Hydrogenation of Ethylbenzene over a Nickel/Mordenite Catalyst. Catalytic Decay by Thiophene Poisoning: The hydrogenation of ethylbenzene (ETB) to ethylcyclohexane (ETCH) over a nickelmordenite catalyst is zero order in both reactants up to an ethylbenzene conversion of 78%. At 553 K, k=5.8 mol ETB/(dm³ of catalyst h). When a 100-ppm thiophene concentration entered the system, the ethylbenzene conversion began to drop.

ETB+H₂ETCH

Time (h)	0	1	2	4	6	8	12
X	0.92	0.82	0.75	0.5	0.3	0.21	0.1

The reaction was carried out at 3 MPa and a molar ratio of H₂/ETB=10. Figure out the catalyst decay quantitatively.