▲ 作者:RICHARD J. CONK, JULES F. STAHLER, JAKE X. SHI, JI YANG, NATALIE G. LEFTON, JOHN N. BRUNN, ALEXIS T. BELL, AND JOHN F. HARTWIG
▲ 链接:
https://www.science.org/doi/10.1126/science.adq7316
▲ 摘要:
原则上,将塑料分解成其原始构件是一种理想的回收策略。但在实践中,这种方法不可能用于目前使用的两种最常见的塑料——聚乙烯和聚丙烯。因为相关反应在能耗上不占优势。最近,几组研究人员表明,用合适的催化剂引入新鲜的乙烯可以将聚烯烃转化为丙烯,但用于催化的贵金属价格过高。
现在Conk等人发现,可以在这个过程中使用地球上更丰富的氧化钨和钠的组合。研究表明,氧化钨在二氧化硅上和钠在γ-氧化铝上的简单组合将聚乙烯和聚丙烯或两者的混合物转化为丙烯或丙烯和异丁烯的混合物,在320°C下产量大于90%,而不需要对起始聚烯烃进行脱氢。
▲ Abstract:
Breaking down plastic into its original building blocks is an ideal recycling strategy in principle. Unfortunately, in practice, this approach isn’t possible for the two most common plastics currently in use, polyethylene and polypropylene, because the reaction is too energetically unfavorable. Very recently, several groups of researchers showed that introducing fresh ethylene with the right catalyst can transform polyolefins into propylene, but the precious metals used for the catalysis are prohibitively expensive. Conk et al. now report that the process works using a more Earth-abundant combination of tungsten oxide and sodium. The research shows that the simple combination of tungsten oxide on silica and sodium on gamma-alumina transforms PE, PP, or a mixture of the two, including postconsumer forms of these materials, to propylene or a mixture of propylene and isobutylene in greater than 90% yield at 320°C without the need for dehydrogenation of the starting polyolefins.