Catalyst Solubility and Experimental Determination of Equilibrium Constants for Heterogeneous Atom Transfer Radical Polymerization
Bibliographic record
Abstract
The solubilities of heterogeneous atom transfer radical polymerization (ATRP) catalysts are determined for the first time and used to calculate previously unquantified ATRP equilibrium constants ( K ATRP ). These new data are essential for understanding, modeling, and designing ATRP processes with low catalyst concentrations. K ATRP values for Cu I Br/1,1,4,7,10,10-hexamethyltriethylenetetramine (Cu I Br/HMTETA) and Cu I Br/ N, N, N ‘, N ‘, N ‘ ‘-pentamethyldiethylenetriamine (Cu I Br/PMDETA) are 8.66 × 10 -6 and 1.44 × 10 -6, respectively. The limited solubility of the Cu I Br/HMTETA catalyst explains why large reductions in metal salt concentration can be made without affecting polymerization rates. Catalyst solubility and polymerization rate increase with ligand concentration. In contrast, increasing the metal salt concentration in excess of the ligand's causes a drop in catalyst solubility. This unexpected observation is attributed to the formation of insoluble catalyst networks (gels). The solubility data point to differences in the ionic character of the catalyst complexes formed. The following solubility trend is observed at ATRP conditions (toluene, 90 °C): Cu I Br/PMDETA ≫ Cu II Br 2 /PMDETA > Cu II Br 2 /HMTETA > Cu I Br/HMTETA.
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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".