Aromatic Amine Purification via Concentrated Base Phase Separation
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Solution Overview
Problem
The purification of aromatic amines, particularly those with phenolic hydroxy groups, faces challenges such as solid separation, fouling, and increased viscosity during distillation, which are exacerbated by the use of high molar excesses of bases and the formation of non-volatile salts that can disrupt the process.
Innovation Solution
A process involving the hydrogenation of aromatic nitro compounds, followed by selective phase separation and treatment with a highly concentrated aqueous base solution, allowing for minimal molar excesses of base and controlled phase separation to facilitate the separation of phenolic compounds, thereby avoiding phase reversal and process disruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high molar excesses of bases are used to remove phenolic compounds, then the separation efficiency is improved, but solid separation and fouling occur during distillation
Solution Approach 1:
The invention changes the concentration parameter of the base solution from conventional low concentrations (0.1-2% NaOH) to high concentration (5-30% NaOH). This parameter change allows effective removal of phenolic compounds with minimal base molar excess, preventing salt formation that causes solid separation and fouling during distillation, thus resolving the contradiction between separation efficiency and process stability
Solution Approach 2:
The invention extracts phenolic compounds from the aromatic amine mixture by reacting them with concentrated base solutions to form water-soluble salts. These salts are then removed in the aqueous phase during phase separation, achieving efficient separation without requiring high molar excesses of base, thereby maintaining process reliability
2Manufacturing precision
If high molar excesses of bases are used to treat aromatic amines, then phenolic compounds are removed effectively, but viscosity increases and distillation is disrupted
Solution Approach 1:
The invention changes the base concentration parameter to high levels (5-30% NaOH), which enables effective phenolic compound removal with minimal base dosage. This prevents excessive salt formation that would increase viscosity and disrupt distillation, thus maintaining both purification quality and distillation efficiency
Solution Approach 2:
The invention applies partial action by using minimal molar excesses of concentrated base (compared to conventional high molar excesses of dilute base). This achieves sufficient phenolic compound removal without over-treatment that would cause viscosity increase and distillation disruption, preserving productivity
3Manufacturing precision
If conventional base treatment methods are used, then phenolic compounds can be removed, but large amounts of base and water are required
Solution Approach 1:
The invention changes the base concentration parameter from conventional low concentrations (0.1-2% NaOH) to high concentrations (5-30% NaOH). This parameter change dramatically reduces base consumption because the same separation effectiveness is achieved with much smaller molar excesses, resolving the contradiction between separation effectiveness and base quantity
Solution Approach 2:
The invention creates a more efficient version of conventional base treatment by using concentrated base solutions. This 'improved copy' achieves the same phenolic compound removal effectiveness as conventional methods but with significantly reduced base and water consumption, eliminating the need for large quantities of substances
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 enables efficient separation of phenolic compounds with reduced base usage, preventing solid separation and viscosity issues, ensuring stable operation and minimizing production losses.
Implementation Method 1
the aromatic amines are produced by hydrogenation of the corresponding aromatic nitro compounds in the presence of a catalyst
Implementation Method 2
hydrogenation of nitrobenzene in the gas phase on stationary, heterogeneous supported catalysts
Implementation Method 3
the water formed during the hydrogenation (process water) is separated off by phase separation
Implementation Method 4
the resulting two-phase mixture is then separated into an organic phase containing the aromatic amines and an aqueous phase
Implementation Method 5
the respective amine is first treated with a as small an amount as possible one as highly concentrated as possible aqueous solution of a base, so that a clearly visible phase separation does not occur at this stage
Data Source
AI summary
The invention relates to a process for the production of aromatic amines by hydrogenation of the corresponding aromatic nitro compounds and subsequent purification. In the purification process, the respective amine is first mixed with an aqueous solution of a base. Subsequently, separation of the organic and aqueous phases is achieved by adding an excess of water.