Process for preparing linear organopolysiloxanes having Si-H groups
AssigneeWacker Chemie AG
InventorsGilbert Geisberger, Tassilo Lindner, Frank Baumann
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Abstract
The invention provides a process for preparing linear organopolysiloxanes (P) having diorganosiloxy units and Si—H groups, in which, in a first step, diorganodichlorosilanes (A) and monochlorosilanes (B) and optionally dichlorosilanes (C), at least one of the monochlorosilanes (B) or dichlorosilanes (C) containing Si—H groups, are reacted with at most 0.5 mol of water per mole of hydrolyzable chlorine to give a partial hydrolyzate (T) and gaseous hydrogen chloride, and, in a second step, the SiCl groups still present in the partial hydrolyzate (T) are removed by treating with water to form hydrochloric acid, and a hydrolyzate (H) containing the organopolysiloxanes (P) is obtained.
Claims12
A process for preparing linear organopolysiloxanes (P) containing both diorganosiloxy units and Si—H groups, comprising,
- in a first step,
- reacting diorganodichlorosilanes (A) and monochlorosilanes (B) and optionally dichlorosilanes (C), at least one of monochlorosilanes (B) or dichlorosilanes (C) containing Si—H groups, with at most 0.5 mol of water per mole of hydrolyzable chlorine to give a partial hydrolyzate (T) and gaseous hydrogen chloride, and,
- in a second step,
- removing SiCl groups still present in the partial hydrolyzate (T) by reacting with water to form hydrochloric acid, and
- recovering a hydrolyzate (H) containing organopolysiloxanes (P), wherein the hydrolyzate (H) obtained after the second step is contacted with a rearrangement catalyst.
A process for preparing linear organopolysiloxanes (P) containing both diorganosiloxy units and Si—H groups, comprising,
- in a first step,
- reacting diorganodichlorosilanes (A) and monochlorosilanes (B) and optionally dichlorosilanes (C), at least one of monochlorosilanes (B) or dichlorosilanes (C) containing Si—H groups, with at most 0.5 mol of water per mole of hydrolyzable chlorine to give a partial hydrolyzate (T) and gaseous hydrogen chloride, and,
- in a second step,
- removing SiCl groups still present in the partial hydrolyzate (T) by reacting with water to form hydrochloric acid, and
- recovering a hydrolyzate (H) containing organopolysiloxanes (P), wherein the hydrolyzate (H) obtained in the second step is separated into organopolysiloxanes (P) and a mixture (M) comprising volatile organopolysiloxanes, and the mixture (M) is recycled into the first step and/or second step or rearranged fully or partly to give less volatile, substantially linear organopolysiloxanes.
Dependencies are inferred from the claim text.