Hydrodesulfurization of Dibenzothiophene Catalyzed by Supported Metal Carbonyl Complexes. (Part 6). Effects of Supports on Activities of HDS Catalysts Prepared from Supported Ruthenium Carbonyl-Cesium Hydroxide Systems.

Abstract

In hydrodesulfurization of dibenzothiophene (DBT) catalyzed by supported ruthenium carbonylcesium hydroxide systems after presulfidation, the effects of various supports such as Al2O3, SiO2-Al2O3, SiO2, TiO2, NaY zeolite on the catalytic activity and product selectivity were investigated. In the absence of cesium, the conversion of DBT decreased in the order SiO2-Al2O3>Al2O3>TiO2>SiO2>NaY zeolite. When cesium hydroxide was added to the catalysts derived from supported Ru3(CO)12, the conversion of DBT increased remarkably with the use of Al2O3, SiO2-Al2O3, and SiO2 and reached the maximum values at Cs/Ru=2, 3 and 2, respectively. The conversion, however, decreased in the order Al2O3>SiO2>SiO2-Al2O3. Further addition of cesium decreased the activity. In contrast to this, when NaY zeolite was used, the conversion of DBT did not increase with the addition of cesium. For obtaining a high catalytic activity, it was essential to load the ruthenium hydride complex Cs[HRu3(CO)11], obtained after reacting Ru3(CO)12 with cesium hydroxide, onto the support.In the supported Ru3(CO)12-cesium hydroxide systems, biphenyl was produced selectively. XP spectra showed that the addition of an appropriate amount of cesium stabilized the ruthenium sulfide on the support even under hydrogen pressure.

Hydrodesulfurization of Dibenzothiophene Catalyzed by Supported Metal Carbonyl Complexes(Part 8) Hydrodesulfurization of 35S-Labeled Dibenzothiophene on Alumina-supported Ruthenium Sulfide-Cesium Catalysts.

“…The values of krelease and S0 for these catalysts were estimated by similar methods described above, using these data, and are shown in Table 1. As described in the previous paper13)- 16), the conversion of DBT increased with increase in the amount of cesium added, reaching the maximum at Ru:Cs=1:2, while further addition of cesium decreased the conversion. Products were biphenyl (BP) and cyclohexylbenzene.…”

Inhibiting effect of H2S on the DBT HDS activity of Ru-based catalysts—effect of the Cs addition

“…Among a large number of attempts, much attention has been focused on unsupported ruthenium sulfides, which were found to be the most active species in hydrodesulfurization of thiophenes using transition metal sulfides [1][2][3][4][5]. Actually, some of our recent studies aimed at optimizing ruthenium-based catalysts by different ways: investigation of the effect of the precursor [6]; addition of alkali [7]; and modification of the carrier [8]. These efforts permitted us to improve the HDS ability of the Ru sulfidebased catalysts.…”

A Review on the Reaction Mechanism of Hydrodesulfurization and Hydrodenitrogenation in Heavy Oil Upgrading

“…However, γ-Al 2 O 3 is resistant to mass-transfer diffusion and has an overly strong metal–support interaction . Replacing the Al 2 O 3 with a more acidic or neutral support has been reported, with materials such as SiO 2 , zeolite, TiO 2 , ZrO 2 , and also the combination of two including Al 2 O 3 –SiO 2 , Al 2 O 3 –TiO 2 , Al 2 O 3 –B 2 O 3 , Al 2 O 3 –MgO, Al 2 O 3 –ZrO 2 , and so on. − Support materials are now tailored depending on the heavy oil’s nature for achieving the optimal upgrading results. − Other catalytic materials that showed excellent efficacy for sulfur and nitrogen removal are metal carbides (e.g., Mo 2 C), metal nitrides (e.g., Mo 2 N), and metal phosphides (e.g., Ni 2 P) . Noble metals such as Pt, Pd, Ru, and Ir also have excellent HDS and HDN activity .…”