Comparison between Oxidative Addition and σ-Bond Metathesis as Possible Mechanisms for the Catalytica Methane Activation Process by Platinum(II) Complexes: A Density Functional Theory Study
Bibliographic record
Abstract
The Catalytica process converts methane to methyl bisulfate in good yield at relatively low temperature in fuming sulfuric acid and may help make methane a useful bulk chemical precursor. We have computationally examined the methane C−H activation step of the process. We find that the most likely catalyst for this step is either (bipyrimidine)Pt(OSO 3 H) + or (bipyrimidine)PtCl + . In the former case C−H activation takes place by σ-bond metathesis, whereas the latter involves C−H activation by an oxidative addition mechanism. It appears that the need to run the reaction at 180−220 °C stems from the fact that methane has to displace either one Cl - ligand or one HSO 4 - oxygen. Protonation of bipyrimidine by sulfuric acid appears unfavorable, although the resulting highly charged catalysts exhibit lower activation barriers.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".