| 摘要 |
Organopolysiloxanes containing units of the formulae O3-a/2RaSi—Y—(SiRaO3-a/2)b and R1cSiO4-c are prepared by catalyzed reaction, in a first step, of a mixture of X3-aRaSi—Y—(SiRaX3-a)b and R1cSiX4-c and siloxanes which have structural units of the formulae O3-a/2RaSi—Y—(SiRaO3-a/2)b and R1cSiO4-c and having weight average molar mass of 100 to 950 g/mol and reacting the mixture obtained therefrom with water or aqueous acid, producing organopolysiloxanes having a weight average molar mass of 1,000 to 100,000 g/mol, wherein R and R1 each are monovalent C1-30 SiC-bonded organic groups optionally containing one or more N and/or O atoms, Y is a 2-12 valent C1-30 organic group optionally containing one or more O atoms, X is a hydrolyzable group, a is 0 or 1, b is 1 to 11, and c is 0, 1, 2, or 3. |
| 主权项 |
1. A method for producing organopolysiloxanes comprising per molecule at least one structural unit of formulae
O3-a/2RaSi—Y—(SiRaO3-a/2)b (I) and R1cSiO4-c (II),comprising:
(a) in a first step, contacting a mixture of compounds of formulae
X3-aRaSi—Y—(SiRaX3-a)b (III) andR1cSiX4-c (IV),and siloxanes which comprise per molecule at least one structural unit of the formulae
O3-a/2RaSi—Y—(SiRaO3-a/2)b (V) and R1cSiO4-c (VI)and mixtures thereof and which have a molar mass (Mw weight-average) of from 100 to 950 g/mol
with a catalyst, wherein the catalyst is an activated carbon, and (b) in a second step the mixture obtained therefrom is reacted with water or an aqueous acid, to obtain organopolysiloxanes which comprise per molecule at least one structural unit of formulae (I) and (II), and having a molar mass (Mw weight-average) of from 1000 to 100,000 g/mol, where R are identical or different and represent a monovalent SiC-bonded organic radical which comprises from 1 to 30 carbon atoms and optionally contains one or more nitrogen and/or oxygen atoms, R1 are identical or different and represent a monovalent SiC-bonded organic radical which comprises from 1 to 30 carbon atoms and which optionally contains one or more nitrogen and/or oxygen atoms, Y are divalent to dodecavalent organic radicals which comprise from 1 to 30 carbon atoms and which optionally contain one or more oxygen atoms, X is a hydrolyzable group, a is 0 or 1, b is an integer of from 1 to 11 and c is 0, 1, 2 or 3,with the proviso that the siloxanes employed which comprise per molecule at least one structural unit of formulae (V) and (VI) and mixtures thereof are by-products which are formed in addition to the organopolysiloxanes comprising the structural units (I) and (II), have been removed from the organopolysiloxanes comprising the structural units (I) and (II), and recycled into the method. |
