Organic Syntheses Procedure

03 Sep.,2022

 

diethyl oxalate supplier

Org. Synth. 1925, 5, 59

DOI: 10.15227/orgsyn.005.0059

ETHYL OXALATE

[

Oxalic acid, ethyl ester

]

Submitted by H. T. Clarke and Anne W. Davis.

Checked by Roger Adams and W. B. Burnett.

1. Procedure

In a

5-l. flask

are placed

1 kg. (7.9 moles) of crystallized (hydrated)

oxalic acid

,

1.66 kg. (2034 cc.) of 95 per cent

ethyl alcohol

, and

1.33 kg. (887 cc.) of

carbon tetrachloride

. The flask is then fitted with a

fractionating column, 1 meter long

, to which are attached a

condenser

and an

automatic separator

so arranged that the lighter liquid flows off to a

receiver

(Fig. 13)

(Note 1)

. The heavier liquid flows through a

tower of anhydrous potassium carbonate

, and then returns to the reaction flask. The bottom of the tower is connected with a small

separatory funnel

through which any

potassium 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solution, which flows from the solid in the tower, may be withdrawn from time to time.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 little

carbon tetrachloride

and moisture, is dried with

potassium 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 is

920–960 g.

of a colorless liquid (

80–83

per cent of the theoretical amount)

(Note 4)

.