A new energetic compound based on the tetrazole-1-acetic acid （tza） and potassium（I） salt, K2（tza）2（H2O）, was synthesized and characterized by elemental analysis and FT-IR spectrum. Its crystal structure was d...A new energetic compound based on the tetrazole-1-acetic acid （tza） and potassium（I） salt, K2（tza）2（H2O）, was synthesized and characterized by elemental analysis and FT-IR spectrum. Its crystal structure was determined by single-crystal X-ray diffraction analysis. The results show that the crystal belongs to the orthorhombic system, space group Pna21 with a = 1.11972（17） nm, b = 0.46647（7） nm, c = 2.5158（4） nm, V = 1.3140（3） nm3, K2C6H8N8O5, Mr = 350.40 g·mol-1, Dc = 1.771 g·cm^-3, μ（MoKα） = 0.759 mm^-1, F（000） = 712, Z = 4, R = 0.023 and wR = 0.0527 for 2961 observed reflections （I 〉 2σ（I））. The K（I） cation is six-coordinated with four O atoms from three carboxylate groups, one O atom from one H2O molecule and one N atom from tetrazolyl ring, in which each tza is coordinated in a tridentate chelating bridging coordination mode. The thermal decomposition mechanism of the title complex was studied by DSC and TG-DTG techniques. Under nitrogen atmosphere at a heating rate of 10 K·min-1, the thermal decomposition of the complex contains one main exothermic process between 191.7 and 243.8 ℃ in the DSC curve. Its combustion heat was mensurated by oxygen bomb calorimetry. The non-isothermal kinetics parameters were calculated by the Kissinger＇s method and Ozawa-Doyle＇s method, respectively. The sensitivity properties of K2（tza）2（H2O） were also determined with standard methods, which was very sensitive to flame.展开更多
The kinetics of the decomposition of dimethylhexane-1,6-dicarbamate to 1,6-hexamethylene diisocyanate was studied. A consecutive reaction model was established and the reaction orders for the two steps were confirmed ...The kinetics of the decomposition of dimethylhexane-1,6-dicarbamate to 1,6-hexamethylene diisocyanate was studied. A consecutive reaction model was established and the reaction orders for the two steps were confirmed to be 1 and 1.3 by the integral test method and the numerical differential method, respectively. The activation energies of the two steps were （56.94 4±5.90） kJ·mol^-1 and （72.07±3.47） kJ·mol^-1 with the frequency factors exp（ 12.53±1.42） min^- 1 and （ 14.254±0.84） tool^-0.33. L^0.33·min^-1, respectively. Based on the kinetic model obtained, the progress of the reaction can be calculated under given conditions.展开更多
The utilization of CO2 as raw material for chemical synthesis has the potential for substantial economic and green benefits. Thermal decomposition of hexamethylene-1,6-dicarbamate （HDC） is a promising approach for i...The utilization of CO2 as raw material for chemical synthesis has the potential for substantial economic and green benefits. Thermal decomposition of hexamethylene-1,6-dicarbamate （HDC） is a promising approach for indirect utilization of CO2 to produce hexamethylene-1,6-diisocyanate （HDI）. In this work, a green route was developed for the synthesis of HD1 by thermal decomposition of HDC over Co3O4/ZSM-5 catalyst, using chlorobenzene as low boiling point solvent. Different metal oxide supported catalysts were prepared by incipient wetness impregnation （IWI）, PEG-additive （PEG） and deposition precipitation with ammonia evaporation （DP） methods. Their catalytic performances for the thermal decomposition of HDC were tested. The catalyst screening results showed that Co3O4/ZSM-525 catalysts prepared by different methods showed different performances in the order of Co3O4/ZSM-5 25（PEG） 〉 Co3O4/ZSM-525（IWI） 〉 Co3O4/ZSM-525（DP）. The physicochemical properties of Co3O4/ZSM- 52s catalyst were characterized by XRD, FTIR, N2 adsorption-desorption measurements, NH3-TPD and XPS. The superior catalytic performance of Co3O4/ZSM-52S（PEG） catalyst was attributed to its relative surface content of Co3 ＋, surface lattice oxygen content and total acidity. Under the optimized reaction conditions： 6.5% HDC concentration in chlorobenzene, 1 wt% Co3O4/ZSM-525（PEG） catalyst, 250℃ temperature, 2.5 h time, 800 ml.min 1 nitrogen flow rate and 1.0 MPa pressure, the HDC conversion and HDI yield could reach 100% and 92.8% respectively. The Co3O4/ZSM-525（PEG） catalyst could be facilely separated from the reaction mixture, and reused without degradation in catalytic performance. Furthermore, a possible reaction mechanism was proposed based on the physicochemical properties of the Co3O4/ZSM-5 25 catalysts.展开更多
A new energetic complex,[Co（3,3？-Hbpt）（Htm）]·H_2O（1,3,3？-Hbpt = 3,5-bis（3-pyridyl）-1H-1,2,4-triazole and H_3tm = trimesic acid）,has been synthesized by hydrothermal reactions and characterized by single...A new energetic complex,[Co（3,3？-Hbpt）（Htm）]·H_2O（1,3,3？-Hbpt = 3,5-bis（3-pyridyl）-1H-1,2,4-triazole and H_3tm = trimesic acid）,has been synthesized by hydrothermal reactions and characterized by single-crystal X-ray diffraction,elementary analysis,IR spectroscopy,thermogravimetric analysis and X-ray powder diffraction. Single-crystal X-ray diffraction indicates that the complex belongs to triclinic system,space group P 1 with a = 10.0911（1）,b = 10.2573（1）,c = 10.6393（1） ？,α = 103.793（2）,β = 101.041（2）,γ = 107.918（3）o,V = 974.9（2） ？~3,Z = 2,D_c = 1.732 g·cm-3,μ = 0.941 mm^（-1）,M_r = 508.31,F（000） = 518,the final R = 0.0523 and wR = 0.0935 with I 〉 2σ（I）. In the title complex,Co（Ⅱ） ions are connected by Htm2-anions generating 1D ladder-like chains which are linked by 3,3？-Hbpt to form 1D cages. In addition,the thermal decomposition of ammonium perchlorate（AP） with complex 1 was explored by differential scanning calorimetry（DSC）. AP is completely decomposed in a shorter time in the presence of complex 1,and the decomposition heat of the mixture is 2.531 kJ·g^（-1）,significantly higher than that of pure AP. By Kissinger＇s method,the ratio of Ea/ln（A） is 11.05 for the mixture,which indicates that complex 1 shows good catalytic activity toward the AP decomposition.展开更多
In order to test the thermal decomposition of 1,3,5-trinitro-1,3,5-triazinane(RDX),the linear temperature rise experiment of RDX was carried out by differential scanning calorimeter under different heating rate condit...In order to test the thermal decomposition of 1,3,5-trinitro-1,3,5-triazinane(RDX),the linear temperature rise experiment of RDX was carried out by differential scanning calorimeter under different heating rate conditions.The kinetic calculation of RDX thermal decomposition curve was carried out by Kissinger and Ozawa methods,respectively,and the thermal analysis software was used to calculate the parameters such as self-accelerating decomposition temperature.The results show that the initial decomposition temperature range,decomposition peak temperature range,and decomposition completion temperature range of RDX are 208.4-214.2,225.7-239.3 and 234.0-252.4℃,respectively,and the average decomposition enthalpy is 362.9 J·g^-1.Kissinger method was used to calculate the DSC experimental data of RDX,the apparent activation energy obtained is 190.8 kJ·mol^-1,which is coincident with the results calculated by Ozawa method at the end of the reaction,indicating that the apparent activation energy calculated by the two methods is relatively accurate.When the packaging mass values are 1.0,2.0 and 5.0 kg,respectively,the self-accelerating decomposition temperatures are 97.0,93.0 and 87.0℃,respectively,indicating that with the increase of packaging mass,the self-accelerating decomposition temperature gradually decreases,and the risk increases accordingly.展开更多
A set of mono-and bimetallic（Zn-Co） supported ZSM-5 catalysts was first prepared by PEG-additive method. The physicochemical properties of the catalysts were investigated by FTIR, XPS, XRD, N2adsorption-desorption m...A set of mono-and bimetallic（Zn-Co） supported ZSM-5 catalysts was first prepared by PEG-additive method. The physicochemical properties of the catalysts were investigated by FTIR, XPS, XRD, N2adsorption-desorption measurements, SEM, EDS and NH3-TPD techniques. The physicochemical properties showed that the Zn Co2O4 spinel oxide was formed on the ZSM-5 support and provided effectual synergetic effect between Zn and Co species for the bimetallic catalyst. Furthermore, bimetallic supported ZSM-5 catalyst exhibited weak, moderate and strong acidic sites, while the monometallic supported ZSM-5 catalyst showed only weak and moderate or strong acidic sites. Their catalytic performances for thermal decomposition of hexamethylene–1,6–dicarbamate（HDC） to hexamethylene–1,6–diisocyanate（HDI） were then studied. It was found that the bimetallic supported ZSM-5 catalysts,especially Zn-2Co/ZSM-5 catalyst showed excellent catalytic performance due to the good synergetic effect between Co and Zn species, which provided a suitable contribution of acidic sites. HDC conversion of 100% with HDI selectivity of 91.2% and by-products selectivity of 1.3% could be achieved within short reaction time of 2.5 h over Zn-2Co/ZSM-5 catalyst.展开更多
The complex of Eu（IH） with 1-（6-hydroxy- 1-naphthyl）- 1,3-butanedione （HNBD） was prepared for the first time and characterized by elemental analysis, IR, UV, fluorescence spectrum, and DTA-TG-DTG techniques. The...The complex of Eu（IH） with 1-（6-hydroxy- 1-naphthyl）- 1,3-butanedione （HNBD） was prepared for the first time and characterized by elemental analysis, IR, UV, fluorescence spectrum, and DTA-TG-DTG techniques. The IR and UV-visible spectra showed that Eu（Ⅲ） ion was coordinated to the HNBD ligand. The fluorescence spectrum showed the presence of Eu^3＋ characteristic emission. The TG-DTA-DTG curves showed that the thermal decomposition of the anhydrous complex was a two-stage process and the final residue was Eu2O3. The thermal decomposition kinetic parameters of the complex were evaluated from TG-DTG data by using three kinds of integral methods （Coat-Redfem equation, Horowitz and Metzger equation, Madhusudanan-Krishnan-Ninan equation）. The kinetic parameters of the first stage are E^＊ = 164.02 kJ.moll, A = 1.31 × 10^15 s^-l, AS^＊= 42.27 J·K^-l·mol^-l, △H^＊ = 159.51 kJ·mol^-l, △G^＊= 136.54 kJ·mol^-l, and n = 3.1, those of the second stage are E^＊= 128.52 kJ·mol^-l, A = 1.44× 106 s^-1, △S^＊= - 136.89 J·K^-l·mol^-l, △H^＊ = 120.41 kJ·mol^-l, △G^＊= 283.85 kJ·mol^-l, and n = 1.1.展开更多
We have investigated the photoinduced decomposition of formaldehyde （CH2O） on a rutile TiO2（100）-（1×1） surface at 355 nrn using ternperature-prograrnrned desorption. Products, formate （HCOO）, methyl radic...We have investigated the photoinduced decomposition of formaldehyde （CH2O） on a rutile TiO2（100）-（1×1） surface at 355 nrn using ternperature-prograrnrned desorption. Products, formate （HCOO）, methyl radical （CH3.）, ethylene （C2H4）, and methanol （CH3OH） have been detected. The initial step in the decomposition of CH2O on the futile TiO2（100）-（1×1） surface is the formation of a dioxyrnethylene intermediate in which the carbonyl O atom of CH2O is bound to a Ti atom at the five-fold-coordinated Ti4＋ （Tisc） site and its carbonyl C atom bound to a nearby bridge-bonded oxygen （Oh） atom, respectively. During 355 nrn irradiation, the dioxymethylene intermediate can transfer an H atom to the Ob atom, thus forming HCOO directly, which is considered as the main reaction channel. In addition, the dioxyrnethylene intermediate can also transfer methylene to the Ob row and break the C-O bond, thus leaving the original carbonyl O atom at the Tisc site. After the transfer of methylene, several pathways to products are available. Thus, we have found that Ob atoms are intimately involved in the photoinduced decomposition of CH2O on the futile TiO2 （100）-（1× 1） surface.展开更多
A comparative thermal decomposition kinetic investigation on Fe(III) complexes of a antipyrine Schiff base ligand, 1,2-Bis(imino-4’-antipyrinyl)ethane (GA)), with varying counter anions viz. CIO4-, NO3-, SCN-, Cl-, a...A comparative thermal decomposition kinetic investigation on Fe(III) complexes of a antipyrine Schiff base ligand, 1,2-Bis(imino-4’-antipyrinyl)ethane (GA)), with varying counter anions viz. CIO4-, NO3-, SCN-, Cl-, and Br-, has been done by thermogravimetric analysis by using Coats-Redfern equation. The kinetic parameters like activation energy (E), pre-exponential factor (A) and entropy of activation (ΔS) were quantified. On comparing the various kinetic parameters, lower activation energy was observed in second stage as compared to first thermal decomposition stage. The same trend has been observed for pre-exponential factor (A) and entropy of activation (ΔS). The present results show that the starting materials having higher activation energy (E), are more stable than the intermediate products, however;the intermediate products possess well-ordered chemical structure due to their highly negative entropy of activation (ΔS) values. The present investigation proves that the counter anions play an important role on the thermal decomposition kinetics of the complexes.展开更多
A series of Cu/Co/Cr nanocomposites with different Cu/Co/Cr molar ratios were obtained by calcination of Cu/ Co/Cr hydrotalcites precursors, which were prepared by a co-precipitation reaction. X-ray diffraction, induc...A series of Cu/Co/Cr nanocomposites with different Cu/Co/Cr molar ratios were obtained by calcination of Cu/ Co/Cr hydrotalcites precursors, which were prepared by a co-precipitation reaction. X-ray diffraction, inductively coupled plasma analysis, and transmission electron microscopy were used to characterize the structure, composition, and mor- phology of Cu/Co/Cr nanocomposites. The results show that Cu/Co/Cr nanocomposites have both CuCr204 and CoCr204 spinel phase. The particle size of Cu/Co/Cr nanocomposites is 15-20 nm and the specific surface area is 95-115 m2/g. Cu/ Co/Cr nanocomposites were used as new catalysts for improving thermal decomposition of ammonium perchlorate （AP）. Their catalytic activities were investigated using differential thermal analysis and thermal gravimetric analyzer coupled with an online mass spectrometer. The results show that the decomposition temperature of AP lowered 132-146℃ by adding 4 wt% Cu/Co/Cr nanocomposites. Catalytic activities of the prepared nanocomposites depend on the calcinations temperature and addition amount of corresponding nanocomposites. The possible catalytic mechanism of Cu/Co/Cr nanocomposites was also studied and discussed.展开更多
Systematic studies of the thermal decomposition mechanism of benzoyl peroxide(BPO) in ground state, leading to various intermediates, products and the potential energy surface(PES) of possible dissociation reactions w...Systematic studies of the thermal decomposition mechanism of benzoyl peroxide(BPO) in ground state, leading to various intermediates, products and the potential energy surface(PES) of possible dissociation reactions were made computationally. The structures of the transition states and the activation energies for all the paths causing the formation of the reaction products mentioned above were calculated by the AM1 semi-empirical method. This method is shown to to be one predict correctly the preferred pathway for the title reaction. It has been found that in ground state, the thermal decomposition of benzoyl peroxide has two kinds of paths. The first pathway PhC(O)O-OC(O)Ph→PhC(O)O · →Ph · +CO 2 produces finally phenyl radicals and carbon dioxide. And the second pathway PhC(O)OO-C(O)Ph→PhC(O)OO · +PhC(O) · → PhC(O) · +O 2 →Ph · +CO+O 2, via which the reaction takes place only in two steps, produces oxygen and PhC(O) · radicals, and the further thermal dissociation of PhC(O) · is quite difficult because of the high activation energy in ground state. The calculated activation energies and reaction enthalpies are in good agreement with the experimental values. The research results also show that also the thermal dissociation process of the two bonds or the three bonds for the benzoyl peroxide doesn′t take place in ground state.展开更多
Perovskite-type La0.8Sr0.2MnO3 was prepared by stearic acid gel combustion method.The obtained powders were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),scaning electron micro...Perovskite-type La0.8Sr0.2MnO3 was prepared by stearic acid gel combustion method.The obtained powders were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),scaning electron micrograph(SEM)and X-ray photoelectron spectroscopy(XPS)techniques.The catalytic activity of La0.8Sr0.2MnO3 was investigated on thermal decomposition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)by thermal gravity-differential scanning calorimetry(TG-DSC)techniques.The experimental results show that La0.8Sr0.2MnO3 is an effective catalyst for HMX thermal decomposition.The surface-adsorbed species such as H2O,OH - and adsorbed oxygen(Oad)could result in an advance in the onset temperature of HMX thermal decomposition.The mixture system of Mn 3+ and Mn 4+ ions and lattice oxygen could play key roles for the increase of the decomposition heat of HMX because these exothermic reactions could be catalyzed by La0.8Sr0.2MnO3 between CO and NOx(from the thermal decomposition of HMX)and the oxidation reaction of CO.According to the previous researches and our results,perovskite-type La0.8Sr0.2MnO3 may be used as a novel catalyst or modifier for nitrate ester plasticized polyether(NEPE)propellant.展开更多
Given their unique and excellent properties,metal-organic frameworks(MOFs)materials have been used in many scientific fields.EMOFs use energetic materials as ligands,which can provide part of the energy for the system...Given their unique and excellent properties,metal-organic frameworks(MOFs)materials have been used in many scientific fields.EMOFs use energetic materials as ligands,which can provide part of the energy for the system while catalyzing ammonium perchlorate.The energetic material 1.1'-dihydroxyazotetrazole(H_(2)AzTO),as a high-energy nitrogen-rich material,was selected as a ligand.Five kinds of La^(3+),Ce^(3+),Pr^(3+),Nd^(3+),and Sm^(3+)lanthanide EMOFs were synthesized and obtained.Single crystal X-ray diffraction tests were conducted to obtain the crystal structures of EMOFs 1-5,which indicate that they have similar crystal structures.The thermal stabilities of EMOFs 1-5,which are obtained by differential scanning calorimetry(DSC)tests,are improved compa red with that of the ligand.The results of thermicdecomposition of ammonium perchlorate(AP)and AP mixtures with 10 wt%EMOFs 1-5 show that except for AP mixed with 10 wt%co mpound 2,the high-temperature decomposition peak tempe rature of AP mixed with other compounds is significantly advanced(up to 59.3-88.3 K),and the decomposition of AP is continuous and violent.EMOFs 3-5 have good application prospects for the catalytic thermicdecomposition of AP.展开更多
A once overlooked source of electrolyte degradation incurred by dissolved manganese(Ⅱ)species in lithium-ion batteries has been identified recently.In order to deactivate the catalytic activity of such manganese(II)i...A once overlooked source of electrolyte degradation incurred by dissolved manganese(Ⅱ)species in lithium-ion batteries has been identified recently.In order to deactivate the catalytic activity of such manganese(II)ion,1-aza-12-crown-4-ether(A12C4)with cavity size well matched manganese(Ⅱ)ion is used in this work as electrolyte additive.Theoretical and experimental results show that stable complex forms between A12C4 and manganese(II)ions in the electrolyte,which does not affect the solvation of Li ions.The strong binding effect of A12C4 additive reduces the charge density of manganese(II)ion and inhibits its destruction of the PF_(6)^(-)structure in the electrolyte,leading to greatly improved thermal stability of manganese(II)ions-containing electrolyte.In addition to bulk electrolyte,A12C4 additive also shows capability in preventing Mn^(2+) from degrading SEI on graphite surface.Such bulk and interphasial stability introduced by A12C4 leads to significantly improved cycling performance of LIBs.展开更多
In this paper, a series of zinc cobaltite catalysts with the general formula Znx-Co1-xCo2O4 (x = 0.25, 0.50, 0.75 and 1.0) has been prepared using the co-precipitation method. Thermal analyzes (TGA and DTA) were used ...In this paper, a series of zinc cobaltite catalysts with the general formula Znx-Co1-xCo2O4 (x = 0.25, 0.50, 0.75 and 1.0) has been prepared using the co-precipitation method. Thermal analyzes (TGA and DTA) were used to follow up the thermal events accompanying the heat treatment of the parent mixture. Based on these results, the various parent mixtures were calcined at 500℃. The obtained solid catalysts were characterized by using XRD, FT-IR and N2-adsorption. The catalytic decomposition of N2O to N2 and O2 was carried out on the zinc-cobaltite catalysts. It was found that partial replacement of Co2+ by Zn2+ in Co3O4 spinel oxide led to a significant improvement in their N2O decomposition activity. Moreover, the catalytic activity was found to be depended on the calcination temperature utilized.展开更多
The thermal behavior and non-isothermal decomposition kinetics of 1-amino-1-hydrazino-2,2-dinitro-ethylene potassium salt[K（AHDNE）] were studied under the non-isothermal conditions by different scanning calorimeter...The thermal behavior and non-isothermal decomposition kinetics of 1-amino-1-hydrazino-2,2-dinitro-ethylene potassium salt[K（AHDNE）] were studied under the non-isothermal conditions by different scanning calorimeter（DSC） method. The thermal behavior of K（AHDNE） presents three exothermic decomposition processes. The kinetic equation of the first thermal decomposition reaction obtained is dα/dT=（1019.63/β）3（1-α）[-ln（1-α）]2/3exp（-1.862× 105/RT）. The self-accelerating decomposition temperature（TSADT） and critical temperature of thermal explosion（Tb） of K（AHDNE） are 162.5 and 171.4 °C, respectively. K（AHDNE） has higher thermal stability than AHDNE.展开更多
The high energy coordination compounds Cu(TZCA)_(2)(ClO_(4))_(2)(ECCs-1) was prepared by 1H-tetrazole-5-carbohydrazide(TZCA) with a high energy skeleton and a strong coordination ability group.At the same time,the rea...The high energy coordination compounds Cu(TZCA)_(2)(ClO_(4))_(2)(ECCs-1) was prepared by 1H-tetrazole-5-carbohydrazide(TZCA) with a high energy skeleton and a strong coordination ability group.At the same time,the reaction activity of the ligand was explored,and the single crystal structure of it and intermediate were obtained.The structures of all substances were characterized by IR and EA.And the structure and composition of ECCs-1 are confirmed by ESP,AC,SEM and ICP-OES.Physical and chemical properties tests show that ECCs-1 has an acceptable thermal stability(T_(d)=177℃) and extremely sensitive mechanical stimulation(IS=1 J,FS=5 N).The comprehensive performance test results show that ECCs-1 has excellent initiation ability.In addition,the decomposition mechanism of ECCs-1 is explored from two aspects of experiment and theoretical calculation.展开更多
基金supported by National Key Laboratory of Science and Technology on Combustion and Explosion (9140C3503010904)the State Key Laboratory of Explosion Science and Technology (No. YBK T 10-05 and ZDKT10-01b)Program for New Century Excellent Talents in University (NCET-10-0051) (CNET-09-0051)
文摘A new energetic compound based on the tetrazole-1-acetic acid （tza） and potassium（I） salt, K2（tza）2（H2O）, was synthesized and characterized by elemental analysis and FT-IR spectrum. Its crystal structure was determined by single-crystal X-ray diffraction analysis. The results show that the crystal belongs to the orthorhombic system, space group Pna21 with a = 1.11972（17） nm, b = 0.46647（7） nm, c = 2.5158（4） nm, V = 1.3140（3） nm3, K2C6H8N8O5, Mr = 350.40 g·mol-1, Dc = 1.771 g·cm^-3, μ（MoKα） = 0.759 mm^-1, F（000） = 712, Z = 4, R = 0.023 and wR = 0.0527 for 2961 observed reflections （I 〉 2σ（I））. The K（I） cation is six-coordinated with four O atoms from three carboxylate groups, one O atom from one H2O molecule and one N atom from tetrazolyl ring, in which each tza is coordinated in a tridentate chelating bridging coordination mode. The thermal decomposition mechanism of the title complex was studied by DSC and TG-DTG techniques. Under nitrogen atmosphere at a heating rate of 10 K·min-1, the thermal decomposition of the complex contains one main exothermic process between 191.7 and 243.8 ℃ in the DSC curve. Its combustion heat was mensurated by oxygen bomb calorimetry. The non-isothermal kinetics parameters were calculated by the Kissinger＇s method and Ozawa-Doyle＇s method, respectively. The sensitivity properties of K2（tza）2（H2O） were also determined with standard methods, which was very sensitive to flame.
基金the National Key Technology R&D Program(2013BAC11B03)the Knowledge Innovation Fund of Chinese Academy of Science(KGCX2-YW-215-2)the National Natural Science Foundation of China(21476244)
文摘The kinetics of the decomposition of dimethylhexane-1,6-dicarbamate to 1,6-hexamethylene diisocyanate was studied. A consecutive reaction model was established and the reaction orders for the two steps were confirmed to be 1 and 1.3 by the integral test method and the numerical differential method, respectively. The activation energies of the two steps were （56.94 4±5.90） kJ·mol^-1 and （72.07±3.47） kJ·mol^-1 with the frequency factors exp（ 12.53±1.42） min^- 1 and （ 14.254±0.84） tool^-0.33. L^0.33·min^-1, respectively. Based on the kinetic model obtained, the progress of the reaction can be calculated under given conditions.
基金National Natural Science Foundation of China(21476244 and 21406245)Youth Innovation Promotion Association CAS
文摘The utilization of CO2 as raw material for chemical synthesis has the potential for substantial economic and green benefits. Thermal decomposition of hexamethylene-1,6-dicarbamate （HDC） is a promising approach for indirect utilization of CO2 to produce hexamethylene-1,6-diisocyanate （HDI）. In this work, a green route was developed for the synthesis of HD1 by thermal decomposition of HDC over Co3O4/ZSM-5 catalyst, using chlorobenzene as low boiling point solvent. Different metal oxide supported catalysts were prepared by incipient wetness impregnation （IWI）, PEG-additive （PEG） and deposition precipitation with ammonia evaporation （DP） methods. Their catalytic performances for the thermal decomposition of HDC were tested. The catalyst screening results showed that Co3O4/ZSM-525 catalysts prepared by different methods showed different performances in the order of Co3O4/ZSM-5 25（PEG） 〉 Co3O4/ZSM-525（IWI） 〉 Co3O4/ZSM-525（DP）. The physicochemical properties of Co3O4/ZSM- 52s catalyst were characterized by XRD, FTIR, N2 adsorption-desorption measurements, NH3-TPD and XPS. The superior catalytic performance of Co3O4/ZSM-52S（PEG） catalyst was attributed to its relative surface content of Co3 ＋, surface lattice oxygen content and total acidity. Under the optimized reaction conditions： 6.5% HDC concentration in chlorobenzene, 1 wt% Co3O4/ZSM-525（PEG） catalyst, 250℃ temperature, 2.5 h time, 800 ml.min 1 nitrogen flow rate and 1.0 MPa pressure, the HDC conversion and HDI yield could reach 100% and 92.8% respectively. The Co3O4/ZSM-525（PEG） catalyst could be facilely separated from the reaction mixture, and reused without degradation in catalytic performance. Furthermore, a possible reaction mechanism was proposed based on the physicochemical properties of the Co3O4/ZSM-5 25 catalysts.
基金Supported by the National Natural Science Foundation of China(No.21263019 and 21467022)
文摘A new energetic complex,[Co（3,3？-Hbpt）（Htm）]·H_2O（1,3,3？-Hbpt = 3,5-bis（3-pyridyl）-1H-1,2,4-triazole and H_3tm = trimesic acid）,has been synthesized by hydrothermal reactions and characterized by single-crystal X-ray diffraction,elementary analysis,IR spectroscopy,thermogravimetric analysis and X-ray powder diffraction. Single-crystal X-ray diffraction indicates that the complex belongs to triclinic system,space group P 1 with a = 10.0911（1）,b = 10.2573（1）,c = 10.6393（1） ？,α = 103.793（2）,β = 101.041（2）,γ = 107.918（3）o,V = 974.9（2） ？~3,Z = 2,D_c = 1.732 g·cm-3,μ = 0.941 mm^（-1）,M_r = 508.31,F（000） = 518,the final R = 0.0523 and wR = 0.0935 with I 〉 2σ（I）. In the title complex,Co（Ⅱ） ions are connected by Htm2-anions generating 1D ladder-like chains which are linked by 3,3？-Hbpt to form 1D cages. In addition,the thermal decomposition of ammonium perchlorate（AP） with complex 1 was explored by differential scanning calorimetry（DSC）. AP is completely decomposed in a shorter time in the presence of complex 1,and the decomposition heat of the mixture is 2.531 kJ·g^（-1）,significantly higher than that of pure AP. By Kissinger＇s method,the ratio of Ea/ln（A） is 11.05 for the mixture,which indicates that complex 1 shows good catalytic activity toward the AP decomposition.
文摘In order to test the thermal decomposition of 1,3,5-trinitro-1,3,5-triazinane(RDX),the linear temperature rise experiment of RDX was carried out by differential scanning calorimeter under different heating rate conditions.The kinetic calculation of RDX thermal decomposition curve was carried out by Kissinger and Ozawa methods,respectively,and the thermal analysis software was used to calculate the parameters such as self-accelerating decomposition temperature.The results show that the initial decomposition temperature range,decomposition peak temperature range,and decomposition completion temperature range of RDX are 208.4-214.2,225.7-239.3 and 234.0-252.4℃,respectively,and the average decomposition enthalpy is 362.9 J·g^-1.Kissinger method was used to calculate the DSC experimental data of RDX,the apparent activation energy obtained is 190.8 kJ·mol^-1,which is coincident with the results calculated by Ozawa method at the end of the reaction,indicating that the apparent activation energy calculated by the two methods is relatively accurate.When the packaging mass values are 1.0,2.0 and 5.0 kg,respectively,the self-accelerating decomposition temperatures are 97.0,93.0 and 87.0℃,respectively,indicating that with the increase of packaging mass,the self-accelerating decomposition temperature gradually decreases,and the risk increases accordingly.
基金supported by National Natural Science Foundation of China(Nos.21476244 and 21406245)Youth Innovation Promotion Association CAS
文摘A set of mono-and bimetallic（Zn-Co） supported ZSM-5 catalysts was first prepared by PEG-additive method. The physicochemical properties of the catalysts were investigated by FTIR, XPS, XRD, N2adsorption-desorption measurements, SEM, EDS and NH3-TPD techniques. The physicochemical properties showed that the Zn Co2O4 spinel oxide was formed on the ZSM-5 support and provided effectual synergetic effect between Zn and Co species for the bimetallic catalyst. Furthermore, bimetallic supported ZSM-5 catalyst exhibited weak, moderate and strong acidic sites, while the monometallic supported ZSM-5 catalyst showed only weak and moderate or strong acidic sites. Their catalytic performances for thermal decomposition of hexamethylene–1,6–dicarbamate（HDC） to hexamethylene–1,6–diisocyanate（HDI） were then studied. It was found that the bimetallic supported ZSM-5 catalysts,especially Zn-2Co/ZSM-5 catalyst showed excellent catalytic performance due to the good synergetic effect between Co and Zn species, which provided a suitable contribution of acidic sites. HDC conversion of 100% with HDI selectivity of 91.2% and by-products selectivity of 1.3% could be achieved within short reaction time of 2.5 h over Zn-2Co/ZSM-5 catalyst.
基金financially supported by the Important Foundation of the Educational Commission of Hubei Province (No. Z200622001)the Natural Science Foundation of the Educational Commission of Hubei Province, China (No. J200522002)
文摘The complex of Eu（IH） with 1-（6-hydroxy- 1-naphthyl）- 1,3-butanedione （HNBD） was prepared for the first time and characterized by elemental analysis, IR, UV, fluorescence spectrum, and DTA-TG-DTG techniques. The IR and UV-visible spectra showed that Eu（Ⅲ） ion was coordinated to the HNBD ligand. The fluorescence spectrum showed the presence of Eu^3＋ characteristic emission. The TG-DTA-DTG curves showed that the thermal decomposition of the anhydrous complex was a two-stage process and the final residue was Eu2O3. The thermal decomposition kinetic parameters of the complex were evaluated from TG-DTG data by using three kinds of integral methods （Coat-Redfem equation, Horowitz and Metzger equation, Madhusudanan-Krishnan-Ninan equation）. The kinetic parameters of the first stage are E^＊ = 164.02 kJ.moll, A = 1.31 × 10^15 s^-l, AS^＊= 42.27 J·K^-l·mol^-l, △H^＊ = 159.51 kJ·mol^-l, △G^＊= 136.54 kJ·mol^-l, and n = 3.1, those of the second stage are E^＊= 128.52 kJ·mol^-l, A = 1.44× 106 s^-1, △S^＊= - 136.89 J·K^-l·mol^-l, △H^＊ = 120.41 kJ·mol^-l, △G^＊= 283.85 kJ·mol^-l, and n = 1.1.
基金supported by the National Natural Science Foundation of China(No.21673235 and No.21403224)the Youth Innovation Promotion Association CAS,and the Key Research Program of the Chinese Academy of Sciences
文摘We have investigated the photoinduced decomposition of formaldehyde （CH2O） on a rutile TiO2（100）-（1×1） surface at 355 nrn using ternperature-prograrnrned desorption. Products, formate （HCOO）, methyl radical （CH3.）, ethylene （C2H4）, and methanol （CH3OH） have been detected. The initial step in the decomposition of CH2O on the futile TiO2（100）-（1×1） surface is the formation of a dioxyrnethylene intermediate in which the carbonyl O atom of CH2O is bound to a Ti atom at the five-fold-coordinated Ti4＋ （Tisc） site and its carbonyl C atom bound to a nearby bridge-bonded oxygen （Oh） atom, respectively. During 355 nrn irradiation, the dioxymethylene intermediate can transfer an H atom to the Ob atom, thus forming HCOO directly, which is considered as the main reaction channel. In addition, the dioxyrnethylene intermediate can also transfer methylene to the Ob row and break the C-O bond, thus leaving the original carbonyl O atom at the Tisc site. After the transfer of methylene, several pathways to products are available. Thus, we have found that Ob atoms are intimately involved in the photoinduced decomposition of CH2O on the futile TiO2 （100）-（1× 1） surface.
文摘A comparative thermal decomposition kinetic investigation on Fe(III) complexes of a antipyrine Schiff base ligand, 1,2-Bis(imino-4’-antipyrinyl)ethane (GA)), with varying counter anions viz. CIO4-, NO3-, SCN-, Cl-, and Br-, has been done by thermogravimetric analysis by using Coats-Redfern equation. The kinetic parameters like activation energy (E), pre-exponential factor (A) and entropy of activation (ΔS) were quantified. On comparing the various kinetic parameters, lower activation energy was observed in second stage as compared to first thermal decomposition stage. The same trend has been observed for pre-exponential factor (A) and entropy of activation (ΔS). The present results show that the starting materials having higher activation energy (E), are more stable than the intermediate products, however;the intermediate products possess well-ordered chemical structure due to their highly negative entropy of activation (ΔS) values. The present investigation proves that the counter anions play an important role on the thermal decomposition kinetics of the complexes.
基金financially supported by the Engineering Research Center of Starch and Vegetable Protein Processing, Ministry of Education, South China University of Technology (No.2012ERC03)
文摘A series of Cu/Co/Cr nanocomposites with different Cu/Co/Cr molar ratios were obtained by calcination of Cu/ Co/Cr hydrotalcites precursors, which were prepared by a co-precipitation reaction. X-ray diffraction, inductively coupled plasma analysis, and transmission electron microscopy were used to characterize the structure, composition, and mor- phology of Cu/Co/Cr nanocomposites. The results show that Cu/Co/Cr nanocomposites have both CuCr204 and CoCr204 spinel phase. The particle size of Cu/Co/Cr nanocomposites is 15-20 nm and the specific surface area is 95-115 m2/g. Cu/ Co/Cr nanocomposites were used as new catalysts for improving thermal decomposition of ammonium perchlorate （AP）. Their catalytic activities were investigated using differential thermal analysis and thermal gravimetric analyzer coupled with an online mass spectrometer. The results show that the decomposition temperature of AP lowered 132-146℃ by adding 4 wt% Cu/Co/Cr nanocomposites. Catalytic activities of the prepared nanocomposites depend on the calcinations temperature and addition amount of corresponding nanocomposites. The possible catalytic mechanism of Cu/Co/Cr nanocomposites was also studied and discussed.
基金Supported by National NaturalScienceFoundation of China( No.2 97730 0 7) and the NaturalScienceFoundation of Qu-jing Normal College( No.2 0 0 0 0 9)
文摘Systematic studies of the thermal decomposition mechanism of benzoyl peroxide(BPO) in ground state, leading to various intermediates, products and the potential energy surface(PES) of possible dissociation reactions were made computationally. The structures of the transition states and the activation energies for all the paths causing the formation of the reaction products mentioned above were calculated by the AM1 semi-empirical method. This method is shown to to be one predict correctly the preferred pathway for the title reaction. It has been found that in ground state, the thermal decomposition of benzoyl peroxide has two kinds of paths. The first pathway PhC(O)O-OC(O)Ph→PhC(O)O · →Ph · +CO 2 produces finally phenyl radicals and carbon dioxide. And the second pathway PhC(O)OO-C(O)Ph→PhC(O)OO · +PhC(O) · → PhC(O) · +O 2 →Ph · +CO+O 2, via which the reaction takes place only in two steps, produces oxygen and PhC(O) · radicals, and the further thermal dissociation of PhC(O) · is quite difficult because of the high activation energy in ground state. The calculated activation energies and reaction enthalpies are in good agreement with the experimental values. The research results also show that also the thermal dissociation process of the two bonds or the three bonds for the benzoyl peroxide doesn′t take place in ground state.
基金Supported by the National Natural Science Foundation of China （20671084）
文摘Perovskite-type La0.8Sr0.2MnO3 was prepared by stearic acid gel combustion method.The obtained powders were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),scaning electron micrograph(SEM)and X-ray photoelectron spectroscopy(XPS)techniques.The catalytic activity of La0.8Sr0.2MnO3 was investigated on thermal decomposition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)by thermal gravity-differential scanning calorimetry(TG-DSC)techniques.The experimental results show that La0.8Sr0.2MnO3 is an effective catalyst for HMX thermal decomposition.The surface-adsorbed species such as H2O,OH - and adsorbed oxygen(Oad)could result in an advance in the onset temperature of HMX thermal decomposition.The mixture system of Mn 3+ and Mn 4+ ions and lattice oxygen could play key roles for the increase of the decomposition heat of HMX because these exothermic reactions could be catalyzed by La0.8Sr0.2MnO3 between CO and NOx(from the thermal decomposition of HMX)and the oxidation reaction of CO.According to the previous researches and our results,perovskite-type La0.8Sr0.2MnO3 may be used as a novel catalyst or modifier for nitrate ester plasticized polyether(NEPE)propellant.
基金Project supported by the National Natural Science Foundation of China(21875192)the Basic Research Project of Sichuan Province for Science and Technology Development(2019YJ0355)+1 种基金Outstanding Youth Science and Technology Talents Program of Sichuan(19JCQN0085)the Project of State Key Laboratory of Environment-friendly Energy Materials,Southwest University of Science and Technology(20fksy04)。
文摘Given their unique and excellent properties,metal-organic frameworks(MOFs)materials have been used in many scientific fields.EMOFs use energetic materials as ligands,which can provide part of the energy for the system while catalyzing ammonium perchlorate.The energetic material 1.1'-dihydroxyazotetrazole(H_(2)AzTO),as a high-energy nitrogen-rich material,was selected as a ligand.Five kinds of La^(3+),Ce^(3+),Pr^(3+),Nd^(3+),and Sm^(3+)lanthanide EMOFs were synthesized and obtained.Single crystal X-ray diffraction tests were conducted to obtain the crystal structures of EMOFs 1-5,which indicate that they have similar crystal structures.The thermal stabilities of EMOFs 1-5,which are obtained by differential scanning calorimetry(DSC)tests,are improved compa red with that of the ligand.The results of thermicdecomposition of ammonium perchlorate(AP)and AP mixtures with 10 wt%EMOFs 1-5 show that except for AP mixed with 10 wt%co mpound 2,the high-temperature decomposition peak tempe rature of AP mixed with other compounds is significantly advanced(up to 59.3-88.3 K),and the decomposition of AP is continuous and violent.EMOFs 3-5 have good application prospects for the catalytic thermicdecomposition of AP.
基金supported by the National Natural Science Foundation of China(21972049)the Guangdong Program for Distinguished Young Scholar(2017B030306013)the Science and Technology Planning Project of Guangdong Province(2017B090901020)。
文摘A once overlooked source of electrolyte degradation incurred by dissolved manganese(Ⅱ)species in lithium-ion batteries has been identified recently.In order to deactivate the catalytic activity of such manganese(II)ion,1-aza-12-crown-4-ether(A12C4)with cavity size well matched manganese(Ⅱ)ion is used in this work as electrolyte additive.Theoretical and experimental results show that stable complex forms between A12C4 and manganese(II)ions in the electrolyte,which does not affect the solvation of Li ions.The strong binding effect of A12C4 additive reduces the charge density of manganese(II)ion and inhibits its destruction of the PF_(6)^(-)structure in the electrolyte,leading to greatly improved thermal stability of manganese(II)ions-containing electrolyte.In addition to bulk electrolyte,A12C4 additive also shows capability in preventing Mn^(2+) from degrading SEI on graphite surface.Such bulk and interphasial stability introduced by A12C4 leads to significantly improved cycling performance of LIBs.
文摘In this paper, a series of zinc cobaltite catalysts with the general formula Znx-Co1-xCo2O4 (x = 0.25, 0.50, 0.75 and 1.0) has been prepared using the co-precipitation method. Thermal analyzes (TGA and DTA) were used to follow up the thermal events accompanying the heat treatment of the parent mixture. Based on these results, the various parent mixtures were calcined at 500℃. The obtained solid catalysts were characterized by using XRD, FT-IR and N2-adsorption. The catalytic decomposition of N2O to N2 and O2 was carried out on the zinc-cobaltite catalysts. It was found that partial replacement of Co2+ by Zn2+ in Co3O4 spinel oxide led to a significant improvement in their N2O decomposition activity. Moreover, the catalytic activity was found to be depended on the calcination temperature utilized.
基金Supported by the National Natural Science Foundation of China(No.20803058)the Shaanxi Provincial Science Program Foundation, China(No.2011kjxx31)the Education Committee Foundation of Shaanxi Province, China(Nos.2010JK881,12JK0636)
文摘The thermal behavior and non-isothermal decomposition kinetics of 1-amino-1-hydrazino-2,2-dinitro-ethylene potassium salt[K（AHDNE）] were studied under the non-isothermal conditions by different scanning calorimeter（DSC） method. The thermal behavior of K（AHDNE） presents three exothermic decomposition processes. The kinetic equation of the first thermal decomposition reaction obtained is dα/dT=（1019.63/β）3（1-α）[-ln（1-α）]2/3exp（-1.862× 105/RT）. The self-accelerating decomposition temperature（TSADT） and critical temperature of thermal explosion（Tb） of K（AHDNE） are 162.5 and 171.4 °C, respectively. K（AHDNE） has higher thermal stability than AHDNE.
基金projects of National Natural Science Foundation of China (Grant Nos.22175025 and 21905023) for their generous financial support。
文摘The high energy coordination compounds Cu(TZCA)_(2)(ClO_(4))_(2)(ECCs-1) was prepared by 1H-tetrazole-5-carbohydrazide(TZCA) with a high energy skeleton and a strong coordination ability group.At the same time,the reaction activity of the ligand was explored,and the single crystal structure of it and intermediate were obtained.The structures of all substances were characterized by IR and EA.And the structure and composition of ECCs-1 are confirmed by ESP,AC,SEM and ICP-OES.Physical and chemical properties tests show that ECCs-1 has an acceptable thermal stability(T_(d)=177℃) and extremely sensitive mechanical stimulation(IS=1 J,FS=5 N).The comprehensive performance test results show that ECCs-1 has excellent initiation ability.In addition,the decomposition mechanism of ECCs-1 is explored from two aspects of experiment and theoretical calculation.
