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
快速回答
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.
可能的官能基指派
排名反映累積的文獻證據，而非單一權威規則。請務必根據您的樣品背景進行確認。
可能的材料
| 材料 | 支持峰 | 重疊基團 | 引用來源 |
|---|---|---|---|
| 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 |
僅當同一文獻庫支援此波段以及至少一個額外特徵峰時，才會顯示材料。
光譜邏輯
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.
實際使用
此類查詢常見於聚合物鑑別、未知塑膠篩選、品管故障排除、再生材料驗證，以及基於文獻的峰值歸屬審查。
常見錯誤
- 將一個孤立的譜帶視為材料的證據，而未檢查至少一兩個支持峰。
- 忽略重疊：多個官能團可能在相同波數附近貢獻。
- 當添加劑、混合物、氧化或污染物可能扭曲譜圖時，跳過驗證。
驗證建議
當仍然存在歧義時，使用DSC、GC-MS或TGA驗證假設，特別是對於混合物、降解樣品和填充聚合物。
這些指派背後的文獻
-
Alkyl C-H 信心 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 信心 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 信心 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 信心 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 信心 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 信心 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 信心 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 信心 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
有包含此波峰的圖譜嗎？
上傳您的FTIR圖譜，幾秒內即可獲得完整的解讀報告——包含帶有文獻引用的峰位指派、圖譜庫比對以及信心等級評估的證據鏈。