What absorbs at 1181 cm⁻¹ in an FTIR spectrum?
A band near 1181 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 1181 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 | 5 | 5 | 1,0 |
| C-O single bond | 5 | 5 | 1,0 |
| Acetate | 5 | 5 | 1,0 |
| Methoxy (OCH3) | 4 | 4 | 1,0 |
| Amide | 2 | 2 | 1,0 |
| Ketone | 1 | 1 | 1,0 |
| Ester | 1 | 1 | 1,0 |
| Carboxyl (COOH) | 1 | 1 | 1,0 |
| Carbonyl (C=O) | 1 | 1 | 1,0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1,0 |
| Silicon (Si) | 1 | 1 | 1,0 |
| N h | 1 | 1 | 1,0 |
| Hydroxyl (O-H) | 1 | 1 | 1,0 |
| Oxygen heterocycle | 1 | 1 | 1,0 |
| Alkyl C-H | 1 | 1 | 1,0 |
| C c single bond | 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 |
|---|---|---|---|
| epoxy resin | 1181, 905, 1100 | Methacrylate, Acetate, Methoxy (OCH3) | 1 |
| keratin | 1181, 1635, 1717 | Methacrylate, Acetate | 1 |
| PMMA | 1181, 1722, 1383 | Methacrylate, Acetate, Methoxy (OCH3) | 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 1181 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
-
C c single bond confiance 1,0
“carbon).37a,b stretching, where the apex denotes a chain bance-frequency spectrum, when the data are collected cm-1 cm-1 A peak at 1181 has contributions from aromatic at a nominal resolution of 4 (see Figure 2 and C-C¢ C-H in-plane bending”
Musto 等 - 2005 - Host-guest interactions and crystalline structure DOI: 10.1021/ma0477899 -
Acetate confiance 1,0
“Figure 8(b) shows that the peaks observed at 1064 maycorrespondto-C-O-C-,whilepeaksobservedbetween1181.33cm(cid:6)1 binding density that characterizes the number of non-electronic-sharing cm(cid:6)1 C-O interactions between atoms such as io”
Optical characterizations of PMMA/metal oxide nanoparticles thin films: bandgap engineering using a novel derived model DOI: 10.1016/j.heliyon.2021.e05952 -
Oxygen heterocycle confiance 1,0
“The decrease of the absorption band near 1181 cm-1, which was derived from the bridge between the benzene rings [40], indicates that the backbone chains of epoxy resin can be cut by thermal aging.”
Reinforced Structure Effect on Thermo-Oxidative Stability of Polymer-Matrix Composites: 2-D Plain Woven Composites and 2.5-D Angle-Interlock Woven Composites DOI: 10.3390/polym14173454 -
Hydroxyl (O-H) confiance 1,0
“0.6 3523cm-1 3000 , O-H deformation vibrastretching vibration at 1441cm-1 1181cm-1 tion at”
Li 和 Yang - 2014 - Fabrication and Characterization of Electrospun Wo DOI: 10.1155/2014/163678 -
confiance 1,0
“cm-1 2847 cm-1 due to the alkyl groups, a peak at 1648 cm-1 related to the N-H bending belonging to -NH2 2847 due to the alkyl groups, a peak at 1648 related to the N-H bending belonging to -NH 2 cm-1 groups, and peaks at around 1181 and 10”
Acrylic Pressure-Sensitive Adhesive Reinforced with Aluminum Nitride and Its Thermal Properties: Effect of Surface Treatment and Particle Size DOI: 10.3390/coatings10020188 -
Acetate confiance 1,0
“1181 which is the C-O stretching in -CH-O and micro (< 2 mm) residues.”
Degradation of Film and Rigid Bioplastics During the Thermophilic Phase and the Maturation Phase of Simulated Composting DOI: 10.1007/s10924-021-02098-2 -
Acetate confiance 1,0
“cm-1 cm-1, cm-1, In addition, the most significant absorptions are observed at 1737 and 1092 1181 cm-1 1274 corresponding to the C=O and C-O-C respectively [12], indicating the existence of ester 1H group.”
Wen 等 - 2018 - A novel oligomer containing DOPO and ferrocene gro DOI: 10.1016/j.polymdegradstab.2018.08.010 -
Acetate confiance 1,0
“The absorption peak at 1181 was the anti-symmetric stretching of the C-O-C of the ester substance [47].”
Nano Catalysis of Biofuels and Biochemicals from Cotinus coggygria Scop. Wood for Bio-Oil Raw Material DOI: 10.3390/polym14214610
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