摘要
采用等体积浸渍法制备了一系列TiO2/SiO2催化剂,通过XRD、NH3-TPD和Py-IR等手段对催化剂进行了表征;在连续流动固定床反应器上,考察了TiO2负载量、反应温度、碳酸二乙酯(DEC)与苯酚的摩尔比及重时空速(WHSV)对苯酚与DEC邻位烷基化反应的影响。实验结果表明,L酸中心是苯酚邻位烷基化反应的活性中心;随TiO2负载量的增加,苯酚的转化率逐渐增加,邻乙基苯酚的选择性先增加后减小,而2,6-二乙基苯酚的选择性则逐渐增加,这主要是由负载TiO2后催化剂的酸中心数目增多引起的。以9%(w)TiO2/SiO2为催化剂,在360℃、0.42MPa、n(DEC)∶n(苯酚)=1.0、WHSV=2h-1、8h的适宜反应条件下,苯酚的转化率为75.4%,邻乙基苯酚和2,6-二乙基苯酚的选择性分别为60.2%和16.3%。
TiO2/SiO2 catalysts were prepared by an impregnation method and characterized by means of XRD, NH3-TPD and Py-IR. ortho-Selective ethylation of phenol with diethyl carbonate （DEC） was carried out over the prepared TiO2/SiO2 catalysts in a continuous flow fixed-bed reactor. The effects of TiO2 loading and reaction conditions on the catalyst performances were investigated. The results indicated that the Lewis acid sites on the TiO2/SiO2 catalysts led to high activity of the catalysts. With increase of TiO2 loading, the conversion of phenol and the selectivity to 2, 6- diethylphenol increased, and the selectivity to ortho-ethylphenol first rose and then lowered when TiO2 loading reached 9%（w）. Under the optimal reaction conditions of 9% （w） TiO2/SiO2 as the catalyst, 360 ℃, 0.42 MPa, n （DEC） ： n （phenol） 1.0, WHSV 2 h^-1 and 8 h, the phenol conversion was 75.4%, and the selectivities to ortho-ethylphenol and 2,6-diethylphenol were 60.2% and 16.3% respectively.
出处
《石油化工》
CAS
CSCD
北大核心
2011年第4期376-380,共5页
Petrochemical Technology
基金
江苏省高技术研究项目(BG2006015)
