Characterization of Heteroatom-Containing Compounds in Thermally Cracked Naphtha from Oilsands Bitumen
Bibliographic record
Abstract
Detailed characterization of feed materials can assist with development of new technology and troubleshooting existing units. In this work a methodology for the compound specific analysis of oxygen-, sulfur-, and nitrogen-containing compounds in naphtha is presented. It was applied to the analysis of industrial thermally cracked naphtha produced from Athabasca oilsands bitumen, with 0.25 wt % O, 0.90 wt % S, and 0.09 wt % N. The main oxygen-containing compound classes were acyclic carboxylic acids, ketones, and phenols. Interestingly, the carboxylic acids were almost exclusively linear and branched species in the C 3 –C 11 range. These compounds could be explained by a thermal cracking pathway involving ring-opening of one or more adjacent naphthenic rings. The main sulfur-containing compound class was cyclic thioethers, with a minor amount of thiols. No thiophenes were identified and identification of the most abundant compound, 2-methyl tetrahydrothiophene, was confirmed with an authentic compound. This suggested that the hydrogen transfer during thermal cracking of oilsands derived material was high; the naphtha also had a correspondingly low aromatic content. The main nitrogen-containing compound class was pyridines, with a minor amount of pyrroles.
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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 | 0.001 | 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".