Methanol-to-hydrocarbons reaction over SAPO-34. Molecules confined in the catalyst cavities at short time on stream

被引:162
作者
Arstad, B [1 ]
Kolboe, S [1 ]
机构
[1] Univ Oslo, Dept Chem, N-0315 Oslo, Norway
关键词
reaction mechanism; methanol-to-hydrocarbons; SAPO-34; hexamethylbenzene;
D O I
10.1023/A:1009034600533
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
In order to obtain more insight into the methanol-to-hydrocarbons (MTH) reaction the organic molecules confined in a working SAPO-34 catalyst have been studied. The reaction was run for varying times, 30 s to 30 min. At a predetermined time the reaction was stopped and the catalyst dissolved in 1 M HCl. The gas phase above the solution as well as a CCl4 extract were analyzed by gas chromatography (MS detector). The gas phase consists mainly of isoalkanes C4-6. The less volatile organic molecules were concentrated in the CCl4 extract. More than 200 different species are present, but polymethylbenzenes, with one to six methyl groups, are always dominating. They constitute 30-50% of the samples. Penta- and hexamethylbenzene easily split off small hydrocarbons and turn into di- and trimethylbenzenes. it is speculated that methylations of arenes which thereupon split off small alkenes and then are remethylated again may be an essential part of the catalytic activity in the MTH reaction.
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页码:209 / 212
页数:4
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