One-Step Synthesis of Siloxanes from the Direct Process Disilane Residue

The well-established Muller-Rochow Direct Process for the chloromethylsilane synthesis produces a disilane residue (DPR) consisting of compounds MenSi2Cl6-n (n=1-6) in thousands of tons annually. Technologically, much effort is made to retransfer the disilanes into monosilanes suitable for introduction into the siloxane production chain for increase in economic value. Here, we report on a single step reaction to directly form cyclic, linear, and cage-like siloxanes upon treatment of the DPR with a 5m HCl in Et2O solution at about 120 degrees C for 60h. For simplification of the Si-Si bond cleavage and aiming on product selectivity the grade of methylation at the silicon backbone is increased to n4. Moreover, the HCl/Et2O reagent is also suitable to produce siloxanes from the corresponding monosilanes under comparable conditions.