What absorbs at 2991 cm⁻¹ in an FTIR spectrum?
A band near 2991 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
Ateb cyflym
A band near 2991 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.
Aseiniadau grŵp swyddogaethol posibl
| Grŵp swyddogaethol | Ffeithiau ategol | Ffynonellau a ddyfynnwyd | Hyder uchaf |
|---|---|---|---|
| Alkyl C-H | 6 | 6 | 1.0 |
| Methyl | 3 | 3 | 1.0 |
Mae＇r safle＇n adlewyrchu tystiolaeth llenyddiaeth gronnwyd, nid rheol awdurdodol sengl. Cadarnhewch bob amser yn erbyn eich cyd-destun sampl.
Deunyddiau posibl
| Deunydd | Copaon ategol | Grwpiau sy＇n gorgyffwrdd | Ffynonellau a ddyfynnwyd |
|---|---|---|---|
| TiO | 2991, 1730, 1699 | Alkyl C-H | 1 |
| rGO | 2991, 2358, 2930 | Alkyl C-H | 1 |
| PLA | 2991, 1650, 1073 | Alkyl C-H | 1 |
| PEG | 2991, 1650, 1342 | Alkyl C-H | 1 |
| PLLA | 2991, 1182, 921 | Alkyl C-H, Methyl | 1 |
Mae deunyddiau＇n cael eu dangos dim ond pan fydd yr un gronfa lenyddiaeth yn cefnogi＇r band hwn ac o leiaf un brig nodweddiadol ychwanegol.
Rhesymeg sbectrwm
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 2991 cm⁻¹ is usually not enough for material identification by itself.
Defnydd yn y byd go iawn
Mae＇r math hwn o ymholiad yn gyffredin mewn adnabod polymer, sgrinio plastig anhysbys, datrys problemau QC, dilysu deunydd wedi＇i ailgylchu, ac adolygiad o aseiniad copa wedi＇i gefnogi gan lenyddiaeth.
Camgymeriadau cyffredin
- Trin un band ynysig fel prawf o ddeunydd heb wirio o leiaf un neu ddau gopa cefnogol.
- Anwybyddu gorgyffwrdd: gall grwpiau swyddogaethol lluosog gyfrannu ger yr un rhif ton.
- Hepgor dilysu pan fo ychwanegion, cymysgeddau, ocsideiddio, neu halogiad yn gallu ystumio＇r sbectrwm.
Cyngor dilysu
Pan fo amwysedd yn parhau, dilyswch y rhagdybiaeth gyda DSC, GC-MS, neu TGA, yn enwedig ar gyfer cymysgeddau, samplau dirywiedig, a pholymerau llawn.
Llenyddiaeth y tu ôl i＇r aseiniadau hyn
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Alkyl C-H hyder 1.0
“The two cm-1 bands at 2991 and 2948 can be attributed to the C-H bond stretching vibrations of the -CH and”
Awad 等 - 2020 - Experimental Investigation of Methyl Methacrylate DOI: 10.3390/ma13245793 -
Alkyl C-H hyder 1.0
“LLM confirmed rule peak-group candidate”
Structural and Surface Compatibility Study of Modified Electrospun Poly(ε-caprolactone) (PCL) Composites for Skin Tissue Engineering DOI: 10.1208/s12249-016-0500-8 -
Alkyl C-H hyder 1.0
“The characteristic band at 2991 cm-1 to 2976 cm-1 cm-1 cm-1 (C=C 2976 corresponds to C-H stretching vibrations, 1652 skeletal vibration), 1521”
Complex Permittivity and Electromagnetic Interference Shielding Effectiveness of OPEFB Fiber-Polylactic Acid Filled with Reduced Graphene Oxide DOI: 10.3390/ma13204602 -
Alkyl C-H hyder 1.0
“The asymmetric and symmetric C-H stretching (St.) cm1 cm1, of the methyl groups were attributed to the transmission bands at 2991 and 2943 respectively.”
Ragab - 2022 - Improved Physical, thermal, and conductivity stren DOI: 10.21203/rs.3.rs-1514992/v1 -
Alkyl C-H hyder 1.0
“The bands at 2991 and 2868 which were attributed to various C-H stretching vibrations, had opposite signs on the PC2 and PC3 loading curves.”
Ex Vivo Vibration Spectroscopic Analysis of Colorectal Polyps for the Early Diagnosis of Colorectal Carcinoma DOI: 10.3390/diagnostics11112048 -
Methyl hyder 0.9
“Explicit assignment: CH3 asymmetric stretching”
Differentiation in MALDI-TOF MS and FTIR spectra between two pathovars of Xanthomonas oryzae DOI: 10.1016/j.saa.2014.06.056 -
Methyl hyder 0.9
“Explicit assignment: 'absorption peak around 2991 ... stretching vibration peak of CH3'”
Li 等 - 2020 - Effect of molecular weight of polyethylene glycol DOI: 10.1039/d0ra08699a -
Alkyl C-H hyder 0.8
“Text: 'strong peak at 2991.3 cm-1 (Q is assigned as the center branch) ... R(2) transition of our 5ν C-H'”
Perez-Delgado 和 Manzanares - 2010 - Cavity Ring Down and Fourier Transform Infrared Sp DOI: 10.1021/jp105382p
Oes gennych sbectrwm gyda＇r band hwn?
Llwythwch eich sbectrwm FTIR i fyny a chael adroddiad dehongli llawn — aseiniadau brig gyda chyfeiriadau llenyddiaeth, cyfateb llyfrgell, a chadwyn dystiolaeth â gradd hyder — mewn eiliadau.