Preparatory Reaction of Si(CH3)4 from SiCl4
SiCl4 (silicon tetrachloride) can be converted into Si(CH3)4 (tetramethylsilane) through a preparatory reaction that involves a series of steps.

Step 1: Reduction of SiCl4
- In the first step, SiCl4 is reduced using a reducing agent, such as lithium aluminum hydride (LiAlH4) or sodium borohydride (NaBH4).
- The reduction reaction leads to the formation of silicon tetrachloride, SiCl4.

Step 2: Grignard Reaction
- The next step involves the reaction of SiCl4 with a Grignard reagent, such as methyl magnesium bromide (CH3MgBr).
- The Grignard reagent attacks the silicon atom in SiCl4, leading to the formation of Si(CH3)4 and magnesium chloride (MgCl2) as a byproduct.

Step 3: Work-Up
- After the reaction is complete, the mixture is usually treated with an acid, such as hydrochloric acid (HCl), to protonate the Grignard reagent byproduct and neutralize any remaining reagents.
- The resulting solution is then typically extracted with an organic solvent, such as diethyl ether, to separate the desired product, Si(CH3)4, from the reaction mixture.

Conclusion
- Through these preparatory steps, SiCl4 can be effectively converted into Si(CH3)4, which is a valuable precursor in the synthesis of various organosilicon compounds. This process allows for the controlled introduction of methyl groups onto a silicon atom, expanding the range of applications for silicon-based materials in various industries.