Richard S- Miller Dr. Richard S, Miller is recognized both as a scientist and as a manager in the Office of Naval Research. His contributions to this field well illustrate the role and value of federal support in nurturing innovative science. Dick Miller is a model for the perfect federal science manager; technically brilliant, adroit in assembling novel yet balanced programs, and most of all entirely dedicated to the welfare of the scientists and graduate students whose research fulfills his mission. As a result of Dr. Miller's efforts, the Navy has benefited from tremendous new knowledge of energetic materials. The articles in this volume provide an overview of the field where Dr. Miller has had such a great influence. The contributions in this critical and rapidly grow- ing area of science have profoundly benefited the advancement of knowledge as well as our national defense. The quality of the contributions herein and the emi- nence of the investigators clearly testifies that the study of energetic materials is no longer only of great practical significance but has also achieved high standing as an area of fundamental scholarly research. We dedicate this volume to Dick Miller as a scientist, a faithful provider of federal funding for science, and a brilliant manager of technology for our future Navy. OJ F. E. Saalfeld Director Office of Naval Research Chemistry of Energetic Materials Edited by George A. Olah Loker Hydrocarbon Research Institute Department of Chemistry University of Southern California Los Angeles, California David R. Squire Defense Sciences Office DARPA Arlington, Virginia I This book is printed on acid-free paper. © No Rights Reserved. All parts of this publication maybe reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system. Library of Congress Cataloging-in-Publication Data Chemistry of energetic materials / (edited by) George A. Olah, David R. Squire p. cm. Includes index. ISBN 0-12-525440-7 t. Combustion. 2. Thermodynamics. 3. Explosives. 4. Propellants. I. Olah, George A. (George Andrew), date U. Squire, David R. QD516.C538 1991 541.361 91-12536 C1P 5 4 3 2 Contents Contributors vii Preface ix 1. The Structural Investigation of Energetic Materials 1 Richard D. Gilardi and Jerome Karle I. Introduction 1 II. Pressure and Impulse 2 III. Energetic Materials Database 3 IV. Bending Angles in Nitramines 6 V. Nitroolefins 11 VI. Cubane and Substituents 16 VII. Conclusions 22 References 23 2. Studies of Initial Dissociation Processes in 1,3,3- Trinitroazetidine by Photofragmentation Translational Spectroscopy 27 Deon S. Anex, John C. Allman, and Yuan T. Lee I. Introduction and Overview 27 II. The Thermal Decomposition of TNAZ 33 III. Analysis and Discussion 42 IV. Summary 53 Referenees/Endnotes 54 3. Studies of Molecular Dissociation by Means of Ultrafast Absorption and Emission Spectroscopy and Picosecond X-Ray Diffraction 55 Peter M. Rentzepis and B. Van Wonterghem I. Introduction 55 II. Photodissociation of Haloaromatics 56 III. Picosecond X-Ray Diffraction 69 References 75 4. Computer-Aided Design of Monopropellants 77 Peter Polttzer, Jane S. Murray, M. Edward Grice, and Per Sjoberg I. Introduction 77 Contents vi II Theoretical Background 78 £ AjicanonofSpecificImpulseFormula 80 IV Calculated Specific Impulse Values 81 V. Perspectives 91 VI. Summary 92 References 92 5. Polycyclic Amine Chemistry 95 AmaidT. Nielsen I. Introduction 95 # II. Approaches to Synthesis of Caged Nitramine Explosives 97 III. Polyazaadamantanes 100 IV. Polyazawurtzitanes 104 V. polyazaisowurtzitanes HO VI. Summary 119 References 120 6. Metallacarboranes of the Lanthanide and Alkaline-Earth Metals: Potential High Energy Fuel Additives 125 Rajesh Khanar, KfarkJ. Manning, and M. Frederick Hawthorne I. Lanthanide Element Metallacarboranes 125 II. Preparation and Characterization of Bis-Dicarbollide Complexes of Sm and Yb 129 III. Alkaline-Earth Element Metallacarboranes 131 References 136 7. Methods for Preparing Energetic Nitro-Compounds: Nitration with Superacid Systems, Nitronium Salts, and Related Complexes 139 George A. Ohh I. Introduction 139 II. Protic-Acid-Catalyzed Nitration 140 HI. Lewis-Acid-Catalyzed Nitration 152 IV. Nitration with Nitronium Salts 158 V. Transfer Nitration 186 VI. Dcmetallative Nitration 191 References 198 Index 205 Contributors Numbers in parentheses indicate the pages on which the authors' contributions begin. John C. Allman (27), Materials and Chemical Sciences Division, Lawrence Berke- ley Laboratory and Department of Chemistry, University of California, Berkeley, California 94720 Deon S. Anex (27), Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory and Department of Chemistry, University of California, Berkeley, California 94720 Richard D. Gilardi (1), Naval Research Laboratory, Washington, D.C. 20375 M. Edward Grice (77), Department of Chemistry, University of New Orleans, New Orleans, Louisiana 70418 M. Frederick Hawthorne (125), Department of Chemistry and Biochemistry, Uni- versity of California, Los Angeles, California 90024 Jerome Karle (1), Naval Research Laboratory, Washington, D.C. 20375 Rajesh Khattar (125), Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90024 Yuan T. Lee (27), Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory and Department of Chemistry, University of California, Berkeley, California 94720 Mark J. Manning (125), Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90024 Jane S. Murray (77), Department of Chemistry, University of New Orleans, New Orleans, Louisiana 70418 Arnold T. Nielsen (95), Chemistry Division, Research Department, Naval Weap- ons Center, China Lake, California 93555 George A. Olah (139), Loker Hydrocarbon Research Institute, and Department of Chemistry, University of Southern California, Los Angeles, California 900S9 Peter Politzer (77), Department of Chemistry, University of New Orleans, New Orleans, Louisiana 70418 Peter M. Rentzepis (55), Department of Chemistry, University of California, Irvine, California 92717 Per Sjoberg (77), Nobel Chemicals, Division Nobelkrut, S-691 85. Kariskoga. Sweden B. Van Wonterghem (55), Department of Chemistry, University of California, Irvine, California 92717 page. Preface The field of energetic materials has long been considered primarily for its practical aspects and it is only recently that the modern fundamental science phenomena began to emerge. This has been particularly true in academic science, where fun- damental acceptance and progress in the field has only recently developed. Ener- getic materials, however, have been of great practical importance from the time of the discovery of gunpowder to modern day explosives and rocket fuels. These materials have had a profound, if not always positive, effect on history. However the significance of their peaceful uses, ranging from the use of explosives in mining and road building to applications such as missile propulsion systems, should not be overshadowed by their potential destructive power. The ultimate use of the knowl- edge gleaned by this research is not a question for debate here. Research on energetic materials extends from bulk synthesis, to engineering and materials science, to the microscopic study of molecular dynamics and struc- ture (i.e., the molecular level understanding of these systems). In order to under- stand the combustion of energetic materials, the detailed chemistry of the decomposition processes must be understood. The nature of the individual reaction steps, the dynamics of the dissociation, and the energy released during combustion reactions must be recognized. Thus, the study of energetic materials spans many disciplines. Chemistry, as the science that can lead to such materials, is at the focal point. Indeed, an ever-extending array of new energetic compounds is continually being synthesized. Historically, nitro derivatives played a special role as the most commonly used compounds. Energetic nitro compounds range from C-nitro deriv- atives such as trinitrotoluene (TNT), to O-nitro compounds such as trinitrogly- cerol, to /V-nitro compounds such as HMX and RDX. Nitrogen oxides continue to be significant oxidants. Any study of energetic materials must clearly start with the characterization of structure. R. D. Gilardi and J. Karle discuss in the first chapter the structural in- vestigation of energetic materials by the use of single crystal x-ray crystallography. In conjunction with their colleagues at the Naval Research Laboratory, they have over the years advanced these studies in a remarkable way and in the process obtained a unique collation of the structural data of more than 500 energetic com- pounds of great significance. Their chapter centers on the structural study of the most recent significant classes of compounds. In addition to facilitating an under- standing of the relationship of structure to function (such as density), this structure* work also plays a valuable role in the development of new and improved materials by facilitating synthesis of promising new types of substances, as weU as charac- terizing those already synthesized. It is even possible now, on occasion, to make Preface 1 he unacr*uu~»*D — ^ his C0 Heagues discuss in ^napicr z also of fundamentaJ importance^ ^^^ spectroscopy of the significant their study bv photofragmentatio nitroalkyl nitramine related to the HVfX and RDX Although a significant portion or the or enerccuu materials U related to condensed phase reactions, the un- derstanding of the chemistry of isolated species is also pertinent. Of particular irion translaiional spectroscope, the compound studied is expanded from a nozzle ,mo a vacuum and the expansion is collimated to form a molecular beam. The molecular beam is then crossed * ith the output of a pulsed CO 2 laser, which excites the molecule of interest above the dissociation threshold; this infrared multiphoton excitation induces dissociation of the molecule. This method has also been applied previously to the study of the initial steps in RDX decomposition. Molecular beam studies provide a useful complement to bulk phase decomposition studies. The characterization of the initial steps in the decomposition allows a better under- standing of the results of bulk phase studies with regard to secondary reactions and the role of the condensed state. Molecular beam studies also contribute signifi- cantly to the theoretical understanding of combustion processes. P M Remzepis and B. Van Wonterghem discuss in Chapter 3 the kinetics and mechanism of dissociation of molecules by means of ultrafast absorption and emis- sion spectroscopy. The spectra of the intermediate states and species are obtained in real time and the formation and decay of these species measured. The develop- ment of picosecond x-ray spectroscopy f PXR), a new field that enables the record- ing of the evolution of the structure of intermediates durin 2 the course of chemical reactions,«. also presented. Application of these new pioneering methods to the study of energetic systems will widen our understanding and knowledge of the fundamentals of molecular dissociation processes. ' ^leagues discuss the computer-aided design of on methods that calculate the spe- lants), a characteristic es- propellants. An energetic per unit weight of the materi-1 s P ecihc impulse /^ is the integral of the thrust, as a means of charactenzin VnT^ 'l ""^ ° f ^ combuslion - h is w 'dely used culation of specific impulse x,till^tfknow^T^ lechniques all ° w 'ng the cal- thus of obvious great sionifi™.^ ° P ote ntial energetic molecules are • r> U * w "- l s c «*- vanu poien- m Chapter 5 gives an account of the [...]... this volume are Nobel laureates and five are members of the National Academy of Sciences speaks well for the maturing nature of the field and the related degree of scientific sophistication Obviously a volume of this size cannot give a comprehensive review of the entire field of the chemistry of energetic materials It offers, however, a good perspective of the present day research in both the structural-physicochemical... present effort to advance the chemistry of energetic materials to new levels of understanding and improved applications The U S Navy has traditionally, through its own research at the renowned Naval Research Laboratory and its sponsorship of outside research administered b> the Office of Naval Research, contributed greatly to the development of the field of energetic materials One of its most devoted and... W-nitramines (RDX and HMX)] Methods of preparing nitro compounds thus remain a key part of the synthesis of energetic materials The study of energetic materials is emerging from a field primarily directed toward practical interests to an advanced area of fundamental research, where state -of- the-art methods and theory are used side by side with modern synthetic methods That two of the contributors to this volume... dejisjtips proportional xo substrtu^nji^najrnely, 1.66,1.74 and 1,81 g/cc^respec- III Energetic Materials Database A virtue of developing a database of energetic materials is its use in the prediction of target structures that have potentially desirable features The large number of crystal structure analyses of energetic materials that have been performed in recent years has provided much useful information... to provide mformation for use in tudies of the relation of structure to activity and the design of substances structures of a large number of energetic materials has provided information for an extensive database for such substances [2] It has served as a useful source of information for making predictions concerning the possible success in the synthesis of new materials II Pressure and Impulse Density... with the substances of interest With careful experimentation in properly chosen cases, electron density distributions can also be evaluated Applications of this type of information in a variety of scientific disciplines are evident Some examples of areas of science that can be benefited are synthetic organic chemistry, natural products chemistry, pharmaceutical chemistry, the study of rearrangement reactions,... display of the N-N distance (in A) and the amino bend (°) of the nitramino group V Nitroolefins There have been a number of investigations involving the study of nitroolefins as useful intermediates in the synthesis of energetic materials A characteristic of many of them is a large twist about the double bond Interest in the structural characteristics that accompany the rotation motivates a discussion of. .. preparative aspects of the field The contributions herein should give all practitioners of the field, whether in academia, industry, or governmental laboratories, a good overview of some of the frontlines of the field It is also hoped that the book will stimulate young scientists and engineers to take interest in the field of energetic materials It is after all the future generation of practitioners who... ^"thesis of strain energy and, in addi- SOme i ti TH average The / The Structural Investigation of Energetic Materials 0 Fig 21 The packing of molecules in the cocrystal of cubylcubane and 2-(/-butyl)cubylcubane The central molecule is cubylcubane; all of the surrounding molecules are 2-(/-butyl)-cubylcubanes The three emphasized molecules comprise the contents of one unit cell (the centroids of only... Structural Investigation of Energetic Materials Richard D Gilardi and Jerome Karle I Introduction Structure determination in the context of this chapter means the determination of the atomic arrangements in materials in the crystalline state There are a number of aspects to structural analyses They may be used to identify substances since they can be performed without previous knowledge of chemical composition . faithful provider of federal funding for science, and a brilliant manager of technology for our future Navy. OJ F. E. Saalfeld Director Office of Naval Research Chemistry of Energetic Materials Edited. W-nitramines (RDX and HMX)]. Methods of preparing nitro compounds thus remain a key part of the synthesis of energetic materials. The study of energetic materials is emerging from a field primarily. this size cannot give a comprehensive review of the entire field of the chemistry of energetic materials. It offers, however, a good perspective of the present day research in both the structural-physicochemical