吡啶在HY分子筛上的脱附反应动力学及酸中心强度的表征  

Kinetics of Pyridine Desorption from Acid Sites on HY Zeolite and Characterization of Its Acid Strength

作　　者：王斌[1,2] 张颖[2] 左敏[2] 郭广生[1] 

机构地区：[1]北京化工大学化工资源有效利用国家重点实验室,北京100029 [2]中国石化北京化工研究院,北京100013

出　　处：《石油化工》2014年第3期264-268,共5页Petrochemical Technology

基　　金：中国石油化工股份有限公司资助项目(410001)

摘　　要：运用改进的程序升温脱附-红外光谱(TPD-IR)技术,采用新的脱附动力学模型,研究了吡啶在HY分子筛B酸中心和L酸中心上的脱附反应动力学,分别计算了吡啶在HY分子筛两种类型酸中心上的脱附活化能,并以此量化了各酸中心的强度,对表面酸中心的类型进行了详细的区分。实验及计算结果表明,吡啶在HY分子筛B酸中心上的程序升温脱附反应符合一级动力学模型,以其为探针分子,可在HY分子筛表面区分出两种强度不同的B酸中心,对应的吡啶脱附活化能分别为32.4,18.6 kJ/mol;吡啶在HY分子筛L酸中心上的程序升温脱附反应符合三级动力学模型,HY分子筛表面同时存在两种不同强度的L酸中心,对应的吡啶脱附活化能分别为24.9,5.3 kJ/mol。The desorption kinetics of pyridine from the B acid sites and L acid sites on HY zeolite was studied by means of an improved temperature programmed desorption-infrared spectrum（TPD-IR） technique.The desorption activation energy ofpyridine as probe molecules adsorbed on the B acid sites or L acid sites was calculated using a new desorption kinetics model to determine the type and strength of the acid sites.The results indicated that the temperature programmed desorption process of pyridine adsorbed on the B acid sites fitted well into the mechanism of the first order desorption reaction.The B acid sites were divided into two types with the desorption activation energies of 32.4 kJ/mol and 18.6 kJ/mol.The temperature programmed desorption process of pyridine adsorbed on the L acid sites of the HY zeolite accorded with the third order desorption reaction kinetics.There were two types of the L acid sites on the HY zeolite with the desorption activation energies of 24.9 kJ/mol and 5.3 kJ/mol.

关 键 词：HY分子筛 吡啶 程序升温脱附-红外光谱技术 脱附动力学 酸中心强度 

分 类 号：TQ032.47[化学工程]