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Williamson ether synthesis: sodium ethoxide + 1-bromobutane → ethyl butyl ether

Et–O⁻ Na⁺ + n-Bu–Br → Et–O–Bu + NaBr↓

Textbook SN2 ether-formation. Sodium ethoxide (typically generated in situ from NaH + EtOH or used as a solid) attacks the primary alkyl bromide via backside attack; the bromide leaves as NaBr, precipitating from DMF as the reaction advances. Primary substrates only — secondary alkyl halides give E2 elimination at these conditions because the alkoxide is sterically demanding.

Conditions: Generate the alkoxide: under N2, suspend NaH (60% in mineral oil, 1.05 equiv) in dry DMF (~3 mL per mmol substrate). Add ethanol (1.05 equiv) dropwise — vigorous H2 evolution; control addition rate. Once H2 stops, add 1-bromobutane (1.0 equiv) via syringe. Stir at 50–80 °C for 6–24 h until starting material is consumed (TLC). NaBr precipitates as a fine white solid. Workup — Quench with sat. NH4Cl; partition into Et2O / water; wash organic with water + brine; dry MgSO4; concentrate. Distil at atmospheric pressure (bp 92 °C) to isolate. Substrate-scope reminder: Williamson works ONLY for primary alkyl halides.

Expected yield
70–88 %
Expected duration
6–24 h at 50–80 °C after in-situ alkoxide generation

Mechanism reference ↗

Scale inputs

Anchor reagent + concentration

Total reactant moles divided by this concentration sets the solvent volume.

Anchor amount

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Computed quantities

Reactants

Reactants for Williamson ether synthesis: sodium ethoxide + 1-bromobutane → ethyl butyl ether: stoichiometric quantities derived from the anchor amount.
Reagent Equiv Moles · mmol Mass · g Volume · mL
Sodium Ethoxide
141-52-6 · C2H6NaO
1.05 10.50 0.725 0.83
109-65-9
109-65-9 · C4H9Br
1.0 10.00 1.370 1.08

Solvent

Solvent for Williamson ether synthesis: sodium ethoxide + 1-bromobutane → ethyl butyl ether: stoichiometric quantities derived from the anchor amount.
Reagent Equiv Moles · mmol Mass · g Volume · mL
68-12-2
68-12-2 · C3H7NO
798.82 58.394 62.12

Product

Product for Williamson ether synthesis: sodium ethoxide + 1-bromobutane → ethyl butyl ether: stoichiometric quantities derived from the anchor amount.
Reagent Equiv Moles · mmol Mass · g Volume · mL
628-81-9
628-81-9 · C6H14O

density unavailable — volume not calculable.

1.0 10.00 1.022

Expected isolated yield

What you should actually weigh out of the recrystallisation flask, scaled from the limiting reactant via the canonical-procedure yield window.

Product
628-81-9 628-81-9 · C6H14O
Theoretical max
1.02 g (10.00 mmol)
Expected isolated · 70–88 % yield
0.72 – 0.90 g

Stoichiometry: moles_X = (moles_anchor / equiv_anchor) × equiv_X. Mass = moles × MW; volume = mass / ρ. Solvent volume = total reactant moles ÷ substrate concentration.

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