- Into a 250- or 500-ml round-bottomed flask provided with a reflux condenser place 46g (38 ml, 1 mol) of formic acid (98/100%) and 37g (46 ml, 0.5 mol) of butan-1-ol.
- Reflux for 24 hours.
- Wash the cold mixture with small volumes of saturated sodium chloride solution, then with saturated sodium hydrogen carbonate solution in the presence of a little solid sodium hydrogen carbonate until effervescence ceases, and finally with saturated sodium chloride solution.
- Dry with anhydrous sodium sulphate, and distil through a short fractionating column.
- Collect the butyl formate at 106-107 °C. Yield: 38g (74%).
Cognate preparations: Ethyl formate
- Reflux a mixture of 61g (50 ml, 1.33 mol) of formic acid (98/100%) and 31g (39.5 ml, 0.67 mol) of absolute ethanol for 24 hours.
- Attach a fractionating column to the flask, distil and collect the liquid passing over below 62 °C.
- Wash the distillate with saturated sodium hydrogen carbonate solution and saturate with salt before removing the ester layer.
- Dry with anhydrous sodium sulphate, filter and distil The ethyl formate passes over at 53-54 °C. The yield is 36g (72%).
Propyl formate
- Use 46g (38 ml, 1 mol) of formic acid (98/100%) and 30g (37.5 ml, 0.5 mol) of propan-1-ol and reflux for 24 hours.
- Proceed as for ethyl formate, but collect the crude propyl formate up to 86 °C; b.p. 80.5-82 °C. Yield: 28g (65%); p.m.r. spectrum (CCl₄, TMS) 𝜹 0.99 (t,3H), 1.67 (m,2H), 4.08 (t,2H), 7.94 (s,1H).
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