Kinetics of the ruthenium‐catalyzed hydrogenation of levulinic acid to γ‐valerolactone in aqueous solutions
Bibliographic record
Abstract
Levulinic acid (LA) is an especially promising feedstock for the production of chemicals and biofuels, because it can be prepared from lignocellulosic biomass. Its conversion to γ‐valerolactone (GVL), a fuel additive and precursor to transportation fuels, appears preferential. In this study, a heterogeneous Ru/C catalyst was employed for investigating the hydrogenation reaction of LA to GVL in the aqueous phase in a three‐phase mechanically agitated contactor. To explore kinetics, runs were performed in a chemical‐control regime between the temperatures 323–353 K, H2 partial pressures 0.69–2.07 MPa, initial LA concentrations 4.31–12.93 mmol/L, and catalyst loadings 0.3–0.7 kg/m3. Langmuir‐Hinshelwood‐Hougen‐Watson (LHHW) models were applied to describe the initial rates of LA disappearance. The model, which presumed that surface reaction between non‐dissociatively chemisorbed H2 and LA is limiting, was most suited to describe reaction kinetics. From an Arrhenius plot, it was found that the value of Eact is 68.1 kJ/mol.
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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 | 0.001 |
| 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 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".