Amide Compound Purification via Solvent Recycling and Hydrogenation
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Solution Overview
Problem
Current methods for producing amide compounds through Beckmann rearrangement result in significant byproducts like ammonium sulfate, requiring extensive facilities and energy, and fail to effectively purify lactams to meet strict quality standards, particularly in reducing impurities that affect polymerization and physical properties.
Innovation Solution
A process involving the reaction of a ketone with hydroxylamine in the presence of an organic solvent, followed by Beckmann rearrangement using a specific catalyst, with solvent recycling to control impurities and purify the amide compound through hydrogenation and crystallization, ensuring low levels of halides, aldehydes, and nitriles, and removing impurities with double bonds and cyclic bridge structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If concentrated sulfuric acid and oleum are used for Beckmann rearrangement, then the rearrangement reaction can be conducted effectively, but salts such as ammonium sulfate are formed as byproducts in large amounts requiring extensive facilities and energy for treatment
Solution Approach 1:
The patent changes the chemical parameters of the rearrangement process by replacing concentrated sulfuric acid and oleum with a liquid-phase catalyst system. This parameter change eliminates the formation of ammonium sulfate byproducts while maintaining effective rearrangement reaction, directly resolving the contradiction between reaction effectiveness and harmful byproduct formation.
Solution Approach 2:
The patent employs a catalyst system that can be used in small amounts and potentially regenerated, replacing the stoichiometric or excess strong acids that generate large amounts of waste salts. This approach reduces the need for extensive waste treatment facilities and energy consumption.
2Productivity
If conventional Beckmann rearrangement methods are used, then amide compounds can be produced, but the lactam purity does not satisfy strict standard values particularly for impurities affecting polymerization and physical properties
Solution Approach 1:
The patent performs preliminary purification actions by controlling the amounts of halides, aldehydes, and nitriles in the solvent before the rearrangement reaction, and by removing impurities with double bonds and cyclic bridge structures. This preliminary action ensures that the produced lactam meets strict quality standards from the outset, eliminating the need for extensive post-production purification.
Solution Approach 2:
The patent uses a liquid-phase catalyst as an intermediary that facilitates the rearrangement reaction while allowing for better control of impurity formation. The catalyst system enables selective reaction pathways that reduce the formation of unwanted impurities, thereby improving manufacturing precision while maintaining productivity.
3Loss of substance
If solvent recycling is implemented to reduce waste, then environmental impact is reduced, but impurities may accumulate and affect catalyst stability and reaction efficiency
Solution Approach 1:
The patent implements a feedback control system for solvent recycling by monitoring and controlling the amounts of halides, aldehydes, and nitriles in the recycled solvent. This feedback mechanism prevents impurity accumulation that would otherwise destabilize the catalyst, allowing sustainable solvent recycling while maintaining catalyst stability and reaction 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 method enables the production of high-purity amide compounds with reduced byproducts, improving yield and quality by stabilizing the Beckmann rearrangement catalyst and minimizing impurities that hinder polymerization and physical properties, thus meeting stringent quality standards.
Implementation Method 1
conducting Beckmann rearrangement of the oxime using a Beckmann rearrangement catalyst to give an amide compound
Implementation Method 2
reacting a ketone and hydroxylamine in the presence of an organic solvent to give an oxime
Implementation Method 3
purify the amide compound through hydrogenation and crystallization
Implementation Method 4
purify the amide compound through hydrogenation and crystallization
Data Source
AI summary
A method for producing a high purity, high quality amide compound, particularly a lactam. An amount of each of a halide, an aldehyde compound, an alcohol compound and a nitrile compound contained in a solution recycled into an oxime-forming step is controlled to an amount of 0.4 mol% or less based on the ketone as a starting material. One or more of a ketone, an oxime and an amide compound are purified by hydrogenation and/or crystallization for eliminating impurities containing a double bond. A content of impurities having a cyclic bridge structure is controlled using a cycloalkanone purified by recrystallization.