Base-Catalyzed Silicone Recycling With Hydrothermal Water
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for recycling silicone materials are inefficient, slow, and unsuitable for industrial application, particularly due to the inability to effectively cleave Si-C and Si-O bonds, leading to toxic residues and environmental issues.
Innovation Solution
A process involving the reaction of silicon with hydrothermal or supercritical water in the presence of a base, which accelerates the cleavage of Si-C and Si-O bonds, forming hydrocarbons and silica, and can convert amorphous silica into crystalline silica, suitable for reintroduction into the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrothermal treatment is used to cleave Si-O-Si and Si-C bonds in silicone rubber, then bond cleavage is achieved, but the reaction rate is very slow and unsuitable for industrial application
Solution Approach 1:
The patent changes the chemical environment parameters by introducing a base catalyst (such as NaOH, KOH, or Ca(OH)2) to the hydrothermal treatment system. This parameter change transforms the reaction conditions from neutral to alkaline, which dramatically accelerates the cleavage rate of Si-O-Si and Si-C bonds while maintaining the effectiveness of bond breaking. The base catalyst enables the reaction to proceed at industrially viable speeds without compromising the completeness of bond cleavage.
2Loss of substance
If acid- or base-catalytic equilibration is used to remove cyclic siloxanes, then cyclic siloxanes are removed, but the residue is highly toxic due to strongly alkaline conditions and the method cannot cleave Si-C bonds
Solution Approach 1:
The patent modifies the reaction parameters by controlling the base concentration and temperature conditions to achieve complete degradation of organic residues. By operating at elevated temperatures (100-300°C) and using controlled amounts of base, the system transforms toxic residues into harmless substances (CO2, H2O, and inorganic salts). Additionally, the extended reaction time ensures complete mineralization of organic matter, eliminating toxicity while maintaining the benefit of cyclic siloxane removal.
3Loss of substance
If incineration is used to dispose of silicone sealants, then disposal is achieved, but silicification clogs filters and complex dust disposal is required
Solution Approach 1:
The patent replaces the thermal incineration process with a chemical hydrothermal treatment system. Instead of using high-temperature combustion that produces silicified ash and complex dust streams, the system uses base-catalyzed hydrothermal degradation at lower temperatures (100-300°C). This substitution transforms the solid silicone polymer into soluble or filterable products (silicates, hydrocarbons, CO2, H2O), eliminating filter clogging issues and simplifying waste disposal. The liquid or slurry output can be easily separated and treated without complex dust handling infrastructure.
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 process achieves complete cleavage of silicone within a few hours, producing valuable hydrocarbons and crystalline silica, promoting a circular economy by enabling the reuse of materials and reducing environmental impact.
Implementation Method 1
it has been possible to cleave Si-C and Si-O bonds in silicones through hydrothermal reactions or reactions with supercritical water... The base accelerates this process, achieving complete cleavage of the silicone within a few hours
Implementation Method 2
silicon is reacted in the presence of a base with hydrothermal water of at least 200°C or supercritical water to form silica and hydrocarbon
Implementation Method 3
Additionally, the base converts amorphous silica into crystalline silica
Data Source
AI summary
The invention relates to a process for reacting silicone in the presence of a base with hydrothermal water of at least 200°C or supercritical water to form silicic acid and hydrocarbon.