What absorbs at 2138 cm⁻¹ in an FTIR spectrum?
A band near 2138 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 6 cited sources
Hurtigt svar
A band near 2138 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.
Mulige funktionelle gruppetildelinger
| Funktionel gruppe | Understøttende fakta | Citerede kilder | Højeste tillid |
|---|---|---|---|
| Carbonyl (C=O) | 3 | 3 | 1,0 |
| Carboxyl (COOH) | 2 | 2 | 1,0 |
| Alkyl C-H | 1 | 1 | 1,0 |
| Methacrylate | 1 | 1 | 1,0 |
| Ketone | 1 | 1 | 1,0 |
| Ester | 1 | 1 | 1,0 |
| Amide | 1 | 1 | 1,0 |
| Acetate | 1 | 1 | 1,0 |
| C#c | 1 | 1 | 0,9 |
| Adsorbed carbon monoxide | 1 | 0 | 1,0 |
Rangering afspejler akkumulerede litteraturbeviser, ikke en enkelt autoritativ regel. Bekræft altid mod din prøvekontekst.
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 2138 cm⁻¹ is usually not enough for material identification by itself.
Anvendelse i virkeligheden
Denne type forespørgsel er almindelig ved polymeridentifikation, screening af ukendt plast, fejlfinding i kvalitetskontrol, verifikation af genanvendt materiale og litteraturunderstøttet gennemgang af peak-tildeling.
Almindelige fejl
- Behandling af et isoleret bånd som bevis på et materiale uden at kontrollere mindst en eller to understøttende toppe.
- Ignorerer overlap: flere funktionelle grupper kan bidrage nær samme bølgetal.
- Spring validering over, når additiver, blandinger, oxidation eller forurening kan forvrænge spektret.
Verifikationsrådgivning
Når tvetydighed fortsat består, valider hypotesen med DSC, GC-MS eller TGA, især for blandinger, nedbrudte prøver og fyldte polymerer.
Litteratur bag disse tildelinger
-
Carbonyl (C=O) tillid 1,0
“With time, the bands at 2138, most stable carbonyl band and the bands in the 1774cm(cid:2)1 2249cm(cid:2)1 region are evidently due to carbonyls on reduced chromium spedevelop, the band at de1902, 1794 and”
Influence of dealumination and treatments on the chromium speciation in zeolite CrBEA DOI: 10.1016/j.micromeso.2009.04.038 -
Carbonyl (C=O) tillid 1,0
“groups34,53-55 to evacuation, characteristic of CH and CH that as corroborated by the observation of their characteristic di3 2 cm-1 evidence the formation of acyclic hydrocarbon species (Figure carbonyl bands at 2138 and 2095 at low CO cov”
Moussa 等 - 2018 - Nature of Active Nickel Sites and Initiation Mecha DOI: 10.1021/acscatal.7b03970 -
Acetate tillid 1,0
“C=O stretch 2138 2343 1722 1700 1590 bend 1494 C-H sym.”
Raunier 等 - 2004 - Tentative identification of urea and formamide in DOI: 10.1051/0004-6361:20034558 -
Carboxyl (COOH) tillid 1,0
“OH asymmetrical stretching 2360.30 OH asymmetrical stretching vibration in carboxylic acids vibration in carboxylic acids 2138 -”
Biocatalytic activity of Aspergillus niger xylanase in paper pulp biobleaching DOI: 10.1007/s13205-016-0480-0 -
C#c tillid 0,9
“Explicit assignment: 2371.88, 2345.87 and 2138.23 (C≡C)”
Pinto Cotrim 等 - 2016 - Preparation of beta-CyclodextrinLatex Dispersion DOI: 10.7569/JRM.2015.634122 -
tillid 0,8
“Text: 'The band at 2138 cm-1 quickly disappear' in context of CO.”
Spezzati 等 - 2017 - Atomically Dispersed Pd-O Species on Ceo(2)(111) a DOI: 10.1021/acscatal.7b02001
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