In view of the growing environmental concerns and the need to involve alternative sources of raw materials in the chemical industry, intensive research efforts in the last decades have focused on carbon dioxide reactions. In this context, the present review discusses prior studies that were aimed at producing commercially important compounds, such as acids, alcohols, organic carbonates, and polycarbonates, in homogeneous catalytic systems that contain transition-metal complexes. Such systems have been traditionally valued for their high activity and selectivity under relatively mild conditions. The review provides systematized information both on CO₂ reactions with hydrogen to produce C₁ chemicals such as formic acid and methanol, and on CO₂ interactions with organics (e.g., olefins, alcohols, and epoxides) to produce valuable chemical compounds.

The current work describes an attempt to synthesize hybrid materials combining porous aromatic frameworks (PAFs) and dendrimers and use them to obtain novel highly active and selective palladium catalysts. PAFs are carbon porous materials with rigid aromatic structure and high stability, and the dendrimers are macromolecules which can effectively stabilize metal nanoparticles and tune their activity in catalytic reactions. Two porous aromatic frameworks, PAF-20 and PAF-30, are modified step-by-step with diethanolamine and hydroxyl groups at the ends of which are replaced by new diethanolamine molecules. Then, palladium nanoparticles are applied to the synthesized materials. Properties of the obtained materials and catalysts are investigated using X-ray photoelectron spectroscopy, transmission electron microscopy, solid state nuclear magnetic resonance spectroscopy, low temperature N₂ adsorption and elemental analysis. The resulting catalysts are successfully applied as an efficient and recyclable catalyst for selective hydrogenation of alkynes to alkenes at very high (up to 90,000) substrate/Pd ratios.

Heterogeneous catalysts for the hydrogenation of unsaturated hydrocarbons have been synthesized on the basis of palladium and platinum nanoparticles immobilized in pores of mesoporous aromatic frameworks, which represent a new class of carbon supports with a diamond-like ordered structure. The resulting materials have been characterized by transmission electron microscopy, IR spectroscopy, and NMR spectroscopy. It has been shown that the catalyst activity in the hydrogenation reaction depends on the substrate molecule size and adsorbability on the surface of nanoparticles. Catalytic activity has been studied in the hydrogenation of a number of unsaturated compounds at temperatures of 60 and 80°C and pressures of 1.0 and 3.0 MPa.

A new phosphorous-free rhodium supported on a nitrogen-doped silica was successfully used as a catalyst for the hydroformylation of alkenes. The obtained material and the catalyst were characterized by XRD, XPS, FTIR, SEM, TEM, ICP AES, and low-temperature nitrogen adsorption–desorption measurements. The catalytic performance was studied by the example of the hydroformylation of octene-1 at temperatures of 80–140 °C and a pressure of 5.0 MPa. The catalyst provided a 99% conversion of 1-octene with a 98% yield of aldehydes and showed a good conversion of styrene and cyclohexene. The catalyst can be repeatedly used in ten consecutive cycles, with its activity remaining constant.

This paper reports on an investigation of the alkylation of guaiacol with isopropanol and cyclohexanol over sulfonated porous aromatic frameworks, designated as PAF-20–SO₃H and PAF-30–SO₃H. The catalyst structures were characterized by infrared spectroscopy and low-temperature nitrogen adsorption; the elemental composition and acidity were measured by CHNS analysis and potentiometric titration. The alkylate composition was found to be sensitive to the reaction conditions and catalyst structure. PAF-30–SO₃H was demonstrated to achieve 58% guaiacol conversion over 2 h of alkylation with cyclohexanol at 250°C and 3 MPa, with the reaction products mostly consisting of benzene ring monoalkylation products. In guaiacol alkylation with isopropanol, the product composition depends on the catalyst structure: after 6 h of reaction, the benzene ring monoalkylation products prevailed (accounting for up to 23% of the total product) in the case of PAF-20–SO₃H, whereas PAF-30–SO₃H promoted the yield of a mixture of monoalkylates (up to 34%) and dialkylates (up to 35%).

A phosphine-containing porous polymer (TPDB), and a rhodium catalyst based on it, were synthesized. Proceeding from the relevant TEM, NMR, IR spectroscopy, and XPS data obtained, it was assumed that both the Rh(I) complexes and the Rh(0) nanoparticles that are stabilized in the polymer pores act as the catalyst’s active phase. The size of the nanoparticles (2–6 nm) is consistent with that of the polymer pores. The catalyst was tested in a model reaction of octene-1 hydroformylation at 2.0 MPa (CO : H ₂ = 1 : 1) in the temperature range of 60–120°C. It was demonstrated that the catalyst can be used repeatedly, and its activity remains constant from the third cycle of its use (aldehyde yield about 30% for 5 h, n / iso 2.5).