What absorbs at 1783 cm⁻¹ in an FTIR spectrum?
A band near 1783 cm⁻¹ can point to several functional groups. Below are the most likely assignments, ranked by how much published evidence supports each — every one traceable to literature (DOI) and cross-validated against our 130,000+ reference spectra and knowledge graph.
Backed by 2 cited sources
Quick answer
A band near 1783 cm⁻¹ is usually interpreted by checking which functional groups repeatedly co-occur there in the literature, then confirming at least one or two additional peaks in the same sample. This page ranks those assignments by accumulated evidence rather than by a single fixed textbook rule.
Attributions possibles de groupes fonctionnels
| Groupe fonctionnel | Faits à l＇appui | Sources citées | Confiance maximale |
|---|---|---|---|
| Methacrylate | 2 | 1 | 1,0 |
| Ketone | 2 | 1 | 1,0 |
| Ester | 2 | 1 | 1,0 |
| Carboxyl (COOH) | 2 | 1 | 1,0 |
| Carbonyl (C=O) | 2 | 1 | 1,0 |
| Amide | 2 | 1 | 1,0 |
| Acetate | 2 | 1 | 1,0 |
| Imide | 2 | 1 | 0,9 |
| Chlorine | 1 | 1 | 1,0 |
Le classement reflète les preuves bibliographiques accumulées, et non une règle faisant autorité. Confirmez toujours dans le contexte de votre échantillon.
Spectrum logic
This band becomes meaningful only when read with its neighboring peaks. In practice, analysts first look at the assignments above, then check whether the same sample also shows other peaks expected for the same structural motif. A lone band near 1783 cm⁻¹ is usually not enough for material identification by itself.
Real-world usage
This type of query is common in polymer identification, unknown plastic screening, QC troubleshooting, recycled-material verification, and literature-backed peak assignment review.
Common mistakes
- Treating one isolated band as proof of a material without checking at least one or two supporting peaks.
- Ignoring overlap: multiple functional groups can contribute near the same wavenumber.
- Skipping validation when additives, blends, oxidation, or contamination may distort the spectrum.
Verification advice
When ambiguity remains, validate the hypothesis with DSC, GC-MS, or TGA, especially for blends, degraded samples, and filled polymers.
Bibliographie derrière ces attributions
-
Acetate confiance 1,0
“cm-1 of the peak at 1820 This is because the first peak at 1820 is the C=O stretching cm-1 vibration of CAC, while the second peak at 1783 is the result of Fermi resonance”
Zhu 等 - 2021 - Separation and Rectification of Chloroacetyl Chlor DOI: 10.3390/pr9020287 -
Imide confiance 0,9
“1783 (symmetric imide stretching)”
Novel organosoluble poly(amide-imide-imide)s synthesized from new tetraimide-dicarboxylic acid by condensation with 4,4′-oxydiphthalic anhydride, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, trimellitic anhydride, and various aromatic diamines DOI: 10.1002/app.23364
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