Org. Synth. 1931, 11, 46
Submitted by Nicholas A. Milas
Checked by Roger Adams and K. L. Amstutz.
A 5-l. flat-bottomed flask, equipped with a long (80–90 cm.) widebore condenser, a separatory funnel, and a mechanical stirrer (Note 1), is supported 10 cm. above an electric hot plate. Two grams of vanadium pentoxide (Note 2), 450 g. (4.2 moles) of sodium chlorate, and 1 l. of water are placed in the flask; the stirrer is started, the mixture is heated to 70–75° (Note 3), and about 5–10 cc. of 200 g. (2.06 moles) of furfural (Note 4) is added. As soon as a vigorous reaction starts the balance of the furfural is added rapidly enough to maintain it (Note 5). The entire addition requires seventy to eighty minutes. Then the mixture is heated at 70–75°, with stirring, for ten to eleven hours and allowed to stand overnight at room temperature. The crude fumaric acid is filtered with suction and dried in the air. It weighs 155–170 g. (65–72 per cent of the theoretical amount) (Note 6).
More fumaric acid may be obtained from the filtrate by heating it on the water bath with 50 cc. of concentrated hydrochloric acid; the solution usually turns blue at the end of the reaction. The solution is concentrated to about 700 cc. and then cooled with running water. The fumaric acid which separates is collected on a filter and dried in the air. It weighs 10–15 g. and melts at 282–284° in a sealed tube.
The crude product is purified by recrystallization from about 1250 cc. of 1 N hydrochloric acid. This gives 100–110 g. of pure fumaric acid, melting at 282–284° in a sealed tube. An additional amount of the acid may be obtained by concentrating the filtrate to a small volume on a water bath. The total yield of pure fumaric acid is 120–138 g. (50–58 per cent of the theoretical amount).
The yields were lower when mechanical stirring was not used.
The catalyst is prepared by suspending 20 g. of c.p. ammonium metavanadate
in 200 cc. of water and adding slowly 30 cc. of concentrated hydrochloric acid
(sp. gr. 1.19). The reddish brown semicolloidal precipitate is washed several times with water by decantation and finally suspended in 300 cc. of water and allowed to stand at room temperature for three days. This treatment makes the precipitate granular and easy to filter. The precipitate is collected on a filter using a pump and washed several times with water to free it from hydrochloric acid
. It is then dried at 120° for twelve hours, finely powdered, and again dried for twelve hours at 120°.
To observe the temperature, a thermometer
may be suspended in the flask through the inner tube of the condenser. The mixture may be heated first to 70–75° over a free flame.
used was the technical grade furnished by the Miner Laboratories, Chicago. According to these laboratories the furfural was "about 99 per cent pure."
The crude furfural
obtained as described in Org. Syn. Coll. Vol. I, 1941, 280
may be used.
The reaction does not seem to start immediately upon the addition of the first few cubic centimeters of furfural
. When the vigorous reaction commences, the temperature rises to about 105° and remains there for some time. The yield of fumaric acid
seems to depend somewhat upon the rapidity of this stage of the reaction. It is therefore necessary to regulate the addition of furfural
so that a vigorous reaction is maintained.
The crude fumaric acid
is from 74 to 78
per cent pure as found by titration with standard alkali. The only impurity present besides inorganic salts is a little sodium hydrogen maleate
which is decomposed by the hydrochloric acid
during the purification process.
has been prepared from bromosuccinic acid
by heating with water,1
or dilute hydrobromic acid
and by heating the acid above its melting point.3
It has also been prepared by heating malic acid
by isomerization of maleic acid
and by the reduction of tartaric acid
with phosphorus and iodine
The procedure described is the most satisfactory for laboratory use, and is a slight modification of one described in the literature.7
This preparation is referenced from:
Chemical Abstracts Nomenclature (Collective Index Number);
hydrochloric acid (7647-01-0)
ammonium metavanadate (7803-55-6)
HYDROBROMIC ACID (10035-10-6)
maleic acid (110-16-7)
sodium chlorate (7775-09-9)
tartaric acid (87-69-4)
Fumaric acid (110-17-8)
sodium hydrogen maleate (3105-55-3)
bromosuccinic acid (923-06-8)
malic acid (617-48-1)
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