Grantee Research Project Results

Engineering Environmentally Benign Solvent Systems

EPA Grant Number: R828169
Title: Engineering Environmentally Benign Solvent Systems
Investigators: Broadbelt, Linda J.
Current Investigators: Broadbelt, Linda J. , Zhang, Qizhi , Khan, Shumaila
Institution: Northwestern University
EPA Project Officer: Hahn, Intaek
Project Period: September 1, 2000 through August 31, 2002
Project Amount: $223,199
RFA: Exploratory Research - Engineering, Chemistry, and Physics) (1999) RFA Text |  Recipients Lists
Research Category: Safer Chemicals , Water , Land and Waste Management , Air

Description:

This research project will develop the capability to construct complex chemical mechanisms for broad compound classes to allow the impact of an engineered solvent system on ozone formation to be probed.

Objectives/Hypothesis:

Ambient ozone in urban and regional air pollution represents one of the country's most pervasive and stubborn environmental problems. Strategies for pollution prevention in the chemical industry aimed at reducing the formation of ground level ozone have focused on identification of fugitive emissions, reduction of amounts of process chemicals and even elimination of organic solvents from product formulations. Less attention has been paid to engineering organic solvent systems with both the properties desired for a particular application and the environmental implications of the emissions in mind. A limitation to effectively implementing this pollution prevention strategy is an inability to predict the ozone formation potential of a given solvent formulation rapidly and reliably. Since the number of experiments required to probe the impact of a given solvent formulation on ozone formation is prohibitive, prediction using detailed kinetic modeling is an attractive alternative that has been shown to successfully capture experimentally-observed behavior. However, uncertainties in the application of chemical mechanisms over a wide range of conditions and to higher molecular weight species, aromatic compounds and reaction of carbonyls still remain, limiting their predictive capability.

Approach:

The proposed work builds upon our capability to generate complex reaction mechanisms via the computer. This tool for automated model construction eliminates the tedious manual effort required to construct detailed kinetic models, links the reaction with computational quantum chemistry techniques and other theoretical approaches for estimating rate constants that are unavailable experimentally, and provides a solution capability. The advantages of the proposed approach over current strategies for developing kinetic models of atmospheric chemistry are:

1. Reduces the need for lumping of higher molecular weight species by pruning the mechanism as it is built.

2. Provides a framework for directly incorporating diverse experimental data as the mechanism is constructed.

3. Establishes a methodology for accurately estimating rate constants in the absence of experimental data using computational quantum chemistry.

4. Allows a wider range of compound classes to be probed through kinetic modeling.

Expected Results:

Detailed kinetic models provide a fast and flexible vehicle for assessing the environmental liability of a given solvent formulation. Since information about the potential environmental impact of a engineered solvent system would be more easily and rapidly obtained, it becomes possible to incorporate pollution prevention through solvent system design into business decisions at the earliest possible stage. However, detailed modeling using existing approaches to describe the atmospheric reactions of compounds not previously examined can be a tedious and time-consuming task. The proposed work has the potential to significantly reduce the effort required to construct a more explicit kinetic description of the role of solvent emissions in ozone formation, both by automating the assembly of the reactions into a model and by providing a reliable means for estimating model parameters. The tangible deliverable of the proposed research will be software that will be able to construct reaction mechanisms used in the prediction of the ozone formation potential of a broad range of hydrocarbon compounds. This software may ultimately be incorporated as a subroutine to complement and enhance the existing reaction mechanisms at the core of the EPA=s Models-3 initiative for air quality modeling.

Publications and Presentations:

Publications have been submitted on this project: View all 13 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 5 journal articles for this project

Supplemental Keywords:

modeling, Models-3, solvents, VOC, green chemistry, environmentally conscious manufacturing, environmental engineering, air, ozone, RFA, Scientific Discipline, Air, Toxics, INTERNATIONAL COOPERATION, Sustainable Industry/Business, air toxics, Environmental Chemistry, cleaner production/pollution prevention, VOCs, tropospheric ozone, Engineering, Chemistry, & Physics, Chemicals Management, air quality standards, urban air, exposure and effects, stratospheric ozone, atmospheric particles, environmentally conscious manufacturing, ozone, chemical composition, chemical kinetics, quantum chemistry, mathematical formulations, pollution dispersion models, urban air , pollution prevention, green chemistry, solvents

Progress and Final Reports:

2001 Progress Report

Final Report