¹H NMR of ethyl acetate template

Ethyl acetate CH₃CO₂CH₂CH₃: OCH₂ quartet δ 4.1 (2H), CH₃C=O singlet δ 2.0 (3H), CH₃ triplet δ 1.2 (3H), with integrals and assignments.

What the template shows

• An ethyl group on oxygen (quartet + triplet) and an isolated acetyl CH₃ (singlet)
• ¹H NMR spectrum of ethyl acetate
• ethyl acetate, C₄H₈O₂ · CDCl₃, 400 MHz, typical values
• δ / ppm (chemical shift; downfield ← → upfield)
• Multiplets are drawn wider than to scale so the lines can be counted; the stepped traces are the integrals (height ∝ number of H).
• why there
• Next to C=O (δ ~2); no H on the neighbouring carbon → singlet
• On the ester O (strongly deshielded); 3 neighbours → quartet
• Alkyl CH₃; 2 neighbours (CH₂) → triplet, J ≈ 7 Hz
• Three signals, integrals 2 : 3 : 3 (total 8 H = C₄H₈O₂).
• Quartet + triplet with the same J is the fingerprint of an ethyl group (CH₃CH₂–).
• OCH₂ of an ester (δ 4.1) is further downfield than OCH₂ of an alcohol (δ 3.7): the acyl group pulls more electron density from the O.
• The acetyl CH₃ has no neighbouring H, so it is a sharp singlet at δ ~2.0, typical of CH₃–C=O.
• Isomer check: methyl propanoate would give OCH₃ singlet δ 3.7, CH₂ quartet δ 2.3, CH₃ triplet δ 1.1.
• Typical literature values; compare real spectra in SDBS · every part of this figure is editable

Drawn with 6 atoms, 120 shapes – every one editable in MolDraw.

Sources

• Pavia, Lampman, Kriz & Vyvyan, Introduction to Spectroscopy, 5th ed., Cengage 2015, ch. 3 Textbook
• SDBS Spectral Database for Organic Compounds (AIST) Database