Binding Energies of Proton-Bound Ether/Alcohol Mixed Dimers Determined by FTICR Radiative Association Kinetics Measurements
Bibliographic record
Abstract
The reactions of protonated diethyl ether with ethanol and protonated di- n -propyl ether with n -propanol, producing the mixed proton-bound dimers, were studied at low pressures in a FTICR cell. The pressure dependence of the apparent rate constant for proton-bound dimer formation was investigated and yielded unimolecular dissociation rate constants, k b, and photon emission rate constants, k ra, for the nascent proton-bound dimers at internal energies equal to the dissociation energies of the dimers. The experimental k ra values were found to be 17 ± 3 and 6.3 ± 0.6 s -1, respectively, for the ethanol/diethyl ether and n -propanol/di- n -propyl ether proton-bound dimers. RRKM modeling of the unimolecular dissociation rate constants as a function of the binding energies yielded the 0 K dissociation energies of the proton-bound dimers as 109 ± 1 and 105.1 ± 0.6 kJ mol -1 for the ethanol/diethyl ether and n -propanol/di- n -propyl ether proton-bound dimers, respectively. Using B3LYP/6-311G** thermal energies, the corresponding 298 K bond strengths were determined to be 103 ± 1 and 99.5 ± 0.6 kJ mol -1 . These agree quite well with those predicted by a simple relationship based upon the differences in proton affinities of the neutral monomers. In addition, the association reaction of n -propanol with protonated di- n -propyl ether reaches what appears to be equilibrium at long reaction times. The relative intensities of the product and reactant ions as well as the pressure of neutral n -propanol were used to obtain an equilibrium constant for the reaction of 9.8(±0.9) × 10 10 at 294 K. From this equilibrium constant and a calculated entropy of reaction of 128 J K -1 mol -1, the 294 K bond strength was determined to be 100.3 ± 6.0 kJ mol -1, in excellent agreement with the values determined from the radiative association kinetics and B3LYP/6-311G** calculations.
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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".