What absorbs at 1791 cm⁻¹ in an FTIR spectrum?
A band near 1791 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 3 cited sources
Quick answer
A band near 1791 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.
可能的官能团归属
| 官能团 | 支持性事实 | 引用来源 | 最高置信度 |
|---|---|---|---|
| Methacrylate | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Anhydride | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 0.9 |
排名反映了累积的文献证据，而非单一的权威规则。请始终对照您的样品背景进行确认。
Possible materials
| 材料 | 支持峰 | Overlapping groups | 引用来源 |
|---|---|---|---|
| polyethylene | 1791, 1737, 1720 | Methacrylate, Carboxyl (COOH) | 1 |
Materials are shown only when the same literature pool supports this band and at least one additional characteristic peak.
Spectrum logic
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 1791 cm⁻¹ is usually not enough for material identification by itself.
Real-world usage
This type of query is common in polymer identification, unknown plastic screening, QC troubleshooting, recycled-material verification, and literature-backed peak assignment review.
Common mistakes
- Treating one isolated band as proof of a material without checking at least one or two supporting peaks.
- Ignoring overlap: multiple functional groups can contribute near the same wavenumber.
- Skipping validation when additives, blends, oxidation, or contamination may distort the spectrum.
Verification advice
When ambiguity remains, validate the hypothesis with DSC, GC-MS, or TGA, especially for blends, degraded samples, and filled polymers.
这些分配背后的文献
-
Anhydride 置信度 1.0
“In the FTIR spectrum of LDPE/TPS composite at 400-4000 cm(cid:1)1 cm(cid:1)1 two main transmission peaks of 1791 and 1714 related to anhydride ring of coupling agent disappeared and a cm(cid:1)1 is formed.”
Physical and thermal mechanical properties of corn starch/LDPE composites DOI: 10.1002/app.37877 -
Acetate 置信度 1.0
“A smaller peak at 1791 could 340 perhaps be assigned to C=O stretching of a 'free' non-H-bonded acid, however the wavenumber is 341 higher than that typically observed;”
Campen 等 - 2022 - Thermal degradation of n-hexadecane base oil and i DOI: 10.1007/s11249-019-1182-7. -
N-O bond 置信度 0.9
“Shoulder assigned to ν(NO) vibration.”
A Structural Model for the Iron–Nitrosyl Adduct of Gentisate Dioxygenase DOI: 10.1002/ejic.201800992
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