CATALYST FOR OXIDIZING O-XYLENE INTO PHTHALIC ANHYDRIDE; TECHNIQUE Russian patent published in 1995 - IPC

FIELD: production of catalysts. SUBSTANCE: catalyst has 15-20 percent (of mass) of vanadium penthoxide, 2-15 percent of silicon dioxide, 0.1-10 percent of potassium phosphate, and titanium dioxide is the remainder. The surface of the catalyst is 10-30 sq. m per gr. Titanium dioxide has sulfate-ions, whose percentage of its mass constitutes 0.15-0.5. The catalyst is prepared by mixing solutions of vanadium oxalate with hydrogel or xerogel of titanium hydroxide (surface: 200-400 sq. m per gr) containing sulfate-ions within the range of 0.15-0.5 percent of the mass of titanium dioxide. The mix obtained in this way is undergone spray drying. Plasticization is carried out in the presence of binder combined of a 0.5-1.0 percent solution of polyethylene oxide and the mixture of solutions of vanadium oxalate and silica sol. The process is followed by forming, drying, crushing, classifying, pelletizing and heat treating at 450-500 C. After this, the product is saturated with the solution of potassium phosphate to be dried and heat treated again at 300- 500 C. EFFECT: higher efficiency and reliability. 2 cl, 2 tbl