A simple, sensitive, and efficient method of using a pipette vial to perform dispersive liquid–liquid microextraction based on the solidification of floating organic droplets was coupled with high-performance liquid chromatography (HPLC) and a diode array detector for the preconcentration and analysis of four benzoylurea insecticides in fruit juice. In this method, 1-dodecanol was used as an extractant, and a snipped pipette was used as an experimental vial to simplify the procedure of collecting and separating solidified extractant. The experimental parameters were optimized using a Plackett–Burman design and one-factor-at-a-time method. Under the optimal conditions in the water model, the limits of detection for analytes varied from 0.03 to 0.28 μg/L, and the enrichment factors ranged from 147 to 206. Linearity was achieved for diflubenzuron and flufenoxuron in a range of 0.5–500 μg/L, for hexaflumuron in a range of 1–500 μg/L, and for triflumuron in a range of 5–500 μg/L. The correlation coefficients for the analytes ranged from 0.9986 to 0.9994 with recoveries of 91.4–110.9%. Finally, the developed technique was successfully applied to fruit juice samples with acceptable results. The relative standard deviations of the analytes at two spiking levels (50 and 200 μg/L) varied between 0.2 and 4.5%.

A planar energetic molecule with high density, 5,5′-dinitramino-3,3′-azo-1,2,4-oxadiazole (4), was obtained by the nitration of 5,5′-diamino-3,3′-azo-1,2,4-oxadiazole using 100 % nitric acid. In addition, selected nitrogen-rich salts were prepared. Of them, the neutral compound 4 and its hydroxylammonium salt, 6, were further confirmed by single-crystal X-ray diffraction. Physicochemical and energetic properties including density, thermal stability, and sensitivity were investigated. The energetic performance from the calculated heats of formation and experimental densities indicates that many of them have potential applications as energetic materials.

A planar energetic molecule with high density, 5,5′-dinitramino-3,3′-azo-1,2,4-oxadiazole (4), was obtained by the nitration of 5,5′-diamino-3,3′-azo-1,2,4-oxadiazole using 100 % nitric acid. In addition, selected nitrogen-rich salts were prepared. Of them, the neutral compound 4 and its hydroxylammonium salt, 6, were further confirmed by single-crystal X-ray diffraction. Physicochemical and energetic properties including density, thermal stability, and sensitivity were investigated. The energetic performance from the calculated heats of formation and experimental densities indicates that many of them have potential applications as energetic materials.

New derivatives of 1,1-diamino-2, 2-dinitroethene (FOX-7) are reported. These highly oxygen- and nitrogen-rich compounds were fully characterized using IR and multinuclear NMR spectroscopy, elemental analysis (EA), and differential scanning calorimetry (DSC). X-ray structure determination of (E)-1,2-bis{(E)-2-chloro-1-(chloroimino)-2,2-dinitroethyl}diazene) (10), N1, N2-dichloro-1, 2-diazenedicarboximidamide (11), and (E,E)-N,N′-1,2-ethanediylidenebis(2, 2-dinitro-2-chloro-ethanamine) (12) was helpful in their characterization. Heats of formation (HOF) were calculated (Gaussian 03) and combined with experimental densities to estimate the detonation velocities (D) and pressures (P) of the high-energy-density materials (HEDMs) (EXPLO5, v6.01). The compounds exhibit good thermal stability, high density, positive HOF, acceptable oxygen balances, and excellent detonation properties, which often are superior to that of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX).

New derivatives of 1,1-diamino-2, 2-dinitroethene (FOX-7) are reported. These highly oxygen- and nitrogen-rich compounds were fully characterized using IR and multinuclear NMR spectroscopy, elemental analysis (EA), and differential scanning calorimetry (DSC). X-ray structure determination of (E)-1,2-bis{(E)-2-chloro-1-(chloroimino)-2,2-dinitroethyl}diazene) (10), N1, N2-dichloro-1, 2-diazenedicarboximidamide (11), and (E,E)-N,N′-1,2-ethanediylidenebis(2, 2-dinitro-2-chloro-ethanamine) (12) was helpful in their characterization. Heats of formation (HOF) were calculated (Gaussian 03) and combined with experimental densities to estimate the detonation velocities (D) and pressures (P) of the high-energy-density materials (HEDMs) (EXPLO5, v6.01). The compounds exhibit good thermal stability, high density, positive HOF, acceptable oxygen balances, and excellent detonation properties, which often are superior to that of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX).

In this work, a novel liquid-phase microextraction approach using nonwoven polypropylene as the extraction solvent holder was developed. Nonwoven polypropylene, a hydrophobic material, is widely used in the cleanup of oil spills. Due to its large surface area, efficient, and full extraction can be achieved. Nonwoven polypropylene containing an ionic liquid was used to extract benzoylurea insecticides (diflubenzuron, teflubenzuron, flufenoxuron, and chlorfluazuron) through vortex-assisted liquid–liquid microextraction. The parameters that affected the extraction efficiency included the type and volume of the extractant, the extraction time, the time and solvent volume for desorption and the mass and surface area of the nonwoven polypropylene. Under the optimized conditions, good linearity was obtained, with coefficients of determination greater than 0.9996, and the limit of detections of these compounds, calculated at S/N = 3, were in the range of 0.73–5.0 ng/mL. The recoveries of the four insecticides at two spiked levels ranged from 93.3 to 102.0%, with relative standard deviations of less than 4.0%. The proposed method was then successfully used for the rapid determination of benzoylurea insecticides in spiked real water samples before liquid chromatographic analysis. The procedure is simple, inexpensive, easy to execute, and can be widely used.

In propellant systems, fuels of choice continue to be hydrazine and its derivatives, even though they comprise a class of acutely carcinogenic and toxic substances which exhibit rather high vapor pressures and require expensive handling procedures and costly safety precautions. Hypergolic ionic liquids tend to have low volatility and high thermal and chemical stability, and often exhibit wide liquid ranges, which could allow the use of these substances as bipropellant fuels under a variety of conditions. A new family of borohydride ionic liquids and borane–ionic-liquid solutions is described which meets nearly all of the desired important criteria for well-performing fuels. They exhibit ignition-delay times that are superior to that of any known hypergolic ionic liquid and may thus be legitimate replacements for hydrazine and its derivatives.

In propellant systems, fuels of choice continue to be hydrazine and its derivatives, even though they comprise a class of acutely carcinogenic and toxic substances which exhibit rather high vapor pressures and require expensive handling procedures and costly safety precautions. Hypergolic ionic liquids tend to have low volatility and high thermal and chemical stability, and often exhibit wide liquid ranges, which could allow the use of these substances as bipropellant fuels under a variety of conditions. A new family of borohydride ionic liquids and borane–ionic-liquid solutions is described which meets nearly all of the desired important criteria for well-performing fuels. They exhibit ignition-delay times that are superior to that of any known hypergolic ionic liquid and may thus be legitimate replacements for hydrazine and its derivatives.

An ultrasound-enhanced in situ solvent formation microextraction has been developed first time and compared with ultrasound-enhanced ionic-liquid-assisted dispersive liquid–liquid microextraction for the HPLC analysis of acaricides in environmental water samples. A ionic liquid ([C₈MIM][PF₆]) was used as the green extraction solvent through two pathways. The experimental parameters, such as the type and volume of both of the extraction solvent disperser solvent, ultrasonication time, and salt addition, were investigated and optimized. The analytical performance using the optimized conditions proved the feasibility of the developed methods for the quantitation of trace levels of acaricides by obtaining limits of detection that range from 0.54 to 3.68 μg/L. The in situ solvent formation microextraction method possesses more positive characteristics than the ionic-liquid-assisted dispersive liquid–liquid microextraction method (except for spirodiclofen determination) when comparing the validation parameters. Both methods were successfully applied to determining acaricides in real water samples.

In this study, ionic liquid (IL) supported magnetic dispersive solid-phase microextraction was developed and a systematic investigation was conducted on imidazolium ILs for their extraction performance. This nano-based pretreatment procedure was then applied for the determination of acaricides in fruit juice samples for the first time. A feature of this technique is that the commonly laborious chemical modification of magnetic nanoparticles (MNPs) was skillfully circumvented. Because of the combination of ILs, dispersive liquid–liquid microextraction, and dispersive MNP solid-phase microextraction, the extraction efficiency can be significantly improved using commercial MNPs. Parameters of the extraction method were investigated by one-factor-at-a-time approach. The optimal experimental conditions were as follows: emulsification for 2 min by sonication with the addition of 50 μL [C₆MIM][NTf₂] in the dispersive liquid–liquid microextraction step and vortexing for 90 s after adding 40 mg spherical barium ferrite nanoparticles (20 nm). The desorption time was 2 min. Good linearity (0.5–500 ng/mL) and detection limits within the range of 0.05–0.53 ng/mL were achieved. The application of the proposed method was demonstrated by the analysis of real fruit juice samples, in which recoveries between 85.1 and 99.6% were obtained.

A dispersive liquid–liquid microextraction (DLLME) method using in situ halide exchange reaction to form ionic liquid (IL) extraction phase was developed to determine four insecticides (i.e. methoxyfenozide, tetrachlorvinphos, thiamethoxam, and diafenthiuron) in water samples. The preconcentration procedure, followed by high-performance liquid chromatography and variable wavelength detectors (VWD), enabled the formation of the immiscible IL extraction phase; the insecticides were transferred into the IL phase simultaneously, which enhanced the efficiency and sufficiency, greatly shortening the operation time. The experimental parameters affecting the extraction efficiency including volume of extraction IL, extraction and centrifugation times, volume of the sample solution and exchanging reagent, and addition of organic solvent and salt were investigated and optimized. Under optimized conditions, the extractions yielded recoveries of the target analytes from 82 to 102%. The calibration curves were linear, and the correlation coefficient ranged from 0.9990 to 0.9999 under the concentration levels of 5–200 μg/L. The relative standard deviation (n=6) was 2.9–4.6%. The limits of detection (LODs) for the four insecticides were between 0.98 and 2.54 μg/L.

Synthesis, characterization, and thermolysis studies of 1-amino-1-hydrazino-2,2-dinitroethene (2) and salts thereof are reported. These compounds have been fully characterized by IR and NMR spectroscopy, elemental analysis, differential scanning calorimetry (DSC), density, and impact sensitivity measurements. Compound 2 decomposes at 124.5 °C (DSC) and the salts decompose over the range 138.6–181.6 °C, thus showing higher thermostability. The calculated detonation pressures (P) for these salts range from 27.2 to 37.8 GPa, and detonation velocities (vD) fall between 8424 to 9482 m s⁻¹; these properties make them competitive energetic materials.