Explain the preparation of straight chain silicons

Asked by rahmani | 15th Nov, 2010, 12:00: AM

Expert Answer:

Polymeric organo-silicon compounds which contain Si — O — Si bonds are called silicones. These have the general formula (R2SiO)n. Where R is CH3-group or C6H5-group.

 
 

 Preparation of Silicones: The preparation of silicones is generally carried out by the hydrolysis of dialkyldichlorosilanes (R2SiCl2) or diaryldichlorosilanes (Ar2SiCl2), which are prepared by passing vapors of RCl or ArCl over silicon at 570 K with copper as a catalyst.

 

 

                      Cu, 570 K
             2RCl + Si ——————> R2 SiCl2

 

                                              R            R           R
                          +H2O            |              |           |
            R2SiCl2 ————> —O — Si — O — Si — O — Si — O —
                          –HCl             |             |            |
                                              R            R           R     

 

 We hope that clarifies your query.

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Answered by  | 16th Nov, 2010, 06:51: PM

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