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1.
研究了过氧化苯甲酸叔丁酯的热分解动力学及不同包装规格下的自加速分解温度(SADT),利用C600微量热仪测试了过氧化苯甲酸叔丁酯的热分解特征,得到升温速率分别为0.1 K/min、0.2 K/min、0.5 K/min、1 K/min下热流随时间的变化曲线,并使用Friedman等转化率法对所得的实验数据进行分析处理,得到了过氧化苯甲酸叔丁酯的分解反应活化能、指前因子等热动力学参数,推算了不同包装规格的过氧化苯甲酸叔丁酯的SADT。结果表明TBPB分解活化能及指前因子随转化率变化而变化,活化能范围为42-135.5 kJ/mol,指前因子范围为0.25-33.5,在25L聚乙烯桶包装下的SADT为59℃,50L下为52℃,200L下为46℃。 相似文献
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二水草酸亚铁热分解反应动力学 总被引:2,自引:0,他引:2
用原位XRD技术和热重法分析了二水草酸亚铁的热分解过程, 并进行了动力学研究. 通过结合主曲线法和统计方法判定了热分解过程的动力学模型函数, 并求算了动力学参数. 在静态自产气氛下, 二水草酸亚铁脱水反应遵循随机成核与核增长模型, 草酸亚铁热分解生成氧化铁遵循相界面控制动力学模型. 结果表明, 该方法可以准确、可靠地判定非等温热分解反应的动力学模型函数,并求算动力学参数. 相似文献
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二水草酸亚铁热分解行为及脱水反应动力学研究 总被引:2,自引:0,他引:2
The thermal behavior of ferrous oxalate dihydrate (FeC2O4·2H2O) was studied by thermogravimetry and differential thermal analysis (TGA and DTA). Three steps could be deduced for the decomposition from the TG,DTG and DTA curves obtained. One of the steps was the dehydration, the mass loss was 20.1%(the found value was in good agreement with the calculated value). Mathematical analysis with the integral and differential methods showed that the kinetics of dehydration of FeC2O4·2H2O could be explained by F1 mechanism in nitrogen atmosphere. The kinetic equation of dehydration of FeC2O4·2H2O could be expressed as: dα/dt=6.25×1019[exp(-170.27×103/RT)](1-α) 相似文献
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3,4-二硝基吡唑热分解及非等温动力学 总被引:4,自引:0,他引:4
采用TG-DSC综合热分析的方法,对3,4-二硝基吡唑(DNP)的热分解和非等温动力学进行了研究。结果表明DNP的热分解分两阶段进行,并且在升温速率达到15K/min时才能明显区分。分别采用Archar微分法和Coats-Redfen积分法计算了DNP第一阶段热分解反应动力学参数:Ea=91.6kJ.mol-1,lnA=42.7s-1。最可能的DNP热分解机理为随机成核和随后生长机理,符合动力学机理函数Avrami-Erofeev方程,n=3。 相似文献
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KNCO通常用氢氧化钾和尿素在熔融态下反应而合成,其中过量的尿素用长时间高温焙烧来除去。我们用热重法对KNCO粗品中的尿素进行了热分解动力学研究,以期确定合理的焙烧温度和时间。将分析纯尿素和氢氧化钾按1.7:1(摩尔比)混合均匀,加热熔融,搅拌反应2小时,得含有剩余尿素的白色KNCO试样。热解用北京光学仪器厂LCT型差热天平,a-Al_zO_3为参比物,空气气氛,升温速率10℃/min。红外光谱用Nicolet 5DX型仪,KBr压片。 结果与讨论 相似文献
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采用化学氧化沉淀法, 以过硫酸钾为氧化剂制备了硅藻土负载过氧化银(AgO)复合材料, 并使用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和激光粒度仪对其进行了表征, 借助热重(TG)分析研究了复合材料的热分解过程和非等温热分解动力学. 结果表明, 制备的复合材料为正方晶系方英石和单斜晶系AgO混合体, 且AgO质量分数为12.7%; 复合材料的中位径为18.53 μm, 比表面积为203.32 m2/kg, 颗粒的粒度分布在0.614~116.5 μm之间. 复合材料中AgO在171 ℃开始分解成Ag2O, 在更高温度时Ag2O进一步分解成Ag; 热分解反应服从以核生成和核成长为控制步骤的A1机理, 其热分解表观活化能为131.37 kJ/mol, 反应频率因子为3.19×1013 s-1. 同自制的AgO粉末相比, 复合材料中AgO的热分解温度升高, 表观活化能上升约40 kJ/mol. 相似文献
11.
Thermal hazard studies for dicumyl peroxide by DSC and TAM 总被引:1,自引:0,他引:1
A differential
scanning calorimetry (DSC) and thermal activity monitor (TAM) were used to
study the thermo-kinetic parameters for dicumyl peroxide (DCPO) at various
concentrations. The potential thermal hazards of intermediates and end products
whose concentrations were at approximately 50, 70, 94 and 99.3 mass%, respectively,
in the process of operating DCPO were investigated. Thermoanalytical curves
indicate that the average heat of decomposition of various DCPO samples in
a manufacturing process was 762 to 1200 J g -1
which made it an inherently hazardous material. In the incompatibilities study,
significant thermal hazards appeared in the presence of H2SO4.
From the TAM experiments, the synthetic process of DCPO could result in an
unexpected reaction in the condition of batch addition with reactants and
H2SO4. 相似文献
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Information
about the kinetics and thermal decomposition of dicumyl peroxide (DCPO) is
required for safety concerns, due to its wide applications and accident cases.
To understand the inherent hazards during DCPO manufacturing, we selected
various concentrations in different stages and analyzed them by differential
scanning calorimetry (DSC). We evaluated thermokinetic parameters to set up
a simple, but comprehensive kinetic model, with various tests conducted at
heating rates of 2, 4, 6 and 10°C min-1
. Subsequently, we established a more efficient, resource-effective, and cost-effective
model of safety evaluation for DCPO with different concentrations, according
to thermokinetic parameters, such as activation energy Ea
is 125.35 kJ mol-1 , frequency factor k0 is 3.124·10 12
s-1 , reaction order n is 0.9 and heat of
decomposition ΔH is 750.52 J g-1
for DCPO 99 mass%. 相似文献
13.
T. Uchida M. Wakakura A. Miyake T. Ogawa 《Journal of Thermal Analysis and Calorimetry》2008,93(1):47-52
In this study, we evaluated the reactivity of organic peroxides with metals. The effect of the metals on the decomposition
of organic peroxides was measured using a differential scanning calorimeter (DSC). Results of DSC measurements showed that
some organic peroxides have high reactivity with a gold plated cell. Especially, hydroperoxides were decomposed at lower temperature
using the gold plated cell when compared to other type of cells.
In order to evaluate the effect of metals on the hydroperoxides, the decomposition characteristics of cumenhydroperoxide (CHP)
with metal powders were studied using a C80 calorimeter and the products were analyzed by a gas chromatograph. These results
indicated that the radical reaction of CHP was catalyzed by the gold and the autocatalytic reaction of CHP was catalyzed by
stainless steel (SUS) and hastelloy c (HC). 相似文献
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R. N. Zaripov R. L. Safiullin E. I. Yaubasarova R. R. Muslukhov V. D. Komissarov 《Russian Chemical Bulletin》1995,44(6):1011-1013
The kinetics of thermal decomposition of acetylcyclohexylsulfonyl peroxide is studied in an-decane solution in an oxygen atmosphere (303–333 K) and under anaerobic conditions (313–333 K); the reaction products are also studied in a cyclohexane solution under oxygenfree conditions (323 K). In the absence of oxygen, the reaction is found to proceedvia a chain-radical mechanism. Some kinetic parameters of the process are determined.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1049–1052, June, 1995.This work was supported by the Russian Foundation for Basic Research (Project No. 93-03-5231). 相似文献
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A. Miyake K. Nomura Y. Mizuta M. Sumino 《Journal of Thermal Analysis and Calorimetry》2008,92(2):407-411
To understand better the thermal decomposition characteristics of organic peroxides, a C80 heat flux calorimeter was used
and the decomposition pattern of cumene hydroperoxide and di-tert-butylperoxide were classified as auto-catalytic and n
th order reaction, respectively. Based on the scanning results with the C80 at several differing rates of heating, the thermal
decomposition behavior of organic peroxides under isothermal storage at lower temperature was simulated with a model-free
simulation. Simulated results showed that the calculated conversion of cumene hydroperoxide as a function of time was in good
agreement with experimental data obtained with the TAM-III high sensitivity thermal activity monitor. 相似文献
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Thermal
analysis of jute fibre reinforced vinylester resin with 30 vol% of fibre were
performed by TG/DTG under dynamic conditions. The fibres were treated with
alkaline solution at different temperatures and the final composition (cellulose,
hemicellulose and lignin) of the fibre was determined by chemical analysis.
Apparent activation energies were determined using a variety of conventional
thermogravimetric methods. Two peaks were found in the composite differential
curves: the first peak close to 327 and the second peak at 408°C. The
apparent activation energy values for the second peak decreased when fibre
were treated. The addition of the jute fibres produced a slightly decrease
in the thermal stability of the composites. 相似文献
17.
Fatma KARA Duygu ADIGÜZEL Ufuk ATMACA Murat ELK Jale NAKTYOK 《Turkish Journal of Chemistry》2020,44(6):1483
A humic substance was obtained from hazelnut husk using an alkali extraction. The chemical and morphological structure of the humic matter was characterized via elemental analysis, Fourier transform infrared spectrometry (FTIR), nuclear magnetic resonance, Brunauer-Emmet-Teller (BET) analysis, scanning electron microscopy (SEM), and thermogravimetric-FTIR (TG-FTIR). In addition, thermal analysis measurements TG analysis-differential thermogravimetry/differential scanning calorimetry (TGA-DTG/DSC) were performed under dynamic air conditions to better determine the origin, physical and chemical structure, and decomposition process of the humic matter. The Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods were used to calculate the kinetic parameters of the high-temperature decomposition process. It was observed that the activation energy values were almost constant at certain conversion and temperature intervals. In addition, the structure of the humic substance at different temperatures was also investigated via FTIR analysis. It was found that the obtained humic substance had a very stable structure and decomposed at a high temperature. The stability of the humic matter can be a useful tool in the environmental quality research of soil. 相似文献
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The thermal decomposition of theophylline, theobromine, caffeine, diprophylline and aminophylline were evaluated by calorimetrical,
thermoanalytical and computational methods. Calorimetrical studies have been performed with aid of a heat flux Mettler Toledo
DSC system. 10 mg samples were encapsulated in a 40 μL flat-bottomed aluminium pans. Measurements in the temperature range
form 20 to 400°C were carried out at a heating rate of 10 and 20°C min−1 under an air stream. It has been established that the values of melting points, heat of transitions and enthalpy for methylxanthines
under study varied with the increasing of heating rate.
Thermoanalytical studies have been followed by using of a derivatograph. 50, 100 and 200 mg samples of the studied compounds
were heated in a static air atmosphere at a heating rate of 3, 5, 10 and 15°C min−1 up to the final temperature of 800°C. By DTA, TG and DTG methods the influence of heating rate and sample size on thermal
destruction of the studied methylxanthines has been determined. For chemometric evaluation of thermoanalytical results the
principal component analysis (PCA) was applied. This method revealed that first of all the heating rate influences on the
results of thermal decomposition. The most advantageous results can be obtained taking into account sample masses and heating
rates located in the central part of the two-dimensional PCA graph. As a result, similar data could be obtained for 100 mg
samples heated at 10°C·min−1 and for 200 mg samples heated at 5°C min−1. 相似文献
19.
利用热重分析法研究了在不同升温速率下新型单组份磷-氮膨胀型阻燃剂六(4-(9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物)-羟甲基苯氧基)环三磷腈(DOPOMPC)在氮气气氛和空气气氛中的热分解动力学.采用Kissinger和Flynn-Wall-Ozawa(FWO)法分别计算出DOPOMPC在相应气氛下的活化能和指前因子. 相似文献
20.
R. N. Zaripov R. L. Safiullin E. I. Yaubasarova A. A. Mukhametzyanova V. D. Komissarov 《Russian Chemical Bulletin》1997,46(5):895-897
The kinetics of the decomposition of acetylcyclohexylsulfonyl peroxide (ACSP) in CCl4, benzene, toluene, ethylbenzene, cumene, acetonitrile, ethanol, and 2-propanol in an atmosphere of O2 were studied at 40–70 °C. The rate constants (k
0) and activation parameters of the monomolecular decomposition of ACSP were determined. A linear dependence between logA
0 and activation energyE
0 (compensation effect) was established. The dependence ofk
0 on the nature of a solvent is described by the four-parameter Koppel-Palm equation.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 935–937, May 1997. 相似文献