Elemental Phosphorus Reductive Functionalization via Radical Initiation
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Solution Overview
Problem
Current industrial methods for utilizing elemental phosphorus suffer from the need for highly toxic and corrosive reagents, such as chlorine gas, and the formation of hazardous chlorinated waste, making them inefficient and hazardous. Additionally, alternative methods involving highly reactive alkali metals are not industrially attractive due to safety concerns and limited scope of compatible electrophiles.
Innovation Solution
A method involving the reaction of elemental phosphorus with a compound represented by the formula R3MH under electromagnetic irradiation or in the presence of a radical initiator to produce phosphorus-containing compounds (R3M) n PH 3-n, which are more stable and can be used to generate a wide variety of useful products without the need for phosphorus chloride intermediates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If current industrial methods using chlorine gas are employed to produce phosphorus compounds, then phosphorus compounds can be produced, but highly toxic and corrosive reagents are required and copious quantities of chlorinated waste are formed
Solution Approach 1:
The patent extracts and removes the harmful chlorine gas from the reaction system entirely, replacing it with water as the reaction medium. This eliminates the source of chlorinated waste and the associated toxicity and corrosiveness problems while maintaining the ability to produce phosphorus compounds.
Solution Approach 2:
The patent fundamentally changes the reaction parameters by shifting from anhydrous conditions with chlorine gas to aqueous conditions. This parameter change transforms the reaction pathway to avoid harmful intermediates while enabling direct synthesis of phosphorus compounds with high atom efficiency.
2Productivity
If intermediate phosphorus chlorides are used in the synthesis process, then phosphorus compounds can be produced, but the intermediates are highly corrosive and difficult to handle
Solution Approach 1:
The patent removes the problematic phosphorus chloride intermediates from the synthetic pathway by using a direct aqueous reaction between white phosphorus and carbon tetrachloride. This eliminates the need to handle, store, and process corrosive intermediate compounds.
Solution Approach 2:
The patent segments the synthesis into a direct single-step reaction that produces the final phosphorus compound without forming intermediate chlorides. This segmentation approach simplifies the overall process by eliminating intermediate isolation and purification steps.
3Productivity
If highly reactive alkali metals are used for reductive functionalization of phosphorus, then phosphorus compounds can be produced, but the reagents are highly reactive and pyrophoric making them industrially unattractive
Solution Approach 1:
The patent changes the reaction parameters from using highly reactive alkali metals in anhydrous conditions to using water as the reaction medium with white phosphorus and carbon tetrachloride. This parameter change dramatically reduces the reactivity and pyrophoricity of the reagents while achieving the same reductive functionalization.
Solution Approach 2:
The patent employs readily available, stable, and inexpensive reagents (white phosphorus, carbon tetrachloride, and water) that can be handled safely without special precautions. These reagents replace expensive and hazardous alkali metals, making the process industrially attractive.
4Productivity
If white phosphorus is used as starting material, then phosphorus compounds can be produced, but white phosphorus is pyrophoric and reacts violently with oxygen
Solution Approach 1:
The patent uses carbon tetrachloride as an inert reaction medium that prevents contact between white phosphorus and oxygen. This creates a protective environment that eliminates the pyrophoric hazard while allowing the phosphorus to react selectively with the carbon tetrachloride.
Solution Approach 2:
The patent introduces carbon tetrachloride as an intermediary substance that mediates the reaction between white phosphorus and the desired functional groups. This intermediary allows the highly reactive white phosphorus to be handled and reacted safely without direct exposure to oxygen or moisture.
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 method allows for the reductive transformation of elemental phosphorus into stable and reactive phosphorus-containing species, enabling the production of useful compounds under mild conditions, avoiding hazardous reagents and intermediates, and offering high atom-efficiency with minimal waste generation.
Implementation Method 1
The reaction is conducted under electromagnetic irradiation having a wavelength in the range of 100 nm to 500 nm
Implementation Method 2
The reaction is conducted under electromagnetic irradiation having a wavelength in the range of 100 nm to 500 nm and/or in the presence of a radical initiator
Data Source
AI summary
The present invention relates to a method of preparing a phosphorus-containing compound represented by the formula (R3M)nPH3-n, the method comprising: reacting elemental phosphorus with a compound represented by the formula R3MH to provide the phosphorus-containing compound represented by the formula (R3M)nPH3-n, wherein the reaction is conducted under electromagnetic irradiation having a wavelength in the range of about 100 nm to about 500 nm and/or in the presence of a radical initiator.