What absorbs at 2720 cm⁻¹ in an FTIR spectrum?
A band near 2720 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
Brzi odgovor
A band near 2720 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 |
|---|---|---|---|
| Alkyl C-H | 3 | 3 | 1,0 |
| Methoxy (OCH3) | 1 | 1 | 1,0 |
| Methacrylate | 1 | 1 | 1,0 |
| C-O single bond | 1 | 1 | 1,0 |
| Acetate | 1 | 1 | 1,0 |
| Methyl | 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 |
|---|---|---|---|
| starch | 2720, 1650, 1540 | Methacrylate, C-O single bond, Alkyl C-H | 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 2720 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
-
Alkyl C-H pouzdanost 1,0
“The medium-weak peak at 2720 cm-1 is due to a combination of the stretching vibrational modes of methyl groups associated with CH2 [49,50].”
Characterization of Waxes in the Roman Wall Paintings of the Herculaneum Site (Italy) DOI: 10.3390/app122111264 -
Alkyl C-H pouzdanost 1,0
“5 TG/DTG curves cm-1), in -CH 2- (sym 2873 and asym 2931 the stretching cm-1), vibrations of C-H in O=C-H (2720 and 2780 the cm-1 stretching vibrations of C=O (1733 with a shoulder higher mass loss under the second decomposition stage.”
Thermal behavior, decomposition mechanism and some physicochemical properties of starch-g-poly(benzyl acrylate) copolymers DOI: 10.1007/s10973-016-5603-7 -
Acetate pouzdanost 1,0
“In addition, the most probable cm-1 carbonyl groups), the bands from 1050 up to 1210 m/z decomposition products with characteristic values [36] cm-1 (the stretching vibrations of C-O), the band at 2720 are given in Table 2.”
TG/DSC/FTIR/QMS studies on the oxidative decomposition of terpene acrylate homopolymers DOI: 10.1007/s10973-016-5753-7 -
Alkyl C-H pouzdanost 1,0
“cm-1, 2000-2200 for aldehydes (the stretching vibrations The type of the emitted gaseous species proved the cm-1, of C-H at 2720 and at 2800 the stretching vibrations decomposition of starch from the copolymers at this stage cm-1),”
Thermo-oxidative decomposition behavior of starch-g-poly(citronellyl methacrylate) and starch-g-poly(citronellyl acrylate) copolymers DOI: 10.1007/s10973-017-6950-8
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