Org. Synth. 1925, 5, 59
DOI: 10.15227/orgsyn.005.0059
ETHYL OXALATE
[
Oxalic acid, ethyl ester
]1. Procedure
In a
5-l. flask
are placed1 kg. (7.9 moles) of crystallized (hydrated)
oxalic acid
,1.66 kg. (2034 cc.) of 95 per cent
ethyl alcohol
, and1.33 kg. (887 cc.) of
carbon tetrachloride
. The flask is then fitted with afractionating column, 1 meter long
, to which are attached acondenser
and anautomatic separator
so arranged that the lighter liquid flows off to areceiver
(Fig. 13)(Note 1)
. The heavier liquid flows through atower of anhydrous potassium carbonate
, and then returns to the reaction flask. The bottom of the tower is connected with a smallseparatory funnel
through which anypotassium carbonate
solution, which flows from the solid in the tower, may be withdrawn from time to time.The mixture in the flask is slowly distilled
(Note 2)
. As soon as about 500 cc. of the lighter liquid has collected, it is placed in a fractionating apparatus and distilled, the material which boils up to 79° being collected separately. This fraction, which consists principally of alcohol, with a littlecarbon tetrachloride
and moisture, is dried withpotassium carbonate
and returned to the reaction mixture(Note 3)
. The higher fractions are redistilled.The above process is continued until the distillate no longer separates into two phases (about twenty-seven hours). The liquid in the flask is then distilled with the use of a column until the temperature of the vapor reaches 85°; the residue is then distilled under reduced pressure, and the fraction which boils at
106–107°/25 mm.
is collected. The yield is920–960 g.
of a colorless liquid (80–83
per cent of the theoretical amount)(Note 4)
.