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until a vigorous reaction commences. The source of heat is removed, and
the reaction allowed to proceed for about twenty minutes. The mixture is
refluxed for one hour longer and then cooled in ice. The light yellow
solid is filtered with suction, washed well with water, and dried at no°.
The yield is 92-96 g. (88-91 per cent of the theoretical amount) of a
product melting at 273-275° (uncorr.).
4. The oxidizing agent employed is not very powerful, and,
although it attacks easily the particularly reactive anthracene, it is
not suitable for the conversion of hydrocarbons of the naphthalene and
phenanthrene series into the corresponding quinones or for the oxidation
of acenaphthene or fluorine (observation of the checkers).
3. Methods of Preparation
The oxidation of hydroquinone by means of sodium dichro-mate in
sulfuric acid solution, and references to other methods of preparation,
are given in earlier volumes of this series.2
1 Milas, J. Am. Chem. Soc. 49, 2005 (1927).
2 Vliet, Org. Syn. 2, 85; Coll. Vol. I, 471.
CH2CO2NH4 heat CH2CO4 ! -> I >NH + NH3 + 2H2O
CH2CO2NH4 CH2C 0/
Submitted by H. T. Clarke and Letha Davies Aaia. Checked
by Wallace H. Carothers and W. L. McEwen.
In a i-J. distilling flask fitted with a side arm 40 cm. in length
and not less than 10 mm. in internal diameter (Note 1) is placed 236 g.
(2 moles) of succinic acid. To this is added slowly, with cooling and
shaking, 270 cc. (243 g., 4 moles) of 28 per cent aqueous ammonia (sp.
gr. 0.90). Most of the acid dissolves, formihg a clear solution. The
flask is set for downward distillation, and a water-cooled 500-cc.
distilling flask is attached to the side arm. Provision may be made for
removal of ammonia from the side tube of the receiver. The mixture is
heated gently over a free flame; solution takes place rapidly, and a
small amount of uncombined ammonia passes over with the first portions of
the distillate. The temperature of the vapor rises to ioo° and remains at
this point until about 200 cc. of water has distilled. The flame is then
increased, and the ammonium succinate begins to decompose, with evolution
of ammonia; the temperature of the vapor falls to 970 during the
distillation of the next 30 cc. When the vapor temperature has risen to
102°, the receiver is changed and an intermediate fraction collected from
this point to 2 750. The succinimide then distils and is collected over
the range 275-289°, largely at 285-289°. Decomposition takes place to a
small extent with formation of a black tar; the distillation is stopped
when the tarry residue begins to decompose with evolution of yellow
The crude sucdnimide, which solidifies completely, amounts to about
168 g. The intermediate fraction is redistilled from a smaller flask,
when a further quantity of about 10 g. is collected over the range 275-
289°. The crude sucdnimide is recrystallized from 95 per cent ethyl
alcohol, employing 1 cc. of solvent for every gram of product. If the
mixture is chilled to o° for some hours before filtration and about 25
cc. of cold alcohol employed for washing the crystals, the first crop
amounts to 163-164 g. (82-83 Per cent of the theoretical amount). On
concentrating the mother liquor to one-third of its volume, a second crop
amounting to 4-5 g. can be secured (Note 2). The product melts at 123-
125° and contains no water of crystallization.
1. It is essential to employ a side arm of at least this diameter
in order to avoid clogging by crystals of sucdnimide when this first
2. A further small quantity of a less pure product can be
obtained by evaporating the dark mother liquor to dryness and
recrystallizing the residue from fresh 95 per cent alcohol.
3. Methods of Preparation
Sucdnimide has usually been prepared by heating succinic add in a
current of ammonia1'2 or by distilling ammonium suc-dnate.1'3
1 Fehling, Arm. 49, 198 (1844).
1 Franchimont and Friedman, Rec. trav. chim. 25, 79 (1906).
3 Bunge, Ann. Suppl. 7, 118 (1870); Menschutkin, Ann. 162, 166 (1872).
TETRAHYDROFURAN (Tetramethylene Oxide; 1,4-Epoxybutane)
CH CH + 2H2 (3-7 atm.)
-> CH2 CH2
Submitted by Donald Stare and R. M. Hixon.
Checked by John R. Johnson and H. B. Stevenson.
(A) Preparation of Palladous Oxide.-In a 350-cc. casserole,
2.2 g. (0.02 gram atom) of palladium metal is dissolved in a small
amount of aqua regia, and the solution (Note 1) is treated with 55 g. of