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Org. Synth. 1956, 36, 1
DOI: 10.15227/orgsyn.036.0001
BISCHLOROMETHYL ETHER
[Ether, bis(chloromethyl)-]
Submitted by Saul R. Buc1
Checked by Charles C. Price, Frederick V. Brutcher, and Jerome Cohen.
1. Procedure
Caution! It has been reported that exposure to bischloromethyl ether in low concentrations has caused severe irritation of the eyes and respiratory tract, and perhaps pulmonary edema.
Proper safeguards should be taken to prevent exposure to this material both during and after its preparation. It is recommended that all operations involving this compound be carried out in a good hood.
In a 1-l. three-necked flask immersed in an ice bath and provided with a stirrer, thermometer, and dropping funnel are placed 168 ml. (200 g.) of concentrated (37–38%) hydrochloric acid (2 moles) and 240 g. of paraformaldehyde (effectively 8 moles of formaldehyde). While the temperature is maintained below 10°, 452 ml. (6.9 moles) of chlorosulfonic acid is added dropwise at such a rate that gaseous hydrogen chloride is not lost from the mixture. This requires about 5.5 hours. The mixture is stirred for 4 hours in the melting ice bath and comes to room temperature. It may be allowed to stand overnight. The layers are separated, and the product (upper layer) is washed twice with ice water. Ice is added to the product, and 250 ml. of 40% sodium hydroxide is then added to the mixture slowly with vigorous agitation until the aqueous phase is strongly alkaline (Note 1). The product is separated and dried rapidly over potassium carbonate and then over potassium hydroxide, keeping the product cold during drying (Note 2). After separation of the drying agent by filtration, 350–370 g. (76–81%) of product sufficiently pure for many purposes is obtained. On distillation there is obtained 330–350 g. (72–76%) of bischloromethyl ether, boiling at 100–104°. Approximately 95% boils at 101–101.5°, n25D 1.4420 (Note 3).
2. Notes
1. Local overheating must be carefully avoided during the alkaline washing, since it may result in vigorous decomposition.
2. The washing and drying are carried out as rapidly as possible to avoid hydrolysis of the product.
3. The submitter reports that operation of this procedure on a scale of 72 moles of paraformaldehyde gave a crude yield of 3601 g. (87%) and a distilled yield of 3519 g. (85%).
3. Discussion
Bischloromethyl ether has been prepared by saturation of formalin with dry hydrogen chloride,2,3,4 by the reaction of paraformaldehyde with phosphorus trichloride5,6 or phosphorus oxychloride,7,8 by solution of paraformaldehyde in concentrated sulfuric acid and treatment with ammonium chloride or dry hydrogen chloride,9 and by suspension of paraformaldehyde in seventy10 or eighty11 percent sulfuric acid and treatment with chlorosulfonic acid. It is formed together with the asymmetrical isomer when methyl ether is chlorinated12 and when paraformaldehyde is treated with chlorosulfonic acid.13 It also is obtained when chloromethyl methyl ether is chlorinated by means of chlorine14 or sulfuryl chloride.15 The present method has been published.16
This preparation is referenced from:

References and Notes
  1. Central Research Laboratory, General Aniline and Film Corporation, Easton, Pennsylvania.
  2. Tishchenko, Zhur. Russ. Fiz. Khim. Obshchestva, 19, 464 (1887); Ber., 20, 701 (1887).
  3. Litterscheid and Thimme, Ann., 334, 1 (1904).
  4. Stephen, Short, and Gladding, J. Chem. Soc., 117, 510 (1920).
  5. Descudé, Bull. soc. chim. Paris, [3] 35, 953 (1906).
  6. Beeby and Mann, J. Chem. Soc., 1949, 1799.
  7. Löbering and Fleischmann, Ber., 70B, 1680 (1937).
  8. Backès, Bull. soc. chim. France, [5] 9, 60 (1942).
  9. Schneider, Z. angew. Chem., 51, 274 (1938); Zahn, Dietrich, and Gerstner, Chem. Ber., 88, 1737 (1955).
  10. Norris, Ind. Eng. Chem., 11, 827 (1919).
  11. Vorozhtov and Yuruigina, Zhur. Obshchei Khim., 1, 49 (1931) [C. A., 25, 4521 (1931)].
  12. Salzberg and Werntz (to E. I. du Pont de Nemours and Co.), U. S. pat. 2,065,400 [C. A., 31, 1046 (1937)]; Evans (to Dow Chemical Co.), U. S. pat. 2,811,485 [C. A., 52, 2886 (1958)]; Badische Anilin- & Soda Fabrik Akt.-Ges., Ger. pat. 857,949 [C. A., 52, 5448 (1958)].
  13. Fuchs and Katscher, Ber., 60B, 2288 (1927).
  14. Evans and Gray, J. Org. Chem., 23, 745 (1958).
  15. Böhme and Dörries, Chem. Ber., 89, 723 (1956).
  16. Buc (to General Aniline and Film Corp.), U. S. pat. 2,704,299 [C. A., 50, 1891 (1956)].

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

potassium carbonate (584-08-7)

sulfuric acid (7664-93-9)

hydrogen chloride,
hydrochloric acid (7647-01-0)

ammonium chloride (12125-02-9)

sodium hydroxide (1310-73-2)

chlorosulfonic acid (7790-94-5)

formaldehyde,
formalin (50-00-0)

methyl ether (115-10-6)

Phosphorus Oxychloride (21295-50-1)

sulfuryl chloride (7791-25-5)

chlorine (7782-50-5)

potassium hydroxide (1310-58-3)

phosphorus trichloride (7719-12-2)

Ether, bis(chloromethyl)- (542-88-1)

chloromethyl methyl ether (107-30-2)

Bischloromethyl ether

paraformaldehyde (30525-89-4)