Dynamic Kinetic Resolution of Secondary Alcohols Combining Enzyme‐Catalyzed Transesterification and Zeolite‐Catalyzed Racemization
Why this work is in the frame
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Bibliographic record
Abstract
Hydrophobic zeolite beta containing low concentrations of Zr or Al was found to be a good catalyst for the racemization of 1-phenylethanol. The formation of styrene as a side product could be minimized by reducing the metal concentration in the zeolite beta. Combined with an immobilized lipase from Candida antarctica, the dynamic kinetic resolution of 1-phenylethanol to the (R)-phenylethylester can be achieved with high yield and selectivity. The reaction was best conducted in toluene as solvent at 60 degrees C, with higher temperatures leading to a loss in the enantioselectivity of the formed ester. By using high-molecular-weight acyl-transfer reagents, such as vinyl butyrate or vinyl octanoate, a high enantiomeric excess of the product esters of 92 and 98 %, respectively, could be achieved. This is attributed to a steric effect: the bulky ester is less able to enter the pore space of the zeolite catalyst where the active sites for racemization are localized. Close to 100 % conversion of the alcohol was achieved within 2 h. If the more common acyl donor, isopropenyl acetate, was used, the enantiomeric excess (ee) of the formed ester was only 67 %, and the reaction was considerably slower.
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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) | 0.000 | 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) | 0.000 | 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 it