DMAc Removal from DMF via Chloroiminium Purification
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Solution Overview
Problem
The presence of dimethylacetamide (DMAc) as a contaminant in dimethylformamide (DMF) used in the chlorination of sucrose-6-acylates significantly reduces the yield of sucralose-6-acylate, making it difficult and costly to purify DMF through fractional distillation, and existing methods do not effectively address this issue.
Innovation Solution
A process involving the recovery of a crude DMF stream containing DMAc, followed by reducing the DMAc concentration using a chlorinating agent like a chloroiminium species to form a reaction product mixture from which purified DMF can be recovered, and adjusting the chlorinating agent quantity based on DMAc content to maintain yield, allowing for the use of DMAc-contaminated DMF in sucrose-6-acylate chlorination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fractional distillation is used to purify DMF contaminated with DMAc, then purity of DMF is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent extracts the harmful DMAc contaminant from the DMF solvent system by adding a water-immiscible organic solvent that selectively extracts DMAc into the organic phase, allowing separation and recovery of purified DMF in the aqueous phase without requiring complex fractional distillation equipment
Solution Approach 2:
The patent introduces a water-immiscible organic solvent as an intermediary substance that mediates the separation between DMF and DMAc. This intermediary selectively interacts with DMAc to form an extractable complex, enabling purification of DMF through simple liquid-liquid extraction rather than complex distillation
2Productivity
If DMAc is present as contaminant in DMF, then recycling and reuse of DMF is simplified, but yield of sucralose-6-acylate decreases significantly
Solution Approach 1:
The patent enables continuous recycling of DMF by implementing a straightforward extraction-recovery process that removes DMAc contaminants and regenerates pure DMF for reuse in subsequent chlorination reactions, maintaining high yields over multiple recycling cycles without complex operational procedures
Solution Approach 2:
The patent creates a simplified model system for DMF purification that copies the essential separation function of complex distillation processes but achieves it through simple liquid-liquid extraction, allowing routine purification without specialized equipment or complex operational procedures
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 method enhances the yield of sucralose-6-acylate by managing DMAc content, reducing the need for expensive distillation equipment and maintaining yields comparable to those achieved with pure DMF, while providing a cost-effective solution for recycling and reusing the DMF.
Implementation Method 1
reducing the DMAc concentration using a chlorinating agent like a chloroiminium species to form a reaction product mixture
Implementation Method 2
purified tertiary formamide can be readily recovered from the reaction product mixture by distillation
Data Source
AI summary
A chlorinating agent such as a chloroiminium species is used to remove or neutralize tertiary acetamide present as a contaminant in a tertiary formamide solvent. Tertiary formamide solvent purified or treated in this manner can be used as a reaction vehicle for the chlorination of sucrose-6-acylates, thereby improving the yields of the desired sucralose-6-acylate (an intermediate in the production of sucralose).