What absorbs at 1781 cm⁻¹ in an FTIR spectrum?
A band near 1781 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
Quick answer
A band near 1781 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 |
|---|---|---|---|
| Carbonyl (C=O) | 4 | 3 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Ketone | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Amide | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Alkyl C-H | 2 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
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。
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 1781 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
-
Alkyl C-H 置信度 1.0
“cm(cid:2)1) (up-shiing This GPEs 2964 CH asymmetrical stretching vibrations from 2937 2 cm(cid:2)1) C]O (up-shied 1789 stretching from 1866 Access cm(cid:2)1) C]O (down-shied 1772 stretching from 1781 cm(cid:2)1) (down-shied 1480 CH sci”
Electrocatalytic and structural properties and computational calculation of PAN-EC-PC-TPAI-I2 gel polymer electrolytes for dye sensitized solar cell application DOI: 10.1039/d1ra01983j -
Carbonyl (C=O) 置信度 1.0
“3 cm-1 either EC or EMC from the electrolyte as evidenced by key new features at 1814 and 1781 cm-1 (comparable to the uc/c carbonyl stretching frequencies at 1807/1773 in free Gen2 cm-1 electrolyte) and prominent C(O)-O stretching modes at”
Pekarek 等 - 2020 - Intrinsic chemical reactivity of solid-electrolyte DOI: 10.1039/c9ta13535a -
Acetate 置信度 1.0
“Comparing the ABS spectrum with the purified samples, it is possible to detect the appearance of three new absorbance peaks that are related to it is possible to detect the appearance of three new absorbance peaks that are related to the su”
Enhancing the Interface Behavior on Polycarbonate/Elastomeric Blends: Morphological, Structural, and Thermal Characterization DOI: 10.3390/polym15071773 -
Acetate 置信度 1.0
“500 The most intense bands of iprodione are located at 1781 cm-1, and 998 which are due to C=O stretching and ring 400 breathing, respectively.”
Armenta 等 - 2007 - Determination of iprodione in agrochemicals by inf DOI: 10.1007/s00216-007-1152-z
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