Abstract: The catalysts with different ratio of Mg and Al were prepared by machine mixing method with MgO and Al₂O₃ as raw materials, the activity of catalysts was evaluated in a fixed bed reactor with the synthesis of isophorone by gas acetone as probe reaction, and the catalysts were characterized by XRD, XPS and TPD. The results showed that the activity of catalysts prepared by machine mixing method was high, the ratio of Mg and Al had little effect on the crystalline structure and surface acid-base strength, but had significant effect on the surface acid-base amount of catalysts. When the ratio of Mg and Al was 1:1.8 to 1:1, the surface acid-base amount of catalysts was higher, so the activity of catalysts was higher. When the ratio of Mg and Al was 1:1, the conversion of acetone and selectivity of isophorone were 11.5% and 62.8% respectively. By adjusting catalyst loading amount, the residence time of reactants was effectively prolong, the conversion of acetone was increased. Under the reaction conditions of atmospheric pressure, reaction temperature 300℃, liquid space velocity 0.67h^-1, the conversion of acetone and the selectivity of isophorone were 21.0% and 73.0% respectively.

Key words: magnesia(MgO), oxidation aluminium(Al₂O₃), catalysis, machine mixing method, synthesis

摘要： 以氧化镁和氧化铝粉体为主要原料,采用机械混合法制备了不同镁铝比的酸碱双功能催化剂,选择丙酮气相合成异佛尔酮为探针反应,在固定床反应器中对其活性进行了评价,并通过XRD、XPS和TPD等表征手段对催化剂的性质和结构进行了分析。结果表明,机械混合法催化剂活性较高,镁铝比对催化剂的晶体结构、表面酸碱强度影响不大,而对催化剂的表面酸碱量有显著影响。当1:1.8≤Mg:Al≤1:1时,催化剂的酸量及碱量较大,催化剂的活性较高。当镁铝比为1:1时,丙酮的转化率和异氟尔酮的选择性分别为11.5%和62.8%。通过调节催化剂的装填量,有效地延长了反应物的停留时间,丙酮的转化率大幅提高。当反应条件为常压、反应温度300℃、空速0.67h^-1时,丙酮的转化率和异佛尔酮的选择性分别为21.0%和73.0%。

关键词: 氧化镁, 氧化铝, 催化, 机械混合法, 合成