Suppressing Dehydroisomerization Boosts n‐Butane Dehydrogenation with High Butadiene Selectivity

Abstract

Butadiene (BD) is a critical raw material in chemical industry, which is conventionally produced from naphtha cracking. The fast‐growing demand of BD and the limited oil reserve motivate chemists to develop alternative methods for BD production. Shale gas, which mainly consists of light alkanes, has been considered as cheap raw materials to replace oil for BD production via n‐butane direct dehydrogenation (n‐BDH). However, the quest for highly‐efficient catalysts for n‐BDH is driven by the current drawback of low BD selectivity. Here, we demonstrate a strategy for boosting the selectivity of BD by suppressing dehydroisomerization, an inevitable step in the conventional n‐BDH process which largely reduces the selectivity of BD. Detailed investigations show that the addition of alkali‐earth metals (e. g., Mg and Ca) into Pt‐Ga2O3/S10 catalysts increases Pt dispersity, suppresses coke deposition and dehydroisomerization, and thus leads to the significant increase of BD selectivity. The optimized catalyst displays an initial BD selectivity of 34.7 % at a n‐butane conversion of 82.1 % at 625 °C, which outperforms the reported catalysts in literatures. This work not only provides efficient catalysts for BD production via n‐BDH, but also promotes the researches on catalyst design in heterogeneous catalysis.

Light olefin synthesis from a diversity of renewable and fossil feedstocks: state-of the-art and outlook

“…Application of Ti-silicalite and LaAlO 3 -perovskite as supports as well as promotion by MgO and CaO increased the dispersion and sintering resistance of Pt nanoparticles and suppressed side reactions and coking. [102][103][104] Promotion with potassium was found to improve the efficiency of Cr-Al catalysts in isobutane DDH. In the activated catalysts, potassium preferably interacts with alumina and modifies the average dispersion of Cr 3+ O x species.…”

Mechanism and Kinetics of n-Butane Dehydrogenation to 1,3-Butadiene Catalyzed by Isolated Pt Sites Grafted onto ≡SiOZn–OH Nests in Dealuminated Zeolite Beta

“…Despite achievements in technologies for direct dehydrogenation of n -butene or n -butane/ n -butene mixtures (e.g., Houdry–Catadiene process), n -butene is generally used as the feedstock to achieve a high yield of 1,3-BD. Compared with significant improvements in product selectivity achieved for ethane and propane dehydrogenation, catalysts for direct n -butane dehydrogenation to 1,3-BD with high selectivity have proven more difficult to identify, , and in studies reported to date, the 1,3-BD selectivity is generally less than 20%. ,, …”

“…Compared with significant improvements in product selectivity achieved for ethane and propane dehydrogenation, catalysts for direct nbutane dehydrogenation to 1,3-BD with high selectivity have proven more difficult to identify, 1,11 and in studies reported to date, the 1,3-BD selectivity is generally less than 20%. 8,12,13 Supported Pt catalysts and Pt bimetallic catalysts, particularly PtSn, have been widely explored for direct dehydrogenation of alkanes to alkenes. Catalysts containing very small Pt, PtSn, or PtZn nanoclusters have been shown to be highly active, selective, and resistant to coking.…”

Effects of n-Butane Coverage on Its Catalytic Dehydrogenation: A Density Functional Theory Study on the Pt(111) Surface

“…6 The main advantages of direct dehydrogenation are environmental friendliness, economic efficiency, and competitive selectivity for the target products. 7 Despite these advantages, the relatively low conversion and C−C cleavage of direct butane dehydrogenation restrict production scaleup. 8,9 Furthermore, alkane dehydrogenation is a catalyst-structuresensitive reaction, and controlling the particle size of the catalyst can effectively tune the conversion and C−C bond cleavage behavior.…”

“…Compared with these existing technologies, direct dehydrogenation is a promising method for alkene production . The main advantages of direct dehydrogenation are environmental friendliness, economic efficiency, and competitive selectivity for the target products . Despite these advantages, the relatively low conversion and C–C cleavage of direct butane dehydrogenation restrict production scale-up. , …”