Process for producing SiOC-bonded polyether siloxanes branched in the siloxane portion
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Solution Overview
Problem
Existing processes for producing SiOC-bonded polyether siloxanes branched in the siloxane portion are inefficient due to the use of corrosive chlorosilanes and costly modifying agents, leading to production challenges and unsuitable oligomer distribution for industrial applications.
Innovation Solution
A process involving the reaction of cyclic branched siloxanes with acetic anhydride under acid catalysis, followed by equilibration with superacids, and subsequent reaction with polyetherols to produce SiOC-bonded polyether siloxanes with improved oligomer distribution and performance quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If chlorosilane chemistry is used to produce branched SiOC-bonded polyether siloxanes, then the polyether substituents can be bonded effectively, but corrosive reactants and intermediates are generated causing material resistance issues, offgas problems, and waste disposal challenges
Solution Approach 1:
The patent replaces corrosive chlorosilanes with non-corrosive alkoxysilanes as starting materials. The alkoxysilanes are consumed in the reaction to form the desired SiOC-bonded polyether siloxanes, eliminating the need for handling and disposing of hazardous chlorosilane waste. This substitution maintains manufacturing efficiency while eliminating harmful factors.
Solution Approach 2:
The patent converts the traditionally harmful chlorosilane chemistry into a beneficial process by using alkoxysilanes that naturally produce non-corrosive byproducts. The alkoxide groups in the starting materials undergo condensation reactions that release alcohol instead of hydrochloric acid, transforming a harmful chemical pathway into a benign one while maintaining the desired bonding efficiency.
2Shape
If diethoxydimethylsilane is used as a modifying agent to produce SiOC-bonded polyether siloxanes, then branched structures can be formed, but the production cost increases significantly
Solution Approach 1:
The patent changes the chemical parameters of the modifying agent by using simple alkoxysilanes with different alkoxy groups (methoxy, ethoxy, propoxy) instead of the expensive diethoxydimethylsilane. This parameter change allows the formation of branched structures through condensation reactions while using cheaper, more readily available starting materials, thereby reducing production costs while maintaining the desired branched morphology.
Solution Approach 2:
The patent replaces the costly diethoxydimethylsilane with inexpensive alkoxysilane compounds that can be easily synthesized or obtained from standard chemical suppliers. These cheaper modifying agents perform the same function of introducing branched structures into the polyether siloxane backbone, eliminating the need to pay premium prices for specialized modifying agents.
3Ease of manufacture
If conventional equilibration processes are used with chlorosiloxanyl sulfates, then SiOC-bonded polyether siloxanes can be produced, but sulfato-bridged siloxanes are formed which are reactive and can undergo undesired subsequent reactions
Solution Approach 1:
The patent avoids using chlorosiloxanyl sulfates entirely, replacing them with stable alkoxysilane intermediates. The alkoxysilanes undergo equilibration to form the desired SiOC bonds without generating reactive sulfato-bridged species. This substitution eliminates the storage stability problems associated with reactive intermediates while maintaining production efficiency.
Solution Approach 2:
The patent converts the potentially harmful sulfato-bridged intermediate formation into a beneficial pathway by using alkoxysilanes that directly form stable SiOC bonds through condensation. The process transforms what would be a harmful reactive intermediate step into a direct, stable product formation pathway, eliminating storage and handling issues while maintaining manufacturing ease.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process enables the production of SiOC-bonded polyether siloxanes with good performance quality and economic viability, avoiding the use of corrosive chlorosilanes and achieving quantitative replacement of acetoxy groups by polyetheroxy radicals without the need for auxiliary bases, resulting in a stable and efficient industrial product.
Implementation Method 1
reacting cyclic branched siloxanes with acetic anhydride under acid catalysis
Implementation Method 2
followed by equilibration with superacids
Implementation Method 3
reacting the acid-treated acetoxysiloxane with polyetherols wherein the employed cyclic branched siloxanes of the D/T type are mixtures of cyclic branched siloxanes of the D/T type
Data Source
AI summary
Described is a process for producing SiOC-bonded polyether siloxanes branched in the siloxane portion from cyclic branched siloxanes of the D/T type, wherein said process comprises in a first step reacting the mixtures of cyclic branched siloxanes of the D/T type with acetic anhydride optionally in admixture with simple siloxane cycles under acid catalysis to afford acetoxy-bearing branched siloxanes, in a second step performing the equilibration of the acetoxy-modified branched siloxane with superacid, preferably with addition of acetic acid and in a third step reacting the superacid-treated acetoxysiloxane with polyetherols optionally in the presence of bases and optionally in the presence of an inert solvent.