| 摘要 |
1,270,877. Silicon-containing cyclic acetals. SOC. INDUSTRIELLE DES SILICONES. 20 Oct., 1969 [18 Oct., 1968], No. 51389/69. Heading C3S. Halogenated silicon-containing cyclic acetals of the formula where R 1 and R 2 are Me, Et, Pr, i-Pr or Ph and X 1 , Xa and X 3 are F or Cl are prepared by reacting a disiloxanediol of the formula with a hexahalogenoacetone of the formula The latter compounds may be used in the anhydrous or hydrated form. Examples are hexachloro -, hexafluoro -, pentafluorochloro-, sym. dichlorotetrafluoro - and 1,1,3 - trichlorotrifluoro-acetone. Mixtures may be used. A catalyst such as an acid or activated clay may be employed. Uses.-Anti-foaming agents. |
