Preparation method of azobenzene-4-benzoic acid_Kain Industrial Additive

Background and overview^[1]

Aromatic azo (AAzo) compounds are key raw materials and are widely used in the synthesis of organic dyes and food additives. The industrial production of diazonium salts of AAzo and the coupling of electron-rich aromatic compounds requires stoichiometric amounts of nitrite to form diazonium salts, producing a large amount of inorganic matter. Therefore, the highly selective AAzo formation process has sustainability and industrial applicability. Efforts have been made to use catalytic oxidation of azobenzene-4-benzoic acid for use as a pharmaceutical synthesis intermediate. If azobenzene-4-benzoic acid is inhaled, 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 attention if you feel uncomfortable; if the eyes are clear In case of contact, 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]

The preparation of azobenzene-4-benzoic acid is as follows: use nano-Pd as a catalyst to prepare the azo compound azobenzene-4-benzoic acid, add hexane-based nano-Pd catalyst to the Schlenk tube, and reduce the pressure Hexane evacuation. Add the nitroaromatic compound, KOH, tert-butylbenzene and solvent to the reaction tube and seal. The reaction tube was evacuated three times and flushed with hydrogen gas at a certain temperature under a hydrogen atmosphere. After the reaction, the hydrogen atmosphere was removed, and the reactant was heated at 120° C. in air for 2 hours. The resulting product mixture was analyzed by GC (VARIANCP-3800GC, HP-5 capillary column, FID detector) and GC-MS (VARIAN450-GC and VARIAN240-GC) equipped with CP8944 capillary column (30mx0.25mm), and the resulting product was Azobenzene-4-benzoic acid, yield 70%. 1HNMR (400MHz, CDCl3): δ=13.23 (brs, 1H), 8.17-8.14 (d, 4H), 8.0-7.88 (d, 4H), 7.61 (s, 1H). 13CNMR (100MHz, CDCl3): δ=123.49, 131.35, 134.06, 136.08, 154.82, 167.25, 171.01.

Main reference materials

[1]AHighlyActiveNano-PalladiumCatalystforthePreparationofAromaticAzosunderMildConditions