Coupling dehydrogenation of isobutane to produce isobutene in carbon dioxide over NiO/γ-Al2O3 catalyst

Abstract

The dehydrogenation of isobutane to produce isobutene coupled with reverse water gas shift (RWGS) reaction in the presence of carbon dioxide was investigated over a NiO/c-Al 2 O 3 catalyst. The results illustrated that the coupling dehydrogenation of isobutane in carbon dioxide over NiO/c-Al 2 O 3 catalyst is effective, and the NiO/Al 2 O 3 catalyst was modified with deposited carbon by impregnation of alumina with an aqueous solution of Ni(H 2 NCH 2 CH 2 NH 2 ) x (NO 3 ) 2 . Carbon modification can decrease the total acidity of the NiO/c-Al 2 O 3 catalyst and enhance the dispersion of NiO active phase. Furthermore, carbon has low acidity and anti-coking performance, so the carbon modification is effective in suppressing the coke formation and side reactions occurrence. Therefore, the catalyst stability and the isobutene selectivity are improved significantly by the carbon modification.

Carbon Deposition Assisting the Enhancement of Catalytic Activity with Time-on-Stream in the Dehydrogenation of Isobutane over NiO/Al₂O₃

“…e preparation procedures for both NiO/γ-Al 2 O 3 and NiO/α-Al 2 O 3 were essentially identical to those reported in previous papers (Ding et al, 2010;Sugiyama et al, 2021). NiO(20)/γ-Al 2 O 3 and NiO(20)/α-Al 2 O 3 , in which "20" represents the weight% of NiO, were the focus in this study, and the impregnation method used to prepare NiO(20)/α-Al 2 O 3 is as follows.…”

“…Furthermore, to clarify the reason for the improvement in the activity over both NiO/γ-Al 2 O 3 and NiO/α-Al 2 O 3 , despite the excessive amount of carbon deposition, the states of the carbon deposit and the catalytically active metallic-nickel species were analyzed using a transmission electron microscope equipped with an energy-dispersive X-ray spectroscope. A study of the coexistence of CO 2 in the present reaction system has been conducted by Ding et al (2010). e purpose of the coexistence with CO 2 was to react with the hydrogen obtained from the dehydrogenation to produce water (reverse water-gas shi reaction), followed by the reaction of water and carbon deposit to suppress carbon deposition.…”

Enhancement of the Catalytic Activity Associated with Carbon Deposition Formed on NiO/Al₂O₃ during the Dehydrogenation of Ethane and Propane

“…is occurs in various reactions: dehydrogenation (Ding et al, 2010a;Ye et al, 2019), steam reforming (Besenbacher et al, 1998;Sehested, 2006;Guo et al, 2007;Ochoa et al, 2017), methane decomposition (Otsuka and Takenaka, 2003;Arevalo et al, 2017), dry reforming (Bradford and Vannice, 1999;Hayakawa et al, 1999;Arora and Prasad, 2016), and partial oxidation reactions (Alvarez-Galvan et al, 2019;Takehira et al, 2002). erefore, the dehydrogenation of isobutane on NiO/γ-Al 2 O 3 in the previous study revealed results that were contrary to conventional wisdom.…”

“…1.1 Preparation of the catalysts e catalyst referred to as NiO(x)/γ-Al 2 O 3 , in which "x" indicates the content by weight %, de ned as 100×NiO [g]/ (γ-Al 2 O 3 [g]+NiO [g]), was prepared via the impregnation method, as previously reported (Ding et al, 2010a;Sugiyama et al, 2021). As an example of the catalyst preparation, the method used to prepare NiO(5)/γ-Al 2 O 3 is as follows.…”

Novel preparation of highly dispersed Ni2P embedded in carbon framework and its improved catalytic performance

“…Due to the thermodynamics equilibrium limit of reaction, it requires relatively high temperature and low pressure to achieve high yield of isobutene [6], which could cause coke deposition, catalyst deactivation and also increase the occurrence of side reactions that drastically lowers the selectivity to isobutene [7][8][9]. CrO x -based [10][11][12] and Pt-Sn-based [13][14][15][16] catalysts have been commercially applied for dehydrogenation of isobutane.…”