SYSTEMATIC APPROACH FOR CHEMICAL REACTIVITY EVALUATION A Dissertation by ABDULREHMAN AHMED ALDEEB Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY December 2003 Major Subject: Chemical Engineering SYSTEMATIC APPROACH FOR CHEMICAL REACTIVITY EVALUATION A Dissertation by ABDULREHMAN AHMED ALDEEB Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved as to style and content by: ____________________________ ____________________________ M. Sam Mannan Kenneth R. Hall (Chair of Committee) (Member) ____________________________ ____________________________ Mark T. Holtzapple Jerald A. Caton (Member) (Member) ____________________________ Kenneth R. Hall (Head of Department) December 2003 Major Subject: Chemical Engineering iii ABSTRACT Systematic Approach for Chemical Reactivity Evaluation. (December 2003) Abdulrehman Ahmed Aldeeb, B.S., Jordan University of Science & Technology; M.S., The University of Texas at Arlington Chair of Advisory Committee: Dr. M. Sam Mannan Under certain conditions, reactive chemicals may proceed into uncontrolled chemical reaction pathways with rapid and significant increases in temperature, pressure, and/or gas evolution. Reactive chemicals have been involved in many industrial incidents, and have harmed people, property, and the environment. Evaluation of reactive chemical hazards is critical to design and operate safer chemical plant processes. Much effort is needed for experimental techniques, mainly calorimetric analysis, to measure thermal reactivity of chemical systems. Studying all the various reaction pathways experimentally however is very expensive and time consuming. Therefore, it is essential to employ simplified screening tools and other methods to reduce the number of experiments and to identify the most energetic pathways. A systematic approach is presented for the evaluation of reactive chemical hazards. This approach is based on a combination of computational methods, correlations, and experimental thermal analysis techniques. The presented approach will help to focus iv the experimental work to the most hazardous reaction scenarios with a better understanding of the reactive system chemistry. Computational methods are used to predict reaction stoichiometries, thermodynamics, and kinetics, which then are used to exclude thermodynamically infeasible and non-hazardous reaction pathways. Computational methods included: (1) molecular group contribution methods, (2) computational quantum chemistry methods, and (3) correlations based on thermodynamic-energy relationships. The experimental techniques are used to evaluate the most energetic systems for more accurate thermodynamic and kinetics parameters, or to replace inadequate numerical methods. The Reactive System Screening Tool (RSST) and the Automatic Pressure Tracking Adiabatic Calorimeter (APTAC) were employed to evaluate the reactive systems experimentally. The RSST detected exothermic behavior and measured the overall liberated energy. The APTAC simulated near-adiabatic runaway scenarios for more accurate thermodynamic and kinetic parameters. The validity of this approach was investigated through the evaluation of potentially hazardous reactive systems, including decomposition of di-tert-butyl peroxide, copolymerization of styrene-acrylonitrile, and polymerization of 1,3-butadiene. v To my parents: Ahmed and Fatima To my brothers: Fahed, Abdulrazaq, Fadi, Mohammad, and Abdullah vi ACKNOWLEDGEMENTS The author wishes to express his sincere gratitude to his supervisor, Professor M. Sam Mannan, for his guidance, inspiration, friendship, and support throughout this research. Thanks also go to a member of the committee, Professor Kenneth Hall for his unlimited support. Special thanks also go to Professors Mark Holtzapple and Jerald Caton for their cooperation and serving as advising committee members. It is a pleasure to recognize the extent to which conversations and collaboration with Dr. William Rogers contributed to this project. Dr. Rogers has been an invaluable source of knowledge and encouragement. Gratitude is expressed to the Mary Kay O’Connor Process Safety Center (MKOPSC) for supporting this research project and the Chemical Engineering Department at Texas A&M University for supporting me financially pursuing my degree. I am grateful to the Texas A&M University Supercomputing Facility staff for their technical support in conducting the theoretical calculations in this research. Also, many thanks go to the MKOPSC and Chemical Engineering Department staff for their help to make this research project reach this final stage. I would like also to thank the National Research Institute of Fire and Disaster, Tokyo, Japan for inviting me to their laboratory to conduct the C80D heat flow analysis. Finally, sincere admiration goes to my parents and brothers for their love and encouragement. I offer sincere thank to Nader and Eman for the unlimited family environment they created. vii TABLE OF CONTENTS Page ABSTRACT ..................................................................................................................iii DEDICATION ................................................................................................................ v ACKNOWLEDGEMENTS ........................................................................................... vi TABLE OF CONTENTS ............................................................................................. vii LIST OF TABLES ......................................................................................................... xi LIST OF FIGURES ..................................................................................................... xvi LIST OF SYMBOLS ................................................................................................... xxi LIST OF ABBREVIATIONS .................................................................................... xxv CHAPTER I INTRODUCTION ........................................................................................... 1 II APPROACHES IN CHEMICAL REACTIVITY ............................................ 4 1. Précis ........................................................................................................... 4 2. Traditional Approaches of Evaluation ........................................................ 5 2.1. Qualitative Methods .......................................................................... 6 2.1.1. Reactive Chemical Listing ...................................................... 6 2.1.2. Molecular Structure Considerations ....................................... 7 2.1.3. Chemical Incompatibility ....................................................... 8 2.2. Quantitative Methods ........................................................................ 9 2.2.1. Thermodynamic Calculations ................................................. 9 2.2.2. Experimental Analysis .......................................................... 12 3. Conclusions ................................................................................................. 14 III SYSTEMATIC APPROACH FOR CHEMICAL REACTIVITY EVALUATION ..................................................................... 15 1. Précis ......................................................................................................... 15 viii CHAPTER Page 2. Characterization of Chemical Reactivity .................................................. 16 3. Description of the Approach ..................................................................... 17 3.1. Level 1: Screening Evaluation ........................................................ 19 3.2. Level 2: Theoretical Evaluation ...................................................... 19 3.2.1. Molecular Group Contribution Methods .............................. 20 3.2.2. Computational Quantum Chemistry Methods ...................... 21 3.2.3. Correlations Based on Thermodynamic Energy Relationships ............................................................ 25 3.3. Level 3: Experimental Analysis ...................................................... 28 4. Reactive Systems Under Investigation ...................................................... 30 5. Conclusions ............................................................................................... 32 IV RESEARCH METHODOLOGY AND PROCEDURES ............................... 33 1. Précis ......................................................................................................... 33 2. Theoretical Evaluation Methods ............................................................... 33 2.1. Molecular Group Contribution Methods ......................................... 34 2.2. Computational Quantum Chemistry Methods ................................ 35 2.3. Thermodynamic-Energy Correlations ............................................. 37 3. Experimental Thermal Analysis ................................................................ 38 3.1. Reactive System Screening Tool .................................................... 39 3.1.1. Apparatus Description .......................................................... 40 3.1.2. Operating Modes and Procedures ......................................... 42 3.1.3. Data Quality .......................................................................... 43 3.2. Heat Flux Calorimeter