Dehydrogenation of propane marches on

Propane dehydrogenation has emerged as a promising and booming method for direct propylene production. This preview highlights some recent important works that are moving forward the propane process toward high performance with excellent conversion, selectivity, durability. Propylene is basic raw material production of polypropylene, oxide, acrylonitrile, acrolein, acetone, various high-value chemicals/intermediates, it mainly produced from petroleum-derived steam cracking, fluid catalytic cracking (FCC), methanol-to-propylene (MTP) process. In years, success in large-scale exploitation natural gas shale motivated development industrial techniques catalytically selective to obtain propylene. Currently, approximate 10% global technology. Compared other methods, possesses many outstanding advantages, such superhigh selectivity without hybrid products, low cost plentiful source feedstock, abundant profits. Generally, there three pathways performing dehydrogenation: (1) oxidant (direct dehydrogenation, denoted PDH), (2) oxygen or air (oxidative ODH), (3) using CO2 mild shifting equilibrium pathway outlined via reaction H2. To date, several commercial processes PDH have been developed, including Oleflex, Catofin, FBD-4, PDH, STAR, ADHO, FCDh, K-PROt. Among them, Oleflex Catofin most commonly applied, wherein Pt-based CrOx-based catalysts involved, respectively.1Chen S. Chang X. Sun G. Zhang T. Xu Y. Wang Pei C. Gong J. catalyst development, new chemistry, emerging technologies.Chem. Soc. Rev. 2021; 50: 3315-3354Crossref PubMed Google Scholar reaction, well accepted activation first C–H bond rate-determining step determines activity. past decades, large number noble metal-based (Pt), non-noble metal oxide-based (CrOx, VOx, GaOx, ZrOx, ZnOx), non-oxide-based (carbides nitrides) developed because their affinity activity C–C cleavage.1Chen commercialized deactivation CrOx occurs due coking short time thus frequent regeneration by coke-burning required, while both sintering, which needs be regenerated oxychlorination chloride. addition, serious threat health, drawbacks involving ecologically harmful Cl2 Cl-containing compounds re-dispersion sintered Pt species spent catalysts. Thus, developing improved sintering resistance eco-friendly cost-efficient natures highly desired. efforts devoted strategies stabilizing against modulating spatial electronic properties coking. These include alloying strategy (i.e. introduction second metal), encapsulation strategy, strong metal-support interaction (SMSI) combination above strategies. Plenty studies shown can effectively suppress coke formation sintering. The introduced alloys around nanoparticles, anchoring them on surface support hindering easy migration. also increase electron density sites alloys, weaken Pt-propylene binding therefore restrain precursors. For example, co-workers prepared single-site [PtZn4] assembling atomically ordered PtZn intermetallic alloys.2Chen Zhao Z.-J. Mu R. Luo Purdy S.C. et al.Propane catalysts.Chem. 7: 387-405Abstract Full Text PDF Scopus (34) resultant enabled more than 95% over temperature range 520°C 620°C no obvious was observed within 160-h test. authors revealed geometrically isolated electron-rich motif readily promoted desorption surface-bonded stability prohibiting side reactions. Additionally, alloy structure particularly assured superior anti-segregation anti-sintering resistance. ultrasmall nanoporous materials regarded an efficient improve during processes. instance, Corma sub-nanometric Pt-Sn clusters (0.5–0.6 nm) encapsulated sinusoidal channels pure silica MFI zeolite, showed dehydrogenation.3Liu L. Lopez-Haro M. Lopes C.W. Li Concepcion P. Simonelli Calvino J.J. A. Regioselective generation reactivity control subnanometric platinum zeolites high-temperature catalysis.Nat. Mater. 2019; 18: 866-873Crossref (171) Scholar,4Liu Rojas-Buzo Manzorro Sattler Serna Structural modulation measurement bimetallic PtSn confined zeolites.Nat. Catal. 2020; 3: 628-638Crossref (77) Yu ligand-protected hydrogen reduction encapsulating sub-nanometer Pt-Zn inside exhibited extremely 99.3% weight hourly space velocity (WHSV) 3.6–54 h?1 at 550°C, conversion 40.4% even after 13,000 min stream (WHSV = 3.6 h?1) co-feeding H2.5Sun Q. N. Fan Zeng Mayoral Miao Yang Jiang Z. Zhou W. al.Subnanometer platinum–zinc dehydrogenation.Angew. Chem. Int. Ed. Engl. 59: 19450-19459Crossref (99) Besides effect, amount Zn could play role improvement deposition Ryoo small rare-earth particles (?3 pore walls mesoporous zeolite framework defects (called “silanol nests”).6Ryoo Kim Jo Han S.W. J.-C. Park H. Shin H.S. J.W. Rare-earth-platinum nanoparticles catalysis.Nature. 585: 221-224Crossref (84) silanol nests enable elements exist single atomic substantially higher chemical potential compared bulk making possible diffuse onto Pt. Thanks effect SMSI different components confinement zeolites, obtained stable, active, reaction. Strikingly, unlike limited thermodynamic, ODH H2 oxidized H2O not only transforms endothermic into exothermic process, but breaks limitation avoids thermal cracking. As such, attracted attention. However, yet far lower rich reactions deep oxidation COx. Recently, Notestein reported preparation nanoscale tandem process.7Yan He K. Samek I.A. Jing D. Nanda M.G. Stair P.C. J.M. Tandem In2O3-Pt/Al2O3 coupling combustion.Science. 371: 1257-1260Crossref (47) In2O3 Pt/Al2O3 were layer technique nanostructures kinetically coupled domains through atom transfer, leading enhanced Pt, then combustion In2O3, avoiding excessive hydrocarbon combustion. composite catalyzed rapid stable oxidative single-pass exceeding equilibrium. Later, Xiao discovered boron durability ODH.8Zhou Yi Hui Chen Qin Ma Chu al.Isolated propane.Science. 372: 76-80Crossref (42) It found –B[OH…O(H)–Si]2 borosilicate active center. discoveries move us big application trade-off made between product (C3H6) (H2) value-added chemicals, cheap water (H2O) assuming over-oxidization completely prohibited. addition catalysts, separation issue needed taken account future research. acknowledged, pass thermodynamic result, consumes energy unconverted must recycled back reactor separation, equipment investment consumption. fact, section energy-intensive Therefore, desired exists Appropriate conditions design, exploration i.e., considered when conducting investigation possessing good performance. summary, we consider challenges involve further stability, durability; understanding mechanism assistance situ characterizations theoretical calculations; rational design reactors under optimal conditions; (Figure 1). We acknowledge financial National Natural Science Foundation China ( 21920102005 , 21835002 U1967215 21621001 ) 111 Project B17020 ).