Process for dehalogenation of polyhalogenated aromatic compounds

Claim 2

A PROCESS FOR THE PREPARATION OF CHLORINATED ANILINES HAVING AT LEAST A CHLORINE ATOM IN THE META POSITION TO THE AMINO GROUP, IN WHICH TRI- TO PENTACHLORANILINES ARE DECHLORINATED, SAID PROCESS CONSISTING ESSENTIALLY OF: REACTING IN A DECHLORINATION ZONE, SAID TRI- TO PENTACHLOROANILINES HAVING AT LEAST A CHLORINE ATOM IN THE META POSITION AND AT LEAST A CHLORINE ATOM IN ANOTHER POSITION, IN THE VAPOR PHASE WITH HYDROGEN, IN THE PRESENCE OF AN HYDROGENATION CATALYST SELECTED FROM THE GROUP CONSISTING OF THE CHLORIDES, OXIDES, NITRATES, SULFATES AND CHROMITES OF COPPER OR SILVER, TO PROVIDE BY DEHCLORINATION SAID CHLORINATED ANILINES HAVING AT LEAST A CHLORINE ATOM IN THE METAL POSITION; AND RECOVERING SAID CHLORINATED ANILINES HAVING AT LEAST A CHLORINE ATOM IN THE METAL POSITION.

Claim 3

A process in accordance with claim 1 wherein said catalyst is present in a fixed bed.

Claim 4

A process in accordance with claim 1 wherein said catalyst is present in a fluidized bed.

Claim 5

A process in accordance with claim 1 wherein said catalyst is deposited on an inert support selected from the group consisting of alumina, silica and activated carbon.

Claim 6

A process in accordance with claim 1 wherein said tri- to pentachloroaniline is prepared in situ by introducing into the dechlorination zone a tri- to pentachloro-nitrobenzene used for obtaining said tri- to pentachloro-aniline.

Claim 7

A process in accordance with claim 1 wherein said recovery operation consists essentially of contacting the gaseous effluent from the reaction with a liquid or vapor selected from the group consisting of an aliphatic alcohol, an hydrocarbon and water, at a temperature substantially lower than the temperature of said effluent.

Claim 8

A process in accordance with claim 6 wherein said liquid or vapor is water at a temperature on the order of 100*C.

Claim 9

A process in accordance with claim 1 wherein, said halogenated aniline obtained is 3,5-dichloro aniline.

Claim 10

A process for the preparation of chlorinated anilines having at least a chlorine atom in the meta position to the amino group, in which tri- to pentachloroanilines are dechlorinated, said process consisting essentially of: reacting, in a dechlorination zone, said tri- to pentachloroanilines having at least a chlorine atom in the meta position and at least a chlorine atom in another position, in the vapor phase with hydrogen, in the presence of an hydrogenation catalyst selected from the group consisting of the chlorides, oxides, nitrates, sulphates and chromites of copper and silver, to prepare by dechlorination said chlorinated anilines having at least a chlorine atom in the meta position; recovering said chlorinated anilines having at least a chlorine atom in the meta- position; and recycling to said dechlorination zone at least a portion of any non-transformed tri- to pentachloroanilines or undesired aniline from which the desired chlorinated aniline having at least a chlorine in the meta- position has been recovered.

Claim 11

A process for the preparation of chlorinated anilines having at least a chlorine atom in the meta position to the amino group, in which tri- to pentachloroanilines are dechlorinated, said process consisting essentially of: reacting, in a dechlorination zone, said tri- to pentachloroanilines having at least a chlorine atom in the meta position and at least a chlorine atom in another position, in the vapor phase with hydrogen, in the presence of an hydrogenation catalyst selected from the group consisting of the chlorides, oxides, nitrates, sulphates and chromites of copper and silver, to prepare by dechlorination said chlorinated anilines having at least a chlorine atom in the meta position; recovering said chlorinated anilines having at least a chlorine atom in the meta- position; and recycling to said dechlorination zone at least a portion of any non-transformed tri- to pentachloroanilines or undesired aniline from which the desired chlorinated aniline having at least a chlorine in the meta- position has been recovered.