Sustainable Production of Reduced Phosphorus Compounds: Mechanochemical Hydride Phosphorylation Using Condensed Phosphates as a Route to Phosphite
Bibliographic record
Abstract
Phosphorus removal and recovery technologies have been implemented to tackle the anthropogenic eutrophication caused by phosphate runoff into waterways. In pursuit of a better utilization of the phosphates recovered from waste water treatment, we herein report that condensed phosphates can be employed to phosphorylate hydride reagents under solvent-free mechanochemical conditions to furnish phosphite (HPO3)2−, a versatile chemical with phosphorus in the +3 oxidation state. Hydride phosphorylation, as a two-electron one-proton reduction of a main group element oxide, constitutes a direct parallel with CO2 reduction to formate. Using potassium hydride as the hydride source, sodium trimetaphosphate (Na3P3O9 ), triphosphate (Na5P3O10), and pyrophosphate (Na4P2O7) engendered phosphite in 44, 58, and 44% yields based on total P content, respectively, under their optimal conditions. Formation of overreduced products including hypophosphite (H2PO2−) was identified as a competing process, and mechanistic investigation revealed that hydride attack on in situ generated phosphorylated phosphite species is a potent pathway for overreduction. The phosphite generated from our method could be easily isolated in the form of barium phosphite, a useful intermediate for production of phosphorous acid. This method circumvents the need to pass through white phosphorus (P4) as a high energy intermediate and mitigates involvement of environmentally hazardous chemicals. A bioproduced polyphosphate from baker’s yeast was demonstrated to be a viable starting material for the production of phosphite. This example demonstrates the possibility of accessing reduced phosphorus compounds in a more sustainable manner, and more importantly, closing the modern phosphorus cycle.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".