Phosphorothioate Purification via Acid Treatment

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Solution Overview

Problem

Conventional processes for producing O-(2,6-dichloro-4-methylphenyl)-O,O-dimethyl phosphorothioate result in crude products with high impurity levels, affecting the purity and stability of the final compound, particularly in terms of heat stability.

Innovation Solution

A process involving the use of an acid, preferably an inorganic acid, to purify crude O-(2,6-dichloro-4-methylphenyl)-O,O-dimethyl phosphorothioate, which includes contacting the crude product with an acid followed by recovery, often using an aromatic hydrocarbon solvent like toluene, to achieve a higher purity and improved heat stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional reaction method is used to produce phosphorothioate, then the production process is simple, but the product contains high impurity levels and has poor heat stability

Engineering Contradiction:
Improveproduct purityVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The production process is divided into three distinct steps: (1) reaction step to produce crude phosphorothioate, (2) purification step using acid treatment, and (3) recovery step. This segmentation allows each step to be optimized independently, achieving high product purity while maintaining reasonable process complexity through modularization of the production流程

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The purification step extracts and removes impurities from the crude phosphorothioate product through acid treatment. By selectively removing impurities in a separate step, the process achieves high product purity without requiring complete redesign of the entire production process, thus balancing purification effectiveness with process complexity

Inventive Principle:
Principle #2Taking out (Extraction)

2Stability of the object's composition

If conventional reaction method is used, then the production process is straightforward, but the product shows significant conversion to S-methyl form after heating

Engineering Contradiction:
Improveheat stabilityVSAvoidprocess complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The acid treatment step is performed as a preliminary action before the final recovery step. This preliminary purification removes impurities that would otherwise cause degradation during heating, thereby enhancing heat stability. The preliminary action prevents subsequent problems rather than addressing them after they occur

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The acid treatment step, which adds complexity to the process, converts harmful impurities into beneficial removed substances. The acid treatment transforms the crude product with high impurity content into a purified product with enhanced heat stability, converting the potential harm of impurity-induced degradation into a benefit through selective removal

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 effectively reduces impurity levels and enhances the heat stability of the final product, with less than 5% conversion to S-methyl form even after heating at 60°C for extended periods, compared to conventional methods which show significant conversion.

Implementation Method 1

the first step of bringing a crude O-(2,6-dichloro-4-methylphenyl)-O,O-dimethyl phosphorothioate into contact with an acid

Methodology Applied
Scientific EffectAcid treatment:

Implementation Method 2

reacting 2,6-dichloro-4-methylphenol and O,O-dimethyl chlorophosphorothioate in the presence of copper chloride in an alkali aqueous solution

Methodology Applied
Scientific EffectSolvation: Solvation

Data Source

PatentUS9024054B2Process for production of purified O-(2,6-dichloro-4-methyl-phenyl) O,O-dimethyl phosphorothioate
Publication Date: 2015.05.05 SUMITOMO CHEM CO LTD

AI summary

A process for producing a purified O-(2,6-dichloro-4-methylphenyl)-O,O-dimethyl phosphorothioate, the process comprising:the first step of bringing a crude O-(2,6-dichloro-4-methylphenyl)-O,O-dimethyl phosphorothioate into contact with an acid; andthe second step of recovering the purified O-(2,6-dichloro-4-methylphenyl)-O,O-dimethyl phosphorothioate from the mixture obtained in the first step.