| 摘要 |
Aromatic hydrocarbons or substituted derivatives thereof are produced by continuously contacting benzoic acid or a substituted benzoic acid in vapour phase with a catalyst comprising one or more oxides of Cd, Cu, Zn, Cr and Fe at 320-450 DEG C. The substituted benzoic acid used may contain alkyl, halogen, amine, hydroxy, nitro or acyl groups. Examples are salicyclic acid and p-bromo, o-amino-, p-nitro-, and o-benzoyl-benzoic acids. Preferred catalysts are cadmium oxide, cadmium, zinc, zinc-cadmium and zinc-iron chromites, copper oxide-zinc oxide, and cadmium oxide-zinc oxide. The acid may be dissolved in an inert solvent such as the product of the reaction and the solution vaporized and fed at a rate of 1.55-20.8 mols. per hour per 1. of catalyst space. An inert carrier gas such as nitrogen, hydrogen or carbon dioxide, which may be recycled exit gas, is generally used. Pressure is suitably about atmospheric. In examples (1) benzoic acid in toluene is vaporized and passed in a stream of nitrogen over cadmium oxide, zinc-iron chromite or cadmium chromite at 400 DEG C.; (2) zinc-iron chromite is used to convert o-toluic acid to toluene, salicylic acid to phenol, o-amino- and p-nitro-benzoic acids to aniline, and p-brom-, o-chlor-, and o-benzoyl-benzoic acids to benzene. The Provisional Specification refers to naphthoic acids and cinnamic acid as suitable starting materials.ALSO:Zinc-iron chromite catalyst having an atomic ratio Zn : Fe : Cr of 80 : 20 : 100 is made by treating with ammonia an aqueous solution of zinc nitrate, ferric nitrate and chromium trioxide, drying the precipitate, calcining at 350 DEG C., granulating, and pelleting after adding graphite. Before use it is reduced in hydrogen at 400 DEG C. Cadmium chromite, atomic ratio Cd : Cr of 1 : 1, is made by treating the aqueous nitrates with aqueous sodium bicarbonate, calcining the precipitate at 400 DEG C., and pelleting with graphite. |
