Before 1863, all the silicon-containing compounds known and utilized by people were inorganic silicon compounds, including natural silicon-based products transformed into modern products such as ceramics, cement, and glass. In 1863, French chemists C. Feidedel and J.M. raft synthesized tetraethyl silane by the reaction of ethyl zinc with silicon tetrafluoride in a sealed tube. It was the first organosilicon compound in history. This also marked the beginning of organosilicon chemistry.
From then on, chemists continuously synthesized new organosilicon compounds. Among them, it is worth mentioning A. Lamenberg, which uses ethyl orthosilicate to replace silicon tetrachloride and react with alkyl zinc to obtain organosilicon compounds with mono -, II -, and III silicon functionals, and A.Polis, which synthesizes the first all-arylsilane, tetraphenylsilane, through the C.A.Wurtz reaction. During the 40 years up to 1903, although no technological achievements that truly promoted the development of silicone were produced, chemists did a lot of pioneering work during this period. Therefore, this stage can be regarded as the founding period of silicone.
The renowned British chemist F.S.Kipping is regarded as the founder of organosilicon chemistry. From 1898 to 1944, he conducted extensive and in-depth research in this field and continuously published 51 related papers in the Journal of the Chemical Society of the United Kingdom.
In 1904, W and the German chemist Dithey independently discovered that organosilicon compounds could be synthesized through the Grignard reaction. This method was significantly improved over the previous metal-organic synthesis methods due to its ease of operation, high yield, wide application range and relatively high safety. This method can be used to synthesize a variety of organosilicon compounds with different silicon functionalities
Kip-ping synthesized a large number of well-defined organosilicon compounds by using this method. This method became the foundation of the organosilicon industry in the future, and it remains one of the most important synthesis methods for organosilicon today. RMgCl+SiCl- RSiCl:+RSiCl+R:SiC1+ RSi +MgCl,(2.3)Kipping synthesized organochlorosilanes using the Grignard reagent method and found that they could be hydrolyzed to form silanols. At the same time, he also noticed that silanediol and siltriol could further undergo intermolecular condensation to form polymers. However, as an organic chemist, he paid no attention to this reaction at all and even detested these polymer products. Therefore, he did not study them. In this regard, Dilthey did do a meaningful job: he condensed diphenylsilanediol to obtain hexaphenylcyclotrisiloxane. This is the first cyclic polysiloxane compound reported in history. It is a pioneer in the synthesis of linear silicon-oxane, and its advent has played a very positive role in promoting the development of organosilicon polymers.
From 1904 to 1937, scientists not only synthesized many simple organosilicon compounds but also developed cyclic and linear polysiloxysaccharides. In addition, A.Stock has discovered many silanhydrides in fundamental research and has begun the synthesis of asymmetric silicon atom compounds. The past three decades have been a period of growth for organosilicon chemistry.
After the 1930s Chemists began to recognize the application prospects of high-molecular organosilicon compounds. The earliest researchers in this field included J.F.Hyde of Corning Glass Company in the United States, W.J. Petnode and E.G.Rochow of General Electric (GE) in the United States, and K.A. of the former Soviet Union Andrianov and B.N.Dolgov, R. Miller from Germany, etc
Hyde, contrary to Kipping's view, was the first to combine organosilicon chemistry with polymer chemistry. Under his guidance, Corning Inc. produced silicone resins, coatings, impregnating agents and many other polyorganosiloxane products for electrical insulating glass cloth. Meanwhile, DowChemicals of the United States also began the production research of polyorganosiloxanes and established pilot plants for dimethyl silicone oil and methyl phenyl silicone resin in 1942. At that time, organochlorosilane monomers were mainly synthesized by the Grignard method, so the supply of monomers became the main bottleneck affecting the development of organosilicon polymers at that time. In 1940, Rochow invented the "direct synthesis method" of methylsilane and applied for a patent. This method does not use solvents. It is a gas-solid phase reaction where chloromethane is directly introduced into silicon powder containing a copper catalyst (Equation 2.4). Just at this time, the German chemist Muller also applied for a similar patent, but the priority date was nine months later than Rochow's. This outstanding contribution has sparked a major revolution in the production of silicone and promoted the further development of the silicone industry.
In 1943, Dow Chemical Company and Corning Inc. jointly established the world-renowned silicone professional company - Dow Corning Corporation, and in the same year, a factory for the production of polyorganosiloxanes was built in Mdand, Michigan, USA. The company soon developed DC#4 ignition sealing material and successfully applied it to high-altitude aircraft. Later, the company developed many types of silicone resin, coatings, shockproof oil, lubricating oil, defoamers and other products. In 1947, General Electric Company also established an organosilicon division, which produced organosilicon gas by the direct method and produced polysiloxane products. The production technology of General Electric Company was adopted by subsequent silicone factories.
The research in the field of silicone polymers in the former Soviet Union was extremely outstanding, especially Andrianov. In addition to doing a lot of work on polysiloxane polymers and synthesizing many organosilicon polymers with practical application value, he also introduced other elements such as boron, aluminum, titanium, tin and phosphorus into the polysiloxane structure for modification. He was also the first person to use silazane as a waterproof coating.
After the end of World War II, due to the successful application of silicone products in military production, the silicone industry developed very rapidly and its production all embarked on a regularized path. In the 1950s, silicone product manufacturing companies were successively established in various countries. A variety of silicone polymer materials, such as silicone rubber (including high-temperature curing rubber, room temperature vulcanizing rubber, transparent silicone rubber, oil-resistant fluorosilicone rubber, etc.), diffusion pump oil, laminating resin, silicone emulsion, silicone surfactant, anti-sticking agent, silicone rubber ablation material, etc., have emerged one after another.
Between 1938 and 1965, both in theory and application; Organosilicon chemistry is making rapid progress both in monomers and polymers. Here, the key points to be emphasized include: silicylation reactions, hydrosilylation reactions, research on photoactive organosilicon compounds, synthesis of organosilicon compounds containing carbon functional groups, exploration of reaction mechanisms, improvement of polymerization methods, as well as the successive emergence of silicone oil, silicone rubber, and coupling agents, etc. There is no doubt that this stage was the development period of silicone
Since 1965, in addition to consolidating, developing, improving and utilizing the existing achievements, people have also turned to the new field of organosilicon chemistry. Among them, the notable ones include: organosilicon stereochemistry, organosilicon compounds with physiological activity, cyclic and linear polysilanes, various silicon-containing reaction intermediates, unsaturated bond compounds of silicon, ternary ring compounds containing silicon, silicon-metal bond compounds, polysilane block copolymers, sesquiloxanes, silicon-containing dendritic and hyperbranched polymer compounds, etc. In the silicone industry, the production scale of silicone monomers and polymers is constantly expanding, production technology is constantly improving, and production costs are constantly decreasing. This makes silicone products more competitive. The continuous development of multi-functional and high-performance silicone products, such as medical, conductive and thermally conductive polysiloxanes, has continuously expanded their application scope. Silicone products are constantly penetrating into various fields of the national economy in the main forms such as silicone oil, silicone rubber, silicone resin, and silane coupling agents.