Selective Palladium‐Catalyzed Dehydrogenation of Limonene to Dimethylstyrene
Bibliographic record
Abstract
Abstract Conditions for the selective dehydrogenation of (+)‐limonene 1 to the polymer building block dimethylstyrene 2 are described. The reaction occurs smoothly in the presence of Pd(OTFA)2 as catalyst and CuCl2 as oxidant. High selectivity for retaining the exocyclic double bond during aromatization is achieved (>14:1). Initially, variable‐temperature NMR experiments, under stoichiometric conditions, showed a stepwise formation of a π‐allyl intermediate and subsequent reaction to give a mixture of products. However, kinetic experiments showed a sigmoidal curve, pointing to the heterogeneous nature of the catalytically active species. A number of experiments were undertaken to differentiate between homogeneous, molecularly defined catalysis and heterogeneous, nanocluster‐based catalysis. Based on the results, it is proposed that the true catalytic system is heterogeneous in nature.
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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 | 0.000 |
| 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 | 0.001 |
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".