CaO对Cr2O3/Al2O3催化剂结构及催化异丁烷脱氢性能的影响

摘要

为了研究碱土金属氧化物对Cr系脱氢催化剂的影响,采用等体积浸渍法制备Cr2 O3/Al2O3、Cr2 O3/Al2O3-CaO催化剂,考察催化剂在异丁烷脱氢制备异丁烯反应中的催化性能,并对催化剂进行了BET,XRD,NH3-TPD表征.结果表明:Cr2.3组分在催化异丁烷脱氢过程中表现出较强的活性,载体的酸碱性对异丁烷脱氢选择性有很大影响,CaO的加入对催化剂的晶相结构及表面酸性都有不同程度的影响,有利于提高目标产物异丁烯的选择性；当催化剂中Cr2 O3质量分数为20％、CaO质量分数为5％时,异丁烷脱氢反应转化率为25.31％,异丁烯选择性为91.08％.%To study the impact of alkali earth metal oxides on the performance of isobutane dehydrogenation by Cr system catalyst,the Cr2O3/A12O3 and Cr2O3/A12O3-CaO catalysts were prepared by incipient wetness impregnation.The performance was evaluated and BET,XRD,NH3-TPD were used to characterize the catalysts.As a conclusion,the active ingredient Cr2O3 plays an important role in the catalysis process of isobutane dehydrogenation.Alkalinity or acidity of the carrier has a great influence on the selectivity of isobutane dehydrogenation.The addition of CaO can modify the surface properties crystalline structure and surface acidity of catalyst in different extent and thus improve the selectivity of the target product as well.At the content of Cr2O3 and CaO are 20％ and 5％,the conversion and the selectivity are 25.31％ and 91.08％,respectively.