| 摘要 |
The specification describes preparation of materials comprising selected boron anions and processes using them as catalysts for condensation reaction of compounds having silicon-bonded hydroxy or alkoxy groups. Preferred anion compounds comprise borates incorporating quadri-substituted boron in which the substituents include highly halogenated hydrocarbon groups for example pentafluorinated phenyl groups or bis (trifluoromethyl) phenyl groups. Preferred anions are {B(C<subscript>6</highlight>F<subscript>5</highlight>)<subscript>4</highlight>}<superscript>-> and {B(C<subscript>6</highlight>(CF<subscript>3</highlight>)<subscript>2</highlight>H<subscript>3</highlight>)<subscript>4</highlight>}<superscript>->. The specification describes condensation in presence of these materials of compounds having at least one unit according to the general formula R<superscript>o><highlight>a</highlight>R<superscript>1><highlight>b</highlight>R<superscript>2><highlight>c</highlight>SiO<subscript>(4-(a+b+c)/2) </highlight>in which each R<superscript>o >is the same or different and represents a hydroxy, alkoxy, alkoxyalkoxy or hydrocarbonoxy group having up to 10 carbon atoms, each R<superscript>1 >is the same or different and represents hydrogen or a monovalent substituted or unsubstituted hydrocarbon group, each R<superscript>2 >is the same or different and represents a divalent substituted or unsubstituted alkylene or oxyalkylene group, a has a value of 1, 2, 3 or 4, b has a value of 0, 1, 2 or 3 and c has a value of 0, 1, 2 or 3.
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