Search

The possibility of using carbon black (CB) as a support of palladium catalysts for the selective hydrogenation of organic compounds is considered. The advantages of Pd/CB catalysts are demonstrated by examples of liquid-phase hydrogenation of aromatic aldehydes and nitro compounds. The combination of high catalytic parameters (activity, selectivity, and stability) achieved by these catalysts in hydrogenation reactions indicates that they are promising for use on an industrial scale, in particular in the syntheses of fine chemicals.

Chlorine-substituted polymers with a system of conjugated double bonds—polyvinylene chlorides, which were prepared by the chemical dehydrochlorination of carbon-chain chloropolymers with a Cl content of higher than 60 wt %, being polymeric electron acceptors, were found to form complexes with alkali metal hydroxides (LiOH, NaOH, and KOH). The resulting complexes exhibit high sorption capacity for phenol. The static exchange capacity of the alkaline complexes of polyvinylene chlorides for phenol is as high as 310 mg/g in an aqueous medium or 90 mg/g in an atmosphere of air; these values are comparable with the sorption capacity of the known sorbents of phenol.

The results of studies on the preparation of Ni-Mo sulfide catalysts based on a carbon-carbon composite material of the Sibunit type for the hydrocracking of heavy petroleum residue are reported. The effects of the support texture and the conditions of catalyst preparation on catalytic activity in the model reactions of 1-methylnaphthalene and dibenzothiophene conversion were demonstrated.

For changing the texture of the mesoporous carbon composite Sibunit, its modification by treatment with furfuryl alcohol and the solutions of furfuryl alcohol in water and benzene followed by the carbonization of a polymer was studied. It was found that the composition of a modifying liquid phase has an effect on the textural characteristics of Sibunit, and the most essential pore-size redistribution occurred with the use of the aqueous solutions of furfuryl alcohol. The conditions under which the micropore structure of the modified Sibunit was maximally developed were determined.

A series of Pd/C catalysts (2–4 wt % Pd) with different particle sizes of the supported metal was prepared under varied conditions of the formation and surface deposition of the polynuclear hydroxo complexes (PHCs) of palladium(II) on powdered Sibunit carbon supports with their subsequent reduction to the metal. It was found that the liquid-phase hydrogenation of ethyl p-nitrobenzoate to anesthesine (benzocaine) on these catalysts is a structurally sensitive process, and the dependence of the activity of catalysts on their dispersity is expressed as an extremal function; in this case, the most effective catalysts had the average Pd particle size of 3–5 nm. It was demonstrated that the degree of catalyst utilization increased with the pH of Pd(II) PHC formation; this fact indicates that egg-shell-type catalysts were formed at high values of pH. The Pd/Sibunit catalysts are promising for use in the pharmaceutical industry for the synthesis of local anesthetics with p-nitrobenzoic acid as an intermediate.

Prospects for the application of porous granulated carbon-carbon materials synthesized based on nanodispersed carbon filling agents and a pyrolytic carbon matrix to processes in the hydrometallurgy of nonferrous metals are demonstrated. The results of the sorption of organic impurities from model and real process liquors used in the hydrometallurgy are considered using Tekhnosorb-1M carbon-carbon sorbent as an example. The results of the use of this material under industrial conditions at OOO NPF Baltiiskaya Manufaktura, one of the largest scale producers of cobalt salts in Russia, are also discussed.

The latest advances in the synthesis of granulated carbon-carbon materials based on nanodispersed globular and pyrolytic carbons modified with silicon or its compounds at the Institute of Hydrocarbons Processing, Siberian Branch, Russian Academy of Sciences are considered. The methods and main regularities of the synthesis and the physicochemical properties of silicon-containing composite materials like C/SiO2, C/SiO2/C, and SiO2/C are discussed. It is shown that the synthesis of modified nanocomposites with the use of polyorganosiloxanes is a promising line in the development of silicon-containing carbon-carbon materials. In this work, a nontraditional approach to the production of mesoporous silicon dioxide based on nanodispersed globular carbon and polyorganosiloxanes is proposed.

The methods of regulating the porous structure and properties of carbon materials of the Sibunit type are considered. The deposition to 10–15 wt % pyrolytic carbon in the pore space of Sibunit makes it possible to regulate pore volume and pore-size distributions by decreasing the fraction of micropores and small mesopores and to enhance the strength characteristics of the support. Heat treatment in an inert atmosphere in a temperature range of 2200–2600°C imparts a number of unique specific properties to the Sibunit supports, in particular, high resistance to oxidative and electrochemical corrosion, which is comparable with the resistance of graphite. At the same time, it retains sufficiently high pore structure characteristics and adsorption properties typical of porous carbon materials. The introduction of water-soluble organic compounds capable of producing microporous carbon upon carbonization at the stage of granulation or the supporting of organic compounds on Sibunit with the subsequent polymerization and carbonization in the support pores makes it possible to form micropores with a volume to 0.20–0.25 cm3/g in Sibunit.