Process for preparing polydimethylsiloxanes on sulphonic acid cation exchange resins

A process for rearranging siloxane bonds in a precursor polydimethylsiloxane to produce a reorganized polydimethylsiloxane, the method comprising contacting said precursor polydimethylsiloxane with a sulphonic acid-containing cation exchange resin having a water content of 10-20% by weight, wherein said precursor polydimethylsiloxane is a mixture of hexamethyldisiloxane and/or octamethyltrisiloxane and siloxane cycles, and said sulphonic acid-containing cation exchange resin is used in an amount, based on the reaction mixture, of from 2 to 10 wt %, wherein said reorganized polydimethylsiloxane has the formula:

• having a chain length N=n+2, wherein reorganized polydimethylsiloxane having N=6 and N=7 is present at ≧20% by weight of the reorganized polydimethylsiloxane, and wherein reorganized polydimethylsiloxane having N≧13 is present at ≦7% by weight of the reorganized polydimethylsiloxane.