Metal-Organic Frameworks Encaged Ru Single Atoms for Rapid Acetylene Harvest and Activation in Hydrochlorination

Ruthenium (Ru)-based catalysts have been candidates in hydrochlorination for vinyl chloride monomer (VCM) production, yet they are limited by efficient acetylene (C₂H₂) utilization. The strong adsorption performance of HCl can deactivate Ru active sites which resulted in weak C₂H₂ adsorption and slow activation kinetics. Herein, we designed a channel that employed metal-organic framework (MOF)-encaged Ru single atoms to achieve rapid adsorption and activation of C₂H₂. Low-Ru (∼0.5 wt %) single-atom catalysts (named Ru-NC@MIL) were assembled by hydrogen-bonding nanotraps (the H-C≡C-H^δ+···O^δ- interactions between C₂H₂ and carboxylate groups/furan rings). Results confirmed that C₂H₂ could easily enter the encapsulation channels in an optimal mode perpendicular to the channel with a potential energy of 42.3 kJ/mol. The harvested C₂H₂ molecules can be quickly passed to Ru-N₄ active sites for activation by stretching the length of carbon-carbon triple bonds (C≡C) to 1.212 Å. Such a strategy guaranteed >99% C₂H₂ conversion efficiency and >99% VCM selectivity. Moreover, a stable long-term (>150 h) catalysis with high efficiency (∼0.85 kg_vcm/h/kg_cat.) and a low deactivation constant (0.001 h^-1) was also achieved. This work provides an innovative strategy for precise C₂H₂ adsorption and activation and guidance for designing multi-functional Ru-based catalysts.

The Pincer Ligand Supported Ruthenium Catalysts for Acetylene Hydrochlorination: Molecular Mechanisms from Theoretical Insights

Pincer ligand supported RuII chloride complexes may be used for acetylene hydrochlorination as non-mercury molecular catalysts. Based on theoretical calculations, the catalytic mechanism and the interaction between catalysts and reactants has been evaluated, indicating that the (pincer)RuIICl2 platform supports electrophilic proton-ruthenation of C2H2. Energy decomposition studies further illustrate the electron-rich property of the RuII center, which can increase the negative charge of C2H2 via 4d-electron backdonation. Thus, the electrophilic reaction mechanism is favored due to lower energetic barriers. By improving the electron-donating ability of ligands, this lowering of energetic barriers can be enhanced. Therefore, non-mercury catalysts for acetylene hydrochlorination with milder reaction conditions and higher catalytic activity can be designed.

Design of choline chloride modified USY zeolites for palladium-catalyzed acetylene hydrochlorination

USY zeolites (USY) were applied to design and synthesize palladium-based heterogeneous catalysts for exploring an efficient non-mercuric catalyst for acetylene hydrochlorination. Choline chloride (ChCl) was selected as the nitrogen-containing ligand to modify the Pd@USY catalysts and the proposed Pd@15ChCl@USY catalyst exhibited obviously the best catalytic performance with a stable acetylene conversion and vinyl chloride selectivity of over 99.0% for more than 20 h. According to the results of characterization and the density functional theory calculations, it is indicated that the addition of ChCl can significantly inhibit the agglomeration and loss of the Pd active species, prevent carbon deposition and enhance the ability of HCl and C2H2 adsorption and C2H3Cl desorption, resulting in promoting the catalytic performance of Pd@USY catalysts during the acetylene hydrochlorination reaction.

Competing on the same stage: Ru-based catalysts modified by basic ligands and organic chlorine salts for acetylene hydrochlorination

To provide reference for the search of efficient ligands for acetylene hydrochlorination, various basic ligands with different alkaline gradients have been employed to modify Ru-based catalysts, and a rule is...

Construction of highly dispersed Au active sites by ice photochemical polishing for efficient acetylene hydrochlorination

Compared to traditional Au/AC, ice-photochemical polishing results in atomically dispersed AuClx-like multi-sites, yielding a significantly improved performance of Au/AC-F1I1 catalysts.

Ru supported on activated carbon and coated with a polydopamine layer for effective acetylene hydrochlorination

Ru/AC@PDA-T catalysts were synthesized by coating a protective layer of PDA derivatives on the Ru/AC catalyst. Significantly improved activity and stability provide directions for the development of environmentally friendly and economical catalysts.

A study on the rules of ligands in highly efficient Ru–amide/AC catalysts for acetylene hydrochlorination

The electron donor ability and steric hindrance of substituents on amide ligands jointly affect the modification effect of ligands on ruthenium based catalysts for acetylene hydrochlorination.

Magnesium hydroxide–supported ruthenium as an efficient and stable catalyst for glycerol-selective hydrogenolysis without addition of base and acid additives

Ru/Mg(OH)₂(S) exhibited high catalytic activity and selectivity to 1,2-propanediol for glycerol hydrogenolysis without any base and acid additives.