What absorbs at 2946 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 2946 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.

Möjliga identifieringar av funktionella grupper

Rankingen speglar ackumulerade litteraturbevis, inte en enda auktoritativ regel. Bekräfta alltid mot din provkontext.

Possible materials

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 2946 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.

Litteratur bakom dessa identifieringar

• Alkyl C-H förtroende 1,0

  “This disappearance of the cm-1 cm-1 N-CH2 vibration bands at 2946 and 2811 indicated proton transfer between the N-CH2 (basic) of ARP and carboxylic groups (acidic) of SA.”

  Multicomponent crystalline solid forms of aripiprazole produced via hot melt extrusion techniques: An exploratory study DOI: 10.1016/j.jddst.2021.102529.
• Alkyl C-H förtroende 1,0

  “Protein 1662 cm-1 Stretching C-H Lipids 2946 Figure 3.”

  Salivary ATR-FTIR Spectroscopy Coupled with Support Vector Machine Classification for Screening of Type 2 Diabetes Mellitus DOI: 10.3390/diagnostics13081396
• Alkyl C-H förtroende 1,0

  “CH asymmetric stretching”

  Kavanaugh 等 - 2016 - Human mesenchymal stem cell behavior on segmented DOI: 10.1007/s10856-015-5654-5.
• Hydroxyl (O-H) förtroende 1,0

  “Researchers reported that cm-1 cm-1 -OH stretch, 2945.51 and 2834.66 for C-H using the fungal strain decolorization of dyes with the cm-1 stretching of alkyl benzene, 1460.07 for -C-H wavelength range 250-700 nm could be degraded to cm-1 be”

  Kiran 等 - 2019 - Lignin Degrading System of Phanerochaete chrysospo DOI: 10.15244/pjoes/89575
• Alkyl C-H förtroende 0,9

  “C-H stretching in alkane”

  Characterization of plastic degrading bacteria isolated from sewage wastewater DOI: 10.1016/j.sjbs.2023.103628
• Alkyl C-H förtroende 0,8

  “Described as typical PU peaks”

  Wang 等 - 2014 - Electrospun polyurethane-core and gelatin-shell co DOI: 10.1088/1758-5082/6/1/015002.