3069
YEGOROV et al., Orient. J. Chem., Vol. 32(6), 3063-3070 (2016)
Preparation of 3,3‘,4,4’-benzophenone
tetracarboxylic acid
Mass spectrum m / z (Irel,%):322 [M - H4O2]
(32,7), 278 [M - CH4O4]
A four-necked round bottom flask equipped
with mechanical stirrer, a reflux condenser, Preparation of 3,3‘,4,4’-benzophenone
thermometer and funnel for loading bulk solids tetracarboxylic dianhydride
was filled with 10.7 g (0.045 mol) of 3,3‘,4,4’-
A two-necked round bottom flask equipped
tetramethylbenzophenone, 64 ml of solvent and with magnetic stirrer, thermometer and Dean-Stark
320 ml of water. Then started stirring and heating, trap with reflux condenser was filled with 5.8 g (0.016
the reaction mixture was adjusted to 85°C. At this mol) of 3,3‘, 4,4’-benzophenonetetracarboxylic acid,
temperature, potassium permanganate (5 - 7 g) 15ml of solvent (forming an azeotrope with water,
was added through the funnel portionwise. Before separating from the water and not reacting with
adding a further portion of potassium permanganate, either an acid or anhydride) was added. Reaction
a sample (2 ml) should be taken from the reactor via mixture was heated while stirring to boiling, and
a Pasteur pipette, and visually observed the moment water was removed from the reaction mixture as
by color change of the mixture from violet to muddy an azeotrope mixture. The process was continued
brown, when all added potassium permanganate until the formation of clear, light brown solution in
reacted, and only then the following portion should the reaction flask and the separation of ~ 0.6 ml
be added.Oxidation is considered to be finished, if a of water. The solution in the reactor was cooled to
new portion of potassium permanganate introduced 50°C and 24 ml of 1,4-dioxane was added. It was
was not oxidized for 1 hour. During the experiment, cooled to room temperature. The precipitated
it was found that 60 g (0.38 mol) of potassium crystals were filtered, washed with 10 ml of boiling
permanganate was necessary to fully oxidize the 1,4-dioxane and dried in vacuo.
3,3‘,4,4’-tetramethyl benzophenone.
According to the results it has
To convert the excess of potassium been found that anhydridization of 3,3‘,4,4’-
permanganate to manganese oxide (IV) 20 ml of benzophenonetetracarboxylic acid requires high
ethanol was added to the reaction mixture and stirred temperatures and therefore high boiling solvent.The
at room temperature until disappearance of the reaction should be conducted in the diphenyl ether
purple color.Manganese oxide (IV) formed during the at a temperature of 230°C for 2 hours for the best
reaction was filtered off and washed with hot water results.
(6 × 50 ml). Basic filtrate and washing water were
combined and water and solvent were evaporated on
Elemental analysis.Calculated,%:C 63.37;
a rotary evaporator so that the 1/3 of the initial volume H 1.88. Found,%: C 63,26; H 1,85.
of the solution was remained. The resultant filtrate
was poured into a glass, cooled to 10°C and under
1H NMR spectrum (DMSO - d6) (d, ppm):
stirring concentrated hydrochloric acid was added 8.96 (2H, dd), 8.35 (2H, d), 8.19 (2H, d).
until acidic reaction on universal indicator.The acidic
solution was left overnight at room temperature.The
crystals precipitated was filtered and recrystallized
from 10% of hydrochloric acid solution. A pyridine
RESULTS AND DISCUSSIONS
As a result of studies it has been found an
solvent should be used for preparation of 3,3 ‘, 4,4’- optimum ratio of o-xylene and aluminum chloride
benzophenonetetracarboxylic acid.
in the preparation of 3,3',4,4'- tetramethyldiphenyl
dichloromethane by alkylation with carbon
Elemental analysis.Calculated,%:C 56.99; tetrachloride is 1:0.67 of o-xylene:aluminum chloride
H 2,81. Found,%: C 57,04; H 2,76.
at 0-5°C. The yield of 3,3 ‘, 4,4’-tetramethyldiphenyl
dichloromethane under these conditions attains the
1H NMR spectrum (DMSO - d6) (d, ppm): value 90%.
11.31 (s, 4H, COOH), 8.59 (d, 2H, HAr, J = 7.69 Hz),
8.29 (d, 2H, HAr, J = 7.53 Hz), 8.07 (c, 2H, HAr).
Optimal conditions for obtaining
3,3‘,4,4’-tetramethylbenzophenone with a yield of