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
Jawapan pantas
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.
Penetapan kumpulan berfungsi yang mungkin
| Kumpulan berfungsi | Fakta sokongan | Sumber dipetik | Keyakinan tertinggi |
|---|---|---|---|
| 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 |
Pemeringkatan mencerminkan bukti literatur terkumpul, bukan satu peraturan berwibawa. Sentiasa sahkan terhadap konteks sampel anda.
Logik spektrum
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.
Penggunaan dunia sebenar
Jenis pertanyaan ini biasa dalam pengenalpastian polimer, saringan plastik tidak diketahui, penyelesaian masalah QC, pengesahan bahan kitar semula, dan semakan tugasan puncak yang disokong oleh literatur.
Kesilapan biasa
- Menganggap satu jalur terpencil sebagai bukti bahan tanpa memeriksa sekurang-kurangnya satu atau dua puncak sokongan.
- Mengabaikan pertindihan: pelbagai kumpulan berfungsi boleh menyumbang berhampiran nombor gelombang yang sama.
- Melangkau pengesahan apabila bahan tambahan, campuran, pengoksidaan, atau pencemaran boleh memesongkan spektrum.
Nasihat pengesahan
Apabila kekaburan masih ada, sahkan hipotesis dengan DSC, GC-MS, atau TGA, terutamanya untuk campuran, sampel terdegradasi, dan polimer terisi.
Literatur di sebalik penetapan ini
-
Carbonyl (C=O) keyakinan 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) keyakinan 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 keyakinan 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) keyakinan 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 keyakinan 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 -
keyakinan 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
Ada spektrum dengan jalur ini?
Muat naik spektrum FTIR anda dan dapatkan laporan tafsiran penuh — penetapan puncak dengan petikan literatur, padanan perpustakaan, dan rantaian bukti berkadar keyakinan — dalam beberapa saat.