NiMo/alumina hydrodesulphurization catalyst modified by saccharose: Effect of addition stage of organic modifier

Abstract

NiMo/Al2O3 catalysts, obtained by one‐pot simultaneous impregnation, were modified by saccharose (SA, at Ni/SA = 1 mol ratio) addition. To address the influence of stage of saccharide impregnation on the hydrodesulphurization activity of sulphided catalysts, three different preparation methodologies were followed: (a) modification of already calcined (400 °C) NiMo/Al2O3 by SA impregnation; (b) SA deposition directly onto the alumina support, prior to Ni + Mo impregnation; (c) simultaneous Ni + Mo + SA deposition. Materials were characterized by N2 physisorption, X‐ray diffraction, infrared (IR) spectroscopy, UV‐vis spectroscopy, and temperature‐programmed reduction (TPR), and tested on liquid‐phase dibenzothiophene (DBT) conversion (batch reactor, T = 320 °C, P = 7.2 MPa, n‐hexadecane as solvent). The last methodology resulted in the catalyst with the highest DBT hydrodesulphurization (HDS) activity, on a pseudo‐first order kinetic constant basis. A decreased proportion of tetrahedral Mo6+ species due to diminished interaction with the carrier, increased reducibility of octahedral Mo6+, and Ni complexation as well seemed to play determining roles in the trends of the activity observed. Simultaneous saccharose addition during NiMo phase impregnation required no additional preparation steps to efficiently integrate the organic modifier.

Dibenzothiophene Hydrodesulfurization over P-CoMo on Sol-Gel Alumina Modified by La Addition. Effect of Rare-Earth Content

“…The HDS test reactions were carried out at T = 320 • C, P = 5.67 MPa, and 1000 rpm (~105 rad s −1 , mixing speed). Catalysts' particle size and operating conditions were carefully chosen to avoid internal/external diffusional limitations [73]. Liquid samples were taken from the reactor, periodically, then analyzed by gas chromatography (Agilent (Santa Clara, CA, USA) 6890N with flame ionization detector and Econo-Cap-5 capillary column length: 30 m, 0.53 mm diameter, and film thickness of 1.2 µm, from Alltech (Nicholasville, KY, USA).…”

Experimental methods in chemical engineering: Ultraviolet visible spectroscopy—UV‐Vis

“…Chemical engineering applications include waste‐water treatment, dye degradation, characterizing colloidal nanoparticles—silver, gold, and copper—metallic coordination of molybdenum and cobalt, bimetallic mesoporous materials with cobalt and chromium, and composites of graphene oxide and silver nanoparticles …”

Surface‐Dependent Activation of Model α‐Al2O3‐Supported P‐Doped Hydrotreating Catalysts Prepared by Spin Coating

“…The most active hydrotreating catalysts are cobalt or nickelp romoted MoS 2 or WS 2 ,t ypicallys upported on g-Al 2 O 3 . [3][4][5][6] Nowadays, there is ag eneral agreement regarding the nature of the active phase, the promotion sites, [6][7][8][9][10][11][12][13][14][15] the additivest hat enhancet he hydrodesulfurization (HDS) activity, [16][17][18][19][20][21] and the structure of the porous support. [22,23] However, despite this rather complete description of hydrotreating catalysts, the role that the support exerts on the genesiso ft he activep hase is still poorly understood,w hilei ti samajor player in the molecular design of optimized catalysts.…”