Coking Kinetics of Asphaltenes as a Function of Chemical Structure
Bibliographic record
Abstract
The dependence of coking kinetics on the chemical structure of asphaltenes was examined by reacting five different asphaltenes in 1-methylnaphthalene and tetralin at 430 °C and ca. 9.8 MPa. The selected heptane-insoluble asphaltenes were Athabasca asphaltenes from Canada, Arabian Light and Arabian Heavy from Saudi Arabia, Maya from Mexico, and Gudao from China. The 13 C NMR aromaticity of the asphaltenes ranged from 0.40 to 0.61, and the sulfur contents ranged from 4.44 wt % to 7.47 wt %. The cracking kinetics of the asphaltenes were consistent with a modified kinetic model for coke formation, incorporating phase separation and hydrogen transfer to the asphaltenes. The rate of cracking of asphaltenes in 1-methylnaphthalene correlated with the content of aliphatic sulfur, and the yield coefficient for coke correlated with the aromaticity. These correlations allowed prediction of coking kinetics for Iranian Light and Khafji asphaltenes on the basis of average structural properties of asphaltenes. Hydrogen transfer to the different asphaltenes did not correlate with any single average structural property.
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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 | 0.001 |
| 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) | 0.001 | 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".