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以PdMgAl水滑石为前体制备了Pd/MgO-Al_2O_3催化剂,再浸渍K_2CO_3制备了K改性的Pd/MgO-Al_2O_3催化剂,并用于丙酮气相一步法合成甲基异丁基酮反应。采用XRD、BET、TPD、TG-DTA等技术表征了催化剂,并测试了常压下丙酮加氢的活性。结果显示,掺加K后催化剂的酸性减低、碱性增加,提高了催化剂的活性,在反应温度140℃,氢酮比为1∶1,液空速为4.8 m L·g_(cat)~(-1)·h~(-1)时,丙酮的转化率达到49%,MIBK的选择性达到70%。稳定性测试结果表明催化剂反应80 h后活性降低,主要由于积碳引起,550℃焙烧再生后催化剂基本恢复到新鲜催化剂的活性。
Pd / MgO-Al_2O_3 catalyst was prepared by using PdMgAl hydrotalcite as precursor, then K_2CO_3 was impregnated to prepare K-modified Pd / MgO-Al_2O_3 catalyst and used for the one-step synthesis of methyl isobutyl ketone in acetone gas phase. The catalysts were characterized by XRD, BET, TPD and TG-DTA techniques. The hydrogenation activity of acetone at atmospheric pressure was also tested. The results showed that after the addition of K, the acidity and alkalinity of the catalyst were increased and the activity of the catalyst was increased. The reaction temperature was 140 ℃, the ratio of hydrogen to ketone was 1: 1, and the liquid space velocity was 4.8 m L · g ~ (cat) ~ ( -1) · h ~ (-1), the conversion of acetone reaches 49% and the selectivity of MIBK reaches 70%. The results of the stability test showed that the activity of the catalyst decreased after 80 h reaction, mainly due to the carbon deposition, and the activity of the catalyst recovered to the fresh catalyst after calcination and regeneration at 550 ℃.