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 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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".