A Publication
of Reliable Methods
for the Preparation
of Organic Compounds
Annual Volume
Org. Synth. 1967, 47, 51
DOI: 10.15227/orgsyn.047.0051
Submitted by H. Gross, A. Rieche, E. Höft, and E. Beyer1.
Checked by G. N. Taylor and K. B. Wiberg.
1. Procedure
In a 2-l. three-necked flask equipped with a stirrer, a reflux condenser, and a dropping funnel (Note 1) 832 g. (4.0 moles) of phosphorus pentachloride is stirred with 250 ml. of phosphorus oxychloride (Note 2). To this is added with stirring 264 g. (272 ml., 4.4 moles) of methyl formate (Note 3). During the addition the reaction vessel is cooled in an ice bath to maintain a reaction temperature of 10–20°. The addition requires about 1.75 hours. When the addition is complete, the solution is stirred at a temperature under 30° until all the phosphorus pentachloride has dissolved (about 1 hour). Then the stirrer is removed, the reflux condenser is replaced by a distilling head, and the reaction mixture is distilled under a pressure of 80–120 mm. with a bath temperature of 50–65° (Note 4). During the distillation the receiver is cooled to −10° to −20° by an ice-salt bath.
The material which is collected is redistilled through a 90-cm. vacuum-jacketed column packed with glass beads (5 mm.) using a 1:10 reflux ratio. The fraction, b.p. 80–100°, is redistilled through the same column to give 353–386 g. (77–84%) of dichloromethyl methyl ether, b.p. 82–85.5°, n20D 1.4303 (Note 5).
2. Notes
1. The reflux condenser and dropping funnel must be provided with calcium chloride tubes.
2. Phosphorus oxychloride serves only as a suspension medium for phosphorus pentachloride and makes possible a homogeneous reaction. The phosphorus oxychloride obtained during workup may be recycled in this preparation.
3. Commercial methyl formate was dried over sodium sulfate and used without special purification.
4. If it is not first distilled under reduced pressure, extensive decomposition will occur during fractional distillation.
5. The product must be protected from moisture when stored.
3. Discussion
Dichloromethyl methyl ether has been prepared by the chlorination of chlorodimethyl ether in the liquid2,3,4 or gas phase,5 by the reaction of chlorodimethyl ether with sulfuryl chloride and benzoyl peroxide,6,7 and by the treatment of methyl formate with phosphorus pentachloride.8,9,10
4. Merits of the Preparation
Dichloromethyl methyl ether may be employed preparatively in various ways. Thus it effects the replacement of carbonyl and hydroxyl oxygens by chlorine,11 and may be used in the preparation of α-acetochlorosugars12 and acid chlorides, particularly those derived from acetylated monocarboxylic acid sugars12,13 and acetylated amino acids.14 In addition, the ortho derivatives of formic acid may be prepared from dichloromethyl methyl ether.15 With aromatic compounds, dichloromethyl methyl ether reacts under Friedel-Crafts conditions followed by hydrolysis to give the corresponding aromatic aldehydes.10,16,17
This preparation is referenced from:

References and Notes
  1. Institute for Organic Chemistry of the German Academy of Sciences at Berlin, Berlin-Adlershof, Germany.
  2. P. L. Salzberg and J. H. Werntz, U.S. Patent 2,065,400 (1936) [C.A. 31, 1046 (1937)].
  3. L. R. Evans and R. A. Gray, J. Org. Chem., 23, 745 (1958).
  4. A. Rieche and H. Gross, Chem. Tech. (Berlin), 10, 515 (1958).
  5. H. Gross, Chem. Tech. (Berlin), 10, 659 (1958).
  6. H. Böhme and A. Dörries, Ber., 89, 723 (1956).
  7. H. Laato, Suomen Kemistilehti, 35B, 90 (1962).
  8. H. Laato, Suomen Kemistilehti, 32B, 67 (1959).
  9. H. Gross, A. Rieche, and E. Höft, Ber., 94, 544 (1961).
  10. A. Rieche, H. Gross, and E. Höft, Ber., 93, 88 (1960).
  11. A. Rieche and H. Gross, Ber., 92, 83 (1959).
  12. H. Gross and I. Farkas, Ber., 93, 95 (1960).
  13. R. Bognar, I. Farkas, I. F. Szabo, and G. D. Szabo, Ber., 96, 689 (1963).
  14. K. Poduska and H. Gross, Ber., 94, 527 (1961).
  15. H. Gross and A. Rieche, Ber., 94, 538 (1961).
  16. H. Gross, A. Rieche, and G. Matthey, Ber., 96, 308 (1963).
  17. A. Rieche, H. Gross, and E. Höft, this volume, p. 49.

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

phosphorus pentachloride (10026-13-8)

sodium sulfate (7757-82-6)

formic acid (64-18-6)

Phosphorus Oxychloride (21295-50-1)

sulfuryl chloride (7791-25-5)

methyl formate (107-31-3)

chlorodimethyl ether (107-30-2)

benzoyl peroxide (94-36-0)

Dichloromethyl methyl ether (4885-02-3)