PMIDA Synthesis Using Phosphoric Acid Medium
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Solution Overview
Problem
Existing methods for manufacturing phosphonomethyl iminodiacetic acid (PMIDA) face challenges such as the use of concentrated acids, formation of undesirable by-products, and the need for special precautions due to corrosive reactants, leading to inefficiencies and high costs in the production of glyphosate.
Innovation Solution
A method involving the reaction of iminodiacetic acid with phosphorous acid in the presence of a substantial level of phosphoric acid, with a molar ratio of 9:0.8 to 1:1, at temperatures between 45° C to 200° C, to produce a substantially insoluble reaction product that can be easily separated and recycled, without the use of concentrated acids and with reduced by-product formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If concentrated acids (hydrochloric acid or sulphuric acid) are used in the reaction medium, then the reaction can proceed effectively, but the process becomes costly and generates undesirable by-products
Solution Approach 1:
The patent changes the chemical composition parameter of the reaction medium by using phosphoric acid instead of conventional hydrochloric or sulphuric acids. This parameter change maintains reaction effectiveness while eliminating the formation of undesirable chlorinated or sulfonated by-products and reducing corrosion issues.
Solution Approach 2:
The patent employs phosphoric acid as a disposable acid medium that can be easily separated from the reaction mixture. The acid serves its catalytic function and then can be removed, avoiding the need for complex purification steps required when using concentrated mineral acids.
2Manufacturing precision
If phosphorous acid is used in stoichiometric levels required for PMIDA synthesis, then the desired product is formed, but the reaction medium becomes complex and difficult to separate
Solution Approach 1:
The patent changes the solubility parameter of the reaction medium by using phosphoric acid, which creates a system where PMIDA has reduced solubility. This allows the product to precipitate or separate easily from the reaction medium, simplifying the separation process while maintaining stoichiometric synthesis precision.
3Productivity
If conventional methods are used to produce PMIDA, then production can proceed, but special precautions are required due to corrosive reactants and by-products
Solution Approach 1:
The patent converts the potential harm of acid-catalyzed reactions into a benefit by using phosphoric acid, which provides the necessary catalysis without the severe corrosion and safety issues of hydrochloric or sulphuric acids. The phosphoric acid system is inherently safer and easier to handle.
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 production of high-purity PMIDA with reduced by-products and simplified recycling of the mother liquid, avoiding the use of corrosive reactants and minimizing the conversion of phosphorous acid to phosphoric acid, thereby improving the economic and quality aspects of the manufacturing process.
Implementation Method 1
The iminodiacetic acid starting component is reacted with phosphorous acid and formaldehyde in the presence of phosphoric acid
Implementation Method 2
the phosphorous acid reactant is prepared in situ by the hydrolysis of liquid P4O6 in the reaction medium
Implementation Method 3
the reaction product, predominantly the phosphonoalkyl iminodiacetic acid, is substantially reaction medium insoluble and can be separated and recovered routinely
Data Source
AI summary
An improved method for the manufacture of phosphonoalkyl iminodiacetic acid M2PO3—X—N—(CH2COOM)2 wherein X is a C1-6 linear or branched alkyl group; and M is selected from hydrogen, alkali, earth-alkali, ammonium and protonated amine is disclosed. The iminodiacetic acid starting material is reacted with a substantially stoichiometric amount of phosphorous acid, in the presence of a large excess of phosphoric acid to thereby yield a reaction medium insoluble reaction product (PAI-DA) which can be separated from the reaction medium. In a particularly preferred approach, the phosphorous acid is prepared in situ starting from liquid P4O6.