Hydrodesulfurization of Diesel Oils by MoS2 Catalyst Prepared by in situ Decomposition of Ammonium Thiomolybdate

An unsupported MoS2 catalyst was prepared by in situ decomposition of ammonium thiomolybdate (ATM) in the presence of water. The catalyst was characterized by XRD, scanning electron microscopy (SEM) and specific surface area measurements (BET, BJH). Its catalytic activity was evaluated for the hydrodesulfurization (HDS) of diesel oils (straight run gas oil, SRGO and light cycle oil, LCO). Selected refractory sulfur compounds: benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) in oils were investigated. The high catalytic activity resulted from the large surface area of the catalyst due to water addition. Reactivity order of the sulfur compounds were determined. The results showed that the reactivity order in SRGO which contains nitrogen content is different from that in LCO. This reveals that matrix effect of the oil has some influences on the reactivity of the sulfur compounds.