What absorbs at 1268 cm⁻¹ in an FTIR spectrum?
A band near 1268 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
Brzi odgovor
A band near 1268 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.
Moguće dodjele funkcionalnih skupina
| Funkcionalna skupina | Potporni dokazi | Citirani izvori | Najveća pouzdanost |
|---|---|---|---|
| Methacrylate | 8 | 7 | 1,0 |
| Acetate | 8 | 7 | 1,0 |
| Methoxy (OCH3) | 7 | 6 | 1,0 |
| C-O single bond | 7 | 6 | 1,0 |
| Amide | 3 | 3 | 1,0 |
| Ester | 3 | 2 | 1,0 |
| Carboxyl (COOH) | 3 | 2 | 1,0 |
| Carbonyl (C=O) | 3 | 2 | 1,0 |
| Ketone | 2 | 2 | 1,0 |
| Hydroxyl (O-H) | 2 | 2 | 1,0 |
| Lignin | 2 | 2 | 1,0 |
| Secondary amine | 1 | 1 | 1,0 |
| C n single bond | 1 | 1 | 1,0 |
| N h | 1 | 1 | 1,0 |
| Phosphate (PO4) | 1 | 1 | 1,0 |
| Alkyl C-H | 1 | 1 | 1,0 |
| C c single bond | 1 | 1 | 1,0 |
| Aromatic ring | 1 | 1 | 1,0 |
Rangiranje odražava akumulirane literaturne dokaze, a ne jedno autoritativno pravilo. Uvijek provjerite u kontekstu vašeg uzorka.
Mogući materijali
| Materijal | Potporni vrhovi | Preklapajuće skupine | Citirani izvori |
|---|---|---|---|
| chitosan | 1268, 1650, 1655 | Acetate, Methacrylate, C-O single bond | 1 |
| methacrylate | 1268, 873, 1725 | Methacrylate, Acetate, C-O single bond | 1 |
| lignin | 1268, 1035, 1510 | Methacrylate, Acetate, C-O single bond | 1 |
| wood | 1268, 1740, 1730 | Methacrylate, Acetate, Methoxy (OCH3) | 1 |
| silver nanoparticles | 1268, 1636, 1631 | Methacrylate, Acetate, C-O single bond | 1 |
Materijali su prikazani samo kada ista literatura podržava ovu traku i barem jedan dodatni karakteristični vrh.
Logika spektra
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 1268 cm⁻¹ is usually not enough for material identification by itself.
Upotreba u stvarnom svijetu
Ova vrsta upita uobičajena je u identifikaciji polimera, probiru nepoznate plastike, rješavanju problema u kontroli kvalitete, provjeri recikliranog materijala i pregledu dodjele vrhova potkrijepljenom literaturom.
Uobičajene pogreške
- Tretiranje jedne izolirane vrpce kao dokaza materijala bez provjere barem jednog ili dva podržavajuća pika.
- Zanemarivanje preklapanja: više funkcionalnih skupina može doprinositi u blizini istog valnog broja.
- Preskakanje validacije kada aditivi, mješavine, oksidacija ili kontaminacija mogu izobličiti spektar.
Savjet za provjeru
Kada nejasnoća ostane, validirajte hipotezu pomoću DSC, GC-MS ili TGA, posebno za mješavine, degradirane uzorke i punjene polimere.
Literatura iza ovih dodjela
-
Acetate pouzdanost 1,0
“The lignin specific FTIR peaks cm-1 noticed at 1268 , depicted the change in lignin's guaicyl ring plus C=O stretch.”
Majeed 等 - 2017 - Lignin macromolecule's implication in slowing the DOI: 10.1002/star.201600362 -
Acetate pouzdanost 1,0
“Although hardwood lignin also contains guacm-1 (12) for syringyl ring and C-O stretch in lignin and iacyl moities, the absorption band at 1268 may have cm-1(13) cm-1.”
Pandey 和 Pitman - 2003 - FTIR studies of the changes in wood chemistry foll DOI: 10.1016/S0964-8305(03)00052-0 -
Acetate pouzdanost 1,0
“The cm-1 peak 1507 could be attributed to an aromatic skeletal of lignin from lignocellulosic cm-1 materials and the medium band at 1268 is attributed to C-O stretching of phenol in lignite”
Optimization of primary sewage sludge and coal lignite by microwave assisted pyrolysis for the production of bio oil DOI: 10.1080/09593330.2020.1797903 -
C-O single bond pouzdanost 1,0
“From the recent degraded sample (A') to the less aged one (B': 19th century), the cm-1 few changes concern the decrease in the intensity band at 1268 related to Car-O of ether group in guaiacyl monomer (methoxyl group branched to aromatic),”
Impact of Natural Degradation on the Aged Lignocellulose Fibers of Moroccan Cedar Softwood: Structural Elucidation by Infrared Spectroscopy (ATR-FTIR) and X-ray Diffraction (XRD) DOI: 10.3390/fermentation8120698 -
Acetate pouzdanost 1,0
“1300-1320 C-O stretch doublet to lower wavenumbers at 1268 and 1245 cm-1 cm-1.”
Modelling ATR-FTIR Spectra of Dental Bonding Systems to Investigate Composition and Polymerisation Kinetics DOI: 10.3390/ma14040760 -
C c single bond pouzdanost 1,0
“The three peaks appearing at 1268, 1390, cm-1 and 2925 are characteristic to C-C, C=C, and C-H stretching vibrations, respectively, proving the presence of alkyl and aryl groups [32,35].”
Fares 等 - 2021 - Influence of Nitrogen-Doped Carbon Dot and Silver DOI: 10.3390/chemosensors9030052 -
Phosphate (PO4) pouzdanost 1,0
“(P-O-C or P-OH stretching), 1268”
Functionalization of poly(glycidylmethacrylate) with iminodiacetate and imino phosphonate groups for enhanced sorption of neodymium - sorption performance and molecular modeling DOI: 10.1016/j.reactfunctpolym.2022.105389 -
Acetate pouzdanost 1,0
“and at 1268 due to cm-1 -C-O-C stretching.”
Kuen 等 - 2017 - Increased Loading, Efficacy and Sustained Release DOI: 10.3390/nano7110379
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