What absorbs at 1761 cm⁻¹ in an FTIR spectrum?
A band near 1761 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 4 cited sources
Quick answer
A band near 1761 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 |
| Alkyl C-H | 1 | 1 | 1,0 |
| Anhydride | 1 | 1 | 1,0 |
| Alkene (C=C) | 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 1761 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
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Alkene (C=C) confiance 1,0
“The evidences of grafting and homopolymerisation reactions were supported by the presence of specific absorption peak of carbonyl (>C=O) cm-1, and the absence of absorption peak of maleic double bond (>C=C<) group of maleic anhydride at 176”
Characteristics of maleic anhydrida-modified polystyrene containing sand aggregate DOI: 10.1063/5.0015713 -
Alkyl C-H confiance 1,0
“cm-1 (O-H stretching), 3505 (O-H stretching), at 3648 cm-1 cm-1 (C-H stretching), 2996 (C-H stretching), 1761 2946 Fig.”
Enhanced efficacy of clindamycin hydrochloride encapsulated in PLA/PLGA based nanoparticle system for oral delivery DOI: 10.1049/iet-nbt.2015.0021 -
Acetate confiance 1,0
“Three bands at 1761, 1746, and 1732 appear in the spectra observed in the regions of C=O vibrations (1800-1650 cm-1)-Figure 5B and H-C=O vibraduring ethanol flow in the presence of the catalysts studied.”
Activation of Ethanol Transformation on Copper-Containing SBA-15 and MnSBA-15 Catalysts by the Presence of Oxygen in the Reaction Mixture DOI: 10.3390/ijms24032252 -
confiance 0,9
“Asp-85 band”
Dioumaev 和 Lanyi - 2008 - Switch from conventional to distributed kinetics i DOI: 10.1021/bi801247e.
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