Process for the preparation of aromatic hydrocarbons and hydrogen from propane

A process for the preparation of aromatic hydrocarbons and hydrogen, which comprises contacting in a contact zone as feed propane or a hydrocarbon mixture which consists of more than 75%w C.sub.4 -paraffins and of at least 50%w propane and less than 20% methane and/or ethane at a temperature of from 400.degree.-700.degree. C., a space velocity of from 0.5 to 10 g.g.sup.-1.h.sup.-1 and a pressure of between 5 and 10 bar with a crystalline silicate containing 0.05 to 20% w zinc as the promoter as the catalyst, which silicate is characterized in having the following properties after 1 hour's calcining in air at 500.degree. C.:

• (a) thermally stable up to a temperature above 600.degree. 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 .theta. 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 ______________________________________
• (c) after conversion of the silicate into the H-form and after evacuation at 2.times.10.sup.-9 bar and 400.degree. C. for 16 hours and measured at a hydrocarbon pressure of 8.times.10.sup.-2 bar and 100.degree. C., the adsorption of n-hexane is at least 0.8 mmol/g, the adsorption of 2,2-dimethylbutanes at least 0.5 mmol/g and the ratio ##EQU4## at least 1.5, (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 y=0.0065 to 0.1;
• and recovering an aromatic hydrocarbon mixture and hydrogen-containing gas from said contact zone.