甲基叔丁基醚光催化降解的反应历程

Reaction Pathway of Photocatalytic Degradation of Methyl-tert-butyl Ether in Water

以自制的TiO2为催化剂,在间歇式光催化反应装置中考察了水中甲基叔丁基醚的光催化降解反应.结果表明,水中MTBE在TiO2催化剂、氧气和紫外光照射的条件下能被光催化转化成无毒产物并最终被矿化.MTBE光催化降解过程中产生的主要中间产物有甲酸叔丁酯、叔丁醇和丙酮,尽管降解速率不同,它们也都能被光催化降解.通过对反应物、中间物及产物的追踪分析,认为MTBE的光催化降解首先是通过羟基化过程来进行,进而提出MTBE光催化降解的可能反应历程.

The use of methyl-tert-butyl ether (MTBE), which is a gasoline additive to enhance the octane rating of gasoline, has resulted in increasing pollution of groundwater. Most of the conventional treatment technologies are inefficient or expensive due to its high solubility in water and low Henry's law constant. To find an ecology friendly and inexpensive method for MTBE remediation, homemade titanium dioxide MOO was used as a photocatalyst, and the photocatalytic degradation of MTBE in a batch TiO2 slurry reactor was studied by using Purge & Trap G-C-MS-SIM and IC. It was showed that MTBE can be photocatalytically transformed to innocuous products and mineralized ultimately in oxygenated TiO2 slurries. The major by-products of this reaction have been identified as t-butyl formate, t-butyl alcohol and acetone, all of which are also readily degraded photocatalytically, albeit at different rates. Based on identification of intermediates and products, the first step in the destruction of MTBE is thought to be abstraction of an a-hydrogen by .OH and a reaction scheme is proposed.