Ionic Nitrate Research Articles

On inorganic N uptake by vascular plants: Can 15N tracer techniques resolve the NH4+ versus NO3− “preference” conundrum?

AbstractThe relative uptake by plants of the two ionic nitrogen (N) forms, ammonium (NH4+) and nitrate (NO3−), has been the subject of much interest during the past 50 years, resulting in a considerable scientific literature. The general idea is that plants have choice, resulting in preference for either one mineral N form or the other. Unfortunately, there is no specific definition of preference or agreement on how it should be measured. In this review, we critically examine the alternative techniques that have been used to measure the relative uptake of NH4+ and NO3− by plants, including those based on unlabelled sources, 15N‐enriched mineral N forms and variations in the 15N natural abundance of mineral N sources. The main difficulty with using unlabelled N is the antecedent N in plant tissue prior to the imposition of treatments. Although 15N‐enrichment overcomes this obstacle, it is nevertheless difficult to separate uptake as 15NH4+, uptake as 15NO3− and uptake as 15NO3− derived from the nitrification of 15NH4+. With 15N natural abundance, isotopic fractionation during plant uptake complicates the interpretation of data. There is increasing evidence that plants exhibit flexibility or plasticity with respect to the use of mineral N forms rather than preference.Highlights The concept of plant preference for NH4+ or NO3− forms of mineral N is examined Experiments using 15N‐enrichment and 15N natural abundance are reviewed The direct uptake of 15NO3− is confounded with the uptake of 15NO3− derived from nitrified 15NH4+ Plants exhibit plasticity rather than preference in the acquisition of ammonium and nitrate

Two-stage decomposition of 2-hydroxyethylhydrazinium nitrate (HEHN)

The hydrazine-derived ionic liquid 2-hydroxyethylhydrazinium nitrate (HEHN) is a promising fuel component of green monopropellants. For successful implementation of these propellants, it is necessary to understand the kinetics and mechanism of HEHN decomposition, but the available data are scarce. The objective of the present work was to investigate the kinetics of HEHN thermal decomposition using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) as well as to identify the evolved gas products with mass spectrometry (MS) and Fourier-transform infrared (FTIR) spectroscopy. Both TGA and DSC have revealed that the decomposition of high-purity HEHN has two distinct stages. The effective kinetic parameters of both stages were determined using the Ozawa-Wall-Flynn, Kissinger, and model-based methods. The model-based analysis has shown autocatalytic behaviour of the involved reactions and produced apparent activation energies of 113.7 ± 1.7 kJ/mol at the first stage and 123.6 ± 2.5 kJ/mol at the second stage, close to the literature data (124.8 kJ/mol) on the autocatalytic reaction between HEHN and HNO3. The evolved gas analysis has shown that the first stage generates H2O, N2, NH3, NO, N2O, and NO2, while the second stage also generates HNO3 and CO2. The observed existence of two stages in the thermal decomposition of HEHN could be explained by the formation of a condensed by product, which, in turn, decomposes via a highly activated reaction during the second (high-temperature) stage.

Understanding of NOx storage property of impregnated Ba species after crystallization of mesoporous alumina powders

The regulation of automobile exhaust gas, especially that concerning hazardous nitrogen oxide (called as NOx) becomes stricter year-by-year, which should be urgently corresponded for cleaning the NOx containing emission. According to surface affinity of γ-alumina to metal catalysts and its thermal stability, crystalline γ-alumina has been frequently utilized as catalyst supports showing relatively high specific surface area. From the viewpoint, we consider that highly porous alumina powders prepared using amphiphilic organic molecules are potential as such a catalyst support for improving NOx removing property. In this study, we report surface property of the mesoporous alumina powders against NOx molecules after crystallizing to its γ-phase and NOx storage property after impregnation of barium (Ba) acetate in the mesopores. Adsorption of NO with O2 on mesoporous γ-alumina powders without Ba species were more likely to be bridging bidentate than chelating bidentate nitrates (NO3−) with comparing to commercially available γ-alumina powders. After impregnating the Ba species, admitted NO molecules were oxidized with enough O2 and stored very strongly as ionic nitrate (NO3−) onto the Ba species even after heating at 500 °C. This preliminary study is helpful for designing mesoporous deNOx catalysts combined with unique storage/adsorption property.

Energetic ionic liquid hydroxyethylhydrazinium nitrate as an alternative monopropellant

The propellant synthesis community is constantly looking for green alternative monopropellants. Energetic ionic liquids have several attractive properties such as high energy content, high bulk density, low vapor pressure, high thermal stability, wide liquidus range, low corrosiveness, low toxicity, and ease of handling. The combustion characteristics of an energetic ionic liquid hydroxyethylhydrazinium nitrate (HEHN) was conducted in a pressurized chamber. The performance of HEHN was compared to that of the monopropellant Otto fuel II (OF-II) typically used for torpedo-propulsion. A liquid strand combustion study was performed in an atmosphere of air and nitrogen with chamber pressures varying from 10 to 90 bar. Regressing surface profiles and subsequent burning rates were obtained at different chamber pressures. A B-type thermocouple of 46 µm wire diameter was used to measure the monopropellant flame temperature of HEHN. Thermogravimetric analysis was performed to study the thermal decomposition of HEHN to understand its thermal stability and Fourier transform infrared spectroscopy (FTIR) was utilized to determine the possible reasons behind the high burning rates of HEHN. The gains in the specific impulse and density specific impulse coupled with enhanced burning rates and reasonable thermal stability are expected to establish HEHN as a frontrunner for propulsion and power-generation in oxygen-deficient scenarios.

Voltammetric codetection of arsenic(III) and copper(II) in alkaline buffering system with gold nanostar modified electrodes

One of the challenges preventing rapid, onsite voltammetric detection of arsenic(III) is the overlapping oxidation peak of copper(II). This paper describes a novel methodology for the voltammetric detection of trace levels of arsenic(III) in the presence of high copper(II) concentrations (up to the action level of 1.3 mg L−1 set by the US EPA for drinking water). Square wave stripping voltammetry tests were performed using disposable carbon screen printed electrodes modified with gold nanostars on samples buffered with Britton-Robinson buffer. The optimized parameters for accurate codetection of arsenic(III) and copper(II) were a buffer pH of 9.5, a loading of gold nanostars of 2.39*10−5 nmol per electrode, a deposition voltage of −0.8 V, and a deposition time of 180 s. Based on calibration testing, the limits of detection for arsenic(III) and copper(II) were determined to be 2.9 μg L−1 and 42.5 μg L−1, respectively. Furthermore, the linear ranges for arsenic and copper were 0–100 μg L−1 and 0–250 μg L−1 with sensitivities of 0.101 μA (μg L−1)−1 and 0.121 μA (μg L−1)−1, respectively. Interference testing was performed with several common ionic species, sodium bicarbonate, sodium chloride, tannic acid, iron(iii) chloride, magnesium chloride, calcium nitrate, and sodium sulfate, with only sodium bicarbonate significantly affecting the response. Validation testing in real-world samples was performed by comparison with graphite furnace atomic absorption spectroscopy. The validation testing demonstrated good accuracy and precision, expressed as percent recovery and relative standard deviation (RSD), respectively, in river water and tap water, with mean percent recoveries of 87.7% (RSD = 4.20%) and 83.2% (RSD = 10.02%), respectively.

Selective Extraction of Americium from Curium and the Lanthanides by the Lipophilic Ligand CyMe4BTPhen Dissolved in Aliquat-336 Nitrate Ionic Liquid

ABSTRACTThe feasibility of separating americium from curium and the lanthanides was studied in batch solvent extraction experiments using an organic solvent composed of 0.01 mol L−1 2,9-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-1,10-phenanthroline (CyMe4BTPhen) in the ionic liquid Aliquat-336 nitrate [A336][NO3] from feed solutions containing N,N,N’,N’-tetraethyl diglycolamide (TEDGA), stable lanthanide ions and tracers of 241Am, 244Cm, and 152Eu. The combined use of a lipophilic and a hydrophilic ligand with opposite selectivity for Am(III) vs. Cm(III) and Ln(III) allowed the separation of Am(III) from Cm(III) and Ln(III) from moderate acidic feed solutions (1 mol L−1 HNO3, SFAm/Cm = 3.1–3.9, SFAm/La > 75, SFAm/Eu ≥ 3000).

Green Synthesis and Characterization of Silver Nanoparticles (AgNPs) Using Leaf Extract of Solanum nigrum and Assessment of Toxicity in Vertebrate and Invertebrate Aquatic Animals

In this study, silver nanoparticle was green synthesized using the leaf extract of Solanum nigrum (Sn-AgNPs) and bio-physically characterized by UV–Vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), High resolution transmission electron microscopy (HR-TEM), Zeta potential analysis and Energy dispersive X-ray (EDX) analysis. The ecotoxicity of silver nanoparticle (Sn-AgNPs) were tested against both invertebrate (Ceriodaphnia cornuta and Paramecium sp.) and vertebrate aquatic animal models (Guppy fish, Poecilia reticulata) in comparison with bare silver nitrate. Sn-AgNPs were observed to be less toxic than ionic silver (silver nitrate). The ecotoxicity levels of Sn-AgNPs were found to be varied between tested organisms. Sn-AgNPs caused 100% mortality of freshwater crustacean, C. cornuta at 50 µg mL−1. At concentration below 50 µg mL−1 (10–30 µg mL−1), abnormality in the swimming behavior of C. cornuta was noticed. The ingestion and accumulation of Sn-AgNPs in the intestine of C. cornuta neonates were visualized under light and confocal laser scanning microscopic images. The ecotoxicity of Sn-AgNPs to the freshwater protozoan ciliate, Paramecium sp. showed that 30 µg mL−1 were lethal and produced 100% mortality at the same concentration. The study concludes that Sn-AgNPs was less toxic to both invertebrate and vertebrate models compared to ionic silver nitrate.

Comprehensive Study of the Interaction and Mechanism between Bistetrazole Ionic Salt and Ammonium Nitrate Explosive in Thermal Decomposition

Bistetrazole energetic ionic salts, such as dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) and diamino 5,5′-bistetrazole-1,1′-diolate (ABTOX), are new insensitive materials and have great potential applications because of their good energy and safety performance. Prior to pure explosive preparation into PBX, the interactions between the components must be evaluated. Examination of interactions between bistetrazole ionic salt and ammonium nitrate explosive in thermal decomposition is beneficial in revealing the interactive mechanism of these two kinds of energetic materials in decomposition, as well as in the evaluation of compatibility, safety, and reliability of PBX explosive based on TKX-50, ABTOX, HMX, and RDX. Herein, the thermal decomposition behavior of TKX-50/HMX, ABTOX/HMX, TKX-50/RDX, and ABTOX/RDX is investigated. Ammonium nitrate explosives can significantly reduce the thermal decomposition peak temperature of the bistetrazole ionic salt. For example, HMX reduces the decomposition p...

Cerium Oxide Nanoparticles Affect Heavy Metals Uptake by Pea in a Divergent Way than Their Ionic and Bulk Counterparts

The impact of cerium oxide nanoparticles, bulk cerium oxide and ionic cerium nitrate on the plant development as well as the uptake and further translocation of Cu, Mn, Zn and Fe by sugar pea (Pisum sativum L.) was investigated. Plants were cultivated in the laboratory pot experiments using the modified Hoagland solutions supplemented with cerium compounds at the 200 mg L−1 Ce level. Analysis of variance proved that cerium oxide nanoparticles significantly decreased Cu, Mn, Zn and Fe concentrations in roots and above ground parts of the pea plants. The latter ions are presumably transported via symplastic pathways and may compete with nanoparticles for similar carriers. The lowest impact on the plant growth and the metal uptake was observed under the bulk CeO2 treatment. On the contrary, strongest interactions were observed for supplementation with ionic cerium nitrate. The highly beneficial effect of cerium oxide nanoparticles on the plant growth was not supported by this study. The latter conclusion is of particular relevance when environmental impact of cerium compounds on the waste management, municipal urban low emissions and food production is to be concerned.

Preparation and characterization of novel solid electrolytes based on [EMIM] BF4 and lithium nitrate confined silica gels

Novel ionic liquid ([EMIM]BF4) and lithium nitrate confined silica gel composites have been prepared via hydrolytic sol-gel process and found to exhibit electrical conductivity up to 10−4 Ω−1cm−1 in the temperature range 150–300 °C. The composites are thermally stable at this temperature range and measurements are repeatable. Powder X-ray diffraction patterns suggest that the composites are amorphous in nature. FE-SEM (EDS elemental mapping) and DSC measurements further confirm IL confinement in the matrix. Electrical conductivity (150–300 °C) has been studied as a function of IL and Li+ ion content. The samples with no IL content are essentially electronic in nature. Addition of IL in small amounts (1 mol%) enhances the total conductivity at least by an order of magnitude. Further addition of salt (LiNO3) enhances ionic transport by orders of magnitude. The electronic conductivity and ionic mobility along with OCV measurements on cells of type Li/composite/LiCoO2 suggests facilitation of Li+ ion transport in presence of IL in small amount. However, further increasing the content of IL in the composition while keeping the salt ion concentration same, does not improve conductivity, rather reduces it. This complex behavior may be due to possibility of Li+ ions forming complex with IL anion and further investigations are required in this regard. Preliminary findings suggest that these materials have good potential for their applications in all-solid-state supercapacitors.

Synthesis, characterization and biological study of new dinuclear zinc(II) and nickel(II) octaaza macrocyclic complexes

Two new nitrato complexes of zinc and nickel with 1,4,8,11-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc), have been synthesized and characterized. The IR spectral peaks showed that the coordinated and ionic nitrate ions are in agreement with the formula proposed by elemental analysis. Conductometric titrations predicted methanol to be a convenient solvent for synthesis and revealed the stoichiometry of the complexes, while molar electrical conductivities indicated a 1 : 3 complex electrolyte type for the zinc complex, and a 1 : 2 complex electrolyte type for the nickel complex. The optimized complex structure was obtained by molecular modeling and density functional theory calculations. The biological activity of the novel complexes was examined by screening eight different bacterial strains and two cancer cell lines. The zinc complex showed better antimicrobial activity against the bacterial strains, while the complexes did not show significance antiproliferative activity toward cancer cells MCF-7 and MDA-MB-231.

Ignition Delays of Mixtures of the Non‐Hypergolic Energetic Ionic Liquid Hydroxyethylhydrazinium Nitrate Blended with Unsymmetrical Dimethylhydrazine

AbstractThe study deals with the investigation of energetic ionic liquids capable of serving as both monopropellants and bipropellants on a single mission. Various blends of the monopropellant hydroxyethylhydrazinium nitrate (HEHN), which was found to be non‐hypergolic with red fuming nitric acid (RFNA) and white fuming nitric acid (WFNA) under ambient conditions, were formulated with known hypergols to impart hypergolicity and to reduce the viscosity and surface tension of pure HEHN. Considering the miscibility and the ignition delays of the chosen hypergols, unsymmetrical dimethylhydrazine (UDMH) was chosen as the candidate for combustion characterization through measurement of ignition delays. UDMH‐HEHN blends containing a minimum of 30 % and 40 % UDMH by weight were found to be hypergolic with RFNA and WFNA, respectively. Meticulous experiments were conducted to measure the ignition delays in a drop test setup, equipped sequentially with a high‐speed camera, which was primarily utilized to observe the physico‐chemical events governing ignition, as well as an optoelectronic diagnostic setup, which was utilized to segregate the physical and chemical ignition delays. Standard hypergolic propellants were chosen to compare the veracity of the data from the optoelectronic diagnostics setup with those obtained using a high‐speed camera. The hypergolic blend containing 60 % UDMH was found to be the best candidate, owing to its low ignition delay of 5.8 ms with RFNA, 80 % lower vapor pressure compared to UDMH, and 30 g‐s/cm3 higher predicted vacuum density specific impulse than UDMH with IRFNA.

Mechanistic investigation of molecular geometry, intermolecular interactions and spectroscopic properties of pyridinium nitrate.

The molecular structure, vibrational frequencies of the fundamental modes and electronic transitions of the ionic liquid pyridinium nitrate ([H-Pyr]+[NO3]-) have been determined by means of density functional theory (DFT) at B3LYP/6-311++G (2d,2p) level. The chemical bonds nature and the intermolecular interactions in the title compound were investigated using the Quantum theory of atoms in molecules and Hirshfeld surface analysis. Natural bond orbital analysis has been performed in order to elucidate the hybridization and delocalization of electron density within the ion pair [H-Pyr]+[NO3]-. A detailed vibrational spectral analysis was carried out and the assignments of the observed bands have been proposed on the basis of potential energy distribution. A good correlation between experimental and theoretical IR frequencies was observed. To study the charge transfers occurred in the title molecule, UV-vis analysis was conducted.

Cavitation Erosion Resistance of Laser Beam Nitride Layers of X5CrNi18-10 Stainless Steel

The use of nitration in technical applications, as thermochemical treatment, regardless of the used method (ionic, gas or laser beam nitration) is realized to obtain a nitrogen rich layer, which increase the resistance to shock or abrasion, as a result of the high hardness obtained. All the previous cavitation researches showed that hardness is an important mechanical properties, for cavitation erosion resistance increase. The present paper show some results regarding the cavitation erosion behavior of laser beam nitrated layers. As basic material was used the austenitic stainless steel X5CrNi18-10. This material is frequently used for manufacturing details subjected to cavitation, such as valves, drawers of hydraulic distribution and regulation devices, or the retaining ring for butterfly valves. There were used three power regimes of the laser beams: 120 W, 180 W and 240 W. To obtain cavitation erosion was used the standard device with piezo-ceramic crystals of Timisoara Polytechnic University Cavitation Laboratory. The cavitation erosion comparisons, both with the basic material subjected only to the common thermochemical treatments and with the laboratory cavitation standard steel (OH12NDL), show that the nitrated surfaces presents increased cavitation erosion behavior, the principal factor being the important hardness increase of the nitrated layer. We mention also, that for higher laser beam powers the thickness of the nitrated layer increases. All the images obtained at the end of tests show that the cavitation exposure was stopped before overtaking the nitrated layer. So, all our results concern only the hardened layers.

A Computational Study of the Essential Transmembrane Protein Nark as Nitrate/Nitrite Exchanger

The ionic molecules nitrate (NO3−) and nitrate (NO2−) were believed to be detrimental to human health, but recently are considered to be beneficial on the nitric oxide regulation in human body. The transporter protein, Nark, efficiently moves the NO3− and NO2− across the membrane to maintain the homeostatic level of the two ionic molecules as vital metabolites. Based on experimental evidence, Zheng and coworkers proposed a NO3−/NO2− exchange mechanism through the Nark. Here, we perform molecular dynamics simulations to probe the protein conformational changes associated with the NO3−/NO2− exchange cycle. Umbrella sampling is utilized to investigate the free energy profiles of NO3− and NO2− migrations.

DFT analysis, reaction kinetics and mechanism of esterification using pyridinium nitrate as a green catalyst

The ionic liquid pyridinium nitrate ([H–Pyr]+[NO3]−) was synthesized and characterized theoretically and experimentally. Different quantum chemical analyses such as molecular electrostatic potential surface, natural bond orbital and frontier molecular orbital analyses were used for investigation of the electronic properties and chemical reactivity of the title compound. It was found the existence of an interaction between the nitrate anion and the pyridinium cation, expressed mainly by formation of the hydrogen bond O7⋯H11N1. The acetic acid esterification with 1-butanol was used as a model reaction in order to study the catalytic properties of the [H–Pyr]+[NO3]−. The influence of various process parameters (catalyst concentration, initial butanol-to-acetic acid molar ratio and reaction temperature) on the acetic acid conversion and reaction rate constant was discussed in details. The obtained experimental data were validated using a pseudo-homogeneous kinetic model. In addition, a plausible reaction mechanism of butyl acetate synthesis catalyzed by the ionic liquid pyridinium nitrate was offered.

Energy and gas dynamic characteristics of ionization nitrogen installations of industrial type

The work provides the analysis of power characteristics of the industrial equipment – ionic nitriding applications – with different types of vacuum chambers – with hot and cold walls. The calculations results and experimental researches of thermal balance of the system “melt-wall chamber” at the process of plasma nitration for industrial applications are given. The work examines the influence of heat-shielding screens quantity in the applications with cold walls on the internal screen temperature and power of thermal losses at warming up parts melt and at its isothermal endurance. It has been displayed the significant influence of the discharge chamber geometry on the discharge power value which is necessary for the melt warming up and its exposition at the certain temperature – the less are geometrical sizes of the chamber (diameter and height), the smaller is the power of the smoldering discharge which is required for ensuring necessary melt temperature. It is shown that at sufficient melt parts distance from the chamber walls, the voltage drop on the skeleton of the smoldering discharge can be tens volts that causes the decrease of cathodic falling potential and, respectively, the increase of the electric power which is required to maintain necessary melt temperature in comparison to melt which is as close as possible to chamber walls. It leads to the fact that at more dense loading, smaller specific consumption of the electric power to ensure the necessary depth of the nitrated layer is required; at the same time the specific energy consumptions by the melt temperature of 525–530 °C are 0.6–1.6 kW∙h/kg, depending on the loading extent of the chamber. It has been displayed that at ionic nitration, the value of working gas pressure must provide the deviance of the smoldering discharge i. e. the whole area the cathode –melt must be captured by the discharge luminescence.

Effect of halides on the solvation of poly(ethylene oxide) in the ionic liquid propylammonium nitrate

HypothesisThe solvation characteristics of poly(ethylene oxide) (PEO) in nanostructured protic ionic liquids (PILs) are driven by polymer-solvent interactions in the polar domains of the PIL. This work hypothesises that the nanostructure of a PIL can be altered via halide addition, directly affecting the solvation of PEO. ExperimentsSmall angle neutron scattering (SANS) is used to explore the conformation of 38 kDa PEO dissolved in the PIL propylammonium nitrate (PAN), a mol fraction of 10% propylammonium chloride (PACl) in PAN, and a mole fraction of 10% propylammonium bromide (PABr) in PAN. FindingsEach of these solutions are shown to behave as a good solvent for PEO, as determined by their Flory exponents and Zimm plot analysis. The quality of solvation is reduced by the addition of the halide salt, with the order of solvation as follows: PAN > Br− addition > Cl− addition. Our experimental observations are consistent with the recently reported solvation structure of PEO in these solutions (Stefanovic et al., 2018). The increased charge density from NO3− to Br− to Cl− results in greater net ionic interaction between the ionic charge centres. As PEO interacts with PAN primarily through the ammonium hydrogens of the cation, this increased ionic interaction effectively displaces the PEO, resulting in poorer solvation.

Redox reaction process between hydrocarbon and adsorbed NOx over lean NOx trap catalyst

In this study, we investigated the redox reaction between a hydrocarbon (HC) and adsorbed NOx over CuPtBa/Al2O3 lean NOx trap (LNT) catalyst. Experimental characterizations included temperature-programmed desorption (TPD), temperature-programmed reduction (TPR), in situ diffuse reflectance Fourier transform spectroscopy (in situ DRIFTs) and Raman spectroscopy. Density functional theory (DFT) calculations were also performed. The model C3H6 first adsorbed to the catalyst surface, and the resulting C3H6-adsorbed species reacted with adsorbed NOx species to form various intermediates such as: carboxylates, enolic compounds, carbonato complexes, Pt-carbonyls, acid anhydrides, basic hydroxyls, nitrogen-containing organic species, acyl chlorides, and ammonium salts. These intermediates participated in subsequent reactions and finally produced the effluent gases CO2, N2, NH3, and H2O. The decomposition ability of adsorbed NOx species indicated that the NOx species participated in the C3H6 oxidation in the order: adsorbed N2O4 > monodentate nitrates > free ionic nitrates > bulk free ionic nitrates. Carbonaceous materials were generated during the C3H6 oxidation process and were consumed as intermediates by gaseous NOx released upon decomposition of the adsorbed NOx species. In summary, the redox reaction between C3H6 and adsorbed NOx followed the Langmuir–Hinshelwood mechanism, and three reaction routes were proposed for the redox process over the studied catalyst. The activation energy barriers determined by DFT + U calculations for the three routes indicated that the initial dissociation of NO3− species in R(2) occurred more easily than the oxidation of C3H6 species in R(1), delivering the active oxygen species that participated in R(1) and R(3). As the reactions proceeded, the higher energy barrier for the complete dissociation of NO2* indicated that the temperature determined the further decomposition of adsorbed NOx species, and R(1) and R(3) were constrained owing to the limited surface active oxygen species from R(2).

Non-isothermal decomposition kinetics of pyridinium nitrate under nitrogen atmosphere

The thermal stability and decomposition kinetics of the ionic liquid pyridinium nitrate was investigated by non-isothermal thermogravimetric analysis in an inert atmosphere (nitrogen). For the kinetic experiments, the thermal behavior of the sample was studied in the temperature interval from 360 up to 600 K at different heating rates (5, 10, 15 and 20 K/min).The kinetic parameters of decomposition including activation energy and pre-exponential factor under nitrogen atmosphere were evaluated by menace of two model-free methods – Friedman and Kissinger-Akahira-Sunose. Depending on the used calculation model, the obtained activation energy and pre-exponential factor values with respect to the degree of sample conversion during the kinetic experiment for method ranged in the intervals of 76.36–112.56 kJ/mol and 1.72×105–1.42×1010 min–1, respectively. Based on the attained kinetic parameter values it was established that the process of pyridinium nitrate decomposition occurred as a first-order reaction. Considering the calculated kinetic parameters, a decomposition mechanism for pyridinium nitrate was proposed.