Sulfentrazone Purification via pH-Adjusted Extraction
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Solution Overview
Problem
Current methods for purifying sulfentrazone, a commercial herbicide, often result in low yields and high impurity levels, with variable color and particle size, making it unsuitable for stable agricultural formulations.
Innovation Solution
A high-yielding extraction process using sequential partitioning with an organic solvent, aqueous sodium carbonate, and a concentrated inorganic acid to selectively remove impurities and improve the purity and particle size distribution of sulfentrazone, achieving greater than 99% purity and a desirable color.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If recrystallization processes are used to purify sulfentrazone, then purity is improved, but yield is significantly reduced and large quantities of effluents are generated
Solution Approach 1:
The invention changes the pH parameter of the aqueous phase to create selective partitioning conditions. By adjusting the pH to basic conditions (pH 8-10), sulfentrazone is converted to its anionic form which preferentially partitions into the aqueous phase, while impurities remain in the organic phase. This parameter change enables high purity separation without the material loss associated with recrystallization.
Solution Approach 2:
The invention uses liquid-liquid extraction to separate sulfentrazone from impurities by distributing them between two immiscible phases. The selective partitioning based on pH-adjusted solubility characteristics allows sulfentrazone to be extracted into the aqueous phase while leaving impurities in the organic phase, achieving both high purity and high yield without the waste generation of recrystallization.
2Manufacturing precision
If recrystallization processes are used to purify sulfentrazone, then purity is improved, but large quantities of effluents are generated
Solution Approach 1:
The invention converts the typically harmful effect of pH adjustment (which can cause precipitation or degradation) into a beneficial selective partitioning mechanism. By carefully controlling the pH to basic conditions, the sulfentrazone is converted to its water-soluble anionic form, allowing it to be selectively extracted into the aqueous phase while impurities remain in the organic phase. This approach eliminates the need for large volumes of solvent and energy-intensive heating/cooling cycles required by recrystallization, significantly reducing effluent generation.
3Quantity of substance
If conventional synthesis routes are used, then sulfentrazone is produced, but the product is colored brown to dark beige with granular and lumpy consistency
Solution Approach 1:
The invention uses pH-adjusted aqueous solution as an intermediary medium to separate sulfentrazone from impurities. The basic pH conditions act as a mediator that converts sulfentrazone to its anionic form, which has different solubility characteristics compared to the neutral or acidic forms of impurities. This intermediary pH adjustment step enables selective partitioning that results in high purity product with desirable white to off-white color and uniform particle size, eliminating the need for additional color correction or grinding steps.
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 achieves a 90% yield of sulfentrazone with 99.4% purity and less than 0.6% impurities, eliminating the need for wasteful recrystallization and chromatographic techniques, while ensuring a consistent white to off-white color and uniform particle size.
Implementation Method 1
This selective partitioning is achieved by the sequential use of an organic solvent, water, aqueous sodium carbonate and a concentrated inorganic acid
Implementation Method 2
To this is added an aqueous solution of sodium carbonate and after further heating and stirring is slowly added an aqueous solution of concentrated hydrochloric acid. After subsequent stirring, N-(2,4-dichloro-5-(4-(difluoromethyl)-3-methyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)methanesulfonamide (sulfentrazone) precipitates out of the solution
Implementation Method 3
a solution of 1-(5-amino-2,4-dichlorophenyl)-4-(difluoromethyl)-3-methyl-1H-1,2,4-triazol-5(4H)-one is dehydrated using toluene
Data Source
AI summary
A high yielding extraction process for the purification of N-(2,4-dichloro-5-(4-(difluoromethyl)-3-methyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)methanesulfonamide (sulfentrazone) by selectively partitioning the desired product from the crude mixture, thereby increasing its purity by decreasing the presence of unwanted impurities and improving the color and particle size distribution of the final sulfentrazone product. The selective partitioning is achieved by the sequential use of an organic solvent, water, aqueous inorganic base and a concentrated aqueous inorganic acid.