Prevention of Catalyst Deactivation in the Oxidative Dehydrogenation of n-Butene to 1,3-Butadiene over Zn-Ferrite Catalysts

Abstract

An efficient method to enhance the catalytic properties of Zn-ferrite catalyst in the oxidative dehydrogenation of n-butene to 1,3-butadiene is proposed. The incorporation of phosphorous compound in Zn-ferrite is very effective to improve the catalytic activity as well as to maintain extremely long useful lives at high oxygen to n-butene ratio. It is found that the amount of phosphorous is critical and the presence of appropriate amount of phosphorous in catalyst may contribute the catalyst stabilization by which unfavorable reduction of Fe 3? sites to Fe 2? is effectively suppressed. This suggests that the oxygen mobility is maintained as high as the redox mechanism keeps constantly working. On the other hand, the effort to increase the population of mobile oxygen species by the introduction of external oxygen donor phase is found to be rather ineffective regardless of the external donor oxides used.

Characteristics of Nanosize Spinel Ni_xFe_3-xO₄ Prepared by Sol-Gel Method Using Egg White as Emulsifying Agent

“…As shown in Table 2, the crystallite sizes of Ni x Fe 3-x O 4 samples are in the range of 33-61 nm, demonstrating the efficacy of the proposed method to produce nano-size spinel Ni x Fe 3-x O 4 . In relation with the Ni contents, it was found that increased Ni-content from x = 0.2 to x = 0.6) resulted in increased particle size of the spinel NiFe 2 O 4 crystalline phase from around 34 to 61 nm.…”

“…Ferrite compounds with spinel structure have attracted major attention due to their suitable properties for diverse technological applications, such as electronic devices [1][2], magnetic storages [3], and catalysis [4][5]. In general, the applications of this type of compound are governed by peculiar properties, which in turn depends on the chemical composition and microstructure [3,6].…”

Oxidative Dehydrogenation of But‐1‐ene at Low Temperature with Copper Ferrite Catalysts

“…Various complex metal oxides, and metal oxides or metal‐supported catalysts, have been investigated for the ODH of many hydrocarbons, including propane, ethylbenzene, ethane, n‐butane, n‐butene, and cyclohexane . For the ODH of n‐butene and n‐butane, Pt−In catalyst, ferrite‐type catalysts,, V‐containing catalysts, Bi−Mo catalysts, and the CuO/Al 2 O 3 catalyst exhibited high activity.…”

“…Among various catalysts, zinc ferrite‐type catalysts such as Zn−Fe,,,, Zn−Fe‐Cr, and Zn−Fe‐Al have been widely studied for the ODH of the C4 fraction. For example, it was reported that a zinc ferrite catalyst that was modified by heteropoly acid or sulfonic acid showed good performance for the ODH of but‐1‐ene ,.…”

“…Here, the reactivity of the lattice oxygen and the regeneration of the used lattice oxygen are important for producing the ODH of n‐butene. However, it was reported that the ferrite‐type catalyst was deactivated as a result of the increase in Fe 2+ produced by reducing Fe 3+ isolated from the spinel phase ,. In order to maintain the reactivity of lattice oxygen to produce BD and the spinel structure, Sb 2 O 4 , BiPO 4 , or SnO 2 was added as an oxygen donor to the zinc ferrite catalyst.…”