Org. Synth. 1929, 9, 58
DOI: 10.15227/orgsyn.009.0058
MONOCHLOROMETHYL ETHER
[Ether, chloromethyl methyl]
Submitted by C. S. Marvel and P. K. Porter.
Checked by H. T. Clarke and E. R. Taylor.
1. Procedure
In a 2-l. round-bottomed flask fitted with a stopper carrying a reflux condenser and a glass tube reaching nearly to the bottom of the flask are placed 350 g. (438 cc., 10.9 moles) of methyl alcohol and 900 g. of technical formalin containing 252 g. (8.4 moles) of formaldehyde (Note 1).
A rapid stream of hydrogen chloride (Note 2) is run into the mixture, which is cooled with running water. In about two hours a layer of chloromethyl ether begins to appear. The stream of hydrogen chloride is continued for two or three hours longer until the solution is saturated. The layer of chloromethyl ether is then separated. The water layer is saturated with calcium chloride (Note 3), and more ether separates. This is added to the main portion, which is then dried over calcium chloride and fractionally distilled. The yield of product boiling at 55–60° is 580–600 g. (86–89 per cent of the theoretical amount based on the formaldehyde).
2. Notes
1.
The following table, showing the relation between the density of
formalin solutions and their
formaldehyde content, has been found useful. It is copied from Beilstein's "Handbuch der organischen Chemie," 4th Ed., Julius Springer, Berlin, 1918, Vol. I,
p. 561.
|
|
d148
|
g. CH2O in 100 cc.
|
g. CH2O in 100 g.
|
|
|
1.0054
|
2.24
|
2.23
|
|
1.0126
|
4.66
|
4.60
|
|
1.0311
|
11.08
|
10.74
|
|
1.0410
|
14.15
|
13.59
|
|
1.0568
|
19.89
|
18.82
|
|
1.0719
|
25.44
|
23.73
|
|
1.0853
|
30.17
|
27.80
|
|
1.1057
|
37.72
|
34.11
|
|
1.1158
|
41.87
|
37.53
|
|
The values in this table are affected by the presence of methyl alcohol in the formalin solution; since it has been pointed out that technical formalin contains 8–10 per cent of methyl alcohol, the table is not satisfactory for determining the formaldehyde content of technical formalin solutions. For example, a solution containing 37 per cent of formaldehyde and 10 per cent of methyl alcohol would have a density of 1.09 and correspond to 28 per cent of formaldehyde in pure water. In view of this the percentage yield in the preparation described above should probably be 64–66 instead of 86–89 (Norman D. Scott, private communication).
2.
The
hydrogen chloride was generated by the method described on
p. 293. About
390–420 g. of hydrogen chloride is required for saturation.
3.
Chloromethyl ether is soluble in the aqueous
hydrochloric acid used so that the salting-out with
calcium chloride is necessary to obtain the maximum yield.
3. Discussion
Monochloromethyl ether can be prepared by saturating an aqueous solution of
formaldehyde and
methyl alcohol with
hydrogen chloride
1 and by saturating a solution of
trioxymethylene in
methyl alcohol with
hydrogen chloride.
2 The procedure described is essentially that developed by Henry.
1
This preparation is referenced from:
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
trioxymethylene
calcium chloride (10043-52-4)
hydrogen chloride,
hydrochloric acid (7647-01-0)
methyl alcohol (67-56-1)
hydrogen (1333-74-0)
formaldehyde,
formalin (50-00-0)
MONOCHLOROMETHYL ETHER,
chloromethyl ether (542-88-1)
Ether, chloromethyl methyl (107-30-2)
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