Muller-Rochow reaction

The synthesis of organosilicones and organosilicone surfactants has been well described elsewhere [36-39] and hence only a brief review is given here. Industrially the manufacture of silicones is performed stepwise via the alkylchlorosilanes, produced through the reaction of elemental silicon with methyl chloride (the Muller—Rochow Process) [40,41]. Inclusion of HC1 and/or H2(g) into the reaction mixture, as in Eq. (1.2), yields CH3HSiCl2, the precursor to the organofunctional silanes, and therefore the silicone surfactants ... 

More than 60 years after its simultaneous discovery by Rochow and Muller, the direct reaction of copper-activated silicon with alkyl chlorides is arguably still the most important industrial process for the preparation of basic organosilanes. An inspiring historic account highlighting the significance of this seminal work has been given by Seyferth.12 A comprehensive review on the subject has been written by Jung and Yoo.13 The most recent work associated with the direct process is concerned with the role of metallic promoters, such as Zn and Cd, as well as mechanistic aspects.14... 

The example of the first category is the formation of alkyl- and arylchlorosilanes in the so-called direct process (DP). The process was discovered over 60 years ago by Rochow in the United States, and, independently, by Muller in Germany, and it is still the most important reaction in organosilicon chemistry. In fact, it is at the very basis of the silicone industry, being the primary source of organochlorosilane precursors (mostly methylchlorosilanes, comprising over 90% of the total) in the production of silicone oligomers and polymers. 

A cornerstone of the modem silicone industry is the direct reaction of methyl chloride with sihcon, discovered in the early 1940s by E. G. Rochow in the United States and independently by R. Muller in Germany.The direct reaction, carried out by all basic producers of silicones, is done in a fluidized bed reactor using finely divided silicon with particle size 30-300 pm, at about 300 °C. In spite of decades of research in many laboratories, the exact course of the reaction is not yet known. 

Of special interest are molecules possessing n electrons only in combination with o bonds. The reactions of silicon atoms with target molecules of this type are relevant for the understanding of the Rochow-MUller (R.-M.) synthesis [2]. In a recent essay Seyferth describes the enormous importance of this direct synthesis of dichlorodimethylsilane by reaction of a silicon/copper alloy with methyl chloride [3]. At the same time he points out that even today, more than 60 years after its discovery in 1940, the mechanism of this process is still not fully understood. It was our hope... 

Summary The Direct Process discovered by Rochow and Muller around 1940 is the basic reaction used to produce methylchlorosilanes, which are the monomeric intermediates used for production of silicones. An understanding of the elementary reactions, the nature of active sites and the action of promotors does not nearly come close to the performance level of the industrial process and the economic importance. The silylene-mechanism is a useful model to understand the complex product mixture from the reaction of silicon with chloromethane. 

The Direct Process is the reaction of silicon with chloromethane to form methylchlorosilanes (Eq.l). This reaction is unique, in that it is the only solid-catalyzed gas-solid reaction applied in the chemical industry. The Direct Process was first discovered by Rochow [1] and independently Muller [2] around 1940. 

Methylchlorosilanes are used in the manufacture of a variety of resins, elastomers, and silicone oils. They are produced as a mixture of chlorosilanes, mainly dimethyldichlorosilane, by the reaction between silicon and methyl chloride by a direct route discovered independently by Rochow (1945) and Muller (1950). In this route, metallic copper, with or without promoters, is used to accelerate the reactions. The form of copper is important and depends on its preparation and association with the silicon phase. The whole system of solids comprising silicon metal, copper... 

Silanes, siloxanes, and silicones are commercially produced from silicon and methyl chloride in a process known as the direct reaction or the Rochow-Muller direct process. ... 

The discovery by E.G. Rochow (General Electric Co.) and by R. Muller (VEB Silikon Chemie) that methylchlorosilanes can be prepared by the direct reaction between methyl chloride and silicon opened up the way for commercial developments using silicon compounds. The reaction... 

The F3 cyclic species is obtained through hydrolysis of the corresponding silane, methyl(3,3,3-trifluoropropyl)dichlorosilane. This silane is the hydrosilylation adduct of 3,3,3-trifluoropropene and methyldichlorosilane, CH3HSiCl2, a minor product of the Rochow-Muller direct process for manufacturing methylchlorosilanes. The hydrosilylation reaction is catalyzed with transition metal complexes of platinum or rhodium such as Speier s catalyst and hexachloroplatinic acid in isopropanol. The reaction conditions are very similar to those employed with unfluorinated reagents, complicated only by the fact that 3,3,3-trifluoropropene is a gas. 

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