Fipronil Polymorphs and Amorphous Forms for Pesticide Purity
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Solution Overview
Problem
There is an urgent need for efficient methods to prepare and purify fipronil, a broad-spectrum insecticide, that can be used on a large scale for industrial manufacture while producing a highly pure product for safe utilization.
Innovation Solution
The development of novel crystalline polymorphs, solvate pseudomorphs, and an amorphous form of fipronil, along with methods for their preparation, which include specific processes such as heating pseudomorphs, crystallization from solvents, and thermal treatments to produce forms like Form I, Form II, Form III, toluene hemi-solvate pseudomorph, and amorphous fipronil, each with distinct spectral characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional preparation methods are used, then production can be carried out, but the purity and stability of fipronil product are insufficient
Solution Approach 1:
The patent applies parameter changes by discovering and utilizing different crystalline polymorphic forms (Form I, Form II, Form III) and amorphous forms of fipronil, each with distinct thermal and spectral properties. By controlling crystallization conditions and thermal treatment parameters, the method achieves high purity product while maintaining ease of large-scale manufacture
Solution Approach 2:
The patent employs phase transitions through thermal treatment processes that convert pseudomorph forms into stable crystalline polymorphic forms. The differential scanning calorimetry data showing endothermic peaks at specific temperatures (e.g., 202.5°C for Form I) demonstrates controlled phase transitions that purify the product while simplifying the preparation process
2Stability of the object's composition
If conventional preparation methods are used, then production can be carried out, but the stability of fipronil product is insufficient
Solution Approach 1:
The patent applies preliminary action by pre-forming pseudomorph crystalline forms that subsequently convert to stable polymorphic forms during controlled thermal treatment. This preliminary crystallization step facilitates later purification and stability enhancement without compromising production efficiency
Solution Approach 2:
The patent replaces mechanical purification methods with thermal treatment processes that utilize differential stability of various polymorphic forms. The controlled heating and cooling cycles enable purification through phase transitions rather than mechanical separation, maintaining high productivity while achieving superior stability
3Reliability
If new polymorphic forms are developed, then purity and stability improve, but the process complexity increases
Solution Approach 1:
The patent applies self-service by utilizing the inherent thermal instability of pseudomorph forms to automatically convert them into stable polymorphic forms during controlled heating. This self-conversion eliminates the need for complex intervention mechanisms, achieving high product quality while keeping the process relatively simple
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
These new forms of fipronil exhibit improved purity and stability, enabling efficient large-scale industrial production and safe use as effective pesticidal agents, with specific forms showing distinct thermal and spectral properties.
Implementation Method 1
crystallization from solvents
Implementation Method 2
heating pseudomorphs
Implementation Method 3
thermal treatments to produce forms
Implementation Method 4
Differential Scanning Calorimetry (DSC) thermogram substantially as shown in FIG. 3, which is characterized by a predominant endotherm peak at about 202.5° C.
Implementation Method 5
X-ray powder diffraction pattern substantially as shown in FIG. 1, having characteristic peaks
Data Source
AI summary
The present invention relates to novel crystalline polymorphs, solvate pseudomorphs and amorphous form of 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfinyl]-1H-pyrazole-3-carbonitrile (fipronil). The present invention also provides methods for preparing the novel polymorphs, pseudomorphs and amorphous form, as well as insecticidal or pesticidal compositions comprising same, and methods of use thereof as pesticidal agents.