What absorbs at 1701 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 1701 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.

Possible functional-group assignments

Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.

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 1701 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.

Literature behind these assignments

• Acetate confidence 1.0

  “The strong absorption peak at 1701 corresponding to C=O stretching [15] is assigned to the noncm-1 hydrogen bonded C=O .”

  Preparation of one-shot and two-shot method of semi-rigid polyurethane film based on functionalized liquid natural rubber DOI: 10.1063/1.5047200
• Silicon carbon confidence 1.0

  “1713cm(cid:2)1, Si-C C¼O at interactions, characterized by stretching intensity from 1701 to”

  Rilda 等 - 2021 - Enhancement of antifungal capability of cotton tex DOI: 10.1080/01932691.2020.1724797
• Carboxyl (COOH) confidence 1.0

  “In this speccm(cid:2)1 trum, the acid band is shifted slightly to 1701 but is [1] G.”

  Topacli 等 - 2006 - Infrared studies of pyroelectric Langmuir-Blodgett DOI: 10.1016/j.molstruc.2006.03.083
• Acetate confidence 1.0

  “Meanwhile, the spectrum of cross-linked PVA reveals another absorption characteristic cm-1 peak at 1701 due to stretching C=O belonging to aldehyde groups of glutaraldehyde Polymers2021,13,2638”

  Highly Conductive Polyelectrolyte Membranes Poly(vinyl alcohol)/Poly(2-acrylamido-2-methyl propane sulfonic acid) (PVA/PAMPS) for Fuel Cell Application DOI: 10.3390/polym13162638
• confidence 1.0

  “Alcohol 2924 strong, Broad N-H Stretching Amine Salt 1701”

  Evaluation of anticandidal activities and phytochemical examination of extracts prepared from DOI: 10.1186/s12906-022-03552-x
• Anhydride confidence 1.0

  “Figure 2 shows that the peak intensities at 1784 cm-1 and 1701 cm-1, which are attributed to absorbance of anhydride and ester bond, respectively, increase overall with temperature rising.”

  Cai 等 - 2019 - Investigation on Reaction Sequence and Group Site DOI: 10.3390/polym11122071
• Amide confidence 1.0

  “PenG TGA 200∘ 1701cm-1 1502 and C in a are characteristic of primary amide and curves show that weight loss occurred only after”

  Fontes 等 - 2013 - Characterization of Antibiotic-Loaded Alginate-Osa DOI: 10.1155/2013/472626
• Acetate confidence 1.0

  “The band at 1701 was attributed to s(C=O) [45,46] and bands at 1621, 1583”

  Ilic-Stojanovic 等 - 2018 - Thermosensitive hydrogels for modified release of DOI: 10.1080/00914037.2017.1354202