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1.
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  
方正东  汪敦佳 《无机化学学报》2005,21(11):1682-1686
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   

2.
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   

3.
高岭土/二甲亚砜插层复合物脱嵌反应热动力学   总被引:1,自引:0,他引:1  
采用TG和XRD研究了高岭土/二甲亚砜插层复合物的脱嵌反应过程, 提出了一种新的动力学计算方法. 首先用迭代的等转化率法求得反应的活化能Ea, 然后用Malek法拟合得到最可能的机理函数G(α)和f(α), 最后用多升温速率-等温法求得了指前因子A. 研究结果表明, 高岭土/二甲亚砜的插层物脱嵌反应的活化能Ea=86.65 kJ/mol, 指前因子A位于1.6050×108~3.6151×108 s-1之间. 其反应机理为n级的化学反应, 机理函数是G(α)=[1-(1-α)1-n]/(1-n), f(α)=(1-α)n. n值和升温速率有一定的关系, 当升温速率较大(30 ℃/min)或较小(5 ℃/min)时, n=1.5, 当升温速率为7~25 ℃/min时, n=1.6.  相似文献   

4.
水合草酸钡脱水过程的机理判别和动力学研究   总被引:1,自引:0,他引:1  
李靖华  张宁  成庆堂 《化学学报》1993,51(6):550-555
用等温热重法和线性升温热重法在氮气气氛中研究B~aC~2O~4·0.5H~2O的脱水过程.运用判断机理的三步判别法对实验数据分析证明:该过程受随机成核和晶核随后生长机理控制.通过晶体结构分析对这种机理的正确性进行了验性.  相似文献   

5.
0引言溶剂作为湿化学法合成无机材料的微环境,其物化性质如极性、粘度、硬度等对无机材料的合成均有重大影响[1]。当前大多数的研究工作主要限于水溶液,有关溶剂性质对无机材料合成影响的研究较少。近年来,利用混合溶剂作为调控合成无机材料的有效手段逐渐引起关注[2 ̄6]。在醇  相似文献   

6.
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   

7.
草酸镁二水合物的非等温热分解动力学   总被引:1,自引:0,他引:1  
张建军  任宁  白继海 《中国化学》2006,24(3):360-364
The thermal decomposition of the magnesium oxalate dihydrate in a static air atmosphere was investigated by TG-DTG techniques. The intermediate and residue of each decomposition were identified from their TG curve. The kinetic triplet, the activation energy E, the pre-exponential factor A and the mechanism functionsf(a) were obtained from analysis of the TG-DTG curves of thermal decomposition of the first stage and the second stage by the Popesou method and the Flynn-Wall-Ozawa method.  相似文献   

8.
顺—反异构体的研究,在配合物化学中占有重要的地位。二水二草酸合铬酸钾这一配合物顺、反异构体的制备和异构化现象的研究已有报导,但多限于水溶液体系。也有关于该配合物热稳定性和热分解动力学研究的报导但对固相中该配合物异构体转变的研究尚未见报导。本文利用DTA方法,对二水二草酸合铬酸钾顺、反异构体的制备以及固相中异  相似文献   

9.
10.
本文合成了铬(Ⅲ)的一个新的双核配合物Cr2(Nica)4Cl5(OH)(H2O)6(Nica表示烟酰胺.通过元素分析、摩尔电导、红外光谱、热重.对该配合物进行了表征,表明烟酰胺以吡啶氮与铬(Ⅲ)配位.文章对该配合物进行了热分解脱水非等温动力学研究,运用Achar法与Coats—Redfern法,推断出该热分解脱水反应为二级反应.其动力学方程为dα/dt=Ac(-E/RT)(1-α)2,动力学补偿效应表达式为InA=0.2992E-10.5682.  相似文献   

11.
Introduction Solid state kinetics has been extensively studied by means of thermal analysis methods[1]. The aim of the study is to determine the mechanism function f(α) , the activation energy E and the pre-exponential factor A. In recent years there have been many methods of processing thermal analysis kinetic data[2-11].  相似文献   

12.
Pan  Y.  Guan  X.  Feng  Z.  Wu  Y.  Li  X. 《Journal of Thermal Analysis and Calorimetry》1999,55(3):877-884
A new method was proposed for determining the most probable mechanism function of a solid phase reaction. According to Coats-Redfern's integral equation Eβ→0 was calculated by extrapolating β to zero using a series of TG curves with different heating rates. Similarly, Eα→0 was calculated according to Ozawa's equation. The most probable mechanism function of the solid phase dehydration of manganese(II) oxalate dihydrate was confirmed to be G(α)=(1-α)1/2 by comparing Eα→0 with Eβ→0. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

13.
草酸钙结石的形成与尿液中草酸钙的存在形式密切相关,一水草酸钙(COM)促进尿石症形成,而二水草酸钙(COD)易随尿液排出体外。本文采用体外模拟方法,比较研究了COD晶体在水溶液、正常人尿液和结石患者尿液3个不同体系中的稳定性及海藻龙须菜多糖(SPS)对COD的稳定作用。在水溶液和患者尿液中,不但COD转化率高,而且得到的转化产物COM晶体聚集程度大;而在正常人尿液中,COD转化率低,转化产物聚集程度较小。COD在不同体系中转化的速度依次为:水溶液>患者尿液>正常人尿液。从海藻龙须菜中提取的硫酸多糖可以稳定COD的存在并减小COM的聚集,这有利于阻止草酸钙结石的形成,因此,海藻龙须菜多糖有可能用于防止草酸钙结石形成。  相似文献   

14.
Thermal decomposition of CoC2O4⋅2H2O was studied using DTA, TG, QMS and XRD techniques. It was shown that decomposition generally occurs in two steps: dehydration to anhydrous oxalate and next decomposition to Co and to CoO in two parallel reactions. Two parallel reactions were distinguished using mass spectra data of gaseous products of decomposition. Both reactions run according toAvrami–Erofeev equation. For reaction going to metallic cobalt parameter n=2 and activation energy is 97±14 kJ mol–1. It was found that decomposition to CoO proceeds in two stages. First stage (0.12<αII<0.41) proceeds according to n=2, with activation energy 251±15 kJ mol–1 and second stage (0.45<αII<0.85) proceeds according to parameter n=1 and activation energy 203±21 kJ mol–1. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

15.
An investigation was carried out on the kinetics of thermal decomposition of plumbo-jarosite. The kinetic models of dissociation of the compounds in the ore were identified. The results of the kinetic studies and the mechanism of the process are discussed. The thermal decomposition of plumbo-jarosite occurs in three stages: the first up to 763, the second up to 1023 and the third up to 1223 K, the corresponding activation energy values being 62.2, 60.3 and 98.0 kJ mol–1 , respectively. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

16.
Thermal decomposition of tetra(piperidinium) octamolybdate tetrahydrate, [C5H10NH2]4[Mo8O26]·4H2O, was investigated in air by means of TG‐DTG/DTA, DSC, TG‐IR and SEM. TG‐DTG/DTA curves showed that the decomposition proceeded through three well‐defined steps with DTA peaks closely corresponding to mass loss obtained. Kinetics analysis of its dehydration step was performed under non‐isothermal conditions. The dehydration activation energy was calculated through Friedman and Flynn‐Wall‐Ozawa (FWO) methods, and the best‐fit dehydration kinetic model function was estimated through the multiple linear regression method. The activation energy for the dehydration step of [C5H10NH2]4[Mo8O26]·4H2O was 139.7 kJ/mol. The solid particles became smaller accompanied by the thermal decomposition of the title compound.  相似文献   

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