A Publication
of Reliable Methods
for the Preparation
of Organic Compounds
Annual Volume
Org. Synth. 1932, 12, 38
DOI: 10.15227/orgsyn.012.0038
[Carbamic acid, methyl-, ethyl ester]
Submitted by W. W. Hartman and M. R. Brethen.
Checked by J. B. Conant and C. F. Bailey.
1. Procedure
In a 2-l. flask, provided with a mechanical stirrer and cooled by an ice-salt mixture, are placed 300 cc. of ether and 186 g. (2 moles) of a 33 per cent aqueous methylamine solution. When the stirred mixture has cooled to 5°, 217 g. (2 moles) of ethyl chloroformate (Note 1) is added without allowing the temperature to rise above 5°. When almost half of the chloroformate has been added a cold solution of 80 g. (2 moles) of pure sodium hydroxide in 120 cc. of water is added gradually along with the rest of the chloroformate at such a rate that the last portions of the two solutions are added simultaneously. Constant mechanical stirring throughout the addition is essential (Note 2). After standing for fifteen minutes, the ether layer is separated and the aqueous solution is extracted with 100 cc. of ether. The combined ether layers are rapidly dried by shaking for a short time with about 8 g. of potassium carbonate in two portions. The ether is then distilled and the residue distilled under reduced pressure, the distillate being collected at 55–60°/12 mm. The yield of colorless oil is 182–185 g. (88–90 per cent of the theoretical amount).
2. Notes
1. Technical ethyl chloroformate (chlorocarbonate) is manufactured by the U. S. Industrial Chemicals Company.
2. The rate of addition is determined by the efficiency with which the heat is removed from the reaction mixture. Five hours was required, using an ice-salt mixture outside.
3. Discussion
Ethyl N-methylcarbamate has been prepared by adding aqueous methylamine to ethyl chloroformate;1 and from methylcarbamyl chloride and ethyl alcohol.2
This preparation is referenced from:

References and Notes
  1. Schreiner, J. prakt. Chem. (2) 21, 124 (1880); Pechmann, Ber. 28, 855 (1895); Eistert, Angew. Chem. 54, 124 (1941).
  2. Gattermann, Ann. 244, 35 (1888).

Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)

ethyl alcohol (64-17-5)

potassium carbonate (584-08-7)

ether (60-29-7)

sodium hydroxide (1310-73-2)

methylamine (74-89-5)

ethyl chloroformate (541-41-3)

Ethyl N-methylcarbamate,
Carbamic acid, methyl-, ethyl ester (105-40-8)

methylcarbamyl chloride