正辛烷和1-辛烯在CeY分子筛上吸附的分子模拟研究

石油炼制与化工 ›› 2018, Vol. 49 ›› Issue (11): 72-79.

正辛烷和1-辛烯在CeY分子筛上吸附的分子模拟研究

任卓然,李强,秦玉才,宋丽娟

辽宁石油化工大学辽宁省石油化工催化科学与技术重点实验室

收稿日期:2018-03-05 修回日期:2018-04-09 出版日期:2018-11-12 发布日期:2018-11-29
通讯作者: 宋丽娟 E-mail:lsong56@263.net
基金资助:
国家自然科学基金

MOLECULAR SIMULATION STUDY ON ADSORPTION BEHAVIOR OF OCTANE AND 1-OCTENE ON CeY ZEOLITE

Received:2018-03-05 Revised:2018-04-09 Online:2018-11-12 Published:2018-11-29
Supported by:

摘要/Abstract

摘要： 采用分子动力学(MD)和巨正则蒙特卡洛(GCMC)方法，模拟正辛烷和1-辛烯在Ce离子改性Y型分子筛上的吸附行为。分析了303 K、423 K温度下正辛烷、1-辛烯分子在CeY中的吸附等温线并对模拟数据进行了Langmuir-Freundlich模型拟合，结合吸附过程的势能分布曲线、分子势能分布密度以及吸附热等数据探究吸附规律。结果表明：正辛烷与1-辛烯在CeY上的吸附，符合Langmuir-Freundlich等温吸附模型，正辛烷与1-辛烯和CeY孔道中的Na+相互作用较强，与Ce(OH)2+间相互作用较弱且随着吸附压力的增大逐渐减小；正辛烷比1-辛烯更容易吸附在CeY上，饱和吸附量更高，最可几相互作用更大，势能随温度变化更大，且正辛烷的吸附热在吸附起始阶段大于1-辛烯，在接近饱和吸附时略小于1-辛烯。这是由于1-辛烯内部存在的C=C键产生了较弱的π-π相互作用，随着温度和吸附量的增加，使得分子间相互作用力较正辛烷更为明显。

关键词: 蒙特卡洛, 分子动力学, 正辛烷, 1-辛烯, CeY分子筛, π-π相互作用

Abstract: The adsorption and diffusion behaviors of octane and 1-octene molecules on CeY zeolite were simulated by the Grand Canonical Monte Carlo method and molecular dynamics method. To investigate the discipline of the adsorption isotherms of octane and octene on CeY, The Langmuir-Freundlich fitting curve, distribution curve of energy, contour maps of density and isosteric heat of adsorption at 303K and 423K were used. The results showed that the adsorption confirms to Langmuir-Freundlich model for octane. The interaction between octane or 1-octene and Na+ in the hierarchical pores of CeY zeolite is stronger, and the strength with Ce(OH)2+is the next and becomes weaker as the adsorption pressure raises. Octane is much easy to adsorb on CeY and has a stronger interaction with it, getting a larger saturation adsorbance than octene, the energy change of octane adsorption is more significant with the change of temperature. The adsorption heat of octane is higher than octene in the beginning of adsorption and turns lower than octene in the end stage, because the π-π interaction between octene becomes more obviously than octane with the increase of adsorbance and temperature.

Key words: GCMC, MD, n-octane, 1-octene, CeY zeolite, π-&pi, interaction.

中图分类号:

任卓然李强秦玉才宋丽娟. 正辛烷和1-辛烯在CeY分子筛上吸附的分子模拟研究[J]. 石油炼制与化工, 2018, 49(11): 72-79.

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