Career: Catalyst-Directed Resource from Waste Polymers

摘要CTS-9623741催化剂导向资源回收技术是一种很有前途的将聚合物废料转化为燃料、石化等高附加值产品的技术。然而，由于缺乏全面的知识库，限制了它的应用。这项研究旨在开发一种严格的、以科学为基础的方法，从聚合物废物中回收高价值的产品，从实验和理论两个方面进行。实验计划的重点是开发新的接触模式以加强聚合物-催化剂的相互作用，并确定最佳催化剂参数，以提高所提供产品的价值。实验工作得到了一项理论研究的补充，该研究利用机理建模和计算量子化学来提供有关控制反应基本原理的信息。人们已经确定了从废旧聚合物中回收有价值产品的有希望的策略，并通过实验对其进行了研究。使用超细颗粒或均相催化剂和液体超强酸的目的是通过利用聚合物的固有空隙体积来克服聚合物熔体穿透固体催化剂时遇到的固有扩散限制。然而，传统的聚合物-催化剂接触模式具有允许在现有加工单元中加工聚合物的优势。因此，考察了多相催化剂的相关设计参数，即酸碱度和结构。作为实验工作的补充，理论研究旨在对给定的聚合物原料和催化剂配方的降解特性进行先验预测。从实验研究中积累的数据库提供了一般定性规则，作为制定预测性、量化机制模型的起点。一般来说，聚合物倾向于特定的降解产物归因于三个因素：(1)聚合物主链上的键强度，(2)叔氢的存在，(3)取代基键的相对强度。这些定性规则中的每一个都被用一种结合了机械建模和计算量子化学的方法进行了定量检查。已经开展了初步工作，以演示应用机理模型来量化不同聚合物热降解为单体的趋势。制定了一项将研究和教学相结合的教育计划，以教导化学工程专业的学生在不断变化和越来越具有创业精神的环境中处理复杂问题。该计划的核心部分是(1)开发将理论概念与现实世界过程联系起来的通用制造模块，(2)将计算量子化学引入本科性质估计课程，以及(3)通过个人和团队口头和书面陈述发展沟通技能。其中的每一个都是可以在整个课程中并入的通用组件。

ABSTRACT CTS-9623741 Catalyst-directed resource recovery is a promising technology for the conversion of polymeric waste materials into high-valued products such as fuels and petrochemicals. However, the lack of a comprehensive knowledge base has limited its application. This research aims at developing a rigorous, science-based methodology for the recovery of high-valued products from polymeric waste using both experiment and theory. The experimental program focuses on the development of novel contacting patterns to enhance the polymer-catalyst interaction and on the identification of optimal catalyst parameters that enhance the value of the products afforded. The experimental work is complemented by a theoretical study exploiting mechanistic modeling and computational quantum chemistry to provide information about the controlling reaction fundamentals. Promising strategies for improved recovery of valuable products from waste polymer have been identified and are investigated through experiment. The use of ultra-fine particle or homogeneous catalysts and liquid superacids aims to overcome the inherent diffusional limitations encountered in a polymer melt penetrating a solid catalyst by exploiting the intrinsic void volume of the polymer. However, traditional polymer-catalyst contacting patterns have the advantage of allowing the polymers to be processed in existing processing units. Therefore, relevant design parameters of heterogeneous catalysts, i.e., acidity//basicity and structure, are examined. The experimental work is complemented by a theoretical study aimed at a priori prediction of the degradation characteristics of a given polymer feedstock and catalyst formulation. The database amassed from experimental studies provides general qualitative rules that serve as a starting point for formulating a predictive, quantitative mechanistic model. In general, the tendency of a polymer toward particular degradation products has been attributed to three factors: ( 1) strength of bonds in the polymer backbone, (2) presence of tertiary hydrogens, and(3) relative strength of substituent bonds. Each of these qualitative rules is examined quantitatively using an approach combining mechanistic modeling and computational quantum chemistry. Preliminary work has already been carried out to demonstrate the application of mechanistic modeling to quantify the tendency of different polymers to degrade thermally to monomer. An education plan linking research and teaching has been formulated to teach chemical engineering students to deal with complex issues in a changing and increasingly entrepreneurial environment. The core components which comprise this plan are (1) development of generic manufacturing modules linking theoretical concepts to real world processes, (2) introduction of computational quantum chemistry into the undergraduate curriculum for property estimation, and (3) development of communication skills through individual and team oral and written presentations. Each of these is a generic component that can be incorporated throughout the curriculum.