Synthesis of Surfactants Based on Pentaerythritol. I. Cationic and Zwitterionic Gemini Surfactants
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Bibliographic record
Abstract
Simple strategies for the synthesis of five series of cationic gemini surfactants and one series of zwitterionic gemini surfactants from pentaerythritol have been developed. Two lipophilic groups were introduced onto pentaerythritol by alkylation of the known compound, O-benzylidenepentaerythritol, with 1-bromooctane, 1-bromodecane, 1-bromododecane, and 1-bromotetradecane. Hydrogenolysis of the benzylidene acetals gave diols which were converted into three different series of trimethylammonium derivatives. The diiodides derived from the diols could be displaced by dimethylamine, even though they are adjacent to a quaternary carbon atom. Alkylation with methyl iodide gave the first series. The iodides were easily displaced by cyanide ion and the resulting dinitriles were hydrolyzed, converted to N,N-dimethylamides, and reduced to give a second series. Oxidation of the diols to dialdehydes under Swern conditions followed by Horner-Wadsworth-Emmons reactions with diethyl N,N-dimethylcarbamoylmethylphosphonate followed by two-stage reduction gave a third series. The dialkoxides derived from the four di-O-alkylpentaerthritol diols were reacted with 2-dimethylaminoethyl chloride and 3-dimethylaminopropyl chloride in neighboring-group assisted double Williamson ether syntheses to give precursors to two more series. As expected because the neighboring group participation occurs through a four-membered-ring intermediate, considerably more vigorous conditions were required for the reactions with 3-dimethylaminopropyl chloride. 2-Diethylaminoethyl bromide was found to be less reactive than 2-dimethylaminoethyl chloride. The products were alkylated with methyl iodide and, in some cases, other alkyl halides to give cationic gemini surfactants. Alkylation of one series with ethyl bromoacetate followed by anion exchange resin catalyzed ester hydrolysis gave zwitterionic gemini surfactants. The members of all series have superior surfactant properties.
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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 | 0.001 | 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) | 0.002 | 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 it