Isopentyl Acetate (Banana Oil)- IR Spectrum

Isopentyl Acetate (Banana Oil)- IR Spectrum

Transmittance 95 90 85 80- 75 70 65- 60- 55 50 45 40 35 30 25 20 15 4000 3500 3318.54 3000 2000 Wavenumbers (cm-1) 2500 1636.85 1500 1276.94 1000 500 414.07 404.67

The Correct Answer and Explanation is :

Isopentyl acetate, commonly known as banana oil, is an ester with the chemical formula C₇H₁₄O₂. Its infrared (IR) spectrum provides valuable insights into its molecular structure by identifying characteristic functional group vibrations.

Key Absorption Peaks in the IR Spectrum of Isopentyl Acetate:

1. Alkane C–H Stretch (2960–2870 cm⁻¹):

• The broad absorption band around 2960 cm⁻¹ corresponds to the C–H stretching vibrations of the alkyl chains. This is typical for aliphatic hydrocarbons. citeturn0search4

1. C=O Stretch (1740–1725 cm⁻¹):

• A strong absorption near 1740 cm⁻¹ is attributed to the stretching vibration of the carbonyl group (C=O) in the ester functional group. This peak is a definitive indicator of ester presence. citeturn0search4

1. C–O Stretch (1300–1000 cm⁻¹):

• The absorption band between 1300 and 1000 cm⁻¹ is associated with the C–O stretching vibrations in the ester group. This region often exhibits multiple peaks due to the complex nature of ester linkages. citeturn0search4

1. Alkane C–H Bend (1450–1375 cm⁻¹):

• The bending vibrations of C–H bonds in the alkyl groups appear in this region, contributing to the overall fingerprint of the compound. citeturn0search4

Additional Observations:

• Absence of O–H Stretch:
• Unlike alcohols, isopentyl acetate lacks an O–H group, so there is no broad O–H stretching absorption around 3200–3550 cm⁻¹. citeturn0search4
• Fingerprint Region (600–1500 cm⁻¹):
• The region below 1500 cm⁻¹, known as the fingerprint region, contains complex absorptions unique to each compound. While specific peaks in this region can be challenging to assign without detailed analysis, they contribute to the compound’s unique spectral fingerprint. citeturn0search4

By analyzing these characteristic absorption peaks, one can confirm the presence of ester functional groups and the specific structure of isopentyl acetate. This IR spectral analysis is essential for structural elucidation and quality control in chemical synthesis and analysis.