An alternative synthesis and mobile phase ion chromatography of alkanedisulfates
Bibliographic record
Abstract
Abstract Preparation of alkane disulfates using chlorosulfonic acid results in a crude product containing significant amounts of chloride, sulfate, and hydroxyalkanesulfates. This paper describes an alternative synthesis using trimethylamine:sulfur dioxide complex in anhydrous pyridine. Workup with sodium hydroxide and washing in acetone results in a crude product with less than 1% inorganic impurity and ∼0–3% hydroxyalkanesulfate. Recrystallization from acetone reduces the inorganic impurity to less than 0.1%. Alkanedisulfates can be separated from the corresponding hydroxyalkanesulfates, chloride, and sulfate using mobile phase ion chromatography with tetrabutylammonium hydroxide (TBAOH) as the ion‐pairing agent and acetonitrile as the organic modifier. With the crude octanedisulfate and decanedisulfate product mixes, the alkanedisulfate is retained more strongly by the ion‐pairing effect; but with the tetradecane species, hydrophobic interaction dominates and the tetradecanedisulfate elutes before the hydroxytetradecanesulfate. The choice of acetonitrile gradient and TBAOH is particularly important for the separation of the dodecane derivatives because the opposing effects of polarity (hydrophobic effect) and electrostatic interaction with TBAOH are of similar strength.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 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 | 0.000 |
| 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 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".