| 70% |
With potassium permanganate; water In pyridine at 85℃; |
A four-necked round bottom ask equipped with mechanical stirrer, a reflux condenser, thermometer and funnel for loading bulk solids was filled with 10.7 g (0.045 mol) of 3,3‘,4,4’-tetramethylbenzophenone, 64 ml of solvent and320 ml of water. Then started stirring and heating, the reaction mixture was adjusted to 85°C. At this temperature, potassium permanganate (5 - 7 g) was added through the funnel portion wise. Before adding a further portion of potassium permanganate, a sample (2 ml) should be taken from the reactor viaa Pasteur pipette, and visually observed the moment by color change of the mixture from violet to muddy brown, when all added potassium permanganate reacted, and only then the following portion should be added. Oxidation is considered to be fnished, if a new portion of potassium permanganate introduced was not oxidized for 1 hour. During the experiment, it was found that 60 g (0.38 mol) of potassiumpermanganate was necessary to fully oxidize the 3,3‘,4,4’-tetramethyl benzophenone. To convert the excess of potassiumpermanganate to manganese oxide (IV) 20 ml of ethanol was added to the reaction mixture and stirred at room temperature until disappearance of the purple color. Manganese oxide (IV) formed during the reaction was fltered off and washed with hot water(6 × 50 ml). Basic fltrate and washing water were combined and water and solvent were evaporated on a rotary evaporator so that the 1/3 of the initial volumeof the solution was remained. The resultant fltrate was poured into a glass, cooled to 10°C and understirring concentrated hydrochloric acid was added until acidic reaction on universal indicator. The acidic solution was left overnight at room temperature. The crystals precipitated was fltered and recrystallized from 10percent of hydrochloric acid solution. A pyridine solvent should be used for preparation of 3,3 ‘, 4,4’-benzophenonetetracarboxylic acid. Elemental analysis. Calculated,percent: C 56.99;H 2,81. Found,percent: C 57,04; H 2,76. 1H NMR spectrum (DMSO - d6) (d, ppm):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). Mass spectrum m / z (Irel,percent): 322 [M - H4O2](32,7), 278 [M - CH4O4] |
| 80 %Chromat. |
With oxygen In acetic acid at 80 - 130℃; for 6 h; |
Example 5; 3,3',4,4'-Tetramethylbenzophenone; Into an air-flow reactor, 71.5 g (0.30 mol) of 3,3',4,4'-tetramethylbenzophenone, 320 g of acetic acid, 0.19 g (0.7 mmol) of cobalt acetate (bivalent), 0.55 g (2.2 mmol) of manganese acetate (bivalent), and 1.06 g (3.0 mmol) of zirconium sulfate were charged. The reactor pressure was raised to 0.8 MPa by nitrogen, and the mixture was heated to 80° C.A catalyst mixture having 13.8 g (120 mmol) of N-hydroxysuccinimide added in 300 g of acetic acid and a mixed gas of air and nitrogen were fed to the reactor, and at this time the reaction was initiated. The catalyst mixture was fed to the reactor over 5 hours by a slurry pump, and the gas was fed to the reactor to adjust the oxygen concentration contained in off-gas to 2 to 8percent. After the reaction was initiated, the reaction temperature was raised to 120° C. over 0.5 hours and then continued being maintained for 0.5 hours. At this point in time, a sample for HPLC analysis was taken. Thereafter, the reaction was continued for 4 hours at 130° C. During the reaction, the feed rate of the gas and that of the catalyst were adjusted, if necessary, to control the reaction.After the catalyst addition was completed (5 hours after the reaction was initiated), the reaction mixture was aged at 130° C. for one hour with maintaining the oxygen concentration contained in off-gas at 8percent. Thereafter, the supply of the gas was stopped, and the reactor was cooled and the pressure was released.The results of the HPLC analysis at one hour after the reaction was initiated revealed that 3 -methylbenzophenone-3,4,4'-tricarboxylic acid (yield 10percent (9.8 g)), 3,3'-dimethylbenzophenone -4,4'-dicarboxylic acid (yield 45percent (40.2 g)), and 3,3',4'-trimethylbenzophenone-4-carboxylic acid (yield 30percent (24.1 g)) were produced. The oxidation degree at this point in time was as follows: 17.5percent+22.5percent+7.5percent=37.5percent. Moreover, the HPLC analysis of the reaction mixture after the pressure was released revealed that benzophenone-3,3',4,4'-tetracarboxylic acid (yield 80percent (86 g)) and 3'-methylbenzophenone-3,4,4'-tricarboxylic acid (yield 3percent (3.0 g)) were produced. |
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