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
Snabbt svar
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.
Möjliga identifieringar av funktionella grupper
| Funktionell grupp | Stödjande fakta | Citerade källor | Högsta förtroende |
|---|---|---|---|
| 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 |
Rankingen speglar ackumulerade litteraturbevis, inte en enda auktoritativ regel. Bekräfta alltid mot din provkontext.
Möjliga material
| Material | Stödjande toppar | Överlappande grupper | Citerade källor |
|---|---|---|---|
| starch | 2720, 1650, 1540 | Methacrylate, C-O single bond, Alkyl C-H | 1 |
Material visas endast när samma litteraturpool stöder detta band och minst en ytterligare karakteristisk topp.
Spektrumlogik
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.
Användning i verkligheten
Denna typ av fråga är vanlig inom polymeridentifiering, screening av okänd plast, felsökning av kvalitetskontroll, verifiering av återvunnet material och litteraturstödd toppidentifieringsgranskning.
Vanliga misstag
- Behandla ett isolerat band som bevis på ett material utan att kontrollera minst en eller två stödjande toppar.
- Ignorerar överlapp: flera funktionella grupper kan bidra nära samma vågtal.
- Hoppa över validering när tillsatser, blandningar, oxidation eller föroreningar kan förvränga spektrat.
Verifieringsråd
När oklarhet kvarstår, validera hypotesen med DSC, GC-MS eller TGA, särskilt för blandningar, nedbrutna prover och fyllda polymerer.
Litteratur bakom dessa identifieringar
-
Alkyl C-H förtroende 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 förtroende 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 förtroende 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 förtroende 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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