固体超强酸SO4^2-／TiO2-SnO2的制备、表征及催化合成D，L-丙交酯  

Preparation and Characterization of Solid Superacid SO_4^(2-)/TiO_2-SnO_2 and Study on Synthesis of D,L-lactide

作　　者：刘文明[1] 黄小强[1] 肖青[2] 李凤仪[1] 

机构地区：[1]南昌大学应用化学研究所,江西南昌330031 [2]江西省科学院应用化学研究所,江西南昌330029

出　　处：《分子催化》2008年第6期519-525,共7页Journal of Molecular Catalysis(China)

基　　金：江西省自然科学基金资助项目(项目编号:2008G2H0065);江西省教育厅科研基金资助项目(项目编号:GJJ09039)

摘　　要：采用沉淀法在不同工艺条件下制备了稀土改性的新型固体超强酸SO24-/TiO2-SnO2催化剂,考察了其对D,L-乳酸合成D,L-丙交酯的催化活性,并通过Hammett指示剂法测定了催化剂的酸强度,用FT-IR和FT-Raman技术考察了焙烧温度、硫酸浸渍液浓度和浸渍时间以及La2O3的负载量对该固体超强酸结构和性能的影响.研究结果表明:SnO2的存在促进了金红石相TiO2的形成,在600℃焙烧3 h、3.0 mol/L H2SO4溶液浸渍12 h、n(Ti4+):n(Sn4+):n(La3+)=1:1:0.05条件下制备的SO42-/TiO2-SnO2的酸强度最大,达-13.75以上,催化合成丙交酯的产率最高(78.4%).并且考察了催化剂用量对D,L-丙交酯粗产率的影响和催化剂重复使用的性能.A new type of solid superacid catalyst SO42-/TiO2-SnO2was prepared by titration precipitation under different conditions and used to catalyze the synthesis of D, L-lactide with D, L-lactic acid as feed stock. The acidity of catalysts was determined with Hammett indicator method, and the characterization of the samples was performed by FI-IR and FT-Raman to probe the effects of calcination temperature, concentration of soakage H2 SO4 liquid and soaking time, loading amount of La203 on the superacids structure and performance. The results showed that SnO2 accelerated the formation of rutile TiO2, and SO4^2-/TiO2-SnO2 prepared under the conditions of calcination temperature ture 600℃ , calcination time 3h, soaking in 3.0 mol/L H2SO4 for 12h, n（Ti^4＋ ）： n（Sn^4＋ ）： n（La^3＋ ） =1： 1：0.05 had the strongest acidity and was the best to the synthesis of D, L-lactide relatively. The effect of catalyst amount on crude yield of D, L-lactide and the activity of catalyst used repeatedly were studied.

关 键 词：固体超强酸 D L-乳酸 D L-丙交酯 指示剂 催化剂 

分 类 号：O643.3[理学—物理化学]