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Lignin obtained by hydrogenolysis of lignocellulose biomass is a prospective source of valuable green fuels and chemicals such as monophenols. One of the key factors in the chemical decomposition of lignin to monophenols is an efficient catalyst. Inert porous materials such as hypercrosslinked polymers are suitable catalytic supports for the immobilization of noble and transition metal nanoparticles. However, such polymers do not have acidic properties, which are crucial for catalyzing hydrolysis. In this work, we report novel, efficient catalysts for lignin hydrogenolysis to produce valuable monophenolic compounds. The synthesized catalysts contained Ni, Ru, and Ni-Ru nanoparticles supported on SiO2-coated hypercrosslinked polystyrene (SiO2@HPS). Ni-Ru/SiO2@HPS demonstrated remarkable stability without any loss of the metallic phase and a high yield of monophenols (>42 wt.%) at close to full lignin conversion (>95 wt.%). This result was attributed to the synergy between the two metals and the support's surface acidity. All catalysts were fully characterized by a series of physico-chemical methods.

Encapsulation of metal nanoclusters in porous solid polymer materials is a promising approach to combine the outstanding properties of both, heterogeneous and homogeneous catalysts. We report heterogeneous nano-engineered catalysts containing Pd-nanoparticles (NPs) confined within highly-porous hollow polymeric framework of hyper cross-linked polystyrene (HPS). HPS with different surface functionalities (amine vs. sulfonate) were used for impregnation by Pd precursors of different nature and followed by a variety of catalyst post-treatments. The catalysts have been tested in two model key reactions for the synthesis of fine chemicals: selective hydrogenation of 2-methyl-3-butyne-2-ol to 2-methyl-3-butene-2-ol (MBE) and Suzuki cross-coupling of 4-bromoanisole with phenylboronic acid. Optimization of the Pd/HPS preparation and reaction conditions allowed attaining high selectivity (similar to 99 %) to target MBE at close to full conversion. For Suzuki cross-coupling more than 90 % yield of coupling product was obtained under mild reaction conditions and the absence of phase transfer agent. Our results demonstrate the potential of HPS as a suitable support for tailoring metal NPs properties and circumvent undesirable metal leaching.

Hydrogenation of aromatic compounds is a widely used catalytic process in modern industry. Selective hydrogenation of benzene (BZ)-toluene (TL) mixtures is an important industrial process as it allows the purification of BZ for further synthetic purposes. In this work, the hydrogenation of a BZ-TL mixture (at a molar ratio close to 1) was studied for varying reaction parameters (temperature in the range of 100-180 degrees C and pressure in the range of 1-7 MPa) using Pt-, Pd-, and Ru-containing nanoparticles stabilized by an amino-functionalized hyper-crosslinked aromatic polymer (HAP). Among the synthesized catalytic systems, Ru/HAP containing ruthenium(IV) oxide was shown to be the most active and selective one, allowing 44 % selectivity with respect to cyclohexane at nearly 100 % of BZ conversion.

This paper describes synthesis of Pd-containing catalysts of Suzuki cross-coupling based on amino-functionalized hyper-cross-linked polystyrene at variation of Pd precursor nature (PdCl2, PdCl2(CH3CN)(2), or PdCl2(PhCN)(2)). The investigation of the influence of palladium, oxidation state (Pd(II) or Pd(0)) and form (Pd-n dusters or Pd nanoparticles) on the rate of Suzuki cross-coupling of 4-bromoanisole and phenylboronic acid is discussed. Developed catalysts are shown to allow achieving, conversion of 4-bromoanisole higher than 98% under mild reaction conditions. Independently of the precursor nature, Pd(II) is mainly responsible for observed catalytic activity. However, preliminary reduction of catalysts with H-2 results in formation of a large number of Pd-n. clusters, the contribution of which in the Suzuki reaction becomes predominant.