EFRI E3P: A novel sequential catalytic solvolysis process for deconstructing municipal waste plastics

城市塑料固体废物是一种巨大的、尚未开发的能源和化学品来源。将废弃塑料升级为高价值产品可以节省数十亿美元的经济成本，并最大限度地减少对环境的负面影响。然而，城市塑料废物流是各种不相容聚合物的混合物，例如聚乙烯、聚丙烯、聚氯乙烯、聚对苯二甲酸乙二醇酯和聚苯乙烯，以及聚合物添加剂、染料和污染物。因此，通过物理分选从混合固体城市废物中回收高质量塑料材料是一项挑战。废塑料的热化学回收并不经济，因为目前的工艺需要大量的能源投入和昂贵的产品升级。因此，需要节能催化解构工艺来克服回收混合塑料的化学和物理挑战。该项目将开发一种创新的废塑料化学升级循环工艺，将混合废塑料选择性地转化为有价值的单体和化学品。该计划旨在促进塑料循环经济，并减轻塑料废物累积对环境造成的负面影响。教育和外展活动将与研究计划相结合，以促进学生和劳动力的发展，并鼓励来自STEM中代表性不足的群体的学生参与。拟议的废塑料解构方法以顺序催化溶剂分解（SeCatSol）过程为中心。SeCatSol工艺是华盛顿州立大学正在开发的一种新技术，用于在温和条件下使用稳健的有机催化剂和多相催化剂选择性地逐步解构聚合物混合物中的单个聚合物或聚合物类别。SeCatSol工艺旨在解决塑料行业的重大挑战：如何选择性地解构混合的城市废塑料。SeCatSol工艺在每个催化转化单元中依次生产单体或增值化学产品，提供了一种可行的“化学分选”方法，在分子水平上对复杂的市政塑料混合物进行升级循环。系统的团队努力旨在为SeCatSol工艺开发高选择性催化剂和高效溶剂。特别是，先进的原位和操作表征工具，如NMR，ATR-FTIR和拉曼光谱，将破译解构废塑料的复杂性。此外，新的预测分子计算方法将加速催化剂设计和溶剂选择。拟议的技术框架符合循环经济模式，即通过设计实现恢复和再生。该项目代表了基础聚合物科学和工程知识显著进步所需的变革性工作。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Municipal plastic solid wastes represent a large, untapped source of energy and chemicals. Upcycling discarded plastics into high-value products could result in economic savings of billions of dollars and minimize negative environmental impact. However, municipal plastic waste streams are a mixture of various incompatible polymers such as polyethylene, polypropylene, polyvinylchloride, polyethylene terephthalate, and polystyrene, as well as polymer additives, dyes, and contaminants. As a result, recovering high-quality plastic materials from mixed solid municipal wastes by physical sorting is a challenge. Thermochemical recycling of waste plastics is not economical since the current processes require intensive energy inputs and costly product upgrading. Therefore, energy-efficient catalytic deconstruction processes are needed to overcome the chemical and physical challenges of recycling mixed plastics. This project will develop an innovative waste plastics chemical upcycling process that selectively converts co-mingled waste plastics to valuable monomers and chemicals. It aims to promote a plastics circular economy and mitigate the negative environmental impact caused by accumulated plastic wastes. Education and outreach activities will be integrated with the research program to facilitate student and workforce development and encourage the participation of students from underrepresented groups in STEM.The proposed waste plastics deconstruction approach is centered around the sequential catalytic solvolysis (SeCatSol) process. The SeCatSol process is a novel technology being developed at Washington State University for the selective stage-by-stage deconstruction of an individual polymer or classes of polymers in a polymer mixture using robust organocatalysts and heterogeneous catalysts under mild conditions. The SeCatSol process is designed to address the grand challenge in the plastic industry: how to deconstruct co-mingled municipal waste plastics selectively. The SeCatSol process sequentially produces monomers or value-added chemical products in each catalytic conversion unit, providing a feasible “Chemical Sorting” method to upcycle the complex municipal plastic mixtures at a molecular level. A systematic team effort aims at developing highly selective catalysts and efficient solvents for the SeCatSol process. In particular, the advanced in-situ and operando characterization tools, such as NMR, ATR-FTIR, and Raman spectroscopy, will decipher the complexity of deconstructing waste plastics. Furthermore, novel predictive molecular computational methods will accelerate catalyst design and solvent selection. The proposed technology framework fits into a circular economic model that is restorative and regenerative by design. This project represents the transformative work required for the significant advancement of fundamental polymer science and engineering knowledge.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.