Cationic Silicon(IV) Catalyst for Noble Metal-Free Hydrosilylation
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Solution Overview
Problem
Current hydrosilylation processes rely on noble metal catalysts, which are expensive and limited in availability, and previously proposed silicon(IV) cations are consumed in the reaction, making them unsuitable for repeated use as catalysts.
Innovation Solution
A hydrosilylatable mixture containing a compound with a hydrogen atom bonded directly to Si, a compound with a carbon-carbon multiple bond, and an intramolecular cationic Si-H-Si group with silicon in oxidation state IV, which acts as a catalyst without consuming itself, enabling efficient and reusable hydrosilylation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If noble metal complexes (platinum, rhodium, or iridium) are used as hydrosilylation catalysts, then the hydrosilylation reaction can proceed efficiently, but the process becomes considerably more expensive and the availability is limited
Solution Approach 1:
The patent replaces expensive noble metal catalysts with a cheaper silicon-based catalyst system. The cationic silicon(IV) compound acts as a reusable catalyst that can be used multiple times without significant degradation, eliminating the need for expensive platinum, rhodium, or iridium complexes while maintaining catalytic efficiency.
Solution Approach 2:
The patent changes the chemical nature of the catalyst from noble metal complexes to silicon-based cationic compounds. This parameter change involves using compounds with silicon in the +4 oxidation state that form cationic species, fundamentally altering the catalytic mechanism while achieving the desired reaction efficiency at lower cost.
2Ease of manufacture
If cationic silicon(II) compounds are used as hydrosilylation catalysts, then the reaction can proceed without noble metals, but the production becomes complex and the catalyst is consumed in the reaction
Solution Approach 1:
The patent raises the oxidation state of silicon from +2 to +4 in the catalyst compound. This parameter change fundamentally improves the catalyst's stability and reusability while simplifying the production process. The silicon(IV) compounds are more stable and easier to handle than silicon(II) compounds, eliminating the complexity associated with producing and stabilizing lower oxidation state silicon species.
Solution Approach 2:
The patent creates a reusable catalyst system based on silicon(IV) compounds that can be used multiple times without significant degradation. This eliminates the consumable nature of previous silicon(II) catalysts and provides a economically viable alternative to noble metal catalysts.
3Duration of action of stationary object
If cationic silicon(IV) compounds with intramolecular hydrogen bonds are used, then the catalyst is not consumed and can be reused, but the silicon centers are saturated by hydrogen bonding and have no free valencies
Solution Approach 1:
The patent uses intramolecular hydrogen bonds as intermediaries that temporarily occupy the silicon centers during catalyst regeneration but do not permanently saturate them. These hydrogen bonds act as transient intermediaries that allow the catalyst to maintain its active form while preventing unwanted side reactions, enabling multiple catalytic cycles without permanent deactivation.
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
The described catalyst system facilitates efficient hydrosilylation reactions without the need for noble metals, allowing for multiple uses and improving accessibility over previous silicon(II) compounds, thus offering economic and technical advantages.
Implementation Method 1
The hydrosilylation only takes place under catalysis... It has now surprisingly been found that the compounds C, namely cationic silicon(IV) compounds with an intramolecular hydrogen bond, catalyze hydrosilylation very efficiently.
Implementation Method 2
The addition of hydrosilicon compounds to alkenes and alkynes to form Si-C bonds plays an important role in technology. These reactions, known as hydrosilylation...
Data Source
AI summary
The invention relates to a hydrosilylable mixture M containing (A) a compound having at least one hydrogen atom directly bound to Si, (B) a compound that contains at least one carbon–carbon multiple bond, and (C) a compound that contains at least one intramolecularly present cationic Si–H–Si grouping having silicon in the oxidation state IV. The invention further relates to a method for hydrosilylation in which the (A) compound that has at least one hydrogen atom directly bound to Si and the (B) compound that contains at least one carbon–carbon multiple bond are reacted in the presence of the (C) compound that contains at least one intramolecularly present cationic Si-H-Si grouping having silicon in the oxidation state IV.