An Introduction to the CHEMISTRY of the SILICONES By EUGENE G. ROCHOW. PREFACE: The organic compounds of silicon, which have been the subject of many scholarly researches during the past 80 years, at last show promise of emerging from the laboratory and finding a place in industry. An understanding of the behavior of organosilicon materials is necessary to their intelligent use and, inasmuch as the chemistry of these substances ordinarily is not treated in our textbooks, it is possible that a compact yet comprehensive survey of our present knowledge in this field would be of service to chemists, engineers, and industrial designers. This volume has just such a purpose. The first few chapters review the silanes and their derivatives in some detail, in order to provide an understanding of the fundamental chemistry of the nonsilicate com pounds of silicon. The later chapters emphasize the silicone polymers which have achieved commercial importance and deal with the methods for their preparation, their chemical and physical properties, and their possible usas. The processes available for large-scale production are treated separately, and a review of methods of analysis is included. In order not to burden the text with definitions and explanations of nomenclature which might already be familiar to some readers, an extensive glossary of terms is appended. An exhaustive review of the literature on organic compounds of sili con cannot very well be included in a volume intended for the non specialist. However, many references are provided, and tables of most of the known compounds and their properties are included in the appropriate chapters. The reader will find comprehensive reviews ofpublications in Friends Textbook of Inorganic Chemistry, Volume 11, Part 2 Krause and von Grossed Chemie der Metallorgamschen Ver bindungen, Dolgows Chemistry of the Silica-Organic Compounds, and Bygdens Silizium als Vertreter des Kohlenstoffs organischen Verbindun gen. A more recent and more complete compilation of the literature on organic compounds of silicon would be welcomed by every investigator in the field. Since this work presents a point of view rather than an uncritical compilation of published fact, the author must assume entire responsi bility for the opinions expressed. However, he is greatly indebted to his coworkers iu the research laboratory of the General Electriq Company for helpful advice and criticisms. In a larger sense this work is the result of many years of common endeavor in a most interesting field of research. Contents include: 1. THE SIMPLE COVALENT COMPOUNDS OF SILICON 1 Introduction 1 Chemical Behavior of the Element 3 The Hydrides 4 The Halides 9 The Esters or Ethers 12 Index of Representative Compounds 16 2. THE ORGANOSILICON MONOMERS 18 Methods for Carbon-Silicon Bonds 19 The Alkyls 30 The Alkylsilanes 32 The Alkylhalosilanes 33 The Alkylalkoxysilanes 37 Index of Representative Compounds 39 3. TYPES OF ORGANOSI LICON POLYMERS 45 Silicon Chains 45 Silicon-Carbon Chains 46 Siloxane Chains 49 Siloxane Networks 53 Index of Representative Compounds 58 4. PROPERTIES OF THE SPECIFIC SILICONS POLYMERS 60 Alkyl Silicones 62 Methyl Silicone Oil 64 Methyl Silicone Resins 70 Silicone Rubber 72 Ethyl Silicone Resins 73 Other Alkyl Silicone Resins 74 Aryl Silicones 77 Alkyl-Aryl Silicones 80 5. WATER-REPELLENT FILMS FROM ORGANOSILICON MATERIALS 83 Reaction ofMethylchlorosilanes 83 Uses 85 6. TECHNICAL ASPECTS OF SILICONES 89 The Intermediates 90 The Grignard Method 91 The Direct Method 96 Processing 101 Toxicity 103 Future Expansion 104 ix

Many people look upon a microscope as a mere instrument(l); to them microscopy is instrumentation. Other people consider a microscope to be simply an aid to the eye; to them microscopy is primarily an expan sion of macroscopy. In actuality, microscopy is both objective and sub jective; it is seeing through an instrument by means of the eye, and more importantly, the brain. The function of the brain is to interpret the eye's image in terms of the object's structure. Thought and experience are required to distinguish structure from artifact. It is said that Galileo (1564-1642) had his associates first look through his telescope microscope at very familiar objects to convince them that the image was a true representation of the object. Then he would have them proceed to hitherto unknown worlds too far or too small to be seen with the un aided eye. Since Galileo's time, light microscopes have been improved so much that performance is now very close to theoretical limits. Electron microscopes have been developed in the last four decades to exhibit thousands of times the resolving power of the light microscope. Through the news media everyone is made aware of the marvelous microscopical accomplishments in imagery. However, little or no hint is given as to what parts of the image are derived from the specimen itself and what parts are from the instrumentation, to say nothing of the changes made during preparation of the specimen.

An Introduction to the CHEMISTRY of the SILICONES By EUGENE G. ROCHOW Research Laboratory, General Electric Company NEW YORK JOHN WILEY SONS, INC. LONDON CHAPMAN HALL, LIMITED COPYRIGHT, 1946 BY EUGENE G. ROCHOW AU Rights Reserved This book or any part thereof must not be reproduced in any form without the written permission of the publisher. SECOND PRINTING, MARCH, 1947 PRINTED IN THE UNITED STATES OF AMERICA To P. G. F. PREFACE The organic compounds of silicon, which have been the subject of many scholarly researches during the past 80 years, at last show promise of emerging from the laboratory and finding a place in industry. An understanding of the behavior of organosilicon materials is necessary to their intelligent use and, inasmuch as the chemistry of these substances ordinarily is not treated in our textbooks, it is possible that a compact yet comprehensive survey of our present knowledge in this field would be of service to chemists, engineers, and industrial designers. This volume has just such a purpose. The first few chapters review the silanes and their derivatives in some detail, in order to provide an understanding of the fundamental chemistry of the nonsilicate com pounds of silicon. The later chapters emphasize the silicone polymers which have achieved commercial importance and deal with the methods for their preparation, their chemical and physical properties, and their possible usas. The processes available for large-scale production are treated separately, and a review of methods of analysis is included. In order not to burden the text with definitions and explanations of nomenclature which might already be familiar to some readers, an extensive glossary of terms isappended. An exhaustive review of the literature on organic compounds of sili con cannot very well be included in a volume intended for the non specialist. However, many references are provided, and tables of most of the known compounds and their properties are included in the appropriate chapters. The reader will find comprehensive reviews of publications in Friends Textbook of Inorganic Chemistry, Volume 11, Part 2 Krause and von Grossed Chemie der Metallorgamschen Ver bindungen, Dolgows Chemistry of the Silica-Organic Compounds, and Bygdens Silizium als Vertreter des Kohlenstoffs organischen Verbindun gen. A more recent and more complete compilation of the literature on organic compounds of silicon would be welcomed by every investigator in the field. Since this work presents a point of view rather than an uncritical compilation of published fact, the author must assume entire responsi bility for the opinions expressed. However, he is greatly indebted to his coworkers iu the research laboratory of the General Electriq Com vii viii PREFACE pany for helpful advice and criticisms. In a larger sense this work is the result of many years of common endeavor in a most interesting field of research. CONTENTS CHAPTER PAGE 1. THE SIMPLE COVALENT COMPOUNDS OF SILICON 1 Introduction 1 Chemical Behavior of the Element 3 The Hydrides 4 The Halides 9 The Esters or Ethers 12 Index of Representative Compounds 16 2. THE ORGANOSILICON MONOMERS 18 Methods for Carbon-Silicon Bonds 19 The Alkyls 30 The Alkylsilanes 32 The Alkylhalosilanes 33 The Alkylalkoxysilanes 37 Index of Representative Compounds 39 3. TYPES OF ORGANOSI LICON POLYMERS 45 Silicon Chains 45 Silicon-Carbon Chains 46 Siloxane Chains 49Siloxane Networks 53 Index of Representative Compounds 58 4. PROPERTIES OF THE SPECIFIC SILICONS POLYMERS 60 Alkyl Silicones 62 Methyl Silicone Oil 64 Methyl Silicone Resins 70 Silicone Rubber 72 Ethyl Silicone Resins 73 Other Alkyl Silicone Resins 74 Aryl Silicones 77 Alkyl-Aryl Silicones 80 5. WATER-REPELLENT FILMS FROM ORGANOSILICON MATERIALS 83 Reaction of Methylchlorosilanes 83 Uses 85 6. TECHNICAL ASPECTS OF SILICONES 89 The Intermediates 90 The Grignard Method 91 The Direct Method 96 Processing 101 Toxicity 103 Future Expansion 104 ix CONTENTS CHAPTER 7...