Facile Polyolefin Plastics Hydrogenolysis Catalyzed by a Surface Electrophilic d0 Hydride

Polyolefins comprise a major fraction of single-use plastics and yet their catalytic deconstruction/recycling has proven challenging due to their inert hydrocarbon connectivities. Here an electrophilic earth-abundant single-site organozirconium catalyst chemisorbed on a highly Brønsted acidic support and characterized by a broad array of experimental and theoretical techniques, is shown to mediate the rapid hydrogenolytic cleavage of molecular and macromolecular saturated hydrocarbons under mild conditions. For n-hexadecane, hydrogenolysis to light hydrocarbons proceeds with an activity of 690 mol n-hexadecane · mol Zr-1 · h-1 at 150°C/2.5 atm H2 pressure. Under similar solventless conditions, polyethylene, polyethylene-co- 1-octene, isotactic polypropylene, and a post-consumer sandwich bag are rapidly hydrogenolyzed to low molecular mass hydrocarbons via a turnover-limiting C-C scission pathway involving ßalkyl transfer rather than more common σ-bond metathesis.

Bifunctional Zeolite- and Aluminophosphate-Based Catalysts for Hydrocracking and Hydroisodeparaffinization. Part 1. The Influence of the Nature and Activity of the Hydrogenating and Acidic Components on the Activity and Selectivity of Hydrocracking Cataly

Sulfur resistance of nickel, platinum and palladium metals on acid supports was studied depending on the support nature. Catalysts comprising nickel, platinum, palladium metals and sulfides as hydro-dehydrogenating components were examined for hydrocracking of n-octane. HY, ZSM-5, ZSM-23, ZSM-12, as well as silicoaluminophosphates SAPO-11 and SAPO-31 were used as the supports. The sulfur resistance of the supported metals in the catalysts was shown different and independent of the properties of the acidic support under the reaction conditions. Hydrocracking follows two different pathways depending on the activity and nature of the hydro-, dehydrogenating component (a metal or the sulfide), as well as on the ratio of activities of the acidic and hydrogenating components. The first pathway is preferable cracking of the initial paraffin at the early stage, and the second is dehydrogenation of the initial paraffin.

Controllable synthesis of supported platinum catalysts: acidic support effect and soot oxidation catalysis

Platinum nanoparticles were synthesized by a classic polyol process in ethylene glycol.

Adsorptive Removal of Nitrogen and Sulfur Containing Compounds by SBA15 Supported Nickel (II) and Tungsten Phosphides and the Adsorption Mechanisms

SBA15 supported transition metal phosphides Ni2P/SBA15 and WP/SBA15 have been identified as promising adsorbents especially for removing neutral nitrogen-containing compounds. Adsorption of model nitrogen- and sulfur-containing compounds as well as light cycled oil (LCO) was performed and applied for the evaluation of kinetics and isotherms. The pseudo second-order kinetic model was well fitted to both nitrogen and sulfur adsorption data. Molecular size of the adsorbates plays an important role in the adsorption. Despite of higher initial adsorption rates, the adsorption capacities for carbazole and DBT were lower than those for indole and quinoline due to their larger molecular size. Monolayer adsorption was observed for quinoline due to the acid-base interaction between the basic nitrogen adsorbate and the weak acidic support. The Freundlich model was suitable in describing the adsorption of nitrogen- and sulfur-containing compounds from LCO. Cooperative adsorption took place when replacing the model compound DBT by the sulfur-containing compounds in LCO.