Glycerol Dehydration to Acrolein over Supported Vanadyl Orthophosphates Catalysts

Abstract

Biodiesel has been identified as one of the notable options for at least complementing conventional fuels. From a transesterification reaction, crude glycerol is produced as the main by-product. Given the difficultly in upgrading to high-grade glycerin and glycerol market saturation, alternative routes to more value-added products have aroused significant interest. In this work, we proposed supported vanadyl orthophosphates (VOP) as catalysts for the glycerol dehydration to acrolein. VOP supported on γ-Al2O3, TiO2, and ZrO2 were prepared, characterized by inductively coupled plasma mass spectrometry (ICP-MS), X-ray diffraction (XRD), N2 physisorption and temperature-programmed desorption of ammonia (NH3-TPD), and tested under different operating conditions. All the samples showed low coke formation in the presence of molecular oxygen in the feed. Acrolein is the main condensable product, with carbon balance being satisfactory under most operating conditions. VOP supported onto alumina provided the best catalytic performance, due to a good balance between the acid (weak and medium acid sites) and redox sites, thereby appearing as a good candidate for glycerol dehydration to acrolein.

Catalytic Conversion of Glycerol to Acetol and Acrolein Using Metal Oxides: Surface Reactions, Prospects and Challenges

“…Glycerol dehydration reactions are also studied in the presence of redox sites [124,[129][130][131] . The influence of the metal oxidation state alters the acetol or acrolein selectivity.…”

“…This change directly involves the redox sites and the different proposed dehydration. [84,124,[129][130][131]…”

Tuning of Selectivity for Sustainable Production of Acrolein from Glycerol

“…This method makes it possible to enhance selectivity since in situ regeneration by co-feeding of oxygen or air can oxidise coke precursors into CO and CO 2 , removing continuously coke from the catalyst surface. [53] Moreover, co-feeding can also reduce the selectivity to side products such as acetol, acetaldehyde, and formaldehyde, but increase the amounts of organic acids, like acrylic acid, acetic acid, and formic acid increased due to the oxidation of acrolein and other aldehydes. [4] Interestingly, the nature of a catalyst has a significant impact on the acrolein selectivity and an increased formation of organic acids.…”

Highly active and durable WO3/Al2O3catalysts for gas-phase dehydration of polyols

“…Although WO 3 / ZrO 2 with 10 wt% WO 3 , 60 WO 3 /TiO 2 with 2.5 wt% WO 3 , H-ZSM-5(90) and H-b(25) showed high acrolein yield at the initial stage of the reaction, the rapid deactivation of these catalysts was observed. H-Y(5.5), H-MOR (20) and Nb 2 O 5 showed low initial activity. On the other hand, WO 3 /Al 2 O 3 catalyst with 20 wt% WO 3 loading showed high catalytic performance regarding both activity and durability.…”

“…Polyols, including ethylene glycol, 1,2-propanediol, 1,2-butanediol, 1,3butanediol, 1,4-butanediol and 1,2-pentanediol, were purchased from Wako Pure Chemical Industries and Tokyo Chemical Industry, Japan. (20), namely, JRC-Z5-90H, JRC-Z-HB25, JRC-Z-HY5.5 and JRC-Z-HM20, where the number in parentheses is the SiO 2 /Al 2 O 3 ratio, were supplied by Japan Reference Catalyst.…”