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 without the need for auxiliary bases or filtration, ensuring a uniform distribution of siloxane units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chlorosilane chemistry is used to produce branched SiOC-bonded polyether siloxanes, then the polyether substituents can be bonded successfully, but corrosive reactants and intermediates are generated causing material resistance issues, offgas problems, and waste disposal challenges
Solution Approach 1:
The patent replaces expensive and problematic chlorosilanes with inexpensive, non-corrosive siloxane cycles (D4, D5, D6) that can be readily disposed of. The siloxane cycles serve as temporary reactants that are consumed in the reaction to form the desired SiOC bonds, eliminating the need for harmful chlorosilane reagents while maintaining bonding reliability
Solution Approach 2:
The patent changes the chemical parameters of the reactants from chlorosilane-based compounds to siloxane cycle-based compounds. This parameter change transforms the reaction system from one producing corrosive HCl offgas to one producing only water and alcohol byproducts, eliminating material resistance and waste disposal issues while preserving the ability to form SiOC bonds
2Shape
If diethoxydimethylsilane is used as a modifying agent to produce SiOC-bonded polyether siloxanes, then branched structures can be formed, but the process becomes costly limiting broad application
Solution Approach 1:
The patent replaces the expensive diethoxydimethylsilane modifying agent with inexpensive siloxane cycles (D4, D5, D6) that serve as the source of branched structures. These siloxane cycles are consumed during the reaction to form the SiOC bonds and branched architecture, providing the same structural function at a fraction of the cost
Solution Approach 2:
The patent extracts the essential function of diethoxydimethylsilane (providing branched SiOC structures) and achieves it through a different, cheaper pathway using siloxane cycles. The modifying agent function is separated from the expensive reagent and achieved through the inherent reactivity of the siloxane cycles with the polyetherol
3Manufacturing precision
If traditional equilibration processes are used with D/T structured siloxanes, then functionalized branched siloxanes can be obtained, but the process requires multiple steps including acidic equilibration and metal-catalysed transesterification
Solution Approach 1:
The patent merges the equilibration and bond-forming steps into a single reaction process. The siloxane cycles react directly with the polyetherol in one step to form the SiOC bonds and branched structures, eliminating the need for separate acidic equilibration and metal-catalysed transesterification steps while maintaining precise structural control
Solution Approach 2:
The patent segments the complex multi-step process into a single elementary reaction step. Instead of performing equilibration, transesterification, and bond formation in sequence, the siloxane cycles undergo direct condensation with polyetherol in one step, simplifying the overall process while preserving product quality
4Ease of manufacture
If the process uses simple and economic reactants, then production cost is reduced, but achieving quantitative conversion and uniform oligomer distribution becomes challenging
Solution Approach 1:
The patent changes the physical parameters of the reaction system, including temperature control and reaction time, to optimize the conversion of inexpensive siloxane cycles. By carefully controlling these parameters, the process achieves quantitative conversion and uniform oligomer distribution while maintaining economic viability through the use of cheap reactants
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 method allows for the production of SiOC-bonded polyether siloxanes with improved performance quality and economic viability, achieving quantitative conversion and minimizing product losses, while avoiding the use of corrosive reactants and costly modifying agents.
Implementation Method 1
reacting cyclic branched siloxanes with acetic anhydride under acid catalysis
Implementation Method 2
performing the equilibration of the acetoxy-modified branched siloxane with acids, preferably superacids
Implementation Method 3
reacting the acid-treated acetoxysiloxane with polyetherols to produce SiOC-bonded polyether siloxanes
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.