Org. Synth. 1943, 23, 57
[I. METHOD A]
Submitted by R. C. Fuson, E. C. Horning, S. P. Rowland, and M. L. Ward.
Checked by C. F. H. Allen and J. VanAllan.
In a 1-l. three-necked round-bottomed flask, fitted with an efficient stirrer, a reflux condenser, an inlet tube, and a thermometer (Note 1) and (Note 2), are placed 102 g. (118 ml., 0.85 mole) of mesitylene, 147 g. (1.25 moles) of zinc cyanide (Note 3), and 400 ml. of tetrachloroethane (Note 4). The inlet tube is connected to a source of hydrogen chloride (Note 5), and the mixture is stirred at room temperature while a rapid stream of dry hydrogen chloride is passed through it. This is continued until the zinc cyanide is decomposed; usually about 3 hours is required. The flask is then immersed in an ice bath, the inlet tube is removed, and 293 g. (2.2 moles) of finely ground anhydrous aluminum chloride is added to the mixture (Note 6) and (Note 7), with very vigorous stirring. The ice bath is then removed, and the passage of hydrogen chloride is resumed for the remainder of the reaction period. The heat of reaction is sufficient to warm the mixture slowly, and a temperature of about 70° is reached at the end of an hour. A temperature of 67–72° is maintained for an additional 2.5 hours. The cooled mixture is decomposed by pouring it cautiously, with stirring by hand, into a 4-l. container about half full of crushed ice, to which has been added 100 ml. of concentrated hydrochloric acid. After the mixture has stood overnight, it is transferred to a 3-l. round-bottomed flask and refluxed for 3 hours. The organic layer is then separated, and the aqueous layer is extracted once with 50 ml. of tetrachloroethane. The combined tetrachloroethane solutions are washed with 150 ml. of a 10% solution of sodium carbonate and distilled with steam. The first 800–900 ml. of distillate is set aside for recovery of the solvent (Note 8) and (Note 9), and the second portion is collected as long as oily drops are observed (Note 10). This distillate is extracted with 500 ml. of benzene, the solvent is removed on the steam bath, and the residue is distilled from a 250-ml. modified Claisen flask. After a small fore-run, the mesitaldehyde distils at 118–121°/16 mm. The yield is 95–102 g. (75–81%) (Note 11) and (Note 12).
Because of the toxic nature of tetrachloroethane
and hydrogen cyanide, all operations
as far as the final distillation should be carried out in a good hood
It is convenient to place the thermometer in the gas inlet tube
. The bulb should be immersed in the liquid, but the inlet tube need extend only just below the liquid surface.
The zinc cyanide
may be commercial material, or it may be prepared as directed by Adams and Levine.1
However, the zinc cyanide
does not react well if it is too carefully purified.2
is a toxic substance; it should be handled with due care.
Commercial cylinders of hydrogen chloride
, now available, are most convenient.
Although it is more convenient to add the zinc cyanide
and aluminum chloride
together, the procedure results in lower yields.
The apparatus shown in Fig. 19
is most convenient. A 250-ml. Erlenmeyer flask
is connected to the side neck of the flask by a 13-cm. length of 20-mm. thin-walled rubber tubing.3
If difficulty is experienced in separating the organic layer, the entire solution may be subjected to steam distillation.
The first portion of the distillate consists almost entirely of tetrachloroethane
and water. The solvent may be recovered by separating the organic layer, drying it with calcium chloride
, and distilling.
About 9 l. of water is obtained; the time required is about 4 hours.
If a smaller yield of mesitaldehyde
is acceptable and time is of importance, the preparation may be carried out without a solvent, and with other changes as follows: The zinc cyanide
and aluminum chloride
are mixed by shaking, the mesitylene
is added, and the flask is immersed in an oil bath
at 100°. The stirrer is started, and a fairly rapid current of dry hydrogen chloride
is passed into the mixture, below the surface of the liquid, for 4 hours; at the end of this time, the current of gas is discontinued, but stirring and heating are maintained for 2 hours longer. The reaction mixture is decomposed and processed as already described. The fraction which boils at 110–120°/9–10 mm.
is taken as mesitaldehyde
; the yield is 73%
(private communication, D. B. Glass).
may be prepared in yields of 69
, respectively, by the procedure described above, with a reaction time of 8 hours and the following modifications:
100 g. (0.62 mole)
100 g. (0.49 mole)
115 g. (0.97 mole)
102 g. (0.74 mole)
215 g. (1.60 moles)
134 g. (1.0 mole)
[II. METHOD B]
Submitted by R. P. Barnes
Checked by Nathan L. Drake, Harry D. Anspon, and Ralph Mozingo.
A 1-l. three-necked flask with ground-glass joints
is fitted with a mercury-sealed stirrer (Note 1)
and (Note 2)
, a glass tube of 6-mm. internal diameter
which runs to the bottom of the flask, and a Friedrich condenser
, protected by a drying tube. A solution of 90 g. (0.49 mole) of mesitoyl chloride (p. 555)
in 270 g. of carefully dried xylene
is placed in the flask together with 20 g. of palladium-barium sulfate (Note 3)
. The contents of the flask are refluxed while a stream of hydrogen (Note 4)
, which has been freed from oxygen
by passage through Fieser's solution,4
and dried by passage through concentrated sulfuric acid
followed by a drying tube of Drierite (Note 5)
, is bubbled through the suspension until hydrogen chloride
ceases to be evolved (Note 2)
. The catalyst is then removed by filtration and the xylene
distilled. The residual liquid is transferred to a 125-ml. modified Claisen flask
and distilled. The product boils at 96–98°/6 mm.
, and weighs 53–60 g.
) (Note 6)
The stirrer is not essential, but without it the time required for the reduction is increased about threefold.
The course of the reaction may be followed conveniently by passing the exit gases into water and titrating with approximately 1 N sodium hydroxide
. The time for complete reduction is about 6–7 hours with stirring, and about 18 hours with no stirrer.
The palladium-barium sulfate
is prepared by the method described by Houben.5
The barium sulfate
should be freshly precipitated material.
The checkers found that electrolytic hydrogen
directly from the cylinder without purification gives only a slightly decreased yield.
Dehydrite or Anhydrone
should not be used because of the danger of sulfuric acid
spraying into it. Drierite
is much more efficient than calcium chloride
This preparation illustrates Rosenmund's method of synthesizing aldehydes without use of a poisoned catalyst. See p. 629
for the more general form of the method.
has been prepared from mesitylglyoxylic acid
from mesitylmagnesium bromide
,8 ethyl orthoformate
, hydrogen cyanide
, and hydrogen chloride10
, carbon monoxide
, and hydrogen chloride11
in the presence of aluminum and cuprous chlorides
; and from mesitylene
, zinc cyanide
, and hydrogen chloride
in the presence of aluminum chloride
The procedures described here are based on the method applied to the preparation of other aldehydes by Rosenmund and Zetzsche;15
and by Nencki, as adapted for mesitaldehyde
This preparation is referenced from:
Chemical Abstracts Nomenclature (Collective Index Number);
aluminum and cuprous chlorides
calcium chloride (10043-52-4)
sulfuric acid (7664-93-9)
hydrochloric acid (7647-01-0)
sodium hydroxide (1310-73-2)
carbon monoxide (630-08-0)
hydrogen cyanide (74-90-8)
sodium carbonate (497-19-8)
barium sulfate (7727-43-7)
aluminum chloride (3495-54-3)
Benzaldehyde, 2,4,6-trimethyl- (487-68-3)
zinc cyanide (557-21-1)
Mesitoyl chloride (938-18-1)
mesitylglyoxylic acid (3112-46-7)
mesitylmagnesium bromide (2633-66-1)
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