Theoretical Analysis of Sulfur Exchange Experiments

Catalyst’s Sulfur Displacement by Thiophene, as Monitored by Exchange of 35S Radiotracer

“…The errors for Y-values in this run were ± 10%, as reported in for Mo, NiW, PdMo, PtMo [3] and for CoMo [15]. The samples after sulfidation were subjected to evacuation treatment in vacuo for 2 h to remove the reversibly adsorbed S species.…”

“…Preparation procedure, and characteristic data for Mo, CoMo, NiW and PdMo, PtMo have been reported earlier [3,[15][16][17]. The Mo content of the catalysts was $ 5 Â 10 20 atoms/g.…”

“…Ref. [3]). Sulfur uptake and exchange studies are carried out also with *S-labeled organic compounds, using mostly thiophene [6,7] and dibenzothiophene (see e.g.…”

“…To answer these questions sulfur exchange data, determined for the same catalysts [3,15] were compared with those of sulfur diplacement (i.e. of catalyst *S exchange with thiophene HDS produced S).…”

“…Literature data indicate a parallelism between catalyst hydrodesulfurization (HDS) activities and the amounts of exchangeable sulfur in sulfided catalysts [1][2][3][4][5]. Sulfur exchange between non-labeled sulfur ( 32 S, denoted through S) and the labeled one ( 35 S, denoted through *S) is monitored by the decrease of gas phase radioactivity of H 2 *S (i.e.…”