Probing the phase transition behavior of acetonitrile confined in mesoporous silica by FT Raman spectroscopy
Bibliographic record
Abstract
Abstract Phase transitions of acetonitrile confined in mesoporous silica SBA‐15 and mesocellular silica foam (MCF) having different pore diameters of 39.0, 39.9, 28.4, 8.7, and 4.6 nm with corresponding pore openings of 20.9, 12.1, 10.0, 8.7, and 4.6 nm were investigated by FT Raman spectroscopy. Melting and freezing temperature depressions were found for acetonitrile confined in mesoporous silica with pore opening sizes of 20.9, 12.1, 10.0 and 8.7 nm. A thermal hysteresis between the cooling and heating cycles was also observed. It appears that the smaller the pore opening, the larger the depression of melting or freezing temperature. Although two solid ( ${\bf \alpha}$ and ${\bf \beta}$ ) phases exist in bulk acetonitrile, only the liquid →β phase transition was detected for acetonitrile confined in the nanopores of mesoporous silica. The ${\bf \beta} \rightarrow {\bf \alpha}$ solid‐to‐solid phase transition was not observed. For the mesoporous silica with the smallest pore size of 4.6 nm, neither the liquid $\rightarrow {\bf \beta}$ nor the ${\bf \beta} \rightarrow {\bf \alpha}$ transition was observed for the confined acetonitrile. The results demonstrate that FT Raman spectroscopy is a useful technique for studying the phase transition behavior of organic compounds confined in silica‐based hosts. Copyright © 2011 John Wiley & Sons, Ltd.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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 teacher head, 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".