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JIA Quan,XUE Bing,XU Jie,LI Yongxin
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贾 泉,薛 冰,许 杰,李永昕
Abstract:
Cr2O3/SiO2 catalysts with different Cr2O3 loadings were prepared by impregnation with Cr(NO3)3?9H2O as precursor.Ortho-selective alkylation of phenol with diethyl carbonate was performed in a continuous flow fixed-bed reactor filled with Cr2O3/SiO2 catalysts.The Cr2O3/SiO2 catalysts were characterized by means of XRD,NH3-TPD,CO2-TPD and FT-IR with pyridine adsorption.The results indicated that with increasing Cr2O3 loading,conversion of phenol and selectivity to o-ethylphenol increased;when Cr2O3 loading reached 7.5%,conversion of phenol and selectivity for o-ethylphenol reached a maximum of 48% and 67%,respectively.The catalyst characterization results showed that the Lewis acid sites were the active centers of ortho-selective alkylation of phenol;and the variations in phenol conversion and selectivity to o-ethylphenol could be mainly ascribed to the change in the number of acid sites and base sites.
摘要:
以Cr(NO3)3?9H2O为前体,采用等体积浸渍法制备了一系列不同Cr2O3负载量的Cr2O3/SiO2催化剂;在固定床连续微反装置上,考察了Cr2O3/SiO2催化剂对苯酚与碳酸二乙酯邻位烷基化反应的催化性能;采用XRD、NH3-TPD、CO2-TPD和吡啶吸附、红外等手段对催化剂进行了表征。实验结果表明,随着Cr2O3负载量的增加,苯酚的转化率和邻乙基苯酚的选择性均逐渐增加;当Cr2O3负载量达到7.5%时,苯酚的转化率和邻乙基苯酚的选择性均达到最大值,分别为48%和67%。催化剂的表征结果表明,L酸中心是苯酚邻位烷基化反应的活性中心,苯酚转化率和邻乙基苯酚选择性的变化主要是由催化剂的酸、碱中心数目变化引起的。
JIA Quan,XUE Bing,XU Jie,LI Yongxin. Ortho-selective alkylation of phenol with diethyl carbonate over Cr2O3/SiO2 catalyst[J]. .
贾 泉,薛 冰,许 杰,李永昕. Cr2O3/SiO2催化苯酚与碳酸二乙酯邻位烷基化反应 [J]. CIESC Journal.
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https://hgxb.cip.com.cn/EN/Y2011/V30/I5/1019