Effects of diethylaluminum ethoxide pre‐reduction and chromium loading over bistriphenylsilyl chromate/silica for ethylene polymerization
Bibliographic record
Abstract
Abstract Bistriphenylsilyl chromate (BC)/silica (S‐2 catalyst) is a commercially used high‐density polyethylene (HDPE) catalyst with great importance. In this work, the catalytic performance of this catalyst was tried to be improved by increasing the loading amount of Cr and pre‐reducing with diethylaluminum ethoxide (DEALE). It is found that, when the Cr loading amount was doubled, the productivity in gPE · g −1 Cat became almost doubled as well, indicating the maintenance of overall efficiency for Cr centres. Meanwhile, pre‐reduction of BC/silica with a small amount of DEALE (the molar ratio of DEALE/Cr < 2.4) was adequate to promote its productivity greatly, while large dose of DEALE led to the activity decay fast, which might originate from the over‐reduction of the Cr centre, as well as pore blockages caused by the added DEALE. Moreover, it is found that both the increased Cr loading and DEALE pre‐reduction offered an alternative way to reduce the weight‐average molecular weight (MW) and molecular weight distribution (MWD) of the polyethylene products mainly by shaving the high MW shoulder.
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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 | 0.000 |
| 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) | 0.001 | 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 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".