Experimental Determination of Activation Energies for Gas-Phase Ethyl and <i>n</i>-Propyl Cation Transfer Reactions
Bibliographic record
Abstract
Alkyl cation transfer reactions between ethanol and protonated ethanol and ethanol and protonated propionitrile, as well as between n -propanol and protonated n -propanol have been investigated experimentally by low-pressure Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. The two ethyl cation transfer reactions were found to be the dominant reaction channels with association being only a minor reaction pathway. The n -propyl cation transfer reaction was found to compete with the association pathway resulting in an approximately 50:50 mixture of protonated di- n -propyl ether and the proton-bound dimer of n -propanol, depending on temperature and pressure. The enthalpies of activation were determined to be −16.1 ± 0.8, −17.5 ± 0.8, and −15.7 ± 0.9 kJ mol -1 for the ethanol/protonated ethanol, ethanol/protonated propionitrile, and n -propanol/protonated n -propanol alkyl cation transfer reactions, respectively. The entropies of activation were found to be essentially the same, −121 ± 28 J K -1 mol -1, for all three reactions. All experimentally determined thermochemical properties agreed very well with those calculated at the MP2/6-31+G(d)//B3LYP/6-31+G* level of theory. Furthermore, the enthalpies and entropies of activation for the methy, ethyl, and n -propyl cation transfer reactions between the neutral alcohols and the respective protonated alcohols were found to be the same within experimental uncertainty.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".