Capturing Coke Precursors in a Pd Lattice: A Carbon‐Supported Heteropoly Acid Catalyst for the Dehydration of Glycerol into Acrolein

Abstract

Supported heteropoly acid catalysts are frequently used in the dehydration of glycerol into acrolein because of their high activity. However, they are easily deactivated by coke that can become deposited on the catalyst surface. Herein, we report a technique that significantly decreases coke formation by capturing coke precursors in a Pd lattice. The Pd‐added H3PW12O40/C catalyst (Pd‐PWC) showed stable catalytic activity and the amount of deposited coke formed was decreased to about 40 % of that without Pd addition. The catalysts were characterized by XRD, HR‐TEM, XPS, NH3‐TPD, and TGA methods. These results showed that the palladium lattice on the carbon support was easily loosened and that coking precursors were incorporated into the Pd lattice of the catalyst under the reaction conditions used. Consequently, the amount of coke that was deposited onto the active sites of the catalysts was significantly decreased.

Glycerol Dehydration to Acrolein Catalyzed by ZSM‐5 Zeolite in Supercritical Carbon Dioxide Medium

“…The catalyst deactivation is mainly due to extensive coke deposition on the active sites of the catalyst . Methods including adding O 2 to inhibit the rate of coking, modifying catalysts by adjusting acid strength and distribution, and amplifying catalyst pore size have slightly extended the catalyst life, but none has been convincingly successful .…”

“…[1b, 2] The catalystd eactivation is mainly due to extensive coke deposition on the activesites of the catalyst. [5] Methods including adding O 2 to inhibit the rate of coking, [6] modifying catalysts by adjusting acids trength and distribution, [7] and amplifying catalyst pore size have slightly extended the catalyst life, but none has been convincingly successful. [8] Catalyst regeneration by coke combustion has also been attempted, but the catalystw as quickly deactivated again in at imeframe unsustainable for industriala pplications.…”

Tuning of Selectivity for Sustainable Production of Acrolein from Glycerol

“…Similar observations were detected by Yi's group who investigated the activity, selectivity and stability of Pd-added H 3 PW 12 O 40 /C catalyst in the dehydration of glycerol. [41] Nevertheless, the introduction of any additional gas into the reactor will increase the cost price of the resulting product and tighten the requirements for the reactor equipment. Our group demonstrated that commercial reforming catalysts Pt/γ-Al 2 O 3 exhibited an excellent selectivity to acrolein and stability to deactivation without introducing any carrier gas into the reactor.…”

Tungsten-substituted molybdophosphoric acid impregnated with kaolin: effective catalysts for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones via biginelli reaction

“…20 Hence, it is imperative to employ an appropriate support to distribute the heteropoly acid. [21][22][23][24][25] Kaolin, a clay mineral which is abundant on the earth, it is composed of abundantly 1 : 1 clay mineral Al 2 Si 2 O 5 (OH) 4 structure per alumina-silicate producing bulky congested particles of SiO 4 tetrahedral sheets and AlO 2 (OH) 4 octahedral sheets. 26,27 Kaolin clay are promising supports due to their common fascinating features, such as their inherent acidity, excellent thermal stability and easily controlled structural morphology.…”