Determination and Quantum Chemical Calculation of the Acid Dissociation Constants of Some Phenoxy Acetic Acids
Bibliographic record
Abstract
The acid dissociation constants of seven phenoxy acetic acids were determined by potentiometric titration. It has been shown that phenoxy acetic acids exhibit stronger acidity than both acetic acid and benzoic acid due to the induction and conjugation of the oxygen atom on —OCH 2COOH that links to the benzene ring. Acidity of phenoxy acetic acids containing two or more —OCH 2COOH groups is lower than that of phenoxy acetic acid by reason of electron donation of oxygen atom to the benzene ring. Quantum chemical calculation of the phenoxy acetic acids was carried out using CNDO/2 method. The bond charge density(ρ) of O—H and C—O bond in carboxyl group of seven phenoxy acetic acids was calculated, and the value f= ρ O—H/ρ C—O, was figured out. The f value of the carboxyl group in phenoxy acetic acid as well as the f values of the most likely dissociated carboxyl group in other six phenoxyl acetic acid derivatives are changed in the corresponding change order of their pK a or pK a1 values. It is concluded that the f value can be used as a judgement criterion of relative acidity for phenoxy acetic acids.
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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 | 0.001 | 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 | 0.001 |
| 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".