Liquid-Phase Synthesis of Isoprene from Methyl <i>tert</i>-Butyl Ether and Formalin Using Keggin-Type Heteropolyacids
Why this work is in the frame
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Bibliographic record
Abstract
A liquid-phase single-stage synthesis of isoprene from methyl tert -butyl ether (MTBE) and formalin using Keggin-type heteropolyacids, phosphotungstic acid (PTA), phosphomolybdic acid (PMA), and silicotungstic acid (STA) was performed in a batch reactor. The effects of catalyst concentration, reaction temperature, MTBE/formaldehyde ratio, and solvent type on isoprene yield were evaluated. At moderate reaction conditions, the two-phase organic–aqueous system with cyclohexane addition and high MTBE/formaldehyde ratio enhanced the isoprene formation. When the catalyst concentration was increased, the formaldehyde conversion and turnover frequency increased, but isoprene selectivity slightly decreased. At high temperature or low MTBE/formaldehyde ratio, isoprene yield decreased because of the formation of 3,4-dihydro-4-methyl-2H-pyran. When the catalyst activities are compared, the STA catalyst exhibited formaldehyde conversion, isoprene yield, and selectivity that were slightly higher than those of the PTA and PMA catalysts. Among the Prins reaction products formed, 4,4-dimethyl-1,3-dioxane was the key precursor of isoprene formation in the two-phase reaction system.
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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 | 0.001 |
| 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 it