| 摘要 |
<p>1422516 Phthalic anhydride RHONEPROGIL SA 11 April 1974 [11 April 1973] 16290/74 Heading C2C Phthalic anhydride is prepared by oxidizing o-xylene in tubes in a reactor, the tubes having an internal diameter of 19 to 25 mm. and containing particles of a catalyst comprising titanium oxide and vanadium oxide deposited on a carrier based on a refractory compound coated with glaze, which catalyst has an equivalent mean diameter of 4 to 8 mm. and is disposed over a length of 1À20 to 2À20 m. of the tubes and the tubes are of sufficient length that a free space is left at the end near the walls of the reactor, at a temperature of 360‹ to 400‹ C., with a weight ratio of air to o-xylene of 18 : 1 to 24 : 1 and an hourly flow rate of the gaseous mixture of 3000 to 6900 g. per litre of catalyst used, collecting the product by condensing it, heating the condensate in the presence of at least one sodium salt for 1 to 6 hours at 240‹ to 285‹ C. and recovering the phthalic anhydride, and subjecting the effluent gases to post-combustion.</p> |
