Zhang Taichang, Wang Jing, Yuan Tao, Hong Xin, Zhang Lidong, Qi Fei
National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, PR China.
J Phys Chem A. 2008 Oct 23;112(42):10487-94. doi: 10.1021/jp803622w. Epub 2008 Sep 30.
An experimental study of methyl tert-butyl ether (MTBE) pyrolysis (3.72% MTBE in argon) has been performed at low pressure (267 Pa) within the temperature range from 700 to 1420 K. The pyrolysis process was detected with the tunable synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam mass spectrometry (MBMS). About thirty intermediates are identified from near-threshold measurements of photoionization mass spectrum and photoionization efficiency spectrum. Among them, H2, CO, CH4, CH3OH and C4H8 are the major pyrolysis products. The radicals such as methyl, methoxy, propargyl, allyl, C4H5 and C4H7 are detected. The isomers of pyrolysis products are identified as well, i.e., propyne and allene, 1,2,3-butatriene and vinylacetylene, isobutene and 1-butene, propanal and acetone. Furthermore, the mole fractions of the pyrolysis products have been evaluated under various temperatures. Meanwhile, the initial formation temperatures of different pyrolysis products can be obtained. This work is anticipated to present a new experimental method for pyrolysis study and help understand the pyrolysis and combustion chemistry of MTBE and other oxygenated fuels.
在267帕的低压下，于700至1420 K的温度范围内开展了甲基叔丁基醚（MTBE）热解（氩气中MTBE含量为3.72%）的实验研究。热解过程通过可调谐同步辐射真空紫外（VUV）光电离和分子束质谱（MBMS）进行检测。从光电离质谱和光电离效率谱的近阈值测量中识别出约30种中间体。其中，H2、CO、CH4、CH3OH和C4H8是主要的热解产物。检测到了甲基、甲氧基、炔丙基、烯丙基、C4H5和C4H7等自由基。还识别出了热解产物的异构体，即丙炔和丙二烯、1,2,3-丁三烯和乙烯基乙炔、异丁烯和1-丁烯、丙醛和丙酮。此外，评估了不同温度下热解产物的摩尔分数。同时，可以获得不同热解产物的初始形成温度。这项工作有望为热解研究提供一种新的实验方法，并有助于理解MTBE和其他含氧燃料的热解及燃烧化学。
