Abstract: The present invention relates to a process for preparing an indene, which involves reacting an indanone with hydrogen in the presence of a catalyst comprising one or more oxides, preferably metal oxides. Preferred oxides comprise elements from groups Ia, IIa, IIa, IVa, Va, VIa, Ib, IIb, IIIb, IVb, Vb, VIb, VIIb and VIII of the Periodic Table, or elements from the lanthanide group.

Abstract: The invention relates to a process for the preparation of substituted 3-arylquinazoline-2,4-diones of the formula (I) ##STR1## in which R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are as defined in claim 1 and Ar is ##STR2## where R.sup.5 to R.sup.9 are as defined in claim 1, by reacting a compound of the formula (II) ##STR3## with a compound Z in the presence of a catalyst, a ligand and a solvent, where Z isa) an anthranilic acid derivative of the formula (III) ##STR4## or b) an alcohol R.sup.10 --OH and where, in case b), the resulting carbamate is then reacted with an anthranilic acid derivative of the formula III.

Abstract: The invention relates to a process for the preparation of halobenzaldehydes of the formula (I): ##STR1## in which Hal is fluorine, chlorine, bromine or iodine and z=1, 2, 3 or 4, by catalytic gas-phase oxidation of a substituted toluene of the formula (II), ##STR2## by oxygen, which comprises carrying out the oxidation in the presence of a catalyst of the formula (III)Me.sup.1.sub.a Me.sup.2.sub.b Me.sup.3.sub.c O.sub.x (III),in which Me.sup.1 is bismuth or vanadium, Me.sup.2 is at least one of the elements selected from the group consisting of lithium, sodium, potassium, rubidium and cesium, Me.sup.3 is at least one element selected from the group consisting of iron, cobalt, nickel, niobium, molybdenum, arsenic, tin, antimony, tungsten, tantalum, phosphorus, chromium, manganese, palladium, copper, zinc, cerium, silver, boron, samarium, barium, calcium, magnesium and rhenium, and the letters a, b and c represent an atomic ratio of the respective elements such that when a=1, b has a value in the range from 0.

Abstract: Process for the preparation of aldehydes by catalytic gas phase hydrogenation of carboxylic acid or their derivatives with the aid of a tin catalystThe invention relates to a process for the preparation of aldehydes by catalytic gas phase hydrogenation of carboxylic acids or carboxylic acid derivatives at elevated temperature, which comprises employing at tin catalyst supplied to an oxidic support material.