the cobalt(III) complex have also been monitored in methanol-water and ethanol-water mixtures, again at 298.2 K. The observed reactivity trends are discussed in terms of the hydrophilic and hydrophobic properties of the respective diols. The dominant factor determining reactivity is hydration of the attacking hydroxide or leaving chloride, as is evidenced by the close correspondence between rate constants and transfer chemical potentials for these anions. The role of hydration has also been probed through the determination of activation volumes for these two reactions in 60% 1,4-butanediol. © 1993 John Wiley & Sons, Inc.     

Reactivity and solvatochromism of pentacyanoferrate(II) complexes in diol–water mixtures

Rate constants are reported for substitution at the pentacyanoferrate(II) ions [Fe(CN)5L]3−, where L=3,5-dimethylpyridine or 3-cyanopyridine, in binary aqueous mixed solvents containing up to 60vol% 1,2-ethanediol, 1,2-butanediol, methanol or ethanol. Trends for diol-containing mixtures are compared with those for monohydroxylic alcohols, and the reactivity pattern for these complexes is compared with those established earlier for base hydrolysis of tris(1,10-phenanthroline)iron(II) and for the aquation of cis-dichloro-bis- (1,2-ethanediamine)cobalt(III). The solvatochromic behaviour of several pentacyanoferrate(II) ions has been established in binary aqueous mixtures containing 1,2-ethanediol, 1,2-butanediol, 1,4-butanediol and 1,2-pentanediol. A correlation between reactivity and solvatochromism is presented. This revised version was published online in June 2006 with corrections to the Cover Date.     

Hydrazine sensors development based on a glassy carbon electrode modified with a nanostructured TiO2 films by electrochemical approach

Microchimica Acta - The authors describe a selective hydrazine sensor that is based on the use of a film of TiO2 nanoparticles faceted predominantly at the 101 and 001 sides. The hydrazine (Hyd)...     

Application of Three Ecological Assessment Tools in Examining Chromatographic Methods for the Green Analysis of a Mixture of Dopamine,Serotonin, Glutamate and GABA: A Comparative Study

The assessment of greenness of analytical protocols is of great importance now to preserve the environment. Some studies have analyzed either only the neurotransmitters, dopamine, serotonin, glutamate, and gamma-aminobutyric acid (GABA), together or with other neurotransmitters and biomarkers. However, these methods have not been investigated for their greenness and were not compared with each other to find the optimum one. Therefore, this study aims to compare seven published chromatographic methods that analyzed the four neurotransmitters and their mixtures using the National Environmental Method Index, Analytical Eco-Scale Assessment (ESA), and Green Analytical Procedure Index (GAPI). As these methods cover both qualitative and quantitative aspects, they offer better transparency. Overall, GAPI showed maximum greenness throughout the analysis. Method 6 was proven to be the method of choice for analyzing the mixture, owing to its greenness, according to NEMI, ESA, and GAPI. Additionally, method 6 has a wide scope of application (13 components can be analyzed), high sensitivity (low LOQ values), and fast analysis (low retention times, especially for glutamate and GABA).     

Investigating Antiarthritic Potential of Nanostructured Clove Oil (Syzygium aromaticum) in FCA-Induced Arthritic Rats: Pharmaceutical Action and Delivery Strategies

The combined application of clove oil in a lipid nanocarrier opens a promising avenue for bone and joints therapy. In this study, we successfully developed a tunable controlled-release lipid platform for the efficient delivery of clove oil (CO) for the treatment of rheumatoid arthritis (RA). The ultra-small nanostructured lipid carriers co-loaded with CO (CONCs) were developed through an aqueous titration method followed by microfluidization. The CONCs appeared to be spherical (particle size of 120 nm), stable (zeta potential of −27 mV), and entrapped efficiently (84.5%). In toluene:acetone:glacial acetic acid (90:9:1 percent v/v/v) solvent systems, high-performance thin layer chromatography (HPTLC) analysis revealed the primary components in CO as eugenol (R_F = 0.58). The CONCs greatly increased the therapeutic impact of CO in both in vitro and in vivo biological tests, which was further supported by excellent antiarthritic action. The CONC had an antiarthritic activity that was slightly higher than neat CO and slightly lower than standard, according to our data. The improved formulation inhibited serum lysosomal enzymes and proinflammatory cytokines while also improving hind leg function. This study provides a proof of concept to treat RA with a new strategy utilizing essential oils via nanodelivery.