制备邻苯基苯酚的Ni-Cr-Al催化剂研究

Study on Ni-Cr-Al Catalysts for Preparing o-phenylphenol

采用共沉淀法制备Ni-Cr-Al催化剂,考察了Al2O3含量对反应活性和选择性的影响,利用X射线衍射、程序升温脱附(H2-TPD、NH3-TPD、CO2-TPD)等手段对催化剂进行了表征,并与反应结果关联。研究表明,催化剂中Al2O3含量显著影响催化剂的酸碱性和活性组分的分散度,同时也影响催化剂吸附氢能力,从而影响催化剂的活性和选择性。共沉淀法制备的Al2O3含量为30%的催化剂活性组分分散度最高,具有适宜的酸、碱性和吸氢能力,因而反应转化率和选择性比其他Al2O3含量催化剂更高,该催化剂在液相空速0.12h-1、H2空速33mL/g·h、反应温度340℃的条件下进行反应,环己烯基环己酮转化率达99.6%,邻苯基苯酚(OPP)选择性达84.1%。

Ni - Cr- Al catalysts used for the synthesis of OPP were prepared by the coprecipitation method. The ef- fects of different Al2O3 contents were studied. These catalysts were characterized by XRD, H2 - TPD, NH3 - TPD and CO2 - TPD techniques. It was found that different Al2O3 contents affected the acidity and basicity, crystal and hydrogen absorption of catalysts, and then effected the activity and selectivity of the catalysts. The catalyst which contains 30% Al2O3 had higher dispersion of Ni, suitable acidity and basicity, and suitable adsorption capacity to H2, accordingly, the activity and selectivity of the catalyst was better than others. Under the conditions that reaction temperature was 340℃ and liquid hour space velocity was 33 mL/g· h, the conversion of o - cyclohexenyl cyclohexanone and yield of OPP were 99.6% and 84.1%.