A new future for polyethylene Most current plastic recycling involves chopping up the waste and repurposing it in materials with less stringent engineering requirements than the original application. Chemical decomposition at the molecular level could, in principle, lead to higher-value products. However, the carbon-carbon bonds in polyethylene, the most common plastic, tend to resist such approaches without exposure to high-pressure hydrogen. F. Zhang et al. now report that a platinum/alumina catalyst can transform waste polyethylene directly into long-chain alkylbenzenes, a feedstock for detergent manufacture, with no need for external hydrogen (see the Perspective by Weckhuysen). Science, this issue p. 437; see also p. 400 Platinum catalysis can transform the most common plastic waste into a feedstock for detergents with no added hydrogen. The current scale of plastics production and the accompanying waste disposal problems represent a largely untapped opportunity for chemical upcycling. Tandem catalytic conversion by platinum supported on γ-alumina converts various polyethylene grades in high yields (up to 80 weight percent) to low-molecular-weight liquid/wax products, in the absence of added solvent or molecular hydrogen, with little production of light gases. The major components are valuable long-chain alkylaromatics and alkylnaphthenes (average ~C30, dispersity Ð = 1.1). Coupling exothermic hydrogenolysis with endothermic aromatization renders the overall transformation thermodynamically accessible despite the moderate reaction temperature of 280°C. This approach demonstrates how waste polyolefins can be a viable feedstock for the generation of molecular hydrocarbon products.

中文翻译：

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通过串联氢解/芳构化将聚乙烯升级为长链烷基芳烃

聚乙烯的新未来 大多数当前的塑料回收涉及将废物切碎并将其重新用于工程要求比原始应用更宽松的材料中。原则上，分子水平的化学分解可以产生更高价值的产品。然而，聚乙烯（最常见的塑料）中的碳-碳键倾向于在不暴露于高压氢气的情况下抵抗这种方法。F. 张等人。现在报告说，铂/氧化铝催化剂可以将废聚乙烯直接转化为长链烷基苯，这是洗涤剂制造的原料，无需外部氢气（参见 Weckhuysen 的观点）。科学，这个问题 p。第437话 另见第 400 铂催化剂可以将最常见的塑料废物转化为不添加氢气的洗涤剂原料。当前的塑料生产规模和随之而来的废物处理问题代表了一个很大程度上尚未开发的化学品升级回收机会。在不添加溶剂或分子氢的情况下，γ-氧化铝负载铂的串联催化转化可将各种聚乙烯等级以高产率（高达 80 重量%）转化为低分子量液体/蜡产品，几乎不产生光气体。主要成分是有价值的长链烷基芳烃和烷基环烷烃（平均 ~C30，分散度 Ð = 1.1）。尽管反应温度适中为 280°C，但将放热氢解与吸热芳构化相结合，使得整体转化在热力学上是可及的。这种方法展示了废聚烯烃如何成为生产分子烃产品的可行原料。