Temperature Dependent Solubility of α-Form <scp>l</scp>-Glutamic Acid in Selected Organic Solvents: Measurements and Thermodynamic Modeling
Bibliographic record
Abstract
In this study the solubility of α-form l -glutamic acid in the six organic solvents methanol, ethanol, 1-propanol, acetone, formic acid, and dimethyl sulfoxide (DMSO) was measured by a static analytic method. The measurements were carried out over the temperature range 278–355 K at around 5 K intervals, and the equilibrium concentration was determined by the gravimetric method. The experimental results show that formic acid has the highest solubility to α-form l -glutamic acid while the other solvents have the solubility order water, acetone, 1-propanol, ethanol, methanol, DMSO, and acetic acid. The hypothetical enthalpy of fusion and melting temperature of l -glutamic acid are estimated. Several commonly used thermodynamic models, including the empirical van’t Hoff equation and the Wilson, NRTL, and UNIQUAC equations, were applied to correlate the experimental solubility data. The binary interaction parameters of the above models are found to have a linear dependency on temperature, and the coefficients were regressed. It was found that all these models can satisfactorily reproduce the experimental solubility and the UNIQUAC equation can provide the best correlation results with an overall standard deviation of 2.7 × 10 –5 .
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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 | 0.001 |
| 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) | 0.000 | 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".