Using the attached infrared spectroscopy spectrum for the compound Ethyl Pentanoate, identify the functional group and any observed characteristic absorbtions in cm-1. Compare with the attached roadmap for interpreting IR spectra.
Using the attached infrared spectroscopy spectrum for the compound Ethyl Pentanoate, identify the functional group and any observed characteristic absorbtions in cm-1. Compare with the attached roadmap for interpreting IR spectra.
Using the attached infrared spectroscopy spectrum for the compound Ethyl Pentanoate, identify the functional group and any observed characteristic absorbtions in cm-1. Compare with the attached roadmap for interpreting IR spectra.
Using the attached infrared spectroscopy spectrum for the compound Ethyl Pentanoate, identify the functional group and any observed characteristic absorbtions in cm-1. Compare with the attached roadmap for interpreting IR spectra.
Transcribed Image Text:### Infrared Spectrum of Ethyl Pentanoate
This image represents the infrared (IR) spectrum of Ethyl Pentanoate. The spectrum displays the characteristic absorbance peaks that correspond to specific bond vibrations within the molecule.
#### X-Axis: Wavelength (cm⁻¹)
- The x-axis ranges from 4000 cm⁻¹ to 650 cm⁻¹, a typical range for infrared spectroscopy, capturing various functional group vibrations.
#### Y-Axis: % Transmittance (%T)
- The y-axis indicates the percentage of light transmitted through the sample. Lower transmittance corresponds to higher absorbance, where specific molecular vibrations occur.
#### Significant Peaks
1. **2960.91 cm⁻¹ & 2875.05 cm⁻¹**: These peaks are typically associated with C-H stretching vibrations, common in alkanes and aliphatic compounds.
2. **1734.91 cm⁻¹**: This sharp peak is characteristic of carbonyl (C=O) stretching vibrations, a central feature of esters like ethyl pentanoate.
3. **1466.16 cm⁻¹ & 1372.23 cm⁻¹**: These peaks can be attributed to C-H bending vibrations, often seen in alkane groups.
4. **1250.71 cm⁻¹ & 1177.04 cm⁻¹**: These peaks are associated with C-O stretching, indicative of ester linkages.
5. **1094.82 cm⁻¹ & 1033.26 cm⁻¹**: Also correspond to C-O stretching vibrations.
6. **931.11 cm⁻¹, 853.85 cm⁻¹ & 754.20 cm⁻¹**: These peaks often relate to bending modes of different functional groups in the molecule, possibly involving out-of-plane C-H bending.
### General Information
Ethyl Pentanoate is an ester known for its fruity odor and is often used in flavorings and fragrances. The infrared spectrum helps in identifying and confirming the structure by exposing unique molecular vibrations that act as a molecular fingerprint.
Transcribed Image Text:**Infrared Spectroscopy Analysis Guide**
I. **Identifying Carbonyl Groups (C=O):**
1. Check for absorption from 1750 to 1650 cm⁻¹.
- **Carboxylic Acids:** Broad, strong absorption between 3300 and 2500 cm⁻¹ due to O-H stretch.
- **Aldehydes:** Two peaks at 2780 and 2670 cm⁻¹ due to C-H stretch.
- **Amides:** Absorption around 1670 cm⁻¹ and N-H stretch from 3050-3550 cm⁻¹.
2. If no identified peaks:
- **Anhydrides:** Two peaks in the carbonyl range.
- **Ketones/Esters:** Carbonyl stretching at frequencies >1725 cm⁻¹.
II. **Non-Carbonyl Absorptions:**
1. **Amines:** N-H stretching >3100 cm⁻¹.
- Primary amines show two peaks.
- Secondary amines show one peak.
2. **Alcohols:** O-H stretching.
- "Free" O-H at 3600 cm⁻¹.
- "Hydrogen-bonded" O-H at 3400 cm⁻¹ (broad, strong).
III. **Triple Bonds:**
- **Alkynes:** C≡C stretching at 2100-2260 cm⁻¹.
- **Nitriles:** Similar band at 2200-2300 cm⁻¹.
IV. **C-H Stretching:**
1. **Aliphatic C-H:** Intense absorption slightly less than 3030 cm⁻¹.
2. **Aromatic/Alkene C-H:** Weaker absorption slightly more than 3030 cm⁻¹.
V. **C=C Bonds:**
- **Alkenes:** C=C stretching around 1660 cm⁻¹.
VI. **Aromatic Benzene Rings:**
1. Large bands in the 650-900 cm⁻¹ range for out-of-plane bending.
2. Several weak absorptions between 1667 and 2000 cm⁻¹.
3. Four bands between 1429 and 1667 cm⁻¹ due to C-C vibrations.
VII. **C-H Bending:**
- Presence of peaks at 1450 and
Definition Definition Group of atoms that shape the chemical characteristics of a molecule. The behavior of a functional group is uniform in undergoing comparable chemical reactions, regardless of the other constituents of the molecule. Functional groups aid in the classification and anticipation of reactivity of organic molecules.
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