Sulfur-Containing Silane Production With Brine Recycling
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Solution Overview
Problem
Existing processes for producing sulfur-containing silanes using phase transfer catalysts face challenges such as high water consumption, energy costs, environmental restrictions on NaCl discharge, catalyst decomposition, excess raw material usage, and inefficiencies in recycling and detoxification of byproducts, leading to increased costs and equipment size.
Innovation Solution
A process that eliminates the use of pure water by utilizing a brine solution and recycling brine and solid residues, continuous or partial addition of phase transfer catalyst, and optimized phase separation to reduce catalyst retention time and minimize waste, allowing for smaller equipment and reduced raw material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pure water is used in the reaction, then the reaction can proceed, but water consumption increases and energy costs increase due to evaporation and distillation
Solution Approach 1:
The patent changes the parameter of the aqueous phase from pure water to brine (saturated or near-saturated NaCl solution). This parameter change reduces water consumption because the brine can be recycled and reused in subsequent reactions, eliminating the need for continuous addition of fresh water and subsequent evaporation/distillation steps.
Solution Approach 2:
The patent implements a recycling system where the brine phase is recovered after reaction and reused in subsequent batches. This recovering principle eliminates waste of water and reduces energy consumption associated with water treatment, while the discarded portion is minimal compared to using pure water that would require complete evaporation and distillation.
2Ease of operation
If the phase transfer catalyst is added in one step before chloropropyltriethoxysilane, then the reaction setup is simple, but the catalyst decomposes due to long retention time leading to higher catalyst consumption
Solution Approach 1:
The patent segments the catalyst addition process into multiple steps: first adding the phase transfer catalyst before sulfur, then adding more catalyst before chloropropyltriethoxysilane. This segmentation ensures the catalyst is present at the right moments for each reaction stage, reducing unnecessary retention time and decomposition while maintaining operational simplicity.
Solution Approach 2:
The patent performs preliminary action by adding the phase transfer catalyst in advance before sulfur is added to the aqueous phase. This preliminary addition allows the catalyst to be ready for the subsequent reactions without being exposed to long retention times that would cause decomposition, thus reducing catalyst consumption.
3Productivity
If raw materials are added in molar excess to drive the reaction to completion, then the reaction completes in reasonable time, but unreacted raw materials are destroyed after reaction resulting in higher raw material usage
Solution Approach 1:
The patent implements feedback by monitoring the reaction progress and adjusting the addition of raw materials accordingly. The continuous or portion-wise addition of halogen alkyl silane and catalyst allows the reaction to proceed efficiently without requiring large molar excesses, as the system can respond to conversion levels and maintain optimal reaction conditions throughout.
Solution Approach 2:
The patent applies continuous action by continuously or in portions adding halogen alkyl silane and phase transfer catalyst during the reaction. This continuous supply maintains optimal reaction conditions throughout the process, driving completion efficiently without requiring large initial excesses of raw materials that would subsequently be wasted.
4Ease of operation
If the aqueous phase is not recycled into subsequent batches, then the process is simple to operate, but sulfides need to be detoxified consuming considerable amounts of treatment chemicals
Solution Approach 1:
The patent recovers the aqueous phase containing brine and unreacted materials after reaction and reuses it in subsequent batches. This recovering principle eliminates the need for detoxification of sulfides in each batch, as the recycled phase already contains the brine system that prevents sulfide precipitation. The only portion discarded is minimal, reducing treatment chemical consumption significantly.
Solution Approach 2:
The recycled aqueous phase with brine serves itself by providing the ionic environment needed to prevent sulfide precipitation in subsequent reactions. This self-service function eliminates the need for external detoxification chemicals, as the system maintains its own chemical balance through recycling.
5Reliability
If a saturated NaCl solution is used in the reaction, then the aqueous phase can be separated, but environmental restrictions prohibit discharge of large amounts of NaCl to public waste water treatment plants
Solution Approach 1:
The patent recycles the brine (saturated or near-saturated NaCl solution) from the aqueous phase after separation and reuse in subsequent reactions. This recovering principle prevents discharge of large amounts of NaCl to public waste water treatment plants, as the brine is continuously reused. Only minimal portions are discarded, dramatically reducing environmental impact while maintaining phase separation efficiency.
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 approach significantly reduces water consumption, lowers energy costs, minimizes catalyst decomposition, and decreases the need for detoxification chemicals, resulting in a more efficient and cost-effective production of sulfur-containing silanes with higher product yield and purity.
Implementation Method 1
One field of process variations to generate sulfur silanes utilizes a phase transfer catalyst to exchange anions between an aqueous phase and an organic phase
Implementation Method 2
After the reaction, the reaction mixture undergoes phase separation between the aqueous phase and the organic phase
Data Source
AI summary
A process for producing sulfur containing silanes may include: (a) preparing an aqueous phase by mixing sodium hydrosulfide or Na2S, sulfur, Na2CO3 and/or NaOH and brine from recycling (f); (b) adding 20 to 100 wt. % of total phase transfer catalyst; (c) continuously or portion-wise adding halogen alkyl silane, and simultaneously adding the rest of the total phase transfer catalyst, portion-wise or continuously; (d) separating into a lower aqueous suspension and an upper organic phase and drawing off organic phase; (e) supplying the aqueous suspension from (d), separating into a salt cake and brine; (f) recycling all or part of the brine of (e) into (a); (i) routing organic phase of (d) to an evaporation to yield organic residue and low boiling distillate; and (j) separating the organic residue from the evaporation (i) into a sulfur containing silane and a solid residue.