Bisphenol Residual Stream Hydrolysis for Sulfide Removal
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Solution Overview
Problem
The challenge in bisphenol production is the formation of sulfides in residual streams, which contaminate the bottoms stream and complicate disposal and further processing, necessitating a method to remove these contaminants and recover the thiol promoter.
Innovation Solution
A process involving acid-catalyzed hydrolysis of organic sulfides in residual streams to convert them into thiols, followed by distillation to recover phenols and thiols, and isomerization of bisphenol isomers to enhance bisphenol-A production, with the use of acidic catalysts like sulfonated ion exchange resins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sulfur-containing promoters (thiols) are used in bisphenol manufacture, then the selectivity and activity of the condensation reaction are enhanced, but sulfide contaminants are formed in the residual stream which complicate disposal and further processing
Solution Approach 1:
The patent applies this principle by converting the harmful sulfide contaminants back into useful thiol promoters through acid-catalyzed hydrolysis. The sulfides, which were previously harmful byproducts, are transformed into the desired thiol form that can be recycled to the reaction process, thereby eliminating the harmful effect while maintaining the beneficial catalytic function.
Solution Approach 2:
The patent changes the chemical state of sulfur-containing compounds from sulfide form to thiol form through acid-catalyzed hydrolysis. This parameter change (chemical transformation) allows the sulfur compounds to be recovered and reused as promoters, resolving the contradiction between using sulfur promoters and dealing with sulfide contaminants.
2Quantity of substance
If distillation is used to recover phenol and water from the residual stream, then phenol and water are recovered, but the heavy sulfides remain in the bottoms stream increasing consumption of thiol promoter
Solution Approach 1:
The patent applies preliminary action by performing acid-catalyzed hydrolysis of sulfides to thiols before the distillation step. This preliminary chemical transformation ensures that the sulfur compounds are in the volatile thiol form, allowing them to be recovered in the distillate stream rather than being lost in the bottoms stream, thereby preventing thiol promoter consumption.
Solution Approach 2:
The acid catalyst serves as an intermediary that facilitates the transformation of sulfides to thiols. This intermediary substance enables the conversion of non-volatile sulfides into volatile thiols, which can then be efficiently recovered through distillation, resolving the contradiction between phenol/water recovery and thiol promoter loss.
3Productivity
If the residual stream is distilled to recover phenol, then phenol is recovered for recycling, but the bottoms stream becomes contaminated with sulfides making disposal complex
Solution Approach 1:
The patent converts the harmful sulfide contaminants into beneficial thiol promoters through acid-catalyzed hydrolysis before distillation. This transformation ensures that sulfur compounds are recovered in the distillate stream alongside phenol, eliminating the contamination problem in the bottoms stream and simplifying disposal while maintaining phenol recovery for recycling.
4Productivity
If thiol promoters are used to enhance reaction activity, then bisphenol production efficiency increases, but sulfide byproducts are formed that require complex removal processes
Solution Approach 1:
The patent changes the chemical parameter of sulfur-containing compounds from non-volatile sulfides to volatile thiols through acid-catalyzed hydrolysis. This parameter change simplifies the removal and processing of sulfur compounds, as they can now be recovered through simple distillation alongside the phenol, thereby maintaining high bisphenol production efficiency while easing the manufacturing process.
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
Reduces the organic sulfide content in residual streams, allowing for their recycling and minimizing thiol promoter loss, thereby simplifying disposal and enhancing the recovery of valuable bisphenol isomers.
Implementation Method 1
contacting at least a portion of the residual stream or a reaction product thereof with an acidic catalyst under conditions sufficient to allow acid-catalyzed hydrolysis of organic sulfides in the residual stream to the corresponding thiols
Implementation Method 2
distilling at least a portion of the effluent stream to recover distillate products comprising phenols and thiols
Implementation Method 3
contacting at least part of the residual stream with an acidic catalyst under conditions effective to isomerize bisphenol isomers to bisphenol-A
Data Source
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AI summary
A method is disclosed for treating a residual stream from bisphenol manufacture, wherein the residual stream comprises unreacted phenols, bisphenol isomers, trisphenols, organic sulfides and water. The method comprises contacting at least a portion of the residual stream or a reaction product thereof with an acidic catalyst under conditions sufficient to allow acid-catalyzed hydrolysis of organic sulfides in the residual stream to the corresponding thiols and produce an effluent stream, and then distilling at least a portion of the effluent stream to recover distillate products comprising phenols and thiols and produce a bottoms product comprising bisphenol isomers and trisphenols, and having a lower content of organic sulfides than the residual stream.