Process for the preparation of aromatic hydrocarbons and hydrogen from butane

Claim 1

A process for the preparation of aromatic hydrocarbons and hydrogen, which comprises contacting in a contact zone as feed a C 4 paraffin or a hydrocarbon mixture which consists of more than 75% w C 4- paraffins and more than 50% w C 4 paraffins with a catalyst consisting essentially of a zinc-promoted crystalline silicate at a temperature of from 350° to 700° C., a space velocity of from 0.1 to 20 g.g -1 .h -1 and at a pressure below 5 bar, which silicate is characterized as having the following properties after 1 hour's calcining in air at 500° C.: (a) thermally stable up to a temperature above 600° C., (b) an X-ray powder diffraction pattern showing, inter alia, the reflections given in Table A. TABLE A ______________________________________ Radiation: Cu-K Wavelength 0.15418 nm 2 θ relative intensity ______________________________________ 7.8-8.2 S 8.7-9.1 M 11.8-12.1 W 12.4-12.7 W 14.6-14.9 W 15.4-15.7 W 15.8-16.1 W 17.6-17.9 W 19.2-19.5 W 20.2-20.6 W 20.7-21.1 W 23.1-23.4 VS 23.8-24.1 VS 24.2-24.8 S 29.7-30.1 M ______________________________________ wherein the letters used have the following VS = very strong; S = strong; M = moderate; W = weak; θ = angle according to Bragg's law, (c) after conversion of the silcate into the H-form and after evacuation at 2×10 -9 bar and 400° C. for 16 hours and measured at a hydrocarbon pressure of 8×10 -2 bar and 100° C., the adsorption of n-hexane is at least 0.8 mmol/g, the adsorption of 2,2-dimethylbutane at least 0.5 mmol/g and the ratio ##EQU4## (d) the composition, expressed in moles of the oxides, is as follows: y(1.0±0.3)M.sub.n/2 O.y.Al.sub.2 O.sub.3.SiO.sub.2 wherein M=H and/or alkali metal and/or alkaline-earth metal, n is the valency of M and 0.0065<y≦0.0017; said catalyst containing 0.05 to 20% w zinc and withdrawing an aromatic hydrocarbon mixture and a hydrogen-containing gaseous mixture from said contact zone.