Atmospheric Chemistry of 4:2 Fluorotelomer Alcohol (CF<sub>3</sub>(CF<sub>2</sub>)<sub>3</sub>CH<sub>2</sub>CH<sub>2</sub>OH): Products and Mechanism of Cl Atom Initiated Oxidation
Bibliographic record
Abstract
Smog chamber/FTIR techniques were used to study the products and mechanism of the Cl atom initiated oxidation of 4:2 fluorotelomer alcohol (CF 3 (CF 2 ) 3 CH 2 CH 2 OH) in 700 Torr of N 2 /O 2 diluent at 296 K. CF 3 (CF 2 ) 3 CH 2 CHO is the sole primary oxidation product. CF 3 (CF 2 ) 3 CHO, CF 3 (CF 2 ) 3 CH 2 COOH, and CF 3 (CF 2 ) 3 CH 2 C(O)OOH are secondary oxidation products. Further irradiation results in the formation of CF 3 (CF 2 ) 3 COOH, COF 2, and CF 3 OH. CF 3 (CF 2 ) 3 CHO, CF 3 (CF 2 ) 3 CH 2 COOH, and CF 3 (CF 2 ) 3 CH 2 C(O)OOH are formed from CF 3 (CF 2 ) 3 CH 2 CHO oxidation in yields of 46%, 27%, and ≤27%, respectively. Using relative rate techniques, a value of k (Cl + CF 3 (CF 2 ) 3 CH 2 CHO) = (1.84 ± 0.30) × 10 -11 cm 3 molecule -1 s -1 was determined. The yield of the perfluorinated acid, CF 3 (CF 2 ) 3 COOH, from the 4:2 fluorotelomer alcohol increased with the diluent gas oxygen concentration. For the experimental conditions used herein and employing >98% consumption of 4:2 fluorotelomer alcohol, the molar yields of CF 3 (CF 2 ) 3 COOH were <0.011, 0.031, 0.042, and 0.056 in experiments conducted with 10, 140, 400, and 700 Torr O 2, respectively. These results suggest that the atmospheric oxidation of fluorotelomer alcohols may be a significant source of the perfluorinated carboxylic acids that are observed in remote areas.
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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 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".