Mesotrione Enolate Formation via pH Control
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Solution Overview
Problem
Current processes for producing mesotrione, a herbicide, face challenges in achieving high yields and purity while minimizing impurities and operational hazards, particularly due to the use of toxic reagents and harsh conditions.
Innovation Solution
A multistage process involving the formation of mesotrione enolate in an aqueous solution using a weak base at a pH of 6 to 8, which allows for high-purity mesotrione precipitation, reducing the need for complex purification techniques and safer handling of reactants, and subsequent stabilization through dissolution in an organic solvent and acid washing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional processes use toxic reagents and harsh conditions to produce mesotrione, then production can proceed, but operational hazards increase and purity decreases
Solution Approach 1:
The patent changes the pH parameter to a moderate range (6-8) and uses a weak base (sodium bicarbonate) instead of strong bases or toxic reagents. This parameter change enables high-purity mesotrione production while eliminating operational hazards associated with conventional toxic reagents and harsh conditions
Solution Approach 2:
The patent employs sodium bicarbonate, a safe, inexpensive, and easily handled reagent that can be used in moderate excess without creating hazardous waste streams. This replaces costly and dangerous reagents while simplifying safety protocols and waste treatment
2Manufacturing precision
If conventional processes use complex purification techniques to achieve high purity, then purity improves, but device complexity increases
Solution Approach 1:
The patent extracts or removes the need for complex purification equipment by designing a process where impurities are naturally minimized through moderate pH control and selective precipitation. The simple filtration and concentration steps replace complex chromatography or multiple extraction units
Solution Approach 2:
The process allows mesotrione to self-purify through controlled precipitation from moderate pH solution. The product crystallizes in high purity form without requiring external complex purification systems, as the moderate conditions selectively favor product formation over impurity incorporation
3Productivity
If conventional processes use strong bases or harsh conditions to form mesotrione enolate, then reaction proceeds, but safety concerns increase
Solution Approach 1:
The patent changes the base strength parameter to use a weak base (sodium bicarbonate) and controls pH in the moderate range of 6-8. This parameter change maintains adequate reaction productivity while eliminating safety hazards associated with strong bases and harsh conditions
Solution Approach 2:
The patent uses sodium bicarbonate as a safe intermediary reagent that mediates the formation of mesotrione enolate without requiring strong bases. This intermediary approach enables the reaction to proceed with acceptable yield while maintaining safety, as bicarbonate decomposes to harmless CO2 and water
Data Source
AI summary
A process for the preparation of mesotrione enolate is provided. The process comprises providing a solution of mesotrione in an organic solvent and contacting the solution with a moderate base in the presence of water at a pH of from 6 to 8, to form an aqueous mesotrione enolate solution. A process for preparing mesotrione from the products of an enol ester rearrangement of 3-oxocyclohex-1-enyl-4-(methylsulfonyl)-2-nitrobenzoate is also provided. The process comprises contacting the products of the rearrangement reaction with an organic solvent to dissolve mesotrione; and contacting the resulting solution with an aqueous solution of an acid.