preparation method of 2,5-dimethyl-p-benzoquinone_kain industrial additive

background and overview^[1]

benzoquinone compounds are not only widely used in medical treatment, chemical industry, biological drugs, etc., but are also important organic intermediates. 2,5-dimethyl-p-benzoquinone can be used as a pharmaceutical synthesis intermediate. if you inhale 2,5-dimethyl-p-benzoquinone, please move the patient to fresh air; if there is skin contact, take off contaminated clothing, rinse the skin thoroughly with soap and water, and seek medical treatment if you feel uncomfortable; if eye contact occurs, separate eyelids, rinse with running water or saline, and seek medical attention immediately; if ingested, rinse mouth immediately, do not induce vomiting, and seek medical attention immediately.

preparation^[1-2]

the preparation of 2,5-dimethyl-p-benzoquinone is as follows:

method 1: add 80 grams of 2,5-dimethylphenol to 300 ml. place dimethylformamide in 500 ml. the resin kettle oxidizer is equipped with an air inlet, a stirrer, a thermometer and a reflux condenser. 2.5 g of saladine catalyst were added and the contents were heated to a temperature of 35°c. air was then introduced at a rate of 0.30 liters/minute. the mixer runs at 277rpm. when the oxidation device reaches a pressure of 150 psi, start venting to control the pressure. oxidation continues until 2,6-dimethylphenol is no longer present. by quenching the reaction solution with cold water, filtering and drying, the 2,5-dimethyl-p-benzoquinone product was isolated with good purity. a yield of 99% of dimethylquinone was obtained.

method 2: add 0.1 mmol 2,5-dimethylphenol, trifluorotoluene, solid catalyst onion carbon, and oxidant tert-butyl hydroperoxide into a closed glass container, mix, and then ultrasonicate to form a suspension (time: 5min). among them, 5 ml of trifluorotoluene, the molar ratio of onion carbon and 2,3,6-trimethylp-phenol is 6.66:1. the molar ratio of oxidant to 2,3,6-trimethyl-p-phenol is 3.6:1. the mixed suspension was placed in an oil bath and heated to 80°c with stirring. after 12 hours of reaction, take out the reaction vessel from the oil bath, cool to room temperature, pour out the liquid-solid mixture, and filter it to obtain the solid catalyst and the remaining liquid mixture, and isolate 2,5-dimethyl-p benzoquinone products.

main reference materials

[1] cn201510154630.9 a method for catalytically oxidizing phenol compounds to synthesize benzoquinone compounds

[2] us4360469 preparation of quinones by salcomine-catalyzed oxidation of phenols