Thermodynamics and kinetics of transesterification reactions to produce diphenyl carbonate from dimethyl carbonate catalyzed by tetrabutyl titanate and dibutyltin oxide
Bibliographic record
Abstract
Abstract The transesterification reactions to diphenyl carbonate (DPC) from dimethyl carbonate (DMC) and phenol are the key steps to the green production of polycarbonate polymers (PC). The transesterification equilibrium constants were determined under temperatures from 453.2 to 493.2 K, and the reaction kinetics catalyzed by single tetrabutyl titanate, dibutyltin oxide, and their combinations was measured. By taking into account the effect of catalyst, the simplified kinetic model was developed involving the transesterification of DMC and methyl phenyl carbonate (MPC) with phenol, the disproportionation of MPC, and the formation of byproduct anisole. The kinetic model fitted experiments well under various temperatures and had an excellent predictive ability on the effect of catalyst concentrations. The reverse reaction of MPC transesterification with phenol, as well as that of the disproportionation of MPC, was found to be independent of temperatures within the investigated conditions. The thermodynamic information and kinetic model reported here will provide valuable insight into the understanding of the transesterification process from DMC to DPC.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.001 |
| Open science | 0.000 | 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".