Evolution of Functional Groups during Pyrolysis Oil Upgrading
Bibliographic record
Abstract
In this work, we examine the evolution of functional groups (carbonyl, carboxyl, phenol, and hydroxyl) during hydrotreatment at 100–200 °C of two typical wood derived pyrolysis oils from BTG and Amaron in a batch reactor over Ru/C catalyst for reaction time of 4 h. An aqueous and an oily phase were obtained. The contents of the functional groups in both phases were analyzed by GC/MS, 31 P NMR, 1 H NMR, CHN, KF titration, UV fluorescence, carbonyl groups by Faix and phenols by Folin−Ciocalteu method. The consumption of hydrogen was between 0.007 and 0.016 g/(g of oil), and 0.001–0.020 g of CH 4 /(g of oil), 0.005–0.016 g of CO 2 /(g of oil), and 0.03–0.10 g of H 2 O/(g of oil) were formed. The contents of carbonyl, hydroxyl, and carboxyl groups in the volatile GC-MS detectable fraction decreased (80, 65, and ∼70%, respectively), while their behavior in the total oil and hence in the nonvolatile fraction was more complex. The carbonyl groups initially decreased having a minimum at ∼125–150 °C and then increased, while the hydroxyl groups had a reversed trend. This might be explained by the initial hydrogenation of the carbonyl groups to form hydroxyls, followed by continued dehydration reactions at higher temperatures that may have increased their content. The 31 P NMR analysis was on the limit of its sensitivity for the carboxylic groups to precisely detect changes in the upgraded nonvolatile fraction; however, the more precise titration method showed that the concentration of carboxylic groups in the nonvolatile fraction remains constant with increased hydrotreatment temperature. The UV fluorescence results show that repolymerization increases with temperature, starting as low as 125 °C. ATR-FTIR method coupled with deconvolution of the region between 1490 and 1850 cm –1 was shown to be a good tool for following the changes in carbonyl groups and phenols of the stabilized pyrolysis oils. The deconvolution of the IR bands around 1050 and 1260 cm –1 correlated very well with the changes in the 31 P NMR silent O groups (likely ethers). Most of the H 2 O formation could be explained from the significant reduction of these silent O groups (from 12% in the fresh oils, to 6 to 2% in the stabilized oils) most probably belonging to ethers.
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How this classification was reachedexpand
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 | 0.000 | 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) | 0.000 | 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, 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".