Direct process

The direct process, also called the direct synthesis, Rochow process, and Müller-Rochow process is the most common technology for preparing organosilicon compounds on an industrial scale. It was first reported independently by Eugene G. Rochow and Richard Müller in the 1940s.^[1]^[2]

The process involves copper-catalyzed reactions of alkyl halides with elemental silicon, which take place in a fluidized bed reactor. Although theoretically possible with any alkyl halide, the best results in terms of selectivity and yield occur with chloromethane (CH₃Cl). Typical conditions are 300 °C and 2–5 bar. These conditions allow for 90–98% conversion for silicon and 30–90% for chloromethane. Approximately 1.4 Mton of dimethyldichlorosilane (Me₂SiCl₂) is produced annually using this process.^[3]

Few companies actually carry out the Rochow process, because of the complex technology and has high capital requirements. Since the silicon is crushed prior to reaction in a fluidized bed, the companies practicing this technology are referred to as silicon crushers.^[4]

^ Rösch, L.; John, P.; Reitmeier, R. (2003). "Organic Silicon Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a24_021. ISBN 978-3527306732..
^ Pachaly, B.; Weis, J. (1997). "The Direct Process to Methylchlorosilanes: Reflections on Chemistry and Process Technology". Organosilicon Chemistry III. pp. 478–483. doi:10.1002/9783527619900.ch79. ISBN 978-3-527-29450-3.
^ Elschenbroich, Christoph Organometallics VCH, Weinheim, Germany: 1992. ISBN 978-3-527-29390-2.
^ "Basic Silicone Chemistry – A Review" (PDF). Archived from the original (PDF) on 2011-05-16. Retrieved 2010-01-26.

[Roesch-1] Rösch, L.; John, P.; Reitmeier, R. (2003). "Organic Silicon Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a24_021. ISBN 978-3527306732..

[2] Pachaly, B.; Weis, J. (1997). "The Direct Process to Methylchlorosilanes: Reflections on Chemistry and Process Technology". Organosilicon Chemistry III. pp. 478–483. doi:10.1002/9783527619900.ch79. ISBN 978-3-527-29450-3.

[Elschenbroich-3] Elschenbroich, Christoph Organometallics VCH, Weinheim, Germany: 1992. ISBN 978-3-527-29390-2.

[4] "Basic Silicone Chemistry – A Review" (PDF). Archived from the original (PDF) on 2011-05-16. Retrieved 2010-01-26.

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