Asphaltene solubility in common solvents: A molecular dynamics simulation study
Bibliographic record
Abstract
Abstract Solubility of all proposed molecular models of asphaltene in various solvents is studied through molecular dynamics simulation to find the structural parameters which have a determining effect on asphaltene solubility. It is found that higher numbers of aromatic rings and heteroatoms such as oxygen, nitrogen, and sulphur in the molecular structure of asphaltenes raises their solubility in the solvents, whereas the length of aliphatic group, which increases the chain length, lowers their solubility. In addition, a cubic correlation equation for evaluating the asphaltene solubility parameter as a ratio of number of aromatic rings in the asphaltene molecular core to the number of carbon atoms in the asphaltene side chains is proposed. The results indicate that the relative energy difference (RED) of asphaltene models and isopropyl benzene, as a solvent, is the lowest compared with other solvents. To elucidate the mechanism of asphaltene dissolution in the common solvents the solubility of two asphaltene structural models in three solvents, including isopropyl benzene, toluene, and heptane, were studied by evaluating the radial distribution functions (RDFs) of the asphaltenes, and the results confirm that asphaltene has the highest solubility in isopropyl benzene.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".