Experimental and Computational Studies on the Gas-Phase Reaction of CBrF<sub>3</sub> with Hydrogen
Bibliographic record
Abstract
Gas-phase hydrogen dehalogenation of halon 1301 (bromotrifluoromethane, CBrF 3 ) has been studied experimentally in a tubular alumina reactor operating at atmospheric pressure. It is found that hydrogen can accelerate the decomposition of halon 1301 and that conversion levels of CBrF 3 and H 2 increase with temperature and residence time. CBrF 3 conversion increases with decreasing input volume ratio of CBrF 3 to H 2 . The species produced are a complex mixture of halogenated hydrocarbons including CHF 3, CH 2 F 2, C 2 HF 3, C 2 F 6, C 2 H 2 F 4, C 2 HF 5, CHBrF 2, CH 3 Br, CH 2 Br 2, CHBr 2 F, and CH 2 BrF in addition to HBr and HF. The production yield of CHF 3, the major product, increases with temperature to 1023 K, after which CHF 3 levels decrease with increasing temperature. Conversely, CHF 3 selectivity decreases with increasing temperature, residence time, or input ratio of CBrF 3 to H 2 . The initiation reaction is believed to be the rupture of the C−Br bond in CBrF 3, and the radical species CF 3 then reacts with H 2 to produce H and CHF 3 . The key step in the process is the attack of H radical on CBrF 3 to produce CF 3 and HBr. Experimental data are compared with the model predictions, and good agreement between experimental and modeling prediction is obtained for CHF 3 production. However, the existing mechanism does not predict the formation of CHBrF 2, which is detected during the experimental study, and the concentrations of CH 2 F 2 and C 2 F 6 measured experimentally are significantly different from those predicted. Modifications to the existing NIST mechanism are suggested to improve the prediction of the quantity of these species produced.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 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".