Patent ID: 8865926

Claim:
A method for preparing cyclosiloxanes comprising: providing a first reagent consisting of a dihydrosilane, dihydrosiloxane, or combination thereof of the structure: H—[R 1 R 2 SiO] n-1 R 1 R 2 SiH, where n is 1 to 6, and R 1 and R 2 are independently: C 1 to C 8 alkyl; C 2 to C 8 alkenyl; C 1 to C 8 halo substituted alkyl having 1 to 13 F, Cl, Br, and/or I; C 6 to C 10 aryl; C 7 to C 31 alkyl mono- or multi-substituted aryl; C 3 to C 9 trialkylsiloxy; C 8 to C 26 aryldialkylsiloxy, C 13 to C 28 alkyldiarylsiloxy, or C 18 to C 30 triarylsiloxy; providing a second reagent consisting of a dihydroxysilane, dihydroxysiloxane, or combination thereof of the structure: HO—[R 3 R 4 SiO] m H, where m is 1 to 6 and R 3 and R 4 are independently: C 1 to C 8 alkyl; C 2 to C 8 alkenyl; C 1 to C 8 halo substituted alkyl having 1 to 13 F, Cl, Br, and/or I; C 6 to C 10 aryl; C 7 to C 31 alkyl mono- or multi-substituted aryl; C 3 to C 9 trialkylsiloxy; C 8 to C 26 aryldialkylsiloxy, C 13 to C 28 alkyldiarylsiloxy, or C 18 to C 30 triarylsiloxy; providing a reaction phase comprising a Lewis acid catalyst and a solvent; and combining the first reagent and the second reagent over a period of time in the reaction phase to produce an initial condensation product, H—[R 1 R 2 SiO] n- [R 3 R 4 SiO] m H, which initial condensation product undergoes intramolecular condensation to form a cyclosiloxane of the structure: wherein the product produced by the reaction contains about 24% or less of higher molecular weight siloxane oligomers.