Abstract: A process for the separation of rhodium from a solution containing a rhodium carbonyl complex such as is obtained in the carbonylation of an alkanol or of an olefinically or acetylenically unsaturated compound with carbon monoxide and water and conversion of the separated rhodium into a soluble rhodium carbonyl complex, in which the solution containing the rhodium carbonyl complex is treated with hydrogen in the presence of a carrier substance at a temperature of from 25.degree. to 300.degree. C and at a pressure of from 1 to 700 atmospheres, the solution freed from rhodium is separated and the rhodium precipitated on the carrier is converted into a soluble rhodium carbonyl complex by treatment with carbon monoxide in the presence of a solvent and a compound which can replace the carbon monoxide as a ligand at a temperature of from 20.degree. to 300.degree. C and at a pressure of from 1 to 700 atmospheres.

Abstract: A supported catalyst for the oxidation of aromatic or unsaturated aliphatic hydrocarbons, comprising an inert nonporous carrier to which is applied a thin layer of a catalytic composition which contains from 1 to 39.9 percent by weight of vanadium pentoxide, from 60 to 98.9 percent by weight of titanium dioxide and from 0.1 to 10% by weight of rubidium and antimony in an atomic ratio Rb : Sb of from 1:2.5 to 1:30, the vanadium pentoxide content being from 0.05 to 4 percent by weight, based on the supported catalyst.

Abstract: A process for the manufacture of phthalic anhydride by oxidizing o-xylene and/or naphthalene over a supported catalyst containing vanadium pentoxide and titanium dioxide, at from 350.degree. to 500.degree. C, in which the o-xylene or naphthalene is passed, with an oxygen-containing carrier gas, over the catalyst, and in which the catalyst in the first 25-50 per cent by volume of the total catalyst volume, in the direction of flow of the mixture of o-xylene or naphthalene and carrier gas, contains from 0.01 to 0.3 per cent by weight, based on titanium dioxide, of rubidium, but no phosphorus, in the active composition, while the remainder of the catalyst contains from 0.02 to 0.8 per cent by weight, based on titanium dioxide, of phosphorus, but no rubidium, in the active composition.

Abstract: A supported catalyst containing vanadium and titanium, comprising a ring-shaped carrier having an external diameter of from 7.3 to 8.6 mm, a length of from 5.3 to 7 mm and a wall thickness of from 0.1 to 2 mm, and an active composition, applied thereto, of from 1 to 30 per cent by weight of vanadium pentoxide and from 70 to 99 per cent by weight of titanium dioxide and/or zirconium dioxide.

Abstract: Supported catalyst for the oxidation of o-xylene or naphthalene to phthalic anhydride, comprising an inert carrier and the active material applied thereto, which contains from 1 to 40 per cent by weight of vanadium pentoxide, from 60 to 98.84 per cent by weight of titanium dioxide and from 0.16 to 0.6 per cent by weight, based on titanium dioxide, of rubidium in the form of rubidium oxide, the vanadium pentoxide content being from 0.05 to 4 per cent by weight, based on the (complete) catalyst.

Abstract: Anthraquinone is manufactured by oxidation of diphenylmethane compounds in the gas phase, in the presence of vanadium(V) oxide and titanium dioxide in a specific weight ratio. The anthraquinone which may be manufactured by the process of the invention is a valuable starting material for the manufacture of dyes and pesticides.