(EP504510-A1)      Benzene is hydrogenated and decyclised, and 4-6C paraffins are isomerised in a feed contg. 4-6C paraffins and at least 2 wt. % of benzene, by: (a) mixing the feed with a gas stream rich in H2 to give a combined feed; (b) passing the combined feed at 100-250 deg. F to a hydrogenation zone and contacting it with a hydrogenation catalyst comprising a Pt gp. metal component and Sn on a solid support, or a Pt gp. metal component, Co and Mo on a solid support, to saturate benzene and heat the feed to 200-450 deg. C; (c) recovering a satd. feed with less than 0.1 wt. % of benzene, (d) passing (part of ) the satd. feed, without addn. of further heat, to an isomerisation zone and decyclisation conditions; and (e) recovering an isomerisate.    ADVANTAGE -   There is no need for an isomerisation zone heater. Hydrocracking and loss of isoparaffin yield are prevented. Additional cyclic hydrocarbons produced by saturation of benzene can be ring-opened in the isomerisation zone to increase available paraffinic feed, or the isomerisation zone can be operated to pass cyclic hydrocarbons to prod. recovery.    (EP504510-B1)      A process for the isomerisation of a C4-C6 paraffinic feedstock containing benzene by catalytic hydrogenation with a hydrogen-rich gas stream in a hydrogenation zone to produce a saturated stream which is catalytically isomerised in an isomerisation zone, characterised in that (a) the feedstock (10) comprises 10 to 25 wt.% of benzene and the feedstock (10) and hydrogen-rich stream (14) are indirectly heat exchanged (26) with an intermediate process stream (28) passing from a first reactor (30) to a second reactor (22) arranged in series in the isomerisation zone, thereby cooling the process stream (28) and heating the feedstock and hydrogen-rich stream (10) which are passed into the hydrogenation zone (32) and reacted therein at a temperature of 32 to 121 degrees C, a pressure of 2170 to 4930 kPa, and an LHSV of 1 to 8 h power -1, to produce said saturated stream (34), containing less than 0.1 wt.% of benzene and having a temperature of 93 to 232 degrees C, and (b) said saturated stream (34) is passed without intermediate heat exchange into the first reactor (30) of the isomerisation zone, the intermediate process stream (28) leaving the first reactor (30) is subjected to said heat-exchange (26) against the feedstock (10) and hydrogen-rich stream (14) in order to pre-heat the feedstock to the hydrogenation zone (32), and the resulting cooled intermediate stream is passed to the second reactor (22) of the isomerisation zone and thereby to produce an isomerate product stream (20) containing less than 0.1 wt.% of benzene, the reaction conditions in both reactors of the isomerisation zone comprising a temperature of 40 to 260 degrees C, a pressure 2600 to 6100 kPa, and with an LHSV of 0.5 to 12 h power -1, the temperature in the second reactor being lower than that in the first reactor.