Synthesis and Evaluation of Sterically Hindered 1,1-Diadamantyl Nitroxide as a Low-Temperature Mediator for the Stable Free Radical Polymerization Process
Bibliographic record
Abstract
An efficient procedure for the oxidation of 1,1-diadamantylamine with m- chloroperbenzoic acid ( m -CPBA) to the corresponding sterically hindered nitroxide in high yield (72%) is reported. The corresponding styrene-based alkoxyamine was synthesized by an atom transfer radical addition (ATRA) reaction. Because of the bulkiness of the adamantyl substituents, the cleavage of the C−ON bond of the alkoxyamine occurred readily at temperatures below 100 °C. However, in spite of the low bond dissociation temperature of the alkoxyamine, the (co)polymerizations of styrene and n -butyl acrylate proceeded poorly. The results in this paper support the argument that the most important determinant in a nitroxide-mediated polymerization of styrene and acrylate is the ability to control the excess concentration of nitroxide in solution either by an inherent instability of the nitroxide or by the use of additives that destroy the excess nitroxide. Thus, for the 1,1-diadamantyl nitroxide case, and maybe more generally, while a lower C−O bond dissociation energy of an alkoxyamine moiety at the end of the chain may allow lower polymerization temperatures and faster reactions rates, it does not enable polymerizations to proceed to high conversions if the excess nitroxide is not controlled in some manner.
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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 | 0.001 |
| 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 | 0.000 | 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".