Diffusion of Mixtures of Light Alkanes and Benzene in Nano-Sized H-ZSM5
Diffusion of Mixtures of Light Alkanes and Benzene in Nano-Sized H-ZSM5
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DOI：
10.1021/jp500451q
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发表时间：
2014-04
影响因子：
3.7
通讯作者：
R. Kolvenbach;L. Peña;A. Jentys;J. Lercher
中科院分区：
文献类型：
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作者：
R. Kolvenbach;L. Peña;A. Jentys;J. Lercher
利用快速时间分辨红外光谱研究了直链C4-C6烷烃和苯在纳米H-ZSM 5晶体上的联合输运。在共吸附的烷烃和芳烃的内部和外部的浓度分布直接监测的沸石，其中运输是由孔入口步骤控制。详细的动力学分析表明，在轻烃分子的吸附和孔隙进入率下降后，加入苯约10- 30%。这是由速率常数和外表面覆盖率的降低引起的。另一方面，苯的表观扩散系数与纯组分相比降低高达80%。这种减少归因于在靠近孔隙口的位点处的竞争性吸附。的程度增加，减少链长的共吸附烷烃，这对应于同时减少轻烃的孔口位置的占用。
The joint transport of linear C4–C6 alkanes and benzene has been studied over nanosized H-ZSM5 crystals by fast-time-resolved infrared spectroscopy. The internal and external concentration profiles during the coadsorption of alkanes and aromatics were directly monitored for a zeolite in which transport is controlled by the pore entrance step. The detailed kinetic analysis revealed a decrease in the adsorption and pore entrance rates of light hydrocarbon molecules upon addition of benzene by about 10–30%. This was caused by both a reduction in the rate constants and in the coverage at the external surface. On the other hand the apparent diffusion coefficient of benzene decreased up to 80% in comparison to the pure component. This decrease is attributed to a competitive adsorption at sites near the pore mouth. The extent increased with decreasing chain length of the cosorbed alkane, which corresponds to a simultaneous decrease in occupation of pore mouth sites by light hydrocarbons.