Iron-Mediated Polyaminocarboxylic Acid Synthesis for Isomer Selectivity
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Solution Overview
Problem
Existing processes for synthesizing polyaminocarboxylic acids and their iron chelate compounds, such as EDDHA and EDDHSA, result in the formation of undesired oligomeric products, which are less stable in soils and less effective as fertilizers, and require excessive phenol use to prevent unwanted isomers, leading to inefficient and unsuitable reaction mixtures.
Innovation Solution
A process involving the use of an iron source during the synthesis of phenolic aryl- or alkyldiaminepolycarboxylic acids, shifting the reaction to a four-component system, which includes phenol, glyoxylic acid, aryl- or alkyldiamine, and iron, to favor the formation of desired racemic isomers with higher stability constants and reduce condensation by-products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a large excess of phenol is used to prevent the formation of unwanted ortho-para and para-para isomers, then the formation of unwanted isomers is reduced, but the reaction mixture becomes unsuitable for the final chelation step with Fe(II/III) salt without prior removal of the phenol excess
Solution Approach 1:
The patent removes the harmful excess phenol from the reaction mixture through extraction with an organic solvent before proceeding to the chelation step. This extraction step separates the unwanted phenol from the desired polyaminocarboxylic acid product, allowing the chelation to proceed without interference while maintaining high isomer selectivity.
Solution Approach 2:
The patent performs the phenol removal extraction step before the chelation reaction. By removing the excess phenol in advance, the reaction mixture is prepared in advance to be suitable for the subsequent chelation step with Fe(II/III) salt, preventing unwanted side reactions and ensuring high product purity.
2Ease of manufacture
If nearly stoichiometric conditions are used for EDDHSA and EDDHCA synthesis to avoid phenol removal, then the synthesis can proceed directly to chelation, but significant amounts of oligomeric products are formed which reduce effectiveness
Solution Approach 1:
The patent extracts and removes the oligomeric products from the reaction mixture through organic solvent extraction. This removal step eliminates the harmful oligomeric by-products that would otherwise reduce the effectiveness of the final chelate product, while allowing the use of simpler near-stoichiometric reaction conditions.
3Device complexity
If conventional synthesis processes are used without iron source, then the synthesis procedure is simpler, but the yield of desired chelating agent is lower and oligomeric products are increased
Solution Approach 1:
The patent introduces an iron source as an intermediary substance during the synthesis step. The iron source acts as a mediator that facilitates the formation of the desired polyaminocarboxylic acid-chelate complex directly during synthesis, increasing the yield of the chelating agent and reducing oligomeric by-products without significantly complicating the procedure.
Solution Approach 2:
The patent combines the synthesis step and chelation step into a single integrated process by adding the iron source during synthesis. This merging of steps allows the formation of the final chelate product to occur concurrently with the synthesis of the polyaminocarboxylic acid, improving overall yield and reducing unwanted by-products.
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
The process increases the yield of the desired chelating agent, particularly the racemic isomers, while significantly reducing oligomeric products, enhancing the stability and effectiveness of the chelate compounds in agricultural applications.
Implementation Method 1
the preparation of chelate compounds which are the corresponding complexes of said polyaminocarboxylic acids with Fe
Data Source
AI summary
The present invention relates to a process for the preparation of polyaminocarboxylic acids, in particular phenolic aryl- or alkyldiaminepolycarboxylic acids, preferably a compound of formula (I): wherein X is selected from the group consisting of: H, COOH, COO−Y+, OH, linear or branched C1-C5 alkyl, CH2OH, SO3H, SO3−Y+, wherein: —Y+ is independently selected from the group consisting of: Li+, Na+, K+, and NH4+; and wherein A is selected from: —A (CH2)n linear aliphatic system, wherein n=2, 3 or 4, preferably 2 or 3; and —an aromatic system of formula (II): wherein R1, R2 are independently selected from the group consisting of H, OH, and linear or branched C1-C5 alkyl; said process comprising the step of reacting, a phenol compound, glyoxylic acid and an aryl- or alkyldiamine in the presence of an iron source to obtain a reaction mixture comprising the compound of formula (I). The invention also relates to a process for the preparation of a chelate compound, which is a complex of the compound of formula (I) with iron.