Chemical upcycling of polyethylene, polypropylene, and mixtures to high-value surfactants
Chemical upcycling of polyethylene, polypropylene, and mixtures to high-value surfactants
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DOI：
10.1126/science.adh0993
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发表时间：
2023-08
期刊：
影响因子：
56.9
通讯作者：
Zhen Xu;N. E. Munyaneza;Qikun Zhang;Mengqi Sun;C. Posada;P. Venturo;Nicholas A. Rorrer;Joel Miscall;B. Sumpter;Guoliang Liu
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文献类型：
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作者：
Zhen Xu;N. E. Munyaneza;Qikun Zhang;Mengqi Sun;C. Posada;P. Venturo;Nicholas A. Rorrer;Joel Miscall;B. Sumpter;Guoliang Liu
将塑料垃圾转化为脂肪酸是补充这些高价值、高产量化学品来源的一种有吸引力的手段。我们报道了一种将聚乙烯(PE)和聚丙烯(PP)在~80%转化率下转化为数均摩尔质量分别高达~700和670道尔顿的脂肪酸的方法。该工艺适用于城市生活垃圾PE和PP及其混合物。温度梯度热解是可控地将PE和PP降解成蜡并抑制小分子生成的关键。通过硬脂酸锰的氧化和随后的加工，蜡被提升为脂肪酸。PPꞵ-裂解比PEꞵ-裂解产生更多的烯烃蜡和更高的酸值脂肪酸。我们进一步将脂肪酸转化为高价值、大市场容量的表面活性剂。工业规模的技术经济分析表明，在不需要补贴的情况下，经济是可行的。随着塑料垃圾的不断积累，化学家们正专注于寻找将其用作有价值化合物的原料的方法。聚烯烃特别难分解成它们原来的单体，但本期的两篇报告表明，它们可以作为其他产品的有用起始材料(参见Van Geem的透视法)。Li等人。报道称，聚乙烯和聚丙烯的热解产生可直接进行氢甲酰化反应的烯烃混合物。众所周知，钴催化的反应会产生醛，然后作者将其氢化成醇和二醇。Xu等人。研究表明，加热过程中精确的温度控制可以将相同的塑料分解成蜡，然后这些蜡可以很容易地在锰催化剂上被氧化，从而生产出有价值的表面活性剂。-杰克·S·耶斯顿在加热过程中进行精确的温度控制，将废塑料分解成蜡质，这些蜡质很容易被氧化成表面活性剂。
Conversion of plastic wastes to fatty acids is an attractive means to supplement the sourcing of these high-value, high-volume chemicals. We report a method for transforming polyethylene (PE) and polypropylene (PP) at ~80% conversion to fatty acids with number-average molar masses of up to ~700 and 670 daltons, respectively. The process is applicable to municipal PE and PP wastes and their mixtures. Temperature-gradient thermolysis is the key to controllably degrading PE and PP into waxes and inhibiting the production of small molecules. The waxes are upcycled to fatty acids by oxidation over manganese stearate and subsequent processing. PP ꞵ-scission produces more olefin wax and yields higher acid-number fatty acids than does PE ꞵ-scission. We further convert the fatty acids to high-value, large–market-volume surfactants. Industrial-scale technoeconomic analysis suggests economic viability without the need for subsidies. Description Editor’s summary As plastic waste continues to accumulate, chemists are focused on finding ways to use it as feedstock for valuable compounds. Polyolefins are especially hard to break back down into their original monomers, but two reports in this issue show that they can be useful starting materials for other products (see the Perspective by Van Geem). Li et al. report that pyrolysis of polyethylene and polypropylene produces olefin mixtures that can be directly subjected to hydroformylation. The well-known cobalt-catalyzed reaction produces aldehydes that the authors then hydrogenated to produce alcohols and diols. Xu et al. show that precise temperature control during heating can break down the same plastics into waxes that can then be readily oxidized over manganese catalysts to produce valuable surfactants. —Jake S. Yeston Precise temperature control during heating breaks down waste plastic into waxes that are readily oxidized to surfactants.