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Skeletal isomerization of n-butane under supercritical conditions

超临界条件下正丁烷的骨架异构化

基本信息

批准号：
17560682
负责人：
SEGAWA Kohichi
金额：
$ 2.3万
依托单位：
Sophia University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17560682/
关键词：
Green engineering Chemical catalyst process Functional structural materials Supercritical fluid

项目摘要

Light isoalkanes have high octane numbers and are widely used as the blendstock for the green gasoline. Sulfated zirconia is a strong solid acid catalyst and is efficient for isomerization of n-alkane. To promote its catalytic activity, I prepared sulfated zirconia-alumina by addition of aluminum, which is a highly electronegative atom, to its surface with a co-precipitation technique. I also investigated the effect of Al on its activity and acidity, and tested the isomerization reaction of the alkanes under supercritical conditions of reactant molecules. However, most of the solid catalysts including sulfated zirconia have a problem of rapid deactivation due to the coke formation. In this research, I applied super critical conditions of reactant molecules because the conditions result in lower viscosity and higher diffusibility. Addition of Al into sulfated zirconia suppressed the crystallization and the phase transition to monoclinic. Al addition to zirconia structure caused the structural strain leading to retarding the phase transitions and improving the thermal stability. IR and XPS results suggested that the enhancement of positive charges on Zr atoms strengthens those acidic sites because of the high electron negativity of Al. Under the supercritical condition, the deactivation was well suppressed, and the higher activity was maintained. Especially for below 5 mol% alumina-added, sulfated zirconia showed the higher catalytic activity for isomerization of n-alkane.

轻质异构烷烃具有高辛烷值，被广泛用作绿色汽油的调合原料。硫酸化氧化锆是一种强固体酸催化剂，对正构烷烃异构化反应有很好的催化效果。为了提高其催化活性，我制备了硫酸化的氧化锆-氧化铝，通过添加铝，这是一个高度电负性的原子，其表面与共沉淀技术。考察了铝对催化剂活性和酸性的影响，并测试了反应物分子在超临界条件下的异构化反应。然而，大多数包括硫酸化氧化锆的固体催化剂由于焦炭形成而具有快速失活的问题。在本研究中，我应用了反应物分子的超临界条件，因为该条件导致较低的粘度和较高的扩散性。Al的加入抑制了硫酸化氧化锆的晶化和向单斜相的转变。Al的加入使ZrO 2结构产生了结构应变，从而延缓了相变，提高了热稳定性。IR和XPS结果表明，由于Al的电子负性，Zr原子上正电荷的增加增强了催化剂的酸性中心，在超临界条件下，催化剂的失活得到了很好的抑制，并保持了较高的活性。特别是当氧化铝含量低于5mol%时，硫酸化氧化锆对正构烷烃异构化反应表现出较高的催化活性。