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首页> 外文期刊>The journal of physical chemistry, C. Nanomaterials and interfaces >Principal Features of Tetrapropylammonium Hydroxide Removal Kinetics from Silicalite-1 in Quasi-isothermal Heating Regimes
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Principal Features of Tetrapropylammonium Hydroxide Removal Kinetics from Silicalite-1 in Quasi-isothermal Heating Regimes

机译：在准等温加热条件下从silicalite-1去除四丙基氢氧化铵动力学的主要特征

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摘要

We study the time dependence of tetrapropylammonium hydroxide (TPAOH) removal from unconsolidated silicalite-1 crystal layers. The changes in the as-synthesized silicalite4 crystals caused by TPAOH removal were investigated by thermogravimetric (TG) measurements using oxidative and nonoxidative gaseous agent. TG experiments were carried out under quasi-isothermal conditions that consisted of fast heating the sample to various temperatures T_(max) and keeping at those temperatures. The shape of the TG curves confirmed the key role of the mobilization reaction that controls the percolation of the mobile products of TPAOH through the zeolite channel system. Another key finding was the existence of clearly defined deviations between the TG curves for air and those for N2. On the basis of these results, we proposed a simplified kinetic model that accounts for the principal features of quasi-isothermal TPAOH removal from silicalite-1. Our model approximates the TG arrangement with a continuous stirred tank reactor, a combined effect of mobilization reaction and bond—site percolation on a diamond lattice, and also possible kinetic steps involved during transport of TPAOH decomposition products from silicalite-1 crystals into the main gas stream. Based on the analysis of the TG curves, we estimated the activation energy (E_a) of the mobilization reaction from the point of deviation as 164 kj/mol.
机译：我们研究了从未固结的silicalite-1晶体层中去除氢氧化四丙基铵（TPAOH）的时间依赖性。通过热重（TG）测量，使用氧化剂和非氧化剂气态剂，研究了由于TPAOH去除而导致的合成硅质岩晶体的变化。 TG实验在准等温条件下进行，包括将样品快速加热至各种温度T_（max）并保持在这些温度下。 TG曲线的形状证实了动员反应的关键作用，该动员反应控制TPAOH的移动产物通过沸石通道系统的渗透。另一个关键发现是空气和N2的TG曲线之间存在明确定义的偏差。基于这些结果，我们提出了简化的动力学模型，该模型解释了从silicalite-1去除准等温TPAOH的主要特征。我们的模型通过连续搅拌釜反应器，移动反应和键位渗漏在金刚石晶格上的综合作用，以及TPAOH分解产物从silicalite-1晶体运输到主要气体中可能涉及的动力学步骤，对TG的布置进行了近似流。基于TG曲线的分析，我们从偏离的角度估计动员反应的活化能（E_a）为164kj / mol。

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