Rate Constants and Toxicity Estimation for the Computer Discovery of Byproducts Fate in Advanced Oxidation Systems

“该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。“0854416 Crittenden高级氧化工艺（AOP）已显示出有希望破坏水中许多新出现的有机污染物，并且正在考虑用于饮用水处理、废水处理、现场修复和工业应用。高级氧化工艺在本质上是机械复杂的，并且相对于每种污染物的降解动力学和途径以及中间体和副产物的命运进行实验研究是困难和昂贵的。随着每年生产超过90，000种有机化学品，对新兴污染物的日益关注使得对分析计算工具的需求变得更加迫切。本计画的主要目的是发展一种预测高级氧化反应路径的计算工具。基本的方法是用数字表示化学分子，并使用数值算法来枚举反应的可能性。图形理论将被应用作为物种形成和反应生成的基本方法。反应物和反应类型由称为键和电子矩阵的二维矩阵表示。根据反应规则操纵反应物和产物的矩阵生成反应路径网络。将筛选所有中间体和副产物的风险。量子理论和定量构效关系（QSAR）将被应用于估计反应途径网络的速率常数。将开发一种算法来编写和求解包括反应途径的常微分方程，以预测每种物质的浓度时间曲线。该模型将使用几个案例研究，已在文献中报道的验证。一个新的亚利桑那州立大学超级计算机设施将用于帮助模拟反应方案，速率常数和毒性。拟议的项目是朝着建立综合路径生成器迈出的一步。这项工作的最终目标是预测在复杂的氧化反应系统中形成的所有副产物的命运。该发生器的更广泛影响包括：1）提供了一种工具，用于更好地理解化学反应机理，并可能扩展到其他系统; 2）预测化学氧化过程中痕量副产物的形成; 3）为所有副产物的风险筛选提供了一个极好的补充工具，并帮助选择更环保的氧化剂和化学处理工艺; 4）为学生提供全面的跨学科教学和培训工具，以研究包括中间体形成在内的过程的化学动力学;以及，5）提供化学见解，以便可以仔细计划耗时的实验机制研究。作为该项目的一部分，PI将开发课程模块，能够为复杂的自由基化学反应提供化学直觉。

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."0854416CrittendenAdvanced oxidation processes (AOPs) have shown promise to destroy many of the emerging organic contaminants in water, and are being considered in potable water treatment, wastewater treatment, site remediation, and industrial applications. AOPs are mechanistically complex in nature and are difficult and expensive to study experimentally relative to the degradation kinetics and pathways of each contaminant and the fate of the intermediates and byproducts. With more than 90,000 organic chemicals produced annually, the increasing concerns about emerging contaminants make the need for an analytical computational tool more urgent. The principal objective of this project is to develop computational tool of predicting reaction pathways that are involved in the AOPs. The fundamental approach is to represent chemical molecules numerically and to enumerate the reaction possibilities using a numerical algorithm. Graph theory will be applied as a basic methodology for species formation and reaction generation. The reactants and reaction types are expressed by a two dimensional matrix called the bond and electron matrix. Manipulating the matrices of reactants and the products according to reaction rules generates the reaction pathway network. The risks of all the intermediates and byproducts will be screened. Quantum theory and quantitative structure-activity relationships (QSARs) will be applied to estimate the rate constants for the reaction pathway network. An algorithm will be developed to write and solve the ordinary differential equations that comprise the reaction pathway to predict the concentration time profile of each species. The model will be validated using several case studies that have been reported in the literature. A new ASU supercomputer facility will be used to aid in simulating reaction schemes, rate constants, and toxicity. The proposed project is a step towards building a comprehensive pathway generator. The ultimate goal of this effort would be to predict the fate of all byproducts that are formed in complex oxidation reaction systems. The broader impact of the generator includes: 1) providing a tool for better understanding of chemical reaction mechanisms that potentially could be extended to other systems; 2) predicting the formation of trace byproducts in chemical oxidation processes; 3) providing an excellent complementary tool for risk screening of all the byproducts, and helping select more environmentally-friendly oxidants and chemical treatment processes; 4) providing a comprehensive interdisciplinary teaching and training tool for students to study the chemical kinetics of processes that include the formation of intermediates; and, 5) providing chemical insight so that time consuming experimental mechanistic studies can be planned carefully. As part of this project, The PIs will develop course modules that will be able to provide chemical intuition for complex radical chemistry reactions.