Potassium Picrate Research Articles

Seeking forensic evidence of preparation routes to 2,4,6-trinitrophenol

ABSTRACT The explosive 2,4,6-trinitrophenol (picric acid) was prepared by five different methods using laboratory-grade chemicals as well as consumer-available chemicals in order to establish background forensic information. Nitrate sources were altered by using three concentrations of nitric acid or nitrate salts; an over-the-counter source of sulfuric acid was also investigated. Recovered products were identified using spectroscopic and thermal techniques. Impurities caused by over-the-counter starting materials were carried throughout the synthesis process to the crude recovered products and were detected by infrared and Raman spectroscopy and differential scanning calorimetry. In cases where nitrate salts were used; potassium picrate was recovered.

The Combined Effect of Ambient Conditions and Diluting Salt on the Degradation of Picric Acid: An In Situ DRIFT Study.

An unexpected promoting effect of KBr, used as a diluting salt, on the degradation of picric acid (PA) was observed during in situ diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy experiments performed here under accelerated ageing conditions—at 80 °C and under an inert or oxidative atmosphere. While the formation of potassium picrate was excluded, this promoting effect—which is undesired as it masks the possible effects of test conditions on the ageing process of the material—was assumed to favor a first step of the decomposition mechanism of PA, which involves the inter- or intramolecular transfer of hydrogen to the nitro group, and possibly proceeds up to the formation of an amino group. An alternative diluting salt, ZnSe, which is much less commonly used in infrared spectroscopy than KBr, was then proposed in order to avoid misleading interpretation of the results. ZnSe was found to act as a truly inert diluting salt, preventing the promoting effect of KBr. The much more chemically inert nature (towards PA) of ZnSe compared to KBr was also confirmed, at much higher temperatures than DRIFT experiments, by dynamic differential scanning calorimetry (DSC) runs carried out on pure PA (i.e., PA without salt) and PA/salt (ZnSe or KBr) solid mixtures.

Energetic and magnetic directional aggregation properties of KPA@Fe3O4 composite particles prepared via a microcrystalline co-precipitation route

The development of new electromagnetic interference materials has attracted much attention in the information warfare. Herein, a novel KPA@ composite particle was synthesized via a microcrystalline co-precipitation method. X-ray diffractions, scanning electron microscopes and vibrating sample magnetometer measurements were used to characterize the products. The results indicated that the surface of the potassium picrate (KPA) crystals was covered by magnetic nanoparticles, and composite particles exhibited excellent magnetic properties. Furthermore, the thermal behavior of the composite particles was investigated by differential scanning calorimetry, which showed that the composite particles inherited the energetic property of pure KPA crystals when the mass fraction of magnetic component was 50%, or 65%. As for the composite particles with 75% magnetic component, the thermal stability of was poor. In addition, the magnetic directional aggregation performance of composite particles was analyzed by dynamic simulation, which moved toward the magnetic source. For the composite particles with 50% magnetic component, the maximum concentration was about 63 times of the initial concentration, and the peak velocity was 0.63 m s−1. With the mass fraction of magnetic component increasing to 65%, the concentration and velocity of the composite particles generally increased at the corresponding moment. As the mass fraction of magnetic component increased to 75%, the change of them was not obvious. Therefore, the composite particles with /KPA mass ratios of 65/35 had the best comprehensive properties. The excellent energetic and magnetic directional aggregation properties can allow the composites to be used in many potential applications in the information warfare.

ИССЛЕДОВАНИЕ ФАКТОРОВ, СПОСОБСТВУЮЩИХ НЕCАНКЦИОНИРОВАННОМУ ИНИЦИИРОВАНИЮ ЭНЕРГОНАСЫЩЕННЫХ МАТЕРИАЛОВ

The results of experimental studies on the initiation of compositions containing energy-saturated materials by high-current electron beams and electrodischarge plasma are presented. Experimental studies simulate the effects on energy-saturated materials of electromagnetic fields of natural and man-made origin. The threshold voltage of the electrical breakdown of the compositions during a high-voltage electric discharge was determined and the possibility of initiation of the compositions by high-current electron beams of nanosecond duration using a pulsed high-current electron accelerator GKVI-300 was studied. Four compositions were selected as objects of study: a composition based on potassium picrate, a composition containing ammonium perchlorate, a composition based on lead minium with zirconium and colloxylin additives, and ballistite composition SBK-3. It is shown in the work that the initiation of compositions by a high-current electron beam is potentially possible only for compositions with low ignition temperatures, ignition of compositions with high ignition temperatures is possible due to the introduction of a powdery nanoscale additive, particles of which have specific heat less than particles of an energy-saturated material, and ignition of ammonium perchlorate is possible only if the particles of the additive have lower thermal conductivity than the particles of perchlorate ammonium.

Photophysical and antimicrobial properties of new double-armed benzo-15-crown-5 ligands and complexes

New double-armed crown ether ligands linked to pyridine derivatives have been synthesized and characterized. These macrocyclic ligands (1–5) have been synthesized by the reactions of 4′,5′-bis(bromomethyl)benzo-15-crown-5 with 3-hydroxy pyridine derivatives. A series of Na+, K+ and Ag+ complexes (1a–5a, 1b–5b and 1c–5c) of the macrocyclic ligands have been prepared from sodium perchlorate, sodium picrate, potassium iodide, potassium picrate and silver nitrate salts, respectively. The most suitable cation Na+ is bound to the 15-crown-5 cavity and 1:1 “filling complexes” are formed (1a–5a) while the K+ cation interacts with the crown ether cavity and forms sandwich-type complexes (1b–5b). The Ag+ complexes (1c–5c) have been obtained with a pyridine moiety of the new crown ethers. New ligands undergo photophysical changes when bonding the cation. The influence of metal cations such as Na+, Li+, K+, Fe3+, Cu2+, Ca2+, Ba2+ and Al3+ on the spectroscopic properties of the pyridine linked to the double-armed crown ether moiety was investigated in EtOH solution by means of absorption and emission spectrometry. The prepared compounds (1–5, 1a–5a, 1b–5b and 1c–5c) were evaluated for antibacterial and antifungal activities against pathogenic microorganisms. The results show that the antimicrobial activity of the synthesized compounds varying a degree of inhibitory effects on the growth of different tested pathogenic strains.

Sensitivity of energy-packed compounds based on superfine and nanoporous silicon to pulsed electrical treatments

The sensitivity of an energy-packed compound based on nanoporous silicon and calcium perchlorate to a high-current electron beam is studied. The initiation of explosive transformations in a mixture of potassium picrate with a highly dispersed powder of boron-doped silicon by means of a high-voltage discharge is examined. It is shown that explosive transformation modes (combustion and explosion) appear in the energy-packed compound under study upon its treatment with an electron beam. A relationship is established between the explosive transformation modes and the density of the energy-packed compound and between the breakdown (initiation) voltage and the mass fraction of the silicon powder.

Initiation of combustion in multilayer energetic compositions with a high-current electron beam

Experimental results on the ignition of energetic two- and three-layer potassium picrate- and lead(II, IV) oxide-based compositions with a high-current electron beam of nanosecond duration are reported. It is shown that the sustainability of explosive transformations in layered compositions depends on the boundary conditions and the additional impact of the cathode flame (high-temperature metal plasma).

Radiolysis of Potassium Picrate in 77 K

The formation of paramagnetic centers in potassium picrate under irradiation at low temperature was investigated. The heating irradiated at 77 K potassium picrate crystal to room temperature results in paramagnetic centers - 2,6-dinitro-para-quinone radicals, ortho- and para-iminoxyl radicals and atomic oxygen. These products are formed under irradiation at room temperature.

Initiation of layered high-energy material compositions by nanosecond high-current electron beams

We present the results of experiments on the initiation of ignition by high-current electron beams of nanosecond duration in high-energy compositions representing layers based on potassium picrate and red lead. Successful initiation of the compositions containing potassium picrate has been achieved for the first time.

The comparison of the dissociation constants of ionophores in solutions as obtained by conductometric and spectrophotometric methods

Communication is devoted to the comparison of ionic association constants determined by the conductance and spectrophotometry methods. The results obtained with various picrates, especially with potassium picrate in organic solvents, in particular ketones, have been compared and discussed. Basing on the literature data as well as on our own measurements, a conclusion has been made about the absence of systematic difference between the association constant values determined by conductance and spectrophotometry in the considered systems.

Particle refinement and graphene doping effects on thermal properties of potassium picrate

The ultrafine potassium picrate (KPA) was prepared under the action of crystalline controlling agent and modified by graphene. KPA, ultrafine FKPA, and graphene-doped GKPA were studied by the particle size analysis, DPTA, DSC, and thermal sensitivity tests. The particle size arranged in an increasing order is FKPA < GKPA < KPA. The kinetic and thermodynamic parameters of thermal decomposition are ranked as FKPA < GKPA < KPA. The results indicate that the particle refinement increases the thermal sensitivity, because the ultrafine particles have large surface area and high surface bonding energy which endow them with high reaction activity. The doped-graphene nanoparticles with larger surface area partly hinder the effective collisions of KPA particles and accelerate the heat dispersion. Thus, the graphene doping improves the thermal stability, while still preserving the ultrafine size. GKPA has better thermal stability than FKPA and higher thermal sensitivity than KPA.

Temperature-dependent IR spectroscopic and structural study of 18-crown-6 chelating ligand in the complexation with sodium surfactant salts and potassium picrate

18-crown-6 ether (18C6) complexes with the following anionic surfactants: sodium n-dodecylsulfate (18C6-NaDS), sodium 4-(1-pentylheptyl)benzenesulfonate (18C6-NaDBS); and potassium picrate (18C6-KP) were synthesized and studied in terms of their thermal and structural properties. Physico-chemical properties of new solid 1:1 coordination complexes were characterized by infrared (IR) spectroscopy, thermogravimetry and differential thermal analysis, differential scanning calorimetry, X-ray diffraction and microscopic observations. The strength of coordination between Na+ and oxygen atoms of 18C6 ligand does not depend on anionic part of the surfactant, as established by thermodynamical parameters obtained by temperature-dependent IR spectroscopy. Each of these complexes exhibit different kinds of endothermic transitions in heating scan. Diffraction maxima obtained by SAXS and WAXS, refer the behavior of the compounds 18C6-NaDS and 18C6-NaDBS as smectic liquid crystalline. Distortion of 18C6-NaDS and 18C6-KP complexes occurs in two steps. Temperature of the decomplexation of solid crystal complex 18C6-KP is considerably higher than of mesophase complexes, 18C6-NaDS, and 18C6-NaDBS. The structural and liquid crystalline properties of novel 18-crown-ether complexes are function of anionic molecule geometry, type of chosen cation (Na+, K+), as well as architecture of self-organized aggregates. A good combination of crown ether unit and amphiphile may provide a possibility for preparing new functionalized materials, opening the research field of ion complexation and of host–guest type behavior.

Synthesis and structure analysis of sandwich complexes of potassium and cesium with benzo-15-crown-5 derivatives

Two novel alkali cation sandwich complexes have been constructed by reaction of potassium and cesium picrate with double-armed benzo-15-crown-5 ether 1. Crystals of the K+Pic−2(B15C5) and Cs+Pic−2(B15C5) complexes (Mr = 1339.81, 2865.23) are all yellow prisms which belong to the orthorhombic space group Pna2(1) with a = 25.757(5), b = 12.927(3), c = 37.507(8) A and a = 25.905(7), b = 12.998(3), c = 39.036(10) A, Z = 8 and 8 respectively. The every K and Cs cation are 11 and 12-coordinate involving ten crown oxygens [K–O, 2.742(3)–3.031(3) A, Cs–O, 3.029(9)–3.271(7) A], one crown carbon for K (K–C, 3.533(5) or 3.496(5)), two crown carbons for Cs (Cs–C, 3.658(10), 3.682(10) or 3.665(13), 3.705(14)). Metal cation had no interaction with picrate. Intermolecular C–H–O hydrogen bonds and π–π face-to-face stacking interactions help to consolidate the crystal packing.

Design, Synthesis and Characterisation of Guanosine-Based Amphiphiles

A small library of sugar-modified guanosine derivatives has been prepared, starting from a common intermediate, fully protected on the nucleobase. Insertion of myristoyl chains and of diverse hydrophilic groups, such as an oligoethylene glycol, an amino acid or a disaccharide chain, connected through in vivo reversible ester linkages, or of a charged functional group provided different examples of amphiphilic guanosine analogues, named G1-G7 herein. All of the sugar-modified derivatives were positive in the potassium picrate test, showing an ability to form G-tetrads. CD spectra demonstrated that, as dilute solutions in CHCl(3), distinctive G-quadruplex systems may be formed, with spatial organisations dependent upon the structural modifications. Two compounds, G1 and G2, proved to be good low-molecular-weight organogelators in polar organic solvents, such as methanol, ethanol and acetonitrile. Ion transportation experiments through phospholipid bilayers were carried out to evaluate their ability to mediate H(+) transportation, with G5 showing the highest activity within the investigated series. Moreover, G3 and G5 exhibited a significant cytotoxic profile against human MCF-7 cancer cells in in vitro bioassays.

Manganese(III)-Assisted Specific Intramolecular Addition

Oligomethylene-tethered ω-alkenyl 3-oxobutanoates and 3-oxobutanamides underwent manganese(III)-mediated oxidative intramolecular addition to produce dihydrofuran-fused macrolides and macrocyclic amides from 8 to 26 members. A similar reaction of the oligooxamethylene-tethered ω-alkenyl 3-oxobutanoates also gave dihydrofuran-fused crown ether type macrolides which had a phase-transfer ability with sodium and potassium pi-crates. The manganese(III)-assisted specific intramolecular addition could be explained by the π-complexation of the ω-alkenyl part with the manganese(III) enolate.

Conductometric and spectroscopic studies of the ion-pair association of sodium and potassium picrate in 2-butanone

The specific conductance of different concentrations of both sodium picrate and potassium picrate in 2-butanone have been measured experimentally at 298 K. The conductance data were analyzed by applying the Lee–Wheaton conductance equation where the molar conductance, the limiting molar conductance and the ion-pair association constant K A (cond) were calculated, and discussed. Also the spectra of solutions of both sodium picrate and potassium picrate in 2-butanone at 298 K in the range of 330–450 nm have been measured as a function of salt concentration and in the presence of added sodium tetraphenylborate. The spectrum of tetran-butylammonium picrate has also been measured. The spectra are consistent with two species being present in sodium picrate and potassium picrate solutions, the free ions and ion pairs. From the spectroscopic measurements, the ion-pair association constant of both sodium picrate and potassium picrate have been calculated and discussed. Values of the ion-pair association constant obtained from spectroscopic study are significantly larger than the value obtained from conductance measurements. The possible significance of the observations that K A (spec) > K A (cond) for the systems under investigation in 2-butanone is discussed.

Molecular Recognition of Redox-Switchable Bis-Crown Moieties Assembled on a Dicobalt Complex

A new dinuclear complex of cobalt(III) having double bis-crown moieties (1) was synthesized in a one-pot multistep reaction between the dinucleating ligand (H(2)L(1)), Co(OAc)(2) x 4 H(2)O, and 4'-aminomethylbenzo-15-crown 5-ether under aerobic conditions. The complex was characterized by UV-vis, IR, NMR, and CSI-mass spectroscopies, and the axial coordination of the 4'-aminomethylbenzo-15-crown 5-ether on both cobalt centers was confirmed. The bis-crown moieties of 1 acted as a potassium ion binding site with a large association constant (K) of 1.97 x 10(5) M(-1) (1:1) caused by the preorganized bis-crown structure. Solvent extraction of K(+) (potassium picrate) with 1 was investigated by UV-vis and NMR, and the extracted K(+) was quantified by an atomic absorption/flame emission spectrophotometer. The cyclic voltammogram of 1 showed irreversible redox waves at -0.57 V and +0.16 V versus Ag/AgCl in DMF, which are ascribed to the Co(III) and Co(II) redox couple. The large peak separation (Delta0.73 V) of this redox couple indicates the association and dissociation of the axial amine on the cobalt centers. The irreversible reduction peak of 1 at -0.57 V was shifted in the positive direction by 80 mV in the presence of the potassium ion, showing the complexation of 1 with the potassium ion. The reversible formation and decomposition of the double bis-crown moieties in 1 caused by the electrical stimulus were also investigated by thin-layer UV-vis spectroelectrochemistry. The switching of the double bis-crown structure of 1 was established over four trials with response to electrical energy.

Synthesis, extraction, and transport properties of dibenzo-18-crown-6 modified with the fragments of 2-amino-1,3,4-thiadiazol and kojic acid

New heterocyclic derivatives of dibenzo-18-crown-6 (DB18C6), the products of coupling of kojic acid (5-hydroxy-2-hydroxymethyl-γ-pyrone) with 4′-DB18C6-yldiazonium chloride, 4′,4″-and 4′,5″-DB18C6-diyldiazonium dichlorides and products of heterocyclization of DB18C6 mono-and dicarboxylic acids with thiosemicarbazide are prepared. Their structures are studied by the methods of 1H NMR and IR spectroscopy. Polyphosphoric acid is found to be the best agent for the heterocyclization of thiosemicarbazide with DB18C6 carboxylic derivatives. It is proven that the parent substrates, the DB18C6 mono or dicarboxylic acids, serve as phase transfer catalysts for the heterocyclization reaction. Extraction and transport properties of the obtained compounds in respect of potassium, sodium and ammonium picrates are explored.

Synthesis and Extraction Studies of Some New Anionic Dye Extractors

A new series of dodecyl derivatives of non‐cyclic and cyclic ethers, as the extractors have been synthesized by imination, reduction of imines and cyclization steps, and the structures were identified by FT‐IR, 1H‐NMR, 13C‐NMR and mass spectroscopy. The extractions abilities of these ligands with some anionic dyes [4‐(2‐pyridylazo)‐resorcinol monosodium salt monohydrate (NaPAR), and sodium picrate (NaPIC), and potassium picrate (KPIC)] were determined by UV‐VIS spectrophotometry using liquid‐liquid extraction method. In this study, all of the synthesized ligands were generally showed higher extraction ability for Na‐dyes.

Solubilities and enthalpies of solution of picric acid and picrates at 298.15 K in DMF, EtOH and acetic acid

The enthalpies of solution of picric acid (PA) in DMF, EtOH and HOAc, potassium picrate (KPA) and Pb(PA) 2·H 2O (lead picrate) in DMF have been determined by a calorimeter at 298.15 K. In addition, the solubilities of PA, KPA and Pb(PA) 2·H 2O in the solvents of DMF, EtOH, HOAc and H 2O are measured.