Rapid Thermolysis Studies of [Pb2（TNR）2（CHZ）2（H2O）2]·4H2O and Cd（CHZ）2（TNR）（H2O）

T-jump/FT-IR spectroscopy was used to study the rapid thermal decomposition activity of [Pb2（TNR）2（CHZ）2（H2O）2]·4H2O and Cd（CHZ）2（TNR）（H2O） under 0.1 MPa Ar atmosphere. The results show that the main gaseous products of [Pb2（TNR）2（CHZ）2（H2O）2]·4H2O are NH3, H2O and HONO, while CO and NO are the major gaseous products of flash pyrolysis of Cd（CHZ）2（TNR）（H2O）. Thus Cd（CHZ）2（TNR）（H2O） is not an eco-friendly and chemically compatible primary explosive. Both compounds liberate volatile metal carbonate, oxide and isocyanate compounds. The combustion temperature and products of the two compounds were calculated by Real code. The results of theoretical calculation show that the combustion temperature of [Pb2（TNR）2（CHZ）2（H2O）2].4H2O is higher than that of Cd（CHZ）2（TNR）（H2O）, there is no HNCO in the combus- tion products and the amount of NO is less than the experiment result from T-jump/FTIR.     

Thermal Decomposition of Ammonium 3-Nitro-1,2,4-triazol-5-onate Monohydrate

The thermal decomposition of ammonium 3-nitro-1,2,4-triazol-5-onate monohydrate[NH4（NTO）·H2O] was studied by means of thermal analysis-MS coupling and the combination technique of in situ thermolysis cell with rapid-scan Fourier transform infrared spectroscopy. The results show that there are two endothermic steps and one exothermic step in the decomposition process of NH4（NTO）·H2O. The detected gas products consist of NH3, H2O, N2, CO2, CO, and NO2.     

Influence of NO on the Reduction of NO2 with CO over Pt/SiO2 in the Presence of O2

Reduction of NO2 with CO in the presence of NO and excess oxygen, a model mixture for flue gas, over a 0.1% Pt/SiO2 catalyst was studied. The related reaction mechanisms, such as oxidation of CO and NO, were discussed. It was found that there was a narrow temperature window （180-190 ℃） for the reduction of NO2 by CO. When the temperature was lower than the lower limit of the window, the reduction hardly occurred, while when the temperature was higher than the upper limit of the window, the direct oxidation of CO by O2 occurred and thereby NO2 could not be effectively reduced by CO. The presence of NO shifted the window to higher temperatures owing to the inhibition effect of NO on the activation of O2 on Pt, which made it possible to reduce NO2 by CO in flue gas.     

Effects of Temperature and Catalyst to Oil Weight Ratio on the Catalytic Conversion of Heavy Oil to Propylene Using ZSM-5 and USY Catalysts

It is useful for practical operation to study the rules of production of propylene by the catalytic conversion of heavy oil in FCC (fluid catalytic cracking). The effects of temperature and C/O ratio (catalyst to oil weight ratio) on the distribution of the product and the yield of propylene were investigated on a micro reactor unit with two model catalysts, namely ZSM-5/Al2O3 and USY/Al2O3, and Fushun vacuum gas oil (VGO) was used as the feedstock. The conversion of heavy oil over ZSM-5 catalyst can be comparable to that of USY catalyst at high temperature and high C/O ratio. The rate of conversion of heavy oil using the ZSM-5 equilibrium catalyst is lower compared with the USY equilibrium catalyst under the general FCC conditions and this can be attributed to the poor steam ability of the ZSM-5 equilibrium catalyst. The difference in pore topologies of USY and ZSM-5 is the reason why the principal products for the above two catalysts is different, namely gasoline and liquid petroleum gas (LPG), repspectively. So the LPG selectivity, especially the propylene selectivity, may decline if USY is added into the FCC catalyst for maximizing the production of propylene. Increasing the C/O ratio is the most economical method for the increase of LPG yield than the increase of the temperature of the two model catalysts, because the loss of light oil is less in the former case. There is an inverse correlation between HTC (hydrogen transfer coefficient) and the yield of propylene, and restricting the hydrogen transfer reaction is the more important measure in increasing the yield of propylene of the ZSM-5 catalyst. The ethylene yield of ZSM-5/Al2O3 is higher, but the gaseous side products with low value are not enhanced when ZSM-5 catalyst is used. Moreover, for LPG and the end products, dry gas and coke, their ranges of reaction conditions to which their yields are dependent are different, and that of end products is more severe than that of LPG. So it is clear that maximizing LPG and propylene and restricting dry gas and coke can be both achieved via increasing the severity of reaction conditions among the range of reaction conditions which LPG yield is sensitive to.     

高氯酸三碳酰肼合镉快速热解反应动力学的研究

The Temperature-jump/FTIR （T-jump/FTIR） spectroscopy was introduced to resolve the decomposition kinetics parameters of [Cd（CHZ）3]（ClO4）2 （CdCP） at high temperature following very rapid heating process. The increase in the absorbances during the flash pyrolysis of CdCP yielded the kinetics parameters in the range of 360-430 ℃ at 0.1 MPa Ar atmosphere： Ea=28.6 kJ/mol and In A= 17. The kinetics parameters of the exothermic decomposition reaction were also determined by using DSC method. The value of Ea determined by T-jump/FTIR spectroscopy is smaller than that by Kissinger method and Ozawa-Doyle method, which makes these values qualitatively consistent with other energetic materials. The T-jump/FTIR spectroscopy might be resembled as the surface of explosion reaction very closely. In addition, the decomposition kinetics of evolution of the major four individual gas products was also resolved by T-jump/FTIR spectroscopy, which might be essential for detailed combustion modeling of solid energetic materials.     

Pyrolysis Process of Plant Fibers北大核心CSCD

The natural plant fiber has a large molecular weight and complex structure and composition,and its thermal cracking products and the composition distribution are also more complex. The fast pyrolysiscomprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry（Py-GC×GC-TOF/MS）,thermogravimetry-Fourier transform infrared spectroscopy（TG-FT-IR）,and in situ Fourier transform infrared spectroscopy（in situ FT-IR）methods were used to study the thermal pyrolysis process of six different natural fibers. The distribution of thermal pyrolysis products of different fibers under different pyrolysis temperatures was investigated and the product form was fully discussed. The research results show that the products of fiber pyrolysis mainly include alcohols,aldehydes,ketones,acids,esters,hydrocarbons, dehydrated sugars and CO2,etc. The types of pyrolysis products of different natural plant fibers are obviously different,and the main product types obtained are all different. At the same time,the results of in situ infrared spectroscopy and mass spectrometry show that pyrolysis products are closely related to the pyrolysis temperature. The results of in situ infrared experiments show that when the pyrolysis temperature is lower than 100 °C,the adsorbed water on the surface of the fiber structure is desorbed,but the fiber structure does not change significantly. When the pyrolysis temperature range is 100~200 °C,the temperature has little effect toward the pyrolysis process. When the temperature exceeds 300 °C,the fiber pyrolysis reaction intensifies and the surface structure changes significantly,and the main products are aldehydes and ketones. © 2022, Science Press (China). All rights reserved.     

Single iron sites for catalytic,nonoxidative conversion of methane

<正>The availability of inexpensive natural gas from the fracturing of shale and as a byproduct of oil production has stimulated the investigation of catalytic processes for the direct conversion of methane to products.Efforts in this direction are further driven by the desire to avoid the generation of CO2 and its emission to the atmosphere,as occurs when methane is steam-reformed to produce synthesis gas,a mixture of CO and H2 that can be used for the production of fuels and chemicals via Fischer-Tropsch synthesis.Dur-     

Nitrogen-doped graphene as an excellent candidate for selective gas sensing

The toxic gases,such as CO and NO,are highly dangerous to human health and even cause the death of person and animals in a tiny amount.Therefore,it is very necessary to develop the toxic gas sensors that can instantly monitor these gases.In this work,we have used the first-principles calculations to investigate adsorption of gases on defective graphene nanosheets to seek a suitable material for CO sensing.Result indicates that the vancancy graphene can not selectivly sense CO from air,because O2 in air would disturb the sensing signals of graphene for CO,while the nitrogen-doped graphene is an excellent candidate for selectivly sensing CO from air,because only CO can be chemisorbed on the pyridinic-like N-doped graphene accompanying with a large charge transfer,which can serve as a useful electronic signal for CO sensing.Even in the environment with NO,the N-doped graphene can also detect CO selectively.Therefore,the N-doped graphene is an excellent material for selectively sensing CO,which provides useful information for the design and fabrication of the CO sensors.     

Pyrometallurgical recycling of spent lithium-ion batteries from conventional roasting to synergistic pyrolysis with organic wastes

The synergistic pyrolysis has been increasingly used for recycling spent lithium-ion batteries(LIBs) and organic wastes(hydrogen and carbon sources), which are in-situ transformed into various reducing agents such as H₂, CO, and char via carbothermal and/or gas thermal reduction. Compared with the conventional roasting methods, this “killing two birds with one stone” strategy can not only reduce the cost and energy consumption, but also realize the valorization of organic wastes. This...     

Performance and Kinetics Studies on Selective Catalytic Reduction of NOx with NH3 over MnOx-WO3/TiO2 Catalyst

The catalytic activities of MnOx-WO3/TiO2 for selective catalytic reduction(SCR) of NO with NH3 were investigated in a wide range of temperature and reaction condition.It yielded a NOx conversion of 80.3%-99.6% and a N2 product selectivity of 100%-98.7% during 100 °C to 350 °C at gas hourly space velocity(GHSV)=18900 h-1.In the presence of 0.01% SO2 and 6% H2O at 120 °C,the NOx conversion can maintain 98.5%.At 300 °C and with 0.07% SO2 in reactant stream,the NOx conversion stabilized at 99% as high as the commercial V-W/TiO2 catalyst's level.The steady-state kinetics study shows that O2 played a promoting role.In the presence of less than 1.5% O2,NOx conversion can increase sharply with the increase of O2 concentration.The reaction order was zero with respect to NH3 and first with respect to NO with excess O2 and H2O.The kinetics active energy(Ea) of Mn-W/TiO2 was calculated to be 6.24 kJ/mol according to the kinetic experiment at various temperatures,much lower than those of other catalysts reported in the literature.Mn-W/TiO2 is an excellent catalyst for SCR of NO with NH3 by now.     

用T-jump/FTIR研究MnCP、NiCP和PbCP的快速热分解(英)

0IntroductionCarbohydrazideisahydrazinederivativewithwhitecrystalofstrongreducingbehaviors.Becauseithasmanycoordinationatoms(fournitrogenatomsandoneoxygenatom),carbohydrazidecan,therefore,beusedasmultidentateligand.Itscoordinationcom鄄poundiswidelyusedint…     

Experimental characterization of gaseous species emitted by the fast pyrolysis of biomass and polyethylene

This study aims to experimentally characterize the carbonaceous and nitrogenous species, from the flash pyrolysis of millet stalks and polyethylene plastic bags, using the device of the tubular kiln, coupled to two gas analyzers: Analyzer Fourier Transform Infrared (FTIR) and an analyzer Infrared Non-Dispersive (IRND). Gaseous products analyzed are: CH₄, C₂H₂, C₂H₄, C₃H₈, C₆H₆, CO, CO₂, NO₂, NO, N₂O, HCN and NH₃. Whatever the temperature of thermal degradation, the pyrolysis shows us that in terms of mass:

• •For the millet stalks, the gaseous compounds are formed mainly CO and CO₂ to the carbonaceous species, HCN and NH₃, for the nitrogenous species analyzed;
• •As regards the polyethylene bags, hydrocarbons for carbonaceous species and HCN, NH₃ and NO₂ for the nitrogenous species, are most abundant.

In addition, the results suppose that in our experimental conditions, the hydrocarbon which is involved primarily in the formation of CO is ethylene C₂H₄. At the end of this characterization, we determined the rate of carbon and nitrogen found in the volatile gas. With millet stalks we have about 45% of volatile carbon and 15% of the nitrogen of fuel that are found in gaseous products. The results obtained with the plastic bags give 68% carbon and 15% nitrogen found in the nitrogenous species analyzed.     

Cu-Doped MoSi2N4 Monolayer as a Potential NH3 Sensor

Cu doped MoSi₂N₄ monolayer (Cu-MoSi₂N₄) was firstly proposed to analyze adsorption performances of common gas molecules including O₂, N₂, CO, NO, NO₂, CO₂, SO₂, H₂O, NH₃ and CH₄ via density functional theory (DFT) combining with non-equilibrium Green's function (NEGF). The electronic transport calculations indicate that Cu-MoSi₂N₄ monolayer has high sensitivity for CO, NO, NO₂ and NH₃ molecules. However, only NH₃ molecule adsorbs on the Cu-MoSi₂N₄ monolayer with moderate strength (−0.55 eV) and desorbs at room temperature (2.36×10⁻³ s). Thus, Cu-MoSi₂N₄ monolayer is demonstrated as a potential NH₃ sensor.     

The thermal decomposition of the new energetic material ammoniumdinitramide (NH4N(NO2)2) in relation to Nitramide (NH2NO2) and NH4NO3

This qualitative study examines the response of the novel energetic material ammonium dinitramide (ADN), NH₄N(NO₂)₂, to thermal stress under low heating rate conditions in a new experimental apparatus. It involved a combination of residual gas mass spectrometry and FTIR absorption spectroscopy of a thin cryogenic condensate film resulting from deposition of ADN pyrolysis products on a KCl window. The results of ADN pyrolysis were compared under similar conditions with the behavior of NH₄NO₃ and NH₂NO₂ (nitramide), which served as reference materials. NH₄NO₃ decomposes into HNO₃ and NH₃ at 182°C and is regenerated on the cold cryostat surface. HNO₃ undergoes presumably heterogeneous loss to a minor extent such that the condensed film of NH₄NO₃ contains occluded NH₃. Nitramide undergoes efficient heterogeneous decomposition to N₂O and H₂O even at ambient temperature so that pyrolysis experiments at higher temperatures were not possible. However, the presence of nitramide can be monitored by mass spectrometry at its molecular ion (m/? 62). ADN pyrolysis is dominated by decomposition into NH₃ and HN(NO₂)₂ (HDN) in analogy to NH₄NO₃, with a maximum rate of decomposition under our conditions at approximately 155°C. The two vapor phase components regenerate ADN on the cold cryostat surface in addition to deposition of the pure acid HDN and H₂O. Condensed phase HDN is found to be stable for indefinite periods of time at ambient temperature and vacuum conditions, whereas fast heterogeneous decomposition of HDN at higher temperature leads to N₂O and HNO₃. The HNO₃ then undergoes fast (heterogeneous) decomposition in some experiments. Gas phase HDN also undergoes fast heterogeneous decomposition to NO and other products, probably on the internal surface (ca. 60°C) of the vacuum chamber before mass spectrometric detection. © 1993 John Wiley & Sons, Inc.     

Physicochemical properties of ceramic tape involving Ca<Subscript>0.05</Subscript> Ba<Subscript>0.95</Subscript> Ce<Subscript>0.9</Subscript>Y<Subscript>0.1</Subscript>O<Subscript>3</Subscript> as an electrolyte designed for electrolyte-supported solid oxide fuel cells (IT-SOFCs)

Energetic materials such as a mixture of guanidine nitrate (GN)/basic copper nitrate (BCN) are used as gas generators in automotive airbag systems. However, at the time of the airbag inflation, the gas generators release toxic combustion gases such as CO, NH₃, and NO_x. In this study, we investigated the combustion and thermal decomposition behaviors of GN/BCN mixture, focusing primarily on their exhaust gas composition. As a result, when the exhaust gas of the combustion under constant pressure in an inert gas stream was analyzed using a detection tube, the amount of NO_x (mainly NO) yielded greater decrease with increasing atmospheric pressure as compared to the amounts of CO and NH₃. Thus, provided GN/BCN is ignited in a closed container, a large amount of NO_x is presumed to have been released during the initial stage of combustion, which yielded comparatively low pressure. Results of the thermogravimetry–differential scanning calorimetry–Fourier transform infrared spectroscopy (TG/DSC/FTIR) indicated that the GN/BCN mixture caused endothermic decomposition at 170 °C and exothermic decomposition at 208 °C, which was accompanied by 66% mass loss. The decomposition gases, CO₂, N₂O, and H₂O, were detected via FTIR spectrum. Because N₂O was not detected in the combustion gas, it was suggested that the detected N₂O was generated at a low temperature and decomposed in high-temperature combustion.     

Fabrication and thermal decomposition of glycidyl azide polymer modified nitrocellulose double base propellants

Glycidyl azide polymer(GAP) with the advantages of non-volatility and excellent thermal stability is a candidate as a replacement for nitroglycerine(NG) in a double base propellant. The GAP-NC double base propellants were formulated with GAP and nitrocellulose(NC) fibers. Tensile test and SEM characterization indicated that GAP-NC propellants had a homogeneous structure. Thermogravimetric analysis of GAP-NC propellants revealed that the onset decomposition temperature reached a high level ranging from 192.9 to 194.6 °C, which indicated that the substitution of NG with GAP contributed to the safe storage and process operations for double base propellant. The result analysis of decomposition products of GAP-NC propellants showed that the main gas decomposition products of the propellants were NO, NO_2, CO, CO_2, NH_3, CH_4, HCN, N_2, CH_2O and C_2H_4O. The thermal decomposition process of the specimens was proposed.     

The thermal properties of inorganic compounds: II. Evolved gas studies of some mercury(I) and (II) compounds

The combined thermal analysis techniques of thermogravimetry, evolved gas analysis and mass spectrometry were used to investigate the thermal decomposition of several selected mercury(I), (II) compounds. Although TG curves are presented, the analysis of the evolved gases formed during the thermal decomposition processes was of greater interest. Gaseous products detected included: HgSO₄SO, SO₂ and O₂; Hg(SCN)₂CS₂, (CN)₂ and N₂; Hg(NO₃)₂NO, N₂O, NO₂ and O₂; HgNO₃ H₂ONO, NO₂ and N₂O; and Hg(C₂H₃O₂)₂—organic fragments. The evolved gas analysis was complicated by sublimation of the compounds at low pressures.     

Flow reactor studies and kinetic modeling of the H2/O2/NOX and CO/H2O/O2/NOX reactions

Flow reactor experiments were performed over wide ranges of pressure (0.5–14.0 atm) and temperature (750–1100 K) to study H₂/O₂ and CO/H₂O/O₂ kinetics in the presence of trace quantities of NO and NO₂. The promoting and inhibiting effects of NO reported previously at near atmospheric pressures extend throughout the range of pressures explored in the present study. At conditions where the recombination reaction H + O₂ (+M) = HO₂ (+M) is favored over the competing branching reaction, low concentrations of NO promote H₂ and CO oxidation by converting HO₂ to OH. In high concentrations, NO can also inhibit oxidative processes by catalyzing the recombination of radicals. The experimental data show that the overall effects of NO addition on fuel consumption and conversion of NO to NO₂ depend strongly on pressure and stoichiometry. The addition of NO₂ was also found to promote H₂ and CO oxidation but only at conditions where the reacting mixture first promoted the conversion of NO₂ to NO. Experimentally measured profiles of H₂, CO, CO₂, NO, NO₂, O₂, H₂O, and temperature were used to constrain the development of a detailed kinetic mechanism consistent with the previously studied H₂/O₂, CO/H₂O/O₂, H₂/NO₂, and CO/H₂O/N₂O systems. Model predictions generated using the reaction mechanism presented here are in good agreement with the experimental data over the entire range of conditions explored. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 705–724, 1999     

Kinetic modeling of the CO/H2O/O2/NO/SO2 system: Implications for high‐pressure fall‐off in the SO2 + O(+M) = SO3(+M) reaction

Flow reactor experiments were performed to study moist CO oxidation in the presence of trace quantities of NO (0–400 ppm) and SO₂ (0–1300 ppm) at pressures and temperatures ranging from 0.5–10.0 atm and 950–1040 K, respectively. Reaction profile measurements of CO, CO₂, O₂, NO, NO₂, SO₂, and temperature were used to further develop and validate a detailed chemical kinetic reaction mechanism in a manner consistent with previous studies of the CO/H₂/O₂/NO_X and CO/H₂O/N₂O systems. In particular, the experimental data indicate that the spin‐forbidden dissociation‐recombination reaction between SO₂ and O‐atoms is in the fall‐off regime at pressures above 1 atm. The inclusion of a pressure‐dependent rate constant for this reaction, using a high‐pressure limit determined from modeling the consumption of SO₂ in a N₂O/SO₂/N₂ mixture at 10.0 atm and 1000 K, brings model predictions into much better agreement with experimentally measured CO profiles over the entire pressure range. Kinetic coupling of NO_X and SO_X chemistry via the radical pool significantly reduces the ability of SO₂ to inhibit oxidative processes. Measurements of SO₂ indicate fractional conversions of SO₂ to SO₃ on the order of a few percent, in good agreement with previous measurements at atmospheric pressure. Modeling results suggest that, at low pressures, SO₃ formation occurs primarily through SO₂ + O(+M) = SO₃(+M), but at higher pressures where the fractional conversion of NO to NO₂ increases, SO₃ formation via SO₂ + NO₂ = SO₃ + NO becomes important. For the conditions explored in this study, the primary consumption pathways for SO₃ appear to be SO₃ + HO₂ = HOSO₂ + O₂ and SO₃ + H = SO₂ + OH. Further study of these reactions would increase the confidence with which model predictions of SO₃ can be viewed. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 317–339, 2000