An Investigation into the Identities and the Relative Concentrations of the Zr−Polymeryl Species Present during Ethylene and Propylene Polymerizations by Zirconocene-Based Ziegler Catalysts
Bibliographic record
Abstract
A protocol is described in which zirconocene-catalyzed alkene polymerization reactions are terminated by bromine to give polymers containing brominated end groups, Br−polymeryl. Using NMR spectroscopy, the Br−polymeryl groups can be identified as primary or secondary, thus providing information concerning the nature of the Zr−polymeryl linkage(s), and (via integrations) quantified, thus giving information about the relative concentration(s) of the Zr−polymeryl linkage(s). The procedure can in principle give very useful information concerning the nature and concentrations of Zr−polymeryl groups in existence during polymerization processes and is tested through ethylene polymerization by the Cp 2 ZrMe 2 /B(C 6 F 5 ) 3 catalyst system and propylene polymerization by the Cp 2 ZrMe 2 /B(C 6 F 5 ) 3, (indenyl) 2 ZrMe 2 /B(C 6 F 5 ) 3, and rac -{C 2 H 4 (1-indenyl) 2 }ZrMe 2 /B(C 6 F 5 ) 3 catalyst systems. To this point the resulting data concerning Zr−polymeryl concentrations are generally consistent with data in the literature but are rather more easily obtained.
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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 | 0.001 | 0.001 |
| 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".