Hydrocarbon upgrading process

A process of upgrading a sulfur containing hydrocarbon comprising a catalytically cracked naphtha feed fraction comprising olefins and boiling in the gasoline boiling range, the feed fraction being selected from a naphtha having a boiling range in the range of C.sub.6 to 330.degree. F., a naphtha having a boiling range in the range of C.sub.5 to 420.degree. F., a naphtha having a boiling range in the range of 260.degree. to 412.degree. F. or a naphtha boiling in the range of 330.degree. to 500.degree. F., which comprises:

• contacting such sulfur containing naphtha feed fraction with a hydrodesulfurization catalyst in a first reaction zone, operating under a combination of elevated temperature, elevated pressure and an atmosphere comprising hydrogen, such as to produce a first intermediate reaction zone product comprising a normally liquid fraction which has a reduced sulfur content and a reduced octane number as compared to the feed;
• cascading the first intermediate reaction zone product to a second reaction zone and contacting the first intermediate product in the second reaction zone in the presence of hydrogen with a different catalyst, comprising a zeolitic behaving refractory solid having an acid activity equivalent to at least about 20 alpha, and a topology such that, in the aluminosilicate form, it would have a constraint index of 2 to 12;
• under a combination of conditions comprising elevated temperature of from 700.degree. to 800.degree. F., sufficient to convert said first intermediate product fraction boiling in the gasoline boiling range to a product comprising a fraction boiling in the gasoline boiling range having a higher octane number than said first intermediate gasoline boiling range fraction;
• and
• recovering at least said upgraded gasoline boiling range product fraction.