摘要
碱性氮化物(如吡啶、喹啉等)在沸石分子筛上的吸附作用是催化裂化催化剂中毒的重要原因,吸附过程复杂,研究费时且费用高。本文采用巨正则蒙特卡罗方法(GCMC)研究了373 K,473 K和573 K时吡啶、2,6-二甲基吡啶、2,4,6.三甲基吡啶在八面沸石分子筛中的吸附性能,得到了有关吸附平衡常数、吸附热、吸附等温线等信息。计算得到的吸附热顺序为:2,4,6-三甲基吡啶(64.2 kJ/mol)>2,6-二甲基吡啶(59.6 kJ/mol)>吡啶(49.3 kJ/mol),吸附热数值处于文献报道的范围内;在373 K、473 K时,吡啶的饱和吸附量高于其他两种衍生物,吸附等温线能够较好地用Langumir模型拟合;573 K时,2,6-二甲基吡啶的吸附量最高,吡啶的吸附量最低,吸附等温线能够很好地用Freundlich模型拟合。吡啶衍生物在八面沸石分子筛上的吸附热和吸附量不同是由于它们的碱性和分子结构不同造成的。模拟所得吸附数据对于生产、研发、设计具有指导意义。
The catalyst of FCC can be deactivated because of the basic nitrogens such as pyridine and adsorbed in the faujasite zeolites. The adsorption process is very complicated, time/labor consumptive and need large amount of money and materials. The sorption of pyridine derivatives in faujasite zeolite was simulated by Grand Canonical Monte Carlo （GCMC） simulations at 373 K, 473 K and 573 K. The Henry constant, isosteric heat of adsorption and the isotherms of pyridine derivatives in the framework were obtained. The resuits showed that the sequence of isosteric heat was 2,4,6-Trimethylpyridine（64. 2 kJ/mol） 〉 2,6-dimethylpyridine（ 59. 6 kJ/mol） 〉 pyridine（49. 3 kJ/mol） ,the value of the isosteric heat was in the range of the experiments. It was observed that the sorption capacity of pyridine was higher than that of the other two derivatives and the isotherms can be well fitted with Langmuir equations at 373 K and 473 K; The sorption loading of 2, 6-dimethylpyridine was highest among the pyridine derivatives and the isotherms can be well fitted with Freundlich equations at 573 K under 0. 1 kPa - 0. 4 kPa, which could be well interpreted based on the differences of basicities and the molecular structures of the adsorbates. The data of adsorption is useful for FCC production and studies and design.
出处
《计算机与应用化学》
CAS
CSCD
北大核心
2008年第12期1553-1556,共4页
Computers and Applied Chemistry
关键词
吡啶衍生物
八面沸石
吸附
分子模拟
pyridine derivatives, faujasite zeolite, adsorption, molecular simulation
