Institute for Interfacial Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
J Am Chem Soc. 2011 Jul 27;133(29):11096-9. doi: 10.1021/ja204235v. Epub 2011 Jul 1.
We report the design and synthesis of nanosized Zn(x)Zr(y)O(z) mixed oxides for direct and high-yield conversion of bio-ethanol to isobutene (~83%). ZnO is addded to ZrO(2) to selectively passivate zirconia's strong Lewis acidic sites and weaken Brönsted acidic sites, while simultaneously introducing basicity. As a result, the undesired reactions of bio-ethanol dehydration and acetone polymerization/coking are suppressed. Instead, a surface basic site-catalyzed ethanol dehydrogenation to acetaldehyde, acetaldehyde to acetone conversion via a complex pathway including aldol-condensation/dehydrogenation, and a Brönsted acidic site-catalyzed acetone-to-isobutene reaction pathway dominates on the nanosized Zn(x)Zr(y)O(z) mixed oxide catalyst, leading to a highly selective process for direct conversion of bio-ethanol to isobutene.
我们报告了纳米级 Zn(x)Zr(y)O(z)混合氧化物的设计和合成，用于将生物乙醇直接高收率转化为异丁烯（~83%）。在 ZrO(2) 中添加 ZnO，可选择性地钝化氧化锆的强路易斯酸性位，并削弱布朗斯台德酸性位，同时引入碱性。因此，抑制了生物乙醇脱水和丙酮聚合/焦化等不需要的反应。相反，表面碱性位催化乙醇脱氢生成乙醛，乙醛通过包括醛缩合/脱氢在内的复杂途径转化为丙酮，以及布朗斯台德酸性位催化丙酮生成异丁烯的反应途径在纳米级 Zn(x)Zr(y)O(z)混合氧化物催化剂上占主导地位，导致生物乙醇直接转化为异丁烯的高选择性过程。
