摘要
采用连续淤浆反应器,在环己酮质量空速为6h-1和温度为70℃的条件下,对TS-1催化剂上环己酮氨肟化制环己酮肟反应过程中的活性变化规律进行了考察,并用热重-差热分析、程序升温脱附、N2物理吸附、程序升温氧化和傅里叶变换红外光谱等测试手段对不同运转时间及再生后的催化剂进行了表征.结果表明,催化剂运转时间在60h以内时活性稳定,然后迅速下降;积炭是引起催化剂失活的主要原因.催化剂表面的积炭主要沉积在TS-1的微孔内,含碳物种有两种类型:易除炭存在于Ti中心附近,可在350℃下氧化除去;难除炭沉积于强酸中心Si-OH处,需在700℃下才能除去.催化剂失活前后的骨架结构未发生显著变化,经烧炭再生后活性可恢复到新鲜催化剂的水平.
The catalytic activity of the TS-1 catalyst for cyclohexanone ammoximation to cyclohexanone oxime was investigated under the conditions of WHSV= 6 h^-1 and 70℃ in a continuous slurry reactor, and the catalyst samples run for different time were characterized by thermogravimetric and differential thermal analysis, temperature-programmed desorption, N2 physisorption, temperature-programmed oxidation, and Fourier transform infrared spectroscopy. The results show that the activity of TS-1 keeps stable within 60 h and then decreases rapidly. Coking is the main reason for the deactivation. Two types of carbon species are formed on the internal surface of TS-1 micropores. Soft coke is located near Ti sites and can be easily oxidized at 350℃ , while refractory coke that deposits on the strong acid centers, Si-OHs, can be removed at 700℃. The framework structure of TS-1 is unchanged before and after deactivation, and the catalytic activity can be recovered completely after calcining the deactivated catalyst at 700℃.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2006年第5期427-432,共6页
基金
国家自然科学基金资助项目(20376056)
关键词
钛硅分子筛
沸石催化剂
积炭
失活
环己酮
氨肟化
环己酮肟
过氧化氢
titanium silicalite
zeolite catalyst
coking
deactivation
cyclohexanone
ammoximation
cyclohexanone oxime
hydrogen peroxide
