固体超强酸催化剂SO2 -4 / ZrO2 在缩醛反应中的应用

以纳米氧化物为前驱体制备的固体超强酸催化剂SO₂ ^-4 / ZrO₂ , 其Hammett 酸强度常数小于-12 .14。将SO₂ ^-4 / ZrO₂ 用于催化苯甲醛与乙酸酐的缩醛反应, 经红外光谱、气相色谱、核磁、熔点测定证明得到的缩醛具有较高的纯度。通过均匀设计实验, 考察催化剂制备过程中焙烧温度、硫酸浓度、浸泡时间和活化温度对缩醛产率的影响。优化出缩醛产率最高的催化剂制备条件为:焙烧温度为300 ℃, 浸渍液中硫酸的浓度为4 .5 mol/ L, 浸泡时间为1.0 h , 活化温度为305 ℃, 缩醛产率为93.6%。红外光谱和热重分析表明,SO₂ ^-4 / ZrO₂ 超强酸中SO₂ ^-4 吸附量大。重复实验表明使用10 次后,SO₂ ^-4 / ZrO₂ 仍保持较高的催化活性, 且催化剂易处理, 易再生。

Application of Solid Superacid Catalyst SO2-4/ZrO2 in Acetalization

By using nanometer oxides as precursor , solid superacid catalystSO₂ ^-4 /ZrO₂ with Hammett constant less than -12 .14was prepared .The catalystSO₂ ^-4 /ZrO₂ was used for the ace talization of benzaldehyde with acetic anhydride .The results of IR, GC ,NMR and melting point measurement show that the purity o f the target product of acetalization is very high .The influence ofcalcining temperature , concentration of sulphuric acid, immersing time and activating temperature on the yield of aldehydeacetal wasinvestigated by uniform design.The optimum conditions for obtaining the highest yield of aldehyde acetal are as follows :the calciningtemperature is 300 ℃, concentration of sulphuric acid in immersion liquid is 4 .5mol/ L, immersing time is 1 hour , activatingtemperature is 305 ℃.The yield of aldehy deacetal is 93.6 %.The analysis of IR and TG indicates that the absorptive capacity ofSO₂ ^-4 onSO₂ ^-4 /ZrO₂ is large .The reusing experiment of catalyst show s that the catalyst can be reused more than ten times with highcatalytic activity .Its treatment and regeneration are easy .