The properties of ammonium dinitramide (ADN): Part 1, basic properties and spectroscopic data

Abstract

Basic properties and spectroscopic data for the energetic oxidizer ADN (Ammonium dinitramide (NH₄N(NO₂)₂)) are presented. The ADN used for this work was synthesized by a new efficient and environmentally friendly method. The method is based on a direct nitration of salts of sulfamic acid by ordinary mixed acid, followed by neutralization and separation of the ADN by the use of an adsorption column. The heat of formation was measured by burning in hydrogen atmosphere in an adiabatic bomb calorimeter and was found to be 148 kJ/mole ±10 kJ/mole. The melting point was determined using DSC technique and is 93.5°C. This paper reports drop weight, friction and bullet impact sensitivity data. The friction sensitivity of ADN is much lower than that of RDX. The impact sensitivity of ADN is of the same magnitude as that of RDX but varies a great deal with the morphology of the particles, e. g. prilled ADN is nearly twice as insensitive as RDX. The bulk density measured by powder X-ray diffraction and was found to be 1.82 gcm^?3. ADN does not show any sign of phase transitions in the -150°C to +80°C temperature interval (measured by single crystal X-ray diffraction). FTIR and FT-Raman spectra are also presented. In the UV-VIS region, ADN is characterized by two absorption peaks at 214 and 284 nm. UV-VIS spectroscopy was also found to be the most useful method for quantitative routine analysis of ADN.     

The decomposition pathways of ammonium dinitramide on the basis of ab initio calculations

Quantum chemistry calculations incorporating solvent effects were used to investigate the decomposition pathways in molten Ammonium dinitramide (ADN). Optimized structures for reactants and products were obtained at the CBS-QB3//ωB97XD/6–311++G(d,p)/SCRF = (solvent = water) level of theory, considering the isomers ADN_I (NH₄–N(NO₂)₂) and ADN_II (NH₄–ON(O)NNO₂) and the four ADN_II conformers, which are minimal clusters of anion and cation in molten ADN. In the initial stage of decomposition, the ADN_II decomposes to NO₂? and NNO₂NH₄. Following the initial decomposition, NNO₂NH₄? decomposes to N₂O, NH₃, and OH?, and the OH? combines NO₂? to yield HNO₃. This decomposition can be written using one global formula: ADN → N₂O + NH₄NO₃ (NH₃ + HNO₃).     

Symmetry,Conjugated System,and N-oxides in 2,4,6-Trinitro-1,3,5-triazine-1,3,5-trioxides: A New Design Concept for Energetic Oxidizers

A new strategy for an energetic oxidizer, 2,4,6-trinitro-1,3,5-triazine-1,3,5-trioxides (TNTATO), was designed by keeping symmetry and conjugation and introducing N-oxides into 1,3,5-triazine. Molecular mechanics (MM) and density functional theory (DFT) were employed to study the crystal structure, infrared (IR) spectrum, electronic structure, thermodynamic properties, gas-phase and condensed-phase heats of formation, detonation performance, and burning rate of TNTATO. The pyrolysis mechanism and thermal stability were predicted by evaluating the bond dissociation energy (BDE) and activation energy. The calculated results indicate that TNTATO has a symmetric hyperconjugation structure, which contributes to its stability. The BDE (210.64 kJ/mol^?1) and activation energy (27.74 kJ/mol^?1) of the weakest bond C3–N8 show that the C–NO₂ bond is the trigger bond during thermolysis. The detonation velocity (8.51 km/s^?1) and detonation pressure (32.69 GPa) are larger than those of 2,4,6-trinitro-1,3,5-triazine (TNTA). TNTATO exhibits better burning properties than ammonium dinitramide (ADN), indicating that TNTATO may be a potential candidate for a highly energetic oxidizer.     

Preparation of Surfactant for Oil Displacing Refined from Furfural Extract Oil

Abstract

Petroleum sulfonate (PS) was prepared in an autoclave sulfonation reactor using HIV-400 furfural extract oil of Daqing Refinery as feedstock and oleum (120%) as sulfonation agent. The effects of synthesis conditions were studied, and the PS yield was 45.1% with 48.2% of active components under the following best synthesis technology conditions: acid–oil ratio of 0.45:1 and reaction temperature of 60°C. The interfacial tension between crude oil and the water phase was effectively reduced by adding the PS at low dosage, when it was compounded with sodium carbonate, the interfacial tension could be under 10^?3 mN/m, meeting the requirements of an oil-displacing surfactant.     

催化裂化烟气脱硫、脱氮吸附剂的初步研究

 在微型连续床式反应装置上,考察了催化裂化催化剂吸附烟气中 SO₂、NO_x的性能。当SO₂、NO_x的体积分数分别为1800和1900 μL/L、反应温度为220℃、微正压操作时,新鲜吸附剂90%的SO₂脱除率维持在140~200s,70%的NO_x脱除率维持在220~470s;吸附容量为11.4~16.2 mg/g。SO₂、NO_x与吸附剂以物理吸附和化学吸附方式相作用;吸附运转剂表面的S和N分别以SO^2-₄和 NO^-₃存在。     

Relative rates of CH3NO2, CH3ONO,and CH3ONO2 formation in the thermal reaction of NO2 with acetaldehyde and DI-T-butyl peroxide at low temperatures

Abstract

The relative yields of CH₃NO₂, CH₃ONO, and CH₃ONO₂ have been measured at five temperatures between 323 and 455 K above 300 torr of pressure. Kinetic modelling of the observed CH₃NO₂/(CH₃ONO + CH₃ONO₂) and CH₃ONO/CH₃ONO₂ ratios from this study and that of Phillips and Shaw (Ref. 5), with and without added NO, led to the rate constant for CH₃ + NO₂ → CH₃NO₂ (1), k₁ = 6.0x10¹² cc/mol-sec, and for CH₃O + NO₂ → CH₃ONO₂ (4), k₄ = 7.5x10¹² cc/mol-sec. The results of the modelling also indicate that the oxidation of CH₃NO by NO₂ accounts for a large fraction of CH₃NO₂ formed in the NO-added mixtures. The rate constant for this reaction is estimated to be k₂₅ ? 1.3×10⁹e^(-10,000/RT) cc/mol-sec. Combination of k₁ with the equilibrium constant for reaction (1) gives rise to the rate constant for the decomposition of CH₃NO₂, k_?1 = 1.3x10¹⁶e^(-60,050/RT) sec^?1.     

Synthesis,Characterization, and Thermal Decomposition of a New Energetic Salt 3-Amino-1,2,4-Triazole Dinitramide

A new energetic salt, 3-amino-1,2,4-triazole dinitramide (ATADN), was synthesized through the combination of 3-amino-1,2,4-triazole cation and oxygen-rich dinitramide anion. The structure of ATADN was confirmed by single-crystal X-ray diffraction, elemental analysis, Fourier transform infrared spectroscopy, ultraviolet–visible spectrometry, and nuclear magnetic resonance spectroscopy. The thermal stability of ATADN was studied using differential scanning calorimetry, thermogravimetric analysis (TG), and TG tandem infrared spectrum. The thermal decomposition kinetics parameter was also calculated using the differential thermal analysis data based on Kissinger’s method. Results indicated that ATADN exhibited resistance to thermal decompositions of up to 439 K, and a corresponding activation energy of E_a = 281.9 kJ·mol^?1. Moreover, its mechanical sensitivity and detonation properties were evaluated, which showed promising results for its potential application as a highly explosive compound.     

ZrO2-SiO2 AEROGEL SUPPORTED COBALT CATALYSTS FOR THE SYNTHESIS OF LONG-CHAIN HYDROCARBON FROM SYNGAS

ABSTRACT

The effect of support and preparation method on the texture, surface area, extent of reduction, H₂ desorption and Fischer-Tropsch synthesis(FTS) reaction properties of ZrO₂-SiO₂ aerogel supported cobalt-based catalysts was investigated. The results indicate that under the conditions that favor the formation of long-chain hydrocarbons, cobalt catalyzed FTS reaction appears to be structure sensitive. Support effects significantly influence the catalytic behavior. Cobalt catalyst supported on zirconia-coated silica aerogel leads to heavy products from syngas, in which case C5⁺ yield could reach 150g/Nm³(CO+H₂) under the optimal conditions (T=293K, P=2.0MPa, GHSV=500h^?1); cobalt catalyst supported on ZrO₂-SiO₂ mixed aerogel, however, was shown to produce middle distillate and the yield of C5-C₂₀ products for this catalyst is about 120g/NM³ (CO+H₂)     

Fischer-Tropsch synthesis in a slurry reactor in the presence of nanosized cobalt catalysts synthesized in situ in a hydrocarbon medium

Fischer-Tropsch synthesis in a slurry reactor at a pressure of 20 atm and a temperature of 220–300°C in the presence of 100Co : 2Pd : (5–50)Al₂O₃ and 100Co : 2Pd : (20–50)ZrO₂ (parts by weight) catalysts in situ synthesized in a hydrocarbon medium has been studied. The catalysts were prepared by the decomposition of cobalt salts and promoters in melted petroleum paraffin P-2 at 300°C and in situ reduced with hydrogen. It has been found that the nanocatalyst containing 20 parts by weight of ZrO₂ exhibits the highest activity in the Fischer-Tropsch synthesis and provides the yield of liquid products of 70 g/m³ at a CO conversion of 80%.     

The synthesis and characterization of methylene bisoxyamine CH2(-o-NH2)2 salts

Abstract

A large family of energetic salts were made using methylene bisoxyamine, CH₂(-o-NH₂)₂, a dibasic, geminal oxyamine of methane. Single salts including the nitrate, perchlorate, dinitramide, and nitroformate, and doubly protonated methylene bisoxyamine salts, nitrate, perchlorate and bisdinitramide, were all synthesized in good to high yields, from simple acid-base reactions with the corresponding aciforms of energetic anions. All of the salts were characterized by vibrational (IR, Raman), multinuclear nmr (¹H, ¹³C), and DSC studies. The single crystal X-ray diffraction study was carried out on the double perchlorate salt. Initial safety studies (impact and friction), were carried out on most of the new materials, as well as the thermal stability of these salts at 75°C.     

Catalytic Materials Based on Hydrotalcite-Like Aluminum,Magnesium, Nickel,and Cobalt Hydroxides for Partial Oxidation and Dry Reforming of Methane to Synthesis Gas

Partial oxidation of methane and dry methane reforming to synthesis gas in the presence of catalysts based on hydrotalcite-like hydroxo salts [AlMg₂Ni _x Co _y (OH)_6.08][(NO₃) _n H₂O], where x = 0, 0.02, 0.04 and y = 0, 0.02, 0.04 with a total Ni and/or Co content of no more than 2 wt % have been first studied. It has been shown that the Ni-containing catalysts provide a synthesis gas yield of 90 and 97% in the case of partial oxidation and dry reforming of methane, respectively; in the presence of these catalysts, a trace amount of carbon nanotubes is formed; the catalyst sample containing both nickel and cobalt does not lead to the formation of any carbon nanotubes during dry reforming of methane.     

Kinetics and mechanism of the thermal decomposition of dimethylnitramine at low temperatures

Abstract

Dimethylnitramine (DMNA) was pyrolyzed between 466 and 524 K at about 475 Torr pure DMNA pressure in static cells. A radical mechanism was proposed and computer-modeled to account for the disappearance of DMNA and the production of (CH₃)₂NNO and CH₃NO₂. The rate constant for DMNA decomposition into (CH₃)₂N and NO₂, based on these low-temperature results and other high-temperature shock tube data, covering 460–960 K, can be given by k₁ = 10^15.9±0.2 exp(?22,000±200/T) sec^?1. This result leads to values for the N-N bond energy of 43.3±0.5 kcal/mole and the heat of formation of the (CH₃)₂N radical, 35±2 kcal/mole at 298 K. Kinetic modeling of the CH₃NO₂ and (CH₃)₂NNO production profiles has been carried out.     

Magnetically Recyclable Cufe2o4 Nanoparticles as an Efficient and Reusable Catalyst for the Green Synthesis of 2,4,6,8,10,12-Hexabenzyl-2,4,6,8,10,12-hexaazaisowurtzitane as CL-20 Explosive Precursor

Magnetic nanoparticles of copper ferrite (CuFe₂O₄ MNPs) have been simply prepared and applied as an efficient recyclable and reusable catalyst for the green synthesis of 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.0^5,9.0^3,11]dodecane (HBIW). The structure of the synthesized pure HBIW (recrystallization from ethanol) was confirmed by using various spectral techniques like infrared (IR), ¹H-NMR, ¹³C-NMR and some of its physical properties. The prepared catalyst was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR). In addition, CuFe₂O₄ MNPs could be reused up to seven runs without any significant loss of activity. Finally, the remarkable advantages of this method are the simple experimental procedure, shorter reaction times, simple workup, and green aspects by avoiding toxic catalysts and high yield of product.     

Gas production from thermal decomposition of explosives: Assessing the thermal stabilities of energetic materials from gas production data

Abstract

The gas formation associated with the thermal decompositions of nineteen energetic materials was determined at three temperatures (120°C, 220°C and 320°C). Although there was considerable variability within classes, among the largest producers of gas were the nitrate esters. PETN (pentaerythritol nitrate) generated about 6.3mole gas per mole, while nitrocellulose, produced almost no gas. Second in gas production were the nitramines, followed by nitroarenes and lastly, energetic salts. NTO (5-nitro-2, 4-dihydro-3H-1, 2, 4-triazol-3-one), which does not fit into the four main classes of energetic materials, exhibited gas production (2.13 mole gas per mole NTO) comparable with some nitroarenes and the energetic salt, ammonium dinitramide (ADN). For selected compounds gas evolution data was used to construct first-order plots, from which Arrhenius parameters were determined and compared with previously reported values.     

The Effect of Metal Dispersion on Ni/Al2O3 Wax Hydrofining Catalyst

Abstract

Positron annihilation spectroscopy for chemical analysis (PASCA), powder x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) were used to study the effect of calcination temperature on active metal dispersion of wax hydrofining catalyst. The experimental results showed that, with the increase of calcination temperature, the metal Ni and the support Al₂O₃ interaction became weaker. When calcination temperature reached 280°C, Ni(NO₃)₂ began to decompose and the inhibition effect of NO₃ ^? began to diminish. At 380°C, Ni(NO₃)₂ was almost decomposed, and NiO still had a high dispersion on the catalyst surface. At 440°C or higher, Ni(NO₃)₂ was completely decomposed, and to some extent, NiO aggregated on the catalyst surface in the form of noncrystalline clusters (atomic clusters). The most suitable calcination temperature in the experiment for the catalyst Ni/Al₂O₃ was 440°C or a little higher.     

天然气脱硫装置吸收塔模拟及增产措施

目的 某天然气净化厂已完成过程气羰基硫(COS)水解的改造工作,解决了商品气中总硫含量超标的问题,但商品气中二氧化碳(CO₂)摩尔分数过低(约0.25%),严重制约了商品气产率的有效提升,探究合适的增产措施可实现企业的降本增效。方法 利用HYSYS流程模拟软件构建了该净化厂两级吸收塔模型,分析了吸收塔塔板数、溶液循环量及脱硫剂组成对天然气净化的影响规律,重点研究了对商品气中CO₂摩尔分数的影响规律。结果 (1)在不调整脱硫剂组成的前提下,减少两级吸收塔共5块塔板,同时,贫液和半富液循环量降至操作下限,商品气中硫化氢(H₂S)质量浓度不会超标,且CO₂摩尔分数可提升至0.87%;(2)在调整脱硫剂组成的前提下,减少两级吸收塔共5块塔板,同时,贫液和半富液循环量降至下限值运行,商品气中H₂S质量浓度仍不会超标,且CO₂摩尔分数可提升至2.47%。结论 对吸收塔模拟及增产措施的研究可指导该天然气净化厂的技改,提高商品气产率,为同类型大型高含硫天然气净化厂的技改优...     

Preparation and characterization of NaY zeolite in a rotating packed bed

NaY Zeolite was synthesized in a rotating packed bed (RPB) for the first time. A Si-Al gel with a specific composition was used as the structure-directing agent. The as-synthesized NaY Zeolite was characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD) and specific surface area (BET). The characterization result showed that the NaY Zeolite had a particle size of approximately 200 nm, n(Si02)/n(Al203) ratio of 5.03, crvstallinitv of 96% and specific surface area of 714 m2/g. The experimental results indicated that the structure of NaY Zeolite was related to the synthesis conditions (such as reactors, crvstalhzation time and so on). The micromixing efficiency was proven to be the most important factor for synthesis of NaY Zeolite in the high-gravity environment in RPB.     

Catalytic transformations of mixtures of ethers with aliphatic and aromatic nitriles on solid acids under supercritical conditions

The catalytic conversion of mixtures of ethers with aliphatic and aromatic nitriles in supercritical conditions on zeolites (HY, HCaREEY), individual oxides (Al₂O₃, SiO₂, MoO₃, WO₃, TiO₂), and oxide systems (Al₂O₃-SiO₂, H₈[Si(Mo₂O₇)₅], Al₂(WO₄)₃) has been studied. It has been found that acid catalysts, such as zeolites, mixed oxides, and TiO₂ (anatase), are active at 350°C in the direct synthesis of N-acylpyrrolidines from tetrahydrofuran and nitriles (CH₃CN, n-C₄H₉CN, C₆H₅CN): the product yield reaches 40% and the selectivity is 65–94%. The activity and selectivity of TiO₂ samples increase with an increase in the specific surface area (from 37 to 139 m²/g) or with a decrease in the particle size of anatase (from 43 to 13 nm according to XRD data). The character of interaction of the components of the reaction mixture with the TiO₂ surface has been studied by the TG-DTA technique. After oxidative regeneration, TiO₂ exhibits the initial catalytic properties, suggesting the possibility of its repeated use in the direct synthesis of acylpyrrolidines. Replacing THF by other compounds (diethyl ether, 1,4-dioxane, tetrahydropyran) drastically reduces the yield of respective alkylamides.     

Effect of methanol, ethanol, and formaldehyde addition on the steam conversion of methane in the presence of nickel catalysts of various porous structure

The effect of CH₂O, CH₃OH, and C₂H₅OH on the methane conversion and the CO, CO₂, and coke yield in the methane steam conversion on commercial nickel catalysts for steam reforming C 11-9-09 (12.8 wt % Ni/α-Al₂O₃) and hydrogenation (54.0 wt % Ni/kieselguhr) was studied at a temperature of 750°C and an H₂O:CH₄ ratio of 1.5–2.0. The action of these compounds was studied both individually and for their joint presence in the methane-steam mixture. Their effect on the reaction depends on the pore structure of the catalyst. Using the catalyst C 11-9-09 as an example, it was found that the introduction of formaldehyde into steam suppressed the methane conversion into C_s and high-boiling-point carbon compounds and gave the desired products with a yield close to the equilibrium value. When all three additives were present in the steam, ethanol was responsible for the formation of C_s.     

H6P2W18O62/MCM-48催化剂的制备、表征及催化绿色合成己二酸

以MCM-48为载体,通过浸渍法制备了H6P2W18O62/MCM-48催化剂,并采用FT-IR、XRD、SEM、EDS对催化剂进行表征。以微波促进30%(质量分数)H2O2氧化环己酮合成己二酸反应为探针,考察了H6P2W18O62/MCM-48的催化性能,并通过正交实验确定了优化的工艺条件。结果表明,采用H6P2W18O62负载量40%的H6P2W18O62/MCM-48催化剂,在优化的合成己二酸的工艺条件下,即催化剂质量分数(以环己酮质量计)5.1%、n(C6H10O)∶n(H2O2)∶n(H2C2O4.2H2O)=100∶450∶1.88、反应温度95℃、微波功率300 W、反应时间3.5h,己二酸收率可达81.3%;催化剂重复使用5次,己二酸收率仍可达到64.6%。