Cyanopyridinium-Based Ionic Liquids and Their Mixtures for Ethylene and Ethane Separation
Bibliographic record
Abstract
High Resolution Image Download MS PowerPoint Slide The solubility of ethane and ethylene was determined in a series of cyanopyridinium ionic liquids known to form charge-transfer complexes with polyaromatic hydrocarbons to determine their potential to form specific interactions with the unsaturated gas. The solubilities of ethylene and ethane in 1-butyl-4-cyanopyridinium bis(trifluoromethane)sulfonimide ([C 4 4 CNPy][NTf 2 ]) and 1-butyl-3-cyanopyridinium bis(trifluoromethane)sulfonimide ([C 4 3 CNPy][NTf 2 ]) were measured using an isochoric saturation method. The mole fraction solubility of ethane in the ionic liquids ranged from 6.0 × 10 –3 to 7.2 × 10 –3 and from 7.5 × 10 –3 to 9.9 × 10 –3 for ethylene in [C 4 3 CNPy][NTf 2 ] and [C 4 4 CNPy][NTf 2 ] at 0.1 MPa and 313 K, respectively. The small preferential solubility of ethylene over ethane in the ionic liquids results in ideal ethylene separation selectivities between 1.2 and 1.4, which is in the same range as typical physisorbent ionic liquids of the same type and molecular weight, indicating that there is no significant preferential interaction between the ionic liquids and ethylene. The calculated thermodynamic properties of solvation reveal that the solvation of both gases is entropically driven. To promote cyanopyridinium–ethylene interactions and decrease the possibility of steric constrictions to the interactions, 1-butyl-4-methylimidazolium bis(trifluoromethane)sulfonimide ([C 4 C 1 Im][NTf 2 ]) was added as diluent to [C 4 4 CNPy][NTf 2 ]. This IL mixture was found to behave almost ideally based on isothermal titration nanocalorimetry results. The solubility of ethylene or ethane in the mixture was found to be the weighted average of the corresponding solubilities in the two pure ionic liquids, still indicating that no specific ethylene–ionic liquid interactions were formed. Molecular dynamics (MD) simulations of the systems were performed and revealed that the slightly higher ethylene solubility in [C 4 4 CNPy][NTf 2 ] is due to a slightly stronger association with this cation compared to the 3-isomer.
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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) | 0.001 | 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".