What absorbs at 1491 cm⁻¹ in an FTIR spectrum?
A band near 1491 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 8 cited sources
Réponse rapide
A band near 1491 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 |
|---|---|---|---|
| Aromatic ring | 5 | 5 | 1,0 |
| Carboxyl (COOH) | 3 | 2 | 1,0 |
| Alkene (C=C) | 2 | 2 | 1,0 |
| Ring structure | 1 | 1 | 1,0 |
| Alkyl C-H | 1 | 1 | 1,0 |
| C c single bond | 1 | 1 | 1,0 |
| Methacrylate | 1 | 1 | 1,0 |
| Ketone | 1 | 1 | 1,0 |
| Ester | 1 | 1 | 1,0 |
| Carbonyl (C=O) | 1 | 1 | 1,0 |
| Amide | 1 | 1 | 1,0 |
| Acetate | 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.
Matériaux possibles
| Matériel | Pics de support | Groupes chevauchants | Sources citées |
|---|---|---|---|
| methylene blue | 1491, 1745, 1739 | Carboxyl (COOH) | 1 |
| HCl | 1491, 1708, 1032 | Aromatic ring | 1 |
Les matériaux sont affichés uniquement lorsque le même ensemble de littérature soutient cette bande et au moins un pic caractéristique supplémentaire.
Logique du spectre
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 1491 cm⁻¹ is usually not enough for material identification by itself.
Utilisation réelle
Ce type de requête est courant dans l＇identification des polymères, le criblage des plastiques inconnus, le dépannage du contrôle qualité, la vérification des matériaux recyclés et l＇examen de l＇attribution des pics appuyée par la littérature.
Erreurs courantes
- Traiter une bande isolée comme preuve d＇un matériau sans vérifier au moins un ou deux pics de support.
- Ignorer le chevauchement : plusieurs groupes fonctionnels peuvent contribuer près du même nombre d＇onde.
- Sauter la validation lorsque des additifs, des mélanges, l＇oxydation ou la contamination peuvent déformer le spectre.
Conseil de vérification
Lorsque l＇ambiguïté persiste, validez l＇hypothèse avec DSC, GC-MS ou TGA, en particulier pour les mélanges, les échantillons dégradés et les polymères chargés.
Bibliographie derrière ces attributions
-
Aromatic ring confiance 1,0
“The peak areas at 1491 and cm-' decreased rapidly, due to the [Nipissing transformation or degradation of the aromatic rings, and the cleavage of the -C-Nof the imide groups, respectively.”
Ha 等 - 2001 - Spectroscopic stuides on the liquid crystal alignm DOI: 10.1080/10587250108028259 -
Aromatic ring confiance 1,0
“The FTIR spectrum of the control dye also showed a large band at 1491 cm-1 corresponding to the aromatic stretching vibration of the C=C (Foo et al.”
Biodegradation of Methylene Blue as an Evidence of Synthetic Dyes Mineralization during Textile Effluent Biotreatment by Acinetobacter pittii DOI: 10.1007/s40710-020-00443-6 -
Acetate confiance 1,0
“In addition, two bands were observed at 1491 and 1388 that corresponds to C=O stretching and C-C stretching of alkanes respectively.”
Ecotoxicity of Musa paradisiaca leaf extract-coated ZnO nanoparticles to the freshwater microcrustacean Ceriodaphnia cornuta DOI: 10.1016/j.limno.2017.09.004 -
Aromatic ring confiance 1,0
“cm-1 [ν(N-H)], to the stretching vibration the band at 1637 cm-1 CO [ν(CO)], stretching vibration the band at 1569 to the quinonoid ring-stretching vibration, the bands at 1505 cm-1 to the benzenoid ring-stretching vibrations, the and 149”
Blaha 等 - 2019 - Role of p-Benzoquinone in the Synthesis of a Condu DOI: 10.1021/acsomega.9b00542 -
Aromatic ring confiance 1,0
“FTIR spectra 1600 (typical aromatic skeletal vibration), 1491 (disubstituted benzene ring), 1222 (antisymmetric C-O-C stretching vibration), 934 (O-C vibration 2 in the oxazine ring with a minor contribution from the phenolic ring), 753 (Ar”
Developing Further Versatility in Benzoxazine Synthesis via Hydrolytic Ring-Opening DOI: 10.3390/polym12030694 -
Aromatic ring confiance 1,0
“The crystallographic data perspectrum displayed absorption bands at 1491 and refinement 1 taining to crystal structure solution and are given corresponding to the aromatic C=C group while at 1294”
Sadia 等 - 2020 - Schiff-Based Fluorescent-ON Sensor L Synthesis and DOI: 10.1155/2020/2192584 -
Carboxyl (COOH) confiance 1,0
“The peaks at 1549 and a cm-1 small peak 1491 are due to the asymmetric and symmetric stretching modes of carboxylic acid, respectively [32].”
Thabede 等 - 2023 - Synthesis of lanthanum metal organic framework usi DOI: 10.15251/DJNB.2023.181.157 -
confiance 0,8
“Significant peaks of PAni due to C=C ring stretching.”
Applications of chitosan (CHI)-reduced graphene oxide (rGO)-polyaniline (PAni) conducting composite electrode for energy generation in glucose biofuel cell DOI: 10.1038/s41598-020-67253-6
Avez-vous un spectre avec cette bande ?
Téléchargez votre spectre FTIR et obtenez un rapport d＇interprétation complet — attributions de pics avec citations bibliographiques, correspondances de bibliothèque et une chaîne de preuves avec évaluation de la confiance — en quelques secondes.