Synthesis and Characterization of Carboxyethylated Lignosulfonate
Bibliographic record
Abstract
Abstract Lignosulfonate is a byproduct of the sulfite pulping process and has limited use in industry. The main objective of this study was to investigate the carboxyethylation of lignosulfonate to increase its charge density to broaden its applications. The carboxyethylation of lignosulfonate was optimized under the conditions of 30 wt % NaOH, 2.0 mol mol −1 2‐chloropropinic acid/lignosulfonate, 90 °C, 0.5 h, and 0.03 mol 2‐chloropropinic acid, which produced carboxyethylated lignosulfonate with a charge density and molecular weight of −3.51 meq g −1 and 46 493 g mol −1 , respectively. The mechanism of the carboxyethylation reaction using 2‐chloropropinic acid by an S N 1 pathway in an alkaline solution was discussed. Methylation was also used to mask the phenolic hydroxide groups of lignosulfonate to investigate if carboxyethylation occurred on aliphatic hydroxide groups of lignosulfonate. The produced carboxyethylated lignosulfonate was characterized by using FTIR spectroscopy, NMR spectroscopy, gel permeation chromatography, and elemental and functional group analyses. Basic 1 H‐ 1 H 2 D COSY NMR spectroscopy was used to record the coupled spins of the carboxyethyl group on carboxyethylated lignosulfonate. The information from 1 D 1 H NMR and 2 D NMR COSY spectroscopy provided evidence for the existence of a 1‐carboxyethyl group on the carboxyethylated lignosulfonate structure.
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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".