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，并将对环境的负面影响降至最低。然而，城市塑料垃圾是各种不相容的聚合物的混合物，如聚乙烯、聚丙烯、聚氯乙烯、聚对苯二甲酸乙二酯和聚苯乙烯，以及聚合物添加剂、染料和污染物。因此，通过物理分类从混合固体城市垃圾中回收高质量的塑料材料是一个挑战。废塑料的热化学回收是不经济的，因为目前的工艺需要密集的能源投入和昂贵的产品升级。因此，需要高能效的催化解构工艺来克服回收混合塑料所带来的化学和物理挑战。该项目将开发一种创新的废塑料化学回收工艺，选择性地将共混的废塑料转化为有价值的单体和化学品。它旨在促进塑料循环经济，减轻塑料垃圾堆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中代表性不足群体的学生参与。拟议的废塑料分解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项新技术，用于在温和的条件下，使用强大的有机催化剂和多相催化剂，逐级选择性地解构聚合物混合物中的单个或几类聚合物。SeCatSol工艺旨在解决塑料行业的重大挑战：如何有选择地解构共混的城市废塑料。SeCatSol工艺在每个催化转化单元中顺序产生单体或增值化学产品，为在分子水平上对复杂的市政塑料混合物进行升级提供了一种可行的“化学分类”方法。一个系统的团队致力于为SeCatSol工艺开发高度选择性的催化剂和高效溶剂。特别是，先进的原位和操作区表征工具，如核磁共振、ATR-FTIR和拉曼光谱，将破解废塑料的复杂性。此外，新的预测分子计算方法将加速催化剂的设计和溶剂的选择。拟议的技术框架符合循环经济模式，该模式在设计上具有恢复性和再生性。该项目代表了基础聚合物科学和工程知识的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智力优势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.