Azoxystrobin Preparation via Butyl Acate Solvent
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Solution Overview
Problem
Existing methods for preparing azoxystrobin face challenges such as low yield and purity due to the high water-solubility of aprotic polar solvents, leading to difficulties in product separation and recovery, environmental pollution, and the risk of oxidation and aggregation of reactants, resulting in impurities entering the environment.
Innovation Solution
The method involves an etherification reaction between a chemical compound with 2-cyanophenol in a butyl acetate medium, catalyzed by an azabicyclo-tertiary amine compound, allowing azoxystrobin to precipitate directly from butyl acetate, which simplifies the process and enhances purity and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aprotic polar solvents are used for etherification reaction, then the reaction proceeds well, but the high water-solubility of the solvent brings difficulties in product separation and recovery
Solution Approach 1:
The patent changes the solvent parameter from high water-solubility aprotic polar solvents to butyl acetate with low water solubility. This parameter change maintains reaction efficiency while enabling easy product separation through simple filtration, as the product precipitates directly from the butyl acetate solution without requiring complex separation procedures.
Solution Approach 2:
The patent creates an inert environment by using butyl acetate, a solvent with low water solubility, which prevents water from interfering with the reaction and product isolation. This inert solvent environment allows the product to precipitate cleanly and facilitates easy separation from the reaction mixture without water-solvent interaction complications.
2Ease of manufacture
If the solvent is removed by distillation, then the product can be isolated, but the product precipitates heavily after solvent removal, hindering stirring and heat transfer
Solution Approach 1:
Instead of removing the solvent first and then isolating the product (conventional approach), the patent inverts the sequence by adding water to precipitate the product directly from the solvent mixture. This inversion allows continuous stirring and heat transfer to be maintained throughout the isolation process, avoiding the problems of heavy precipitation that would otherwise hinder these operations.
Solution Approach 2:
The patent introduces water as an intermediary substance that triggers product precipitation without requiring complete solvent removal. The water acts as a mediator that reduces the solubility of the product in the butyl acetate solution, causing it to precipitate while maintaining a liquid medium that allows continued stirring and heat transfer.
3Productivity
If 2-cyanophenol and/or its salt are used in the etherification reaction, then the reaction proceeds, but the reactant can be oxidized easily and produces tar
Solution Approach 1:
The patent creates an inert reaction environment by using butyl acetate as the solvent, which has low water solubility and provides a non-aqueous atmosphere that protects 2-cyanophenol from oxidation. This inert environment prevents the formation of tar and other oxidation byproducts while allowing the etherification reaction to proceed efficiently.
Solution Approach 2:
The patent changes the reaction medium parameter from aqueous or high-water-content solvents to butyl acetate, a low-water-solubility solvent. This parameter change fundamentally alters the oxidation potential of the reaction environment, preventing 2-cyanophenol from being oxidized and eliminating tar formation while maintaining reaction productivity.
4Productivity
If the crude product is obtained with low azoxystrobin content, then the reaction can proceed, but the product has low purity and requires recrystallization treatment
Solution Approach 1:
The patent inverts the conventional purification sequence by precipitating the product directly in high purity form during the reaction process itself, rather than obtaining a low-purity crude product and then recrystallizing it. This inversion is achieved by using butyl acetate as the solvent, which causes the product to precipitate in pure form directly from the reaction mixture, eliminating the need for separate recrystallization steps.
Solution Approach 2:
The patent changes the solvent parameter to butyl acetate, which has specific solubility characteristics that cause azoxystrobin to precipitate in high purity form (99% or higher) directly from the reaction mixture. This parameter change in solvent selection fundamentally improves the purity of the precipitated product without requiring additional purification 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
This approach significantly increases the yield and purity of azoxystrobin to 99% or higher, simplifies industrial operations, reduces environmental pollution, and eliminates the need for solvent evaporation, resulting in a more efficient and environmentally friendly production process.
Implementation Method 1
cooling down the butyl acetate solution that contains azoxystrobin to precipitate the azoxystrobin with a structure represented by formula (1) from butyl acetate
Data Source
AI summary
Disclosed in the present invention is a preparation method of azoxystrobin having a structure as shown by formula (1), the method comprising: a) performing an etherification reaction by reacting the compound having a structure shown by formula (2) with 2-cyanophenol and/or a salt thereof under the catalysis of an azabicyclo tertiary amine compound and/or a salt thereof as the catalyst in a butyl acetate medium to obtain a butyl acetate solution containing azoxystrobin; and b) cooling the butyl acetate solution containing azoxystrobin to precipitate Azoxystrobin having a structure as shown by formula (1) from the butyl acetate solution. Using the method provided by the present invention to prepare azoxystrobin can significantly improve the yield of azoxystrobin, and can obtain azoxystrobin products having high purity.