SiOC Compound Synthesis via Segmented Column Process
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Solution Overview
Problem
The productivity of continuous processes for preparing SiOC-containing compounds is limited by the throughput of column units, particularly where hydrogen chloride (HCl) formation generates excessive pressure, causing the liquid phase to be discharged at the top instead of flowing downward.
Innovation Solution
A process utilizing two column units where a prereactor partially reacts chlorosilane with alcohol and water, allowing the majority of HCl formation to occur and be removed in the prereactor, thereby reducing the burden on downstream columns and increasing space-time yield by using recycled distillate from the second reaction unit in the prereactor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single column unit is used for continuous preparation of SiOC-containing compounds, then the process is simpler, but the productivity is limited by the column throughput
Solution Approach 1:
The reaction process is divided into two separate column units: a first reaction unit for initial alkoxylation and a second reaction unit for complete reaction and purification. This segmentation allows each column to be optimized for its specific function, increasing overall productivity while managing complexity through functional specialization.
Solution Approach 2:
The process transitions from a single-column sequential operation to a two-column parallel operation, adding a dimensional aspect to the reaction system. This enables simultaneous conduct of different reaction stages, effectively doubling the throughput capacity without proportionally increasing complexity.
2Productivity
If high throughput is maintained in the column, then productivity increases, but excessive HCl gas pressure prevents liquid phase from flowing downward
Solution Approach 1:
The system separates HCl removal function into a dedicated first reaction unit with its own gas-liquid separation mechanism, allowing the second column to operate at high throughput without being constrained by HCl pressure buildup. Each column handles a specific function, preventing pressure-related flow disruption.
Solution Approach 2:
The first reaction unit acts as an intermediary stage that pre-processes the reaction mixture, removing excess HCl before the mixture enters the second column. This intermediary step protects the main production column from pressure issues while maintaining high overall throughput.
3Productivity
If alcohol is continuously recycled into the first reaction unit, then SiCl conversion increases, but the first column becomes overloaded with reaction load
Solution Approach 1:
The reaction load is segmented between two columns: the first column handles initial alkoxylation with recycled alcohol, and the second column completes the reaction and removes volatile constituents. This distribution prevents any single column from becoming overloaded while maintaining high conversion rates.
Solution Approach 2:
The first reaction unit performs preliminary alkoxylation reactions, converting a portion of SiCl groups before the mixture enters the second column. This preliminary action reduces the reaction burden on the main production column, enabling it to operate more efficiently at higher throughput.
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 increases the space-time yield by utilizing recycled alcohol for additional reactions, effectively deburdening the first reaction unit and allowing for higher SiCl conversion without condensation, thus enhancing the efficiency of SiOC compound production.
Implementation Method 1
a prereactor partially reacts chlorosilane with alcohol and water to give a crude product which still comprises volatile constituents
Implementation Method 2
transferred to a second reaction unit comprising a column in which alcohol is additionally introduced and the product freed there of the volatile constituents
Implementation Method 3
increasing space-time yield by using recycled distillate from the second reaction unit in the prereactor
Data Source
AI summary
A process for continuously preparing compounds containing SiOC groups, in which chlorosilane(s) are partially reacted with alcohol and optionally also with water in a prereactor, and the partial reaction product therefrom is fed to a first reaction unit comprising a column, reacted with alcohol and optionally water to give a crude product which still comprises volatile constituents, and the crude product is transferred to a second reaction unit comprising a column in which alcohol is additionally introduced, and freed there of volatile constituents, optionally in the presence of an unreactive organic solvent, the desired end product being removed at the lower end of the second reaction unit.