Method for preparing high-quality dimethyl silicone oil

The invention provides a method for preparing dimethyl silicone oil, which comprises the following steps: mixing hydroxyl-terminated polydimethylsiloxane with low molecular weight, a methyl end-capping reagent, a polycondensation telomerization agent and a phosphazene catalyst, and sequentially carrying out a normal compression polytelomerization reaction and a negative compression polytelomerization reaction to obtain the dimethyl silicone oil. The polycondensation telomerization agent added in the preparation method can effectively regulate and control the polycondensation rate, methyl silicone oil with different viscosities can be prepared, meanwhile, the viscosity peak of polycondensation is avoided, and the advantage is more obvious especially for high-viscosity products. The dimethyl silicone oil prepared by the preparation method disclosed by the invention has the advantages of low content of ring bodies, especially low content of macrocyclic byproducts and low content of metal ions, so that the applic