Читать книгу Concise Handbook of Fluorocarbon Gases - Sina Ebnesajjad - Страница 10

Preface

I have worked in the fluoropolymers industries for the better part of four decades. During those years I have encountered fluorocarbon gases as monomers of the fluoropolymers. In time I learned about the detrimental impact of some of those gases on the ozone layer and contribution to global warming. Curiosity led me to attempt educating myself about those impacts. The facts relied on the well-known basic chemical reactions of chlorine free radicals with ozone and as such they were undeniable. Interest in the environmental impact of chlorofluorocarbons gases ignited my long apprenticeship in this field. I set a goal to learn about the topics related to commercial applications of fluorocarbons.

Today, one often hears about the ozone layer, global warming, climate change, recycling and sustainability. Some of these terms had not yet been coined at the onset. In the1970s there was little if any reported news about the ozone monitoring that had been started by the scientists from the British Antarctic Survey who began monitoring ozone in 1957. Paul Crutzen, Mario Molina and Sherwood Rowland raised concerns about the effect of man-made chemicals, especially chlorofluorocarbons, on the Ozone Layer as early as in the 1970’s, to little effect. Exception is the unilateral move by the US Environmental Protection Agency banning the production of chlorofluorocarbons in 1978.

Then came the momentous article written by Joe Farman, Brian Gardiner and Jonathan Shanklin, in the prestigious journal Nature in May 1985. The authors reported the discovery of the annual depletion of ozone above the Antarctica for the first time (Figure). The information withstood reanalysis by NASA scientists who confirmed the findings. Loss of atmospheric ozone would weaken/remove the filter for harmful ultraviolet light thus subject the entire earth and the living organisms to excess UV radiation, expected to lead to known and unknowns damages. The subject caught the attention of the public. Something had to be done.

Source: https://undsci.berkeley.edu/article/0_0_0/ozone_depletion_09

[The international community was uncharacteristically quick to act, perhaps because the seemingly sudden appearance of a “hole” in the atmosphere made for such a compelling and easily understandable story. Within two years, in direct response to the Nature article and corroborating studies, 46 nations signed the Montreal Protocol, pledging to phase out substances known to cause ozone depletion. All 197 members of the United Nations would eventually ratify the treaty…], as described by the www.History.com. Today, over 98% of the 100 ozone depleting chemicals have been phased out. A great deal of change has taken place in the decades since 1987 to not only eliminate/minimize ozone depleting substances but reduce the emissions of global warming gases.

Many treaties have followed the original Montreal Protocol and colossal numbers of scientific articles have been published. Learning about the technological changes and the state of the ozone layer is a bewildering task. An in depth understanding requires the knowledge of such a large volume of literature that it is impractical even for the practitioners in the areas of fluorocarbon gases. That was the dilemma the author faced in his quest to learn about the topics surrounding the ozone layer. There was no single book to read or refer to for learning. Not finding a source, in 2016 the author set out to write the book he wished he could buy and read: in-depth coverage of important topics yet concise to fit practical time limits. The focus of this book is placed on the commercial and practical subjects as opposed to the theoretical ones.

The outcome of the author’s efforts during nearly five years is the book before you. The contents begin at the ground level by providing an introduction to fluorocarbons, that is fluorinated small molecules and polymeric materials. The rest of the book is focused on industrial fluorocarbon, gases and liquids. The issue of ozone depletion is discussed in conjunction with the subject of most chapters to ensure clarity of the relationship of the compounds with the current rules and regulations. In the early chapters some basic topics have been covered including fluorine sources, basic reactions for fluorine entry into organic compounds and applications of fluorocarbon gases and liquids.

Emphasis has been placed on refrigeration though other applications have also been discussed. The preparation methods and properties of fluorocarbons occupy Chapters 6 and 7. Chapter 8 delves into the topics of ozone depletion and global warming by discussing the various treaties and changes since 1987. A reader should be able to gain a complete understanding of the current state of technology and the future directions as foreseen by experts by reading the Chapters 8 and 11. Chapter 9 contains a great deal of data about the industrial fluorocarbons blends. Chapter 10 focuses on fluorocarbon substitutes, including non-fluorinated substances, in current use in the industry.

I would like to thank all authors, companies, government agencies, international organizations and others who have contributed data and information to this book. The author has made every effort to acknowledge the contributors in the references section of each chapter and throughout the narrative.

Last but not least I would like to offer my sincere apologies for any errors the readers may find in this book. The errors are the responsibility of the author. A note to the publisher would be most appreciated so that corrections could be made in the future editions.

I would like to thank Scrivener Publishing for the contracting and production of the book and John Wiley & Sons for its distribution and marketing.

Sina Ebnesajjad, PhD www.FluoroConsultants.com Chadds Ford, Pennsylvania January 2, 2021