Organosilicon, also known as organosilicon compounds, is an important chemical substance. Since its discovery in the early 20th century, the application of organosilicon has been widely developed in various fields.

I. Definition and properties of organosilicon.

Organosilicon compounds contain silicon-carbon bonds, with at least one organic group connected to a silicon atom via a carbon bond. CH₃SiH₃, (C₂H₅)₄SiCl, C₆F₅SiCl₃, (CH₃)₂Si, (OCH₃)₂, etc. are all organic silicon compounds. SiCl₄, SiC, Si₃N₄, Na₂SiO₃, HSiCN, etc. are inorganic silicon compounds. Although ethyl orthosilicate Si(OC₂H₅)₄, triethoxysilane HSi(OC₃H₇)₃, etc. contain organic groups, they are connected to silicon atoms through oxygen atoms and are not organosilicon compounds. No organosilicon compounds are found in nature, and silicate compounds are only found in animal feathers and grasses. Silicone chemistry studies the synthesis, structure, properties, and uses of organosilicon compounds. There are many types of silicone polymers, including polysiloxane, polysilane, polycarbosilane, polynitrogen silane, etc. Organopolysiloxanes with polysiloxane as the main chain have high temperature resistance, moisture resistance, insulation and other properties, and are widely used in aviation, electronics, construction and other fields.

II. Early research and discovery of organosilicon.

Prior to 1863, the known and utilized silicon-containing compounds were inorganic silicon compounds, including natural compounds and other transformed products such as ceramics, cement, and glass. In 1863, French chemists C. Fiedler and J. M. Crafts synthesized tetraethylsilane (Si(C2H5)4) by the reaction of ethylene with silicon tetrachloride in a sealed tube, which marked the beginning of organosilicon chemistry.

From 1904 to 1937, scientists not only synthesized many simple organosilicon compounds but also discovered cyclic and linear polysiloxanes. A. Stock also discovered many silanes. This period of over thirty years was a period of growth for organosilicon chemistry.

After 1940, chemists began to recognize the application prospects of polymeric organosilicon compounds. The earliest research in this field was conducted by J. F. Hyde of Corning Glass Company, W. J. Patnode and E. G. Rochow of General Electric (GE), and K. A. Andrianov and B. N. Dolgov of the former Soviet Union. These researchers developed organic silicon resins, coatings, impregnants, and many other polyorganosiloxane products. The use of organosilicon compounds expanded during World War II, with applications in thermal insulation, lubricants, and sealing materials for military equipment, promoting the development of the organosilicon industry.

III. Further development and application of organosilicon.

Modern and future societies require energy-saving, renewable, environmentally friendly, safe, versatile, multi-form, and high-performance new materials. Organosilicon, which entered the market in the 1940s, is a type of new high-performance polymer synthetic material that can meet these requirements. It is known for solving various technical problems and improving production technology. Its wide-ranging applications have left a deep impression in almost every industrial and scientific sector, and its remarkable efficacy is unparalleled by other materials. Therefore, it has been aptly dubbed the "industrial monosodium glutamate." With the development of high-tech, countries around the world have invested a lot of human and financial resources in the development of organosilicon, and major organosilicon producers worldwide are expanding their production capacity.

New application technologies and fields continue to emerge, creating new markets. For example, the use of light-curable organosilicon as a coating material for optical fibers has brought optical fibers into practical use; the aerospace industry uses high-temperature-resistant and chemically inert high-performance silicon carbide fibers, increasing the strength of metals and ceramics, thereby improving the performance of spacecraft; modified organosiloxane polymer films are used to produce oxygen-rich films, permeable membranes, and artificial gills for deep-sea operations and the separation and enrichment of high-purity gases, which are of great significance for the development of biomedicine and marine engineering; the rise of bioactive and alkylated organosilicon reagents has brought about significant changes in organic synthesis, pharmaceuticals, and biochemistry.

In today's world, almost every new technology in various fields of science and industrial production requires the use of organosilicon to solve problems that other materials cannot. For example, without high-performance silicon oil, explosions are prone to occur in underground railway transformers; organic silicon rubber seals are necessary for reliable and fireproof purposes in high-rise building curtain walls, glass, and indoor wire and cable conduits; textiles and wool sweaters require organic silicon finishing agents for a comfortable feel; without organic silicon injection, oil well production cannot be increased; cosmetics and daily chemical products cannot improve their performance and grade without the addition of organic silicon; in the field of medical and health care, many advanced surgeries cannot be performed without organic silicon, and the efficacy of many drugs cannot be improved. It can be seen that organosilicon materials are closely linked to the development of the national economy. Since the establishment of the world's first organosilicon factory by Dow Corning in the United States in 1943, the organosilicon materials industry has undergone nearly 70 years of development. Due to its excellent performance, it has become a new type of sophisticated chemical industry system that is technologically intensive and occupies an important position in the national economy. Its application has deeply penetrated into contemporary national defense technology, the national economy, and even people's daily lives, making it one of the most adaptable and developed varieties of synthetic materials. Therefore, promoting and developing organosilicon is a hot topic in the contemporary chemical industry.

Ⅳ. Future development trends of organosilicon

For the entire chemical industry, developing more efficient and environmentally friendly processes and better controlling product structures are common trends in development. The organosilicon industry is no exception. Starting with the production of its raw materials, the direct method is currently the only manufacturing method for industrial organosilanes. Although this method has now developed to a very advanced level, it is not a perfect method. The main problem is that this method requires the use of metal silicon, which does not exist in nature and requires high energy consumption for production. A more ideal process should start with silicates as the starting material, selectively removing oxygen atoms while introducing alkyl groups, and forming dialkylsiloxanes. Such a process would be revolutionary, but to date there have been almost no reports in this regard. Currently, efforts are being made to further increase the yield of dialkylsiloxanes while reducing the generation of by-products.

Any new application of polysiloxanes is related to its special properties. Polysiloxanes have a high ability to withstand adverse environments (i.e., high temperature, ultra-low temperature, radiation, and oxidation). As new application areas with higher requirements in this regard emerge, polysiloxanes should be one of the best candidate polymers. Polydimethylsiloxanes have no sudden change from low glass transition temperature to decomposition point, with small and continuous changes in its physical properties, making it suitable not only for constant high-stress situations but also for environments with wide-ranging variations in temperature, humidity, radiation, and other environmental stresses. This is also one of the reasons why there is currently extensive research on the application of organosilicon in new energy sources (including solar and nuclear energy) and aerospace. The high breathability, chemical inertness, and biocompatibility of polydimethylsiloxane have made it shine in the field of life sciences, making it a very important research direction for polysiloxane materials. The flexible molecular chain and weak intermolecular forces of polysiloxanes make them have low surface energy and high spreadability. The surface properties of polysiloxanes have been utilized in many areas where interface modification or control is required, and they are used as defoamers, release agents, coupling agents, surfactants, (yarn) sizing agents, and pressure-sensitive adhesives. The emergence of new organic silicon surfactants and other types of surface-active polysiloxanes will bring about more new applications.

A promising trend now is the combination of siloxane chemistry with organic chemistry to obtain a large number of new organosilicon-organic compositions, among which people are especially hoping to develop a simple and economical process route for the preparation of organosilicon/organic block copolymers. This method is simpler than the ionic polymerization process, but because there are not many polymers obtained with appropriate end functional groups, and the cost of preparing these polymers is also high, it has not yet been widely used commercially. However, it is worth noting that the industry has adopted this route to produce polydimethylsiloxane/polyethylene glycol block copolymer surfactants. Other technical methods (such as selective degradation, reactive processing, etc.) are currently being evaluated. The ideal process should be as follows: use easily obtainable starting materials, utilize existing equipment, and should not be as sensitive to impurities or water vapor as the ionic copolymerization process; at the same time, it is hoped that the polymerization process can be used to prepare copolymers with different structures, such as AB, ABA, (AB)n, star-shaped, comb-shaped, etc., and can well control the size of the copolymer segments and the total molecular weight of the copolymer. It is currently impossible to predict which polysiloxane/organic copolymers will be successful in the future. Although many such copolymers have been prepared, their commercial applications are still limited. Perhaps the emergence of new demands or new applications will be the driving force for the development of these copolymers.

V. Conclusion

Combining the history and development of organosilicon, it can be seen that its importance and wide application in the chemical industry. From the initial synthesis to modern advanced applications, organosilicon has been continuously evolving and innovating. With the advancement of technology and globalization, the organosilicon industry has ushered in new opportunities and challenges.

In the past, organosilicon was mainly used in insulation, lubrication, and sealing, providing important support for military, aerospace, and industrial production. Today, with the increasing demand for new materials and the promotion of technological progress, the application of organosilicon is constantly expanding, involving electronics, photovoltaics, medicine, agriculture, and other fields. Its unique properties and versatility make it an indispensable part of the contemporary chemical industry.

In the future, the organosilicon industry will continue to face challenges but will also encounter more opportunities. From improving production process efficiency to developing new application technologies, the organosilicon industry will continue to innovate and progress. The demand for new materials, increased environmental awareness, and technological development will drive the organosilicon industry towards broader directions, making greater contributions to the progress and sustainable development of human society.

In summary, the history and development of organosilicon are full of brilliance and challenges. It is not only an important part of the chemical industry but also a key force driving technological progress and social development. Looking to the future, the organosilicon industry will continue to grow, contributing to a better tomorrow for humanity.