Preis S, Falconer J L
Department of Chemical Engineering, Lappeenranta University of Technology, P.O. Box 20, Lappeenranta 53851, Finland.
Water Sci Technol. 2004;49(4):141-5.
Methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) were oxidized in the gas phase by photocatalytic oxidation (PCO). Transient PCO was carried out at room temperature on TiO2 (Degussa P25), 0.2% Pt-TiO2, and 2% Pt-TiO2 catalysts. Surface-adsorbed reaction by-products were characterized by temperature-programmed desorption (TPD) and oxidation (TPO). Continuous flow PCO was also carried out at 373 K on TiO2. Acetone, H2O, and CO2 were the gas-phase products for PCO of TBA and MTBE, and formic acid was adsorbed on the TiO2 surface. Temperature-programmed desorption of TBA and MTBE formed 2-methyl-1-propene, water (TBA), and methanol (MTBE). During continuous-flow PCO, acetone desorbed in molar amounts equal to the amount of decomposed TBA and MTBE. The Pt/TiO2 catalysts had higher rates of complete oxidation during PCO and TPO. Injection of water during transient PCO increased the rates of oxidation of adsorbed TBA, formic acid, and acetone. Photocatalytic oxidation of TBA proceeded faster in humid air than dry air, but MTBE oxidation was less sensitive to humidity. The TiO2 catalyst was stable for MTBE, TBA, and acetone PCO at 373 K. The PCO at low conversions followed the Langmuir-Hinshelwood model.
甲基叔丁基醚（MTBE）和叔丁醇（TBA）在气相中通过光催化氧化（PCO）进行氧化。在室温下，在TiO₂（德固赛P25）、0.2%Pt-TiO₂和2%Pt-TiO₂催化剂上进行瞬态PCO。通过程序升温脱附（TPD）和氧化（TPO）对表面吸附的反应副产物进行了表征。在373K下也在TiO₂上进行了连续流动PCO。丙酮、H₂O和CO₂是TBA和MTBE的PCO的气相产物，甲酸吸附在TiO₂表面。TBA和MTBE的程序升温脱附生成2-甲基-1-丙烯、水（TBA）和甲醇（MTBE）。在连续流动PCO过程中，丙酮的脱附摩尔量与分解的TBA和MTBE的量相等。Pt/TiO₂催化剂在PCO和TPO过程中具有较高的完全氧化速率。在瞬态PCO过程中注入水提高了吸附的TBA、甲酸和丙酮的氧化速率。TBA在潮湿空气中的光催化氧化比在干燥空气中进行得更快，但MTBE氧化对湿度不太敏感。TiO₂催化剂在373K下对MTBE、TBA和丙酮的PCO是稳定的。低转化率下的PCO遵循朗缪尔-欣谢尔伍德模型。
