Direct process
In the chemical industry, the direct process is a type of chemical reaction that makes organosilicon compounds by adding alkyl groups directly to pure elemental silicon. It is the most important process in organosilicon chemistry.[1] The direct process is also called the Müller-Rochow process.
The most common application of the direct process is making dimethyldichlorosilane (DMDCS), the monomer used to make silicone. This reaction uses methyl chloride and a copper catalyst. The reaction is usually written
- 2 CH3Cl + Si → Si(CH3)nCl4−n
The n is used to show a mixture of five different products: tetramethylsilane Si(CH3)4, trimethylsilyl chloride Si(CH3)3Cl, DMDCS, methyltrichlorosilane, and silicon tetrachloride. The process also makes oligomers like Si2(CH3)4Cl2. These products need to be separated by fractional distillation.
Sources
[change | change source]- ↑ Seyferth, Dietmar (2001). "Dimethyldichlorosilane and the Direct Synthesis of Methylchlorosilanes. The Key to the Silicones Industry". Organometallics. 20 (24): 4978–4992. doi:10.1021/om0109051.