Primary Amine Separation via Schiff Base Imine Formation
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Solution Overview
Problem
Current methods fail to economically separate and purify N,N-dialkylbisaminoalkylethers from mixtures containing secondary and tertiary amines, such as N,N-dimethylbisaminoethylether, N,N,N′-trimethylbisaminoethylether, and N,N,N′,N′-tetramethylbisaminoethylether, due to similar boiling points, making distillation ineffective and economically unviable.
Innovation Solution
A method involving a Schiff base reaction with ketones or aldehydes to form a primary amine-based imine, followed by distillation to separate the imine from the secondary and tertiary amines, and subsequent hydrolysis to recover the primary amine in high purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation is used to separate primary amines from secondary and tertiary amines, then separation is attempted, but the similar boiling points make distillation ineffective and economically unviable
Solution Approach 1:
The patent transforms the primary amine into an imine derivative through reaction with a carbonyl compound. This chemical transformation fundamentally changes the physical properties of the compound, particularly the boiling point, enabling effective distillation separation that was previously impossible due to similar boiling points of the original amine mixture
Solution Approach 2:
The patent introduces a carbonyl compound (ketone or aldehyde) as an intermediary reagent that reacts with the primary amine to form an imine. This intermediary compound serves as a temporary carrier that enables separation through distillation, after which the original primary amine is recovered through hydrolysis
2Manufacturing precision
If conventional distillation is applied to separate N,N-dialkylbisaminoalkylethers from N,N,N′-trialkylbisaminoalkylethers and N,N,N′,N′-tetraalkylbisaminoalkylethers, then separation is attempted, but the similar boiling points render the process ineffective
Solution Approach 1:
By converting the primary amine to an imine derivative, the boiling point parameter is significantly altered. This allows the imine to be separated by distillation from the secondary and tertiary amines, which do not form imines under the reaction conditions, thereby achieving effective separation without excessive energy consumption
3Manufacturing precision
If no separation method is used, then the mixture remains as-is, but the primary amine cannot be recovered in high purity for economic utilization
Solution Approach 1:
The patent separates the separation process into distinct stages: (1) selective imine formation with carbonyl compound, (2) distillation separation of the imine from other amines, and (3) hydrolysis to recover the pure primary amine. This segmented approach achieves high purity separation through multiple simpler steps rather than a single complex operation
Solution Approach 2:
The patent performs preliminary chemical modification of the primary amine into an imine derivative before separation. This preliminary action prepares the compound for easier separation by distillation, and the original compound is subsequently recovered through hydrolysis, achieving both separation and purification
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 allows for the separation and recovery of primary amines like N,N-dimethylbisaminoethylether in high purity (>95 wt.%) with an economically acceptable yield, overcoming the limitations of existing distillation methods by altering the physical properties of the primary amine-based imine to facilitate easier separation.
Implementation Method 1
joining said mixture and at least one of a ketone and an aldehyde for reacting said primary amine with said at least one of a ketone and an aldehyde, thereby providing a primary amine based imine by a Schiff base reaction
Implementation Method 2
separating the primary amine based imine from said at least one of the secondary or tertiary amine by distillation
Implementation Method 3
recovering the primary amine from its primary amine based imine by hydrolysis of the primary amine based imine
Data Source
AI summary
According to the present invention, a method for separating a primary amine being an N,N-dialkylbisaminoalkylether, from mixtures comprising said primary amine and at least one of a secondary amine being an N,N,N′-trialkylbisaminoalkylether and a tertiary amine being an N,N,N′,N′-tetraalkylbisaminoalkylether, comprising the steps:(α) joining said mixture and at least one of a ketone and an aldehyde for reacting said primary amine with said at least one of a ketone and an aldehyde, thereby providing a primary amine based imine by a Schiff base reaction;(β) separating the primary amine based imine from said at least one of the secondary or tertiary amine; and(γ) recovering the primary amine from its primary amine based imine by hydrolysis of the primary amine based imine.