Cu-La_(2)O_(3)-Al_(2)O_(3)/SBA-15催化剂上乙醇催化转化制正丁醇

Catalytic upgrading of ethanol to n-butanol over Cu-La_(2)O_(3)-Al_(2)O_(3)/SBA-15 catalyst

为了进一步提高Cu基催化剂的活性、选择性及稳定性,提出一种以有序介孔氧化硅分子筛(SBA-15)为载体制备负载型Cu基催化剂的方法。采用共浸渍法制备Cu-La_(2)O_(3)-Al_(2)O_(3)/SBA-15催化剂,并将该催化剂应用于固定床乙醇制正丁醇反应。在温度为533 K,压力为3 MPa,液体时空速率(LHSV)=2 mL×h^(-1)×g^(-1),N_(2)与乙醇的体积比V(N_(2))/V(EtOH)为250:1的反应条件下,该催化剂具有46.8%的乙醇转化率和48.9%的正丁醇选择性,并且在120 h的连续反应中展现出优异的稳定性。SBA-15载体孔道中高度分散的Al_(2)O_(3)和La_(2)O_(3)提供了大量彼此邻近的酸碱活性位点,而高度分散且稳定的Cu提供了大量脱氢/加氢活性中心,两者的协同作用是Cu-La_(2)O_(3)-Al_(2)O_(3)/SBA-15催化剂在乙醇制正丁醇反应中表现优异的原因。

The ordered mesoporous silica zeolite(SBA-15)was used as support to prepare Cu-supported catalyst for improving the activity,selectivity and stability of Cu-based catalysts.Cu-La_(2)O_(3)-Al_(2)O_(3)/SBA-15 catalyst was prepared by simple co-impregnation method and applied to catalytic upgrading of ethanol to n-butanol reaction in a fixed-bed reactor.Under the reaction conditions of 533 K,3 MPa,liquid hourly space velocity(LHSV)=2 mL×h^(-1)×g^(-1) and V(N_(2))/V(EtOH)=250:1,the catalyst exhibited 46.8%ethanol conversion and 48.9%n-butanol selectivity,and showed excellent stability in 120 h on-stream evaluation.The highly dispersed Al2O3 and La2O3 species on the SBA-15 support provided a large number of acid-base sites which can efficiently promote aldol condensation of acetaldehyde,while the highly dispersed and stable Cu species provided a large number of dehydrogenation/hydrogenation sites.The synergy of the Cu and acid-base sites is responsible for the excellent catalytic properties of Cu-La_(2)O_(3)-Al_(2)O_(3)/SBA-15 catalyst.