Ethyl oxalate has been prepared in poor yields by the following methods:
by distilling a mixture of anhydrous oxalic acid and absolute
alcohol;[1] by heating a mixture of anhydrous oxalic acid and 97 per
cent alcohol under a reflux condenser and fractionating the resulting
mixture;[2] by distilling a mixture of anhydrous oxalic acid
and absolute alcohol, the vapor of absolute alcohol being passed
simultaneously into the mixture;[3] by allowing a saturated solution
of oxalic acid in alcohol to stand for a long time at 40-50'0.[4]
A good yield has been obtained by Anschutz[5] by a method involving
saturation of a mixture of crystallized oxalic acid and alcohol
with hydrogen chloride, removal of the alcohol and water by
distillation under reduced pressure, and repetition of the treatment
with the alcohol and hydrogen chloride, the process being carried
out several times.
[1] Jahresb. 1861, 598.
[2] J prakt. Chem. (2), 34, 500 (1886).
[3] Monatsh. 17, 614 (1896).
[4] Ann. 65, 350 (1848).
[5] Ber. 16, 2414 (1883),