Effect of catocene on the thermal decomposition of ammonium perchlorate and octogen

Simultaneous TG/DSC-FT-IR was employed to study the effect of catocene with a high concentration (5, 15, and 25 %) on the thermal decomposition of ammonium perchlorate (AP) and octogen (HMX) with different particle sizes. The experimental results show that catocene has effect on the thermal decomposition of AP and HMX, but the role that catocene playing changes with the concentration of catocene and the particle size of AP and HMX. High concentration of catocene (more than 15 %) benefits the decomposition of fine AP and HMX at low temperature, but has little effect on the decomposition of median and coarse AP. The thermal decomposition of HMX is affected by catocene mainly through increasing the heat release of the first decomposition step, while through both increasing the heat release and decreasing the decomposition temperature of the first decomposition step for the thermal decomposition of AP.     

Effect of γ-irradiation on the thermal decomposition of strontium bromate

The effect of irradiation on the thermal decomposition of strontium bromate has been studied by dynamic thermogravimetry. Irradiaton enhances the decomposition and decreases the energy of activation but does not change the mechanism of decomposition.     

Mg2NiH4对高氯酸铵热分解过程的影响

采用置换-扩散法制备了储氢材料Mg2NiH4, 用XRD, ICP和DSC-TG方法对其结构进行了表征. 用热分析法(DSC)研究了Mg2NiH4对高氯酸铵(AP)热分解过程的影响. 研究结果表明, Mg2NiH4对AP热分解过程有较大影响. Mg2NiH4可以显著促进AP的低温热分解过程, 降低高温热分解温度, 使DSC表观分解热明显增大. 随着加入量的增加, Mg2NiH4对AP热分解的催化促进作用增强, 当Mg2NiH4加入的质量分数为30％时, DSC表观分解热最大. 吸氢量越大, 储氢材料对AP的催化促进作用越强. Mg2NiH4催化促进AP分解过程的作用机理为: Mg2NiH4分解释放的H2及Mg和Ni与AP分解产物发生反应.     

镧对红壤硝化、磷转化和酚分解作用的影响

通过室内培养和盆栽试验研究了La对红壤硝化作用,磷转化作用和酚分解作用的影响,低浓度下,La对土壤的硝化作用和磷转化作用均有某些刺激作用,但随着浓度的升高产生抑制作用并不断增加,La对土壤酚分解作用表现为剧烈的抑制作用,并随着浓度的升高,抑制作用不断增强,随着培养时间的延长,La对土壤硝化作用和酚分解作用的抑制作用有降低的趋势。     

The effect of specific surface area of TiO<Subscript>2</Subscript> on the thermal decomposition of ammonium perchlorate

The thermal decomposition of ammonium perchlorate (AP) is considered to be the first step in the combustion of AP-based composite propellants. In this report, the effect of the specific surface area of titanium oxide (TiO₂) catalysts on the thermal decomposition characteristics of AP was examined with a series of thermal analysis experiments. It was clear that the thermal decomposition temperature of AP decreased when the specific surface area of TiO₂ increased. It was also possible that TiO₂ influences the frequency factor of AP decomposition because there was no observable effect on the activation energy.     

镁铜合金储氢材料的制备及对高氯酸铵热分解过程的影响

采用置换-扩散法制备了镁铜合金储氢材料(Mg2Cu-H), 并对其结构进行了表征. 结果表明, Mg2Cu经过氢化得到的镁铜合金储氢材料不是单一晶相, 而是MgCu2和MgH2的混合物. 用热分析法(DSC)研究了镁铜合金储氢材料对固体火箭推进剂常用氧化剂——高氯酸铵(AP)热分解过程的影响. 结果表明, 镁铜合金储氢材料可以显著促进AP的热分解过程, 加快热分解速率, 降低高温热分解温度, 使DSC表观分解热明显增大. Mg2Cu-H对AP热分解过程的促进作用明显强于Mg2Cu. 随着加入量增加, 镁铜合金储氢材料对AP热分解的催化促进作用增强. 探讨了镁铜合金储氢材料促进AP热分解过程的作用机制.     

Effect of the medium on the decomposition rate of di-t-butyl trioxide

Using the chemiluminescence method, the effect of the medium on the overall rate constant of the thermal decomposition of di-tert-butyl trioxide has been studied. In all solvents investigated the decomposition occurs in accordance with a first order rate law. The effect of solvent on the rate constant (0°C) is analyzed.     

Ru上有氧条件下氨分解的动力学研究

IthasbeenshownthatRuisvalidforthesyn thesisanddecompositionofammonia[1,2 ] .FurtherstudyofammoniaadsorptionanditsdecompositionproductsdesorptiononRuwillbeimportant .Previ ousstudiesofammoniaadsorptiononRumainlyfo cusedontheammoniasynthesisandhydrogenpro ductionintheabsenceofoxygen[3] ,onlyafewinves tigationsonammoniadecompositioninthepresenceofoxygenhavebeenreported[4 ,5] ,andtheeffectofad sorbedoxygenontheratesofammoniadecompositionandproductformationonRuarestillnotwellunder stood .Inthispa…     

Effects of fluorescent light and vacuum packaging on the rate of decomposition of pigments in paprika (Capsicum annuum) powder determined by reversed-phase high-performance liquid chromatography.

The effect of storage time, the presence of light and oxygen on the decomposition rate of carotenoid pigments in paprika (Capsicum annuum) powders was determined by reversed-phase high-performance liquid chromatography (RP-HPLC). The similarities and dissimilarities of pigment composition of samples under various storage conditions was elucidated by principal component analysis (PCA) and stepwise regression analysis (SRA). Calculations proved that the overall decomposition rate of pigment sections equally depended on the storage time and on the presence of light and oxygen, the effect of storage time being the most decisive factor while the impact of oxygen was the lowest. The selectivity of decomposition also depended on the storage time and on the presence of oxygen the influence of storage time being the most important. RP-HPLC followed by PCA and SRA can be successfully used for the study of the impact of environmental conditions on the decomposition of carotenoid pigments of paprika powders.     

几种碳卤化物多通道激光化学的研究

本文用CW和TEA CO2激光器研究了F12(CF2Cl2)、F114(CF2ClCF2Cl)和F22(CF2HCl)等碳卤化合物的激光诱导解离反应, 实验发现, 在激光作用下, 这些化合物的解离方式不仅与化合物的性质有关, 还与激光的能量密度密切相关; F22的激光解离为一级反应,并存在“瓶颈效应".     

Studies on the kinetics of decomposition of diacyl peroxides: III. Kinetics and mechanism of decomposition of 3, 5, 5-trimethylhexanoyl peroxide in benzene

The kinetics of decomposition of 3,5,5-trimethylhexanoyl peroxide (1) in benzene at 30, 40, and 50°C respectively have been studied and the cage effect, main products and the products obtained in scavenging experiment with galvinoxyl determined and characterized. The results show that the decomposition of 1, with initial concentration between 0.04 to 0.43 mol. L^?1, followed first plus three halves order kinetics with cage effect of 0.6, and the mechanism of decomposition is basically the same as previously proposed for lauroyl peroxide (2).⁴ In comparison with 2, the decomposition of 1 at the same temperature showed a faster rate for spontaneous decomposition, a larger cage effect and lesser induced decomposition, which is attributed to the branching in molecule of 1, especially to the presence of β-methyl group, which caused a larger entropy increase between the peroxide molecule and the transition state for decomposition.     

脂族酰基过氧化物分解动力学的分研究 III: 过氧化3,5,5-三甲基己酰在萃中的解动力学和机理

The kinetics of decomposition of 3, 5, 5-trimethylhexanoyl peroxide (1) in benzene has been studied at 30, 40 and 50`C and the cage effect of decomposition has been determined by scavenging method. The relative amounts of the main products of decomposition of 1 at 50`C with change of initial concentration have been determined. The results showed that the decomposition of 1 followed first plus three halves order kinetics as reported for lauroyl peroxide (2), but had a larger cage effect of 0.6. The mechanism of decomposition of 1 is practically the same as what we have proposed for 2. The faster rate and larger cage effect but less induced decomposition of 1 than that of 2 are attributed to the branching of the molecule of 1, especially to the presence of β-methyl group, which causes a larger entropy increase in the transition state.     

The photolysis of barium and strontium azides

The effect of very high intensity UV light on powdered barium and strontium azides in vacuo in the temperature ranges −70° to 100°, and −80° to 90°, has been studied. The photolytic decompositions were characterized by a high percentage decomposition and sigmoid pressure vs time plots similar to those obtained by thermal decomposition. Kinetic analysis, the determination of activation energies, studies of the dependence of reaction rates on light intensity, and the effect of water vapour, were carried out. Mechanisms for decomposition over well defined temperature ranges are proposed.     

Research of thermal decomposition of hydrated methanesulfonates

Hydrated methanesulfonates Ln(CH₃SO₃)₃·nH₂O (Ln=La, Ce, Pr, Nd and Yb) and Zn(CH₃SO₃)₂·nH₂O were synthesized. The effect of atmosphere on thermal decomposition products of these methanesulfonates was investigated. Thermal decomposition products in air atmosphere of these compounds were characterized by infrared spectrometry, the content of metallic ion in thermal decomposition products were determined by complexometric titration. The results show that the thermal decomposition atmosphere has evident effect on decomposition products of hydrated La(III), Pr(III) and Nd(III) methanesulfonates, and no effect on that of hydrated Ce(III), Yb(III) and Zn(II) methanesulfonates. This revised version was published online in August 2006 with corrections to the Cover Date.     

光照对高铁酸盐溶液稳定性的影响

The effects of light wave on the stability of fen'ate solution have been examined. The results showed that UV-light accelerates the decomposition of ferrate with decomposition rate 1.6 times as much as that in dark whereas infrared light has only unclear effect on the stability of ferrate, with decomposition rate 1.1 times as much as in dark. The polythene container is found to the best for preservation of ferrate solution in dark.     

The thermal decomposition behavior of RDX-base propellants

In this paper, the thermal decomposition of cyclotrimethylenetri-nitramine (RDX)-base propellants involving many components has been investigated by differential scanning calorimeter (DSC). The decomposition characters at different heating rates and the activation energies are determined by DSC measurement. The results show that the decomposition of RDX is accelerated obviously during the decomposition of nitroglycerin (NG). Though the content of dibutyl-benzene-dicarbonate (DBP) ingredient in the propellants is less, it has a remarkable effect on the initial decomposition temperature of the propellants. The azido-nitromine compound (DIANP) brings about the shift of the peak of decomposition of RDX and nitrocellulose (NC) to lower temperature due to its liquefying or dissolving.     

Preparation of nano-cerium dioxide and its effect on the thermal decomposition of ammonium perchlorate

Detonation synthesis method was introduced to prepare nano-cerium dioxide. Nano-cerium oxide was obtained by this novel method and its effect on the thermal decomposition of ammonium perchlorate (AP) was studied. X-ray diffraction and transmission electron microscope were used to characterize as-prepared materials. Results showed that as-prepared cerium dioxide was cubic phase and its morphology was nearly spherical. The mean size of as-prepared cerium dioxide particles was 55 nm. Differential scanning calorimetry (DSC) was used to test the effect of as-prepared nano-cerium dioxide on the thermal decomposition of AP. Kissinger method was introduced to calculate activation energy of different specimens according to DSC data. Results indicated that nano-cerium dioxide synthesized by detonation method had catalytic effect on thermal decomposition of AP and could decrease activation energy of AP/CeO₂ mixture.     

Mg(OH)2热分解反应的非等温动力学研究

用非等温动力学方法对氢氧化镁的热分解动力学进行了研究. 分解反应机理符合晶核形成及生长机理A，且随着升温速率的升高，机理由A2转变为A1.5. 根据Kissinger非机理方程计算和数值回归方法验证所得的分解反应活化能结果相互印证，约为148 kJ•mol^-1. 进一步研究发现，水蒸气的存在对氢氧化镁热分解反应具有非常明显的影响，可能是其动力学机理随升温速率升高而改变的主要影响因素.     

EPR characterization of carbonate ion effect on TCE and PCE decomposition by gamma-rays

Carbonate ions significantly inhibit the decomposition of TCE (trichloroethylene) and PCE (perchloroethylene) by gamma-rays. The inhibition effect is larger in the case of TCE than PCE due to a greater dependence of TCE decomposition on hydroxyl radicals. The inhibition effect of carbonate ions was characterized by an EPR/spin-trapping technique. The intensity of DMPO-OH adduct signal decreased as the carbonate ion concentration increased and the percent of signal reduction was linearly proportional to the logarithm of carbonate ion concentration. This directly proves that the carbonate ions inhibit the decomposition of TCE and PCE by scavenging hydroxyl radicals.     

Thermal behavior of ammonium perchlorate and metal powders of different grades

The effects of aluminum (Al) and nickel (Ni) powders of various grain sizes on the thermal decomposition of ammonium perchlorate (AP) were investigated by TG and DSC in a dynamic nitrogen atmosphere. The TG results show that Al powders have no effect on the thermal decomposition of AP at conventional grain size, while the nanometer-sized Ni powders (n-Ni) have a great influence on the thermal decomposition of AP with conventional and superfine grain size. The results obtained by DSC and an in situ FTIR analysis of the solid residues confirmed the promoting effects of n-Ni. The effects of n-Ni have been ascribed to its enhancement on the gas phase reactions during the second step decomposition of conventional grain size AP.