DADPM Phase Separation via Density Control
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Solution Overview
Problem
In the large-scale commercial production of poly-(diamino diphenyl methane) (DADPM), the separation of organic and aqueous phases based on density differences is challenging when using low acid catalyst levels, leading to insufficient density differences and increased operational costs due to phase inversion or complex process streams.
Innovation Solution
The process involves modifying the density of the aqueous phase by removing water through evaporation or adding solid sodium chloride or a concentrated brine stream to ensure proper phase separation without introducing additional chemicals, thereby maintaining efficient phase separation and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If low acid catalyst levels are used in the production of DADPM, then process costs are reduced and environmental impact is minimized, but phase separation becomes insufficient due to decreased density differences between organic and aqueous phases
Solution Approach 1:
The patent modifies physical parameters of the aqueous phase by controlling water removal through evaporation and adjusting sodium chloride concentration. These parameter changes increase the density of the aqueous phase, thereby restoring sufficient density difference for effective phase separation even when using low acid catalyst levels. This resolves the contradiction by allowing cost-effective low-acid processes to maintain reliable phase separation through controlled parameter adjustments.
Solution Approach 2:
The patent utilizes evaporation (phase transition from liquid to vapor) to remove water from the aqueous phase. This phase transition reduces the water content and increases the density of the remaining aqueous phase, enabling sufficient density difference for phase separation. By controlling this phase transition process, the patent maintains reliable phase separation while operating with low acid catalyst levels, thus resolving the technical contradiction between cost reduction and separation efficiency.
2Reliability
If water is removed from the aqueous phase to increase density difference, then phase separation is improved, but additional energy consumption is required for evaporation
Solution Approach 1:
The patent applies partial water removal through evaporation rather than complete drying. By removing only sufficient water to achieve the required density increase for effective phase separation, the process avoids excessive energy consumption. This partial action approach optimizes the balance between improving phase separation efficiency and minimizing additional energy requirements, resolving the technical contradiction.
3Reliability
If sodium chloride is added to the aqueous phase to increase density, then phase separation is enhanced, but the complexity of the aqueous phase increases
Solution Approach 1:
The patent uses sodium chloride as an intermediary substance to increase the density of the aqueous phase. Sodium chloride serves as a mediator that facilitates phase separation by adjusting density without requiring complex equipment or additional processing steps. This simple intermediary approach enhances phase separation efficiency while maintaining relatively simple process streams, resolving the technical contradiction between separation efficiency and process complexity.
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 facilitates effective separation of organic and aqueous phases, even at low acid catalyst levels, enhancing process efficiency and reducing operational costs by maintaining sufficient density differences without introducing additional chemicals or process complexity.
Implementation Method 1
removal of some of the water by evaporation from the neutralised reaction mixture obtained in step (b) before the separation step (c)
Implementation Method 2
separating the neutralised reaction mixture into an organic phase containing di- and polyamines and an aqueous phase
Implementation Method 3
adding solid sodium chloride or a concentrated brine stream to ensure proper phase separation
Data Source
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AI summary
Process for the production of di- and poly( diamino diphenyl methane) comprising the steps of (a) reacting aniline and formaldehyde in the presence of an acid catalyst to produce a reaction mixture containing di- and polyamines; (b) neutralising the reaction mixture containing di- and polyamines; (c) separating the neutralised reaction mixture into an organic phase containing di- and polyamines and an aqueous phase; (d) further treating the organic phase separated off in step (c) by (d1) washing with water followed by (d2) separating the washed mixture into an organic phase and an aqueous phase and (d3) further fractionation of the organic phase to produce purified di- and polyamines on the one hand and aniline/water on the other hand; (e) further treating the aqueous phase separated off in step (c) by (e1) washing with aniline followed by (e2) separating the washed mixture into an aqueous phase and an organic phase and (e3) further treatment of the aqueous phase to remove the aniline thereby leaving an effluent stream wherein phase separation in step (c) and/or step (e2) is facilitated by using any of the following methods either on its own or in combination with one or more of the other methods: (A) removal of some of the water from the neutralised reaction mixture obtained in step (b) or the aqueous phase separated in step (c); (B) addition of inorganic salt to the neutralised reaction mixture obtained in step (b) or the aqueous phase separated in step (c); (C) return of some of the aqueous phase obtained in step (e2) or (e3) to the neutralised reaction mixture obtained in step (b) or to the washed mixture in step (e1).