A Quantitative <sup>1</sup>H NMR Method for the Determination of Alkoxyamine Dissociation Rate Constants in Stable Free Radical Polymerization. Application to Styrene Dimer Alkoxyamines
Bibliographic record
Abstract
A high-resolution 1 H NMR method was developed and applied to the determination of the dissociation rate constants ( k d values) of seven stable free radical polymerization (SFRP) model compounds, including three pairs of styrene dimer alkoxyamines, using oxygen as the alkyl radical scavenger. The efficiency and completeness of oxygen irreversible trapping were tested by taking advantage of the diastereoisomerism of the dimer alkoxyamines. The effects of alkoxyamine stereochemistry on the C−ON bond dissociation kinetics were also demonstrated. The 1 H NMR method was validated by comparing k d values obtained by this method with ESR and HPLC results previously reported for 2,2,6,6-tetramethyl-1-(1-phenylethoxy)piperidine, a commonly studied alkoxyamine. In contrast to ESR methods, the 1 H NMR procedure allows for the simultaneous determination of multiple k d values in a single experiment.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".