Production of anthraquinone

Claim 1

A process for the production of anthraquinone which comprises oxidizing with oxygen in the gas phase, in the presence of a catalyst, an indan having the formula: ##STR3## where R 1 , R 2 and R 3 may be identical or different and each denotes an alkyl radical, R 1 and/or R 3 may also each denote hydrogen wherein the reaction is carried out with an indan having the formula (I) in the presence of a catalyst consisting essentially of a vanadium (V) compound and a compound of an element selected from the group consisting of potassium, boron, thallium, antimony and/or caesium, or a diphenylmethane derivative having the formula: ##STR4## where the individual radicals R 4 , R 5 and R 6 may be identical or different and each denotes hydrogen or an alkyl radical having one to eight carbon atoms, or a benzophenone derivative having the formula ##STR5## where R 4 and R 5 have the meanings given above, or an indene having the formula ##STR6## or an naphthalene derivative having the formula ##STR7## wherein R 4 , R 5 , R 6 and R 7 have the meanings given above, R 9 and R 10 may be identical or different and each denotes hydrogen, or one of the two denotes hydrogen and the other an alkyl radical having one to six carbon atoms, or R 9 and R 10 each denotes an alkyl radical and the two radicals having together two to six carbon atoms, as starting material in the presence of a catalyst consisting essentially of a vanadium (V) compound with or without additionally a compound of an element selected from the group consisting of potassium, boron, thallium, antimony and/or caesium, wherein in the process in which an indan (I) is used as the starting material the atomic ratio of vanadium in the catalyst to the additional element or elements is from 1000 to 5 of vanadium to 1 of additional element of potassium, boron, thallium, and antimony, and 2000 to 5 of vanadium to 1 of additional element caesium and wherein the atomic ratio is from 500 to 4 of vanadium to 1 of antimony, from 200 to 15 of vanadium to 1 of potassium, from 500 to 20 of vanadium to 1 of thallium and 20 to 5 of vanadium to 1 of boron and from 1000 to 12 of vanadium to 1 of caesium, wherein said additional element or elements are added to the catalysts in an amount sufficient to obtain at least about 50.9% of theory of an anthraquinone based upon the starting material recited.