Production of aromatic hydrocarbons

Claim 1

PROCESS FOR THE PRODUCTION OF BENZENE AND HIGHER AROMATIC HYDROCARBONS FROM NAPHTHENIC PETROLEUM WHICH COMPRISES SEPARATING FROM NAPHTHENIC PETROLEUM BY FRACTIONATION A C6 FRACTION CONTAINING C6 CYCLOALKANES AND A SEPARATE HIGHER BOILING FRACTION CONTAINING C7 CYCLOALKANES, CONTACTING THE LATTER FRACTION IN THE VAPOR PHASE AT A TEMPERATURE BETWEEN 450* AND 525* C. IN THE PRESENCE OF RECYCLED HYDROGEN UNDER A PRESSURE BETWEEN 20 AND 80 ATMOSPHERES WITH A PLATINUM CATALYST HAVING ISOMERIZATION ACITVITY, COOLING THE PRODUCT AND SEPARATING THE CONDENSED LIQUID FROM A GAS FRACTION CONTAINING HYDROGEN, RECYCLING A PART OF SAID GAS FRACTION TO SAID TREATMENT AND CONTACTING THE REMAINDER OF SAID GAS FRACTION WITH THE SAID C6 FRACTION IN THE VAPOR PHASE AT A TEMPERATURE BETWEEN 450* C. AND 525* C. WITH A PLATINUM ISOMERIZATION CATALYST AT A PRESSURE BELOW THE ABOVE-MENTIONED PRESSURE AND BETWEEN 10 AND 35 ATMOSPHERES, WHEREBY ALL OF THE HYDROGEN REQUIRED IN SAID OPERATION AT THE LOWER PRESSURE IS SUPPLIED FROM HYDROGEN PRODUCED IN SAID OPERATION AT THE HIGHER PRESSURE, COOLING THE PRODUCT FROM SAID LATTER TREATMENT AND SEPARATING SUBSTANTIALLY PURE BENZENE FROM THE CONDENSED LIQUID PRODUCT.