TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The content of n-alkanes (without methane and hydrogen) in the reaction product is 50-95 (preferably 66-90) wt%, the content of cycloalkanes is not more than 0.2 wt% and there is no increase in the content of aromatics (compared with the starting material).The process is carried out with a hydrogen pressure of 40-80 (preferably 50-70) bar, a temperature of 300-500degrees C and a WHSV of 0.5-3.0 (preferably 1.3-1.9) h-1, using a zeolite catalyst containing 0.0001-5 wt% active metal(s) as above, preferably a shape-selective zeolite in which the sizes of the pores and the reactant are of the same order of magnitude.The starting material may be prehydrogenated, preferably by performing hydrogenation and n-alkane production in the same reactor, using:(a) a catalyst bed with a layer of commercial hydrogenation catalyst followed by a layer of zeolite and with temperatures of 250 and 400degreesC at the reactor inlet and outlet respectively; or(b) the same zeolite-based catalyst with more than 0.01 wt% active hydrogenation metal (see above) and with the given properties; the heat of reaction from the hydrogenation step may be used for heating in the n-alkane production step.Preferred Products: Mainly n-alkanes selected from ethane, propane and n-butane.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Catalysts: Zeolites of structural type MFI (ZSM-5), preferably in the H-form and also carbonized to increase the yield of n-alkanes. EXAMPLE - A precious metal-free ZSM-5 zeolite catalyst (H-form) was used for the conversion of methylcyclohexane (MCH) at 400degrees C and 6 MPa, with a WHSV of 0.73 h-1. This zeolite showed a silicon/aluminum ratio of 19 and a 2-d 10-R pore system with a pore diameter of 0.56 x 0.53 or 0.55 x 0.51 nm. The process gave an MCH conversion of 100 (99.6)% after 0.5 hour, with yields of 4.3, 70.7, 22.0, 0.1 and 2.9 (1.1, 53.9, 39.6, 1.7, 3.2) % for methane, n-alkanes other than methane, iso-alkanes, cycloalkanes and aromatics respectively, a n-butane/iso-butane ratio of 0.70 (0.54) and a n-alkane (other than methane)/iso-alkane ratio of 3.21 (1.36); the ratio of ethane plus propane to total 4C hydrocarbons was 1.61 (0.61); conversion after 8 hours was 100 (99.7) %. Values in brackets are for ZSM-12 zeolite (H form) with a 1-d 12-R pore structure and a pore diameter of 0.59 x 0.55 nm. ZSM-22 zeolite (1-d 10-R; 0.55 x 0.44 nm) gave 23.3% conversion after 0.5 hour or 8 hours, with a low yield (15.9%) of n-alkanes; Y zeolite (3-d 12-R; 0.74 nm; super-cage: d = 1.3 nm) gave 100% after 0.5 hour and 74.7% after 8 hours, with 47.3% n-alkanes, 43.8% iso-alkanes and a low n-/iso- ratio (1.08).