Understanding the Mechanism of Nitrobenzene Nitration with Nitronium Ion: A Molecular Electron Density Theory Study
Bibliographic record
Abstract
Abstract The nitration reaction of nitrobenzene with nitronium ion yielding ortho ‐, meta ‐ and para ‐dinitrobenzenes has been studied within the Molecular Electron Density Theory, using DFT computational methods at the B3LYP/6‐311G(d,p) level. This electrophilic aromatic substitution (EAS) reaction takes place through a two‐step mechanism involving the formation of a tetrahedric cation intermediate. The electrophilic attack of nitronium ion on nitrobenzene is the rate‐determining step of this EAS reaction, and consequently, responsible for the composition of the reaction mixture. The subsequent proton abstraction from the cation intermediate is barrierless. From the computed activation Gibbs free energies, a relationship 11.0 ( ortho ) : 87.3 ( meta ) : 1.7 ( para ) of the dinitrobenzenes is estimated, in clear agreement with the experimental outcome. The similar nucleophilic activation of the ortho and meta carbons of nitrobenzene makes it possible to question the hypothesis for the orientation in EAS reactions involving nucleophilically deactivated benzenes based on the relative stability of the tetrahedric cation intermediates.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".