Coke deposition and characterization on titanium silicalite-1 catalyst in cyclohexanone ammoximation
Coke deposition and characterization on titanium silicalite-1 catalyst in cyclohexanone ammoximation
复制标题
DOI：
10.1016/j.apcata.2006.03.050
复制
发表时间：
2006-07
影响因子：
5.5
通讯作者：
X. Zhang;Yan Wang;F. Xin
中科院分区：
文献类型：
--
作者：
X. Zhang;Yan Wang;F. Xin
在模拟工业条件下，在连续槽浆态反应器中考察了工业钛硅沸石(TS-1)催化剂活性的变化，以及催化剂的主要失活方式。根据催化剂的活性、转化率和选择性的变化，得出了催化剂失活行为的结论。X射线衍射和红外光谱分析表明，反应过程中沸石分子筛的MFI骨架结构没有明显变化。通过对比实验发现，催化剂失活的主要原因是TS-1催化剂表面结焦。TGA-DTA、N_2吸附和吡啶TPD分析结果表明，催化剂上有两种积炭类型，主要分布在微孔上。软焦位于钛中心附近，350℃以下可被氧化脱除，而难焦炭可被空气氧化至700℃。对可溶焦和不溶焦的GC-MS分析结果表明，含氮多环芳烃和/或聚烯烃物种是焦炭的主要成分。
In this work, the changes of catalytic activity, as well as the main deactivation mode were investigated on a commercial titanium silicalite-1 (TS-1) catalyst under simulated industrial conditions in continuous tank slurry reactor. The conclusions about deactivation behavior have been achieved based on the changes of activity, conversion and selectivity. XRD and FTIR analyses indicate the MFI framework structure of zeolite cannot be changed evidently during the reaction. It is found by comparative experiments that the main reason for catalyst deactivation is coke formation on the surface of TS-1. Results from TGA-DTA, N2adsorption and pyridine TPD analyses of used catalysts demonstrate there are two types of coke deposited mainly on micropores. Soft coke is located near Ti sites and can be removed by oxidation under 350°C, while refractory coke can be oxidized by air until 700°C. Analysis results of GC–MS for soluble coke and NMR, FTIR spectra for insoluble coke indicate that N-containing polycyclic aromatic and/or polyalkene species are the main components of coke deposits.