CATALYTIC ACTIVITY AND PRODUCT DISTRIBUTION IN THE CRACKING OF C-6-C-8 ALKENES ON THE AMMONIUM SALT OF 12-TUNGSTOPHOSPHORIC ACID

The cracking of C6-C-8 alkenes has been studied on the ammonium salt of 12-tungstophosphoric acid (NH4PW). The products range from C3 hydrocarbons to aromatics, the latter appearing in amounts up to 30% of the products. The primary products from the alkenes provide strong evidence that condensation processes are strongly favoured on these catalysts. The cracking ability of the catalyst decreases rapidly with time on stream but attains a steady state after approximately three hours. The activity of the catalyst is shown to be dependent on the source of the ammonium ion employed in the preparation of the salt with the activity of NH4PW for hexene cracking decreasing in the order NH4Cl > NH4NO3 > (NH4)2CO3 > (NH4)2SO4. The cracking activity of NH4PW for the C6-C-8 alkenes decreases in the order: octenes > heptenes > hexenes.