Mikhail G. Sulman

Functionalization of monodisperse iron oxide NPs and their properties as magnetically recoverable catalysts.

Here we report the functionalization of monodisperse iron oxide nanoparticles (NPs) with commercially available functional acids containing multiple double bonds such as linolenic (LLA) and linoleic (LEA) acids or pyridine moieties such as 6-methylpyridine-2-carboxylic acid, isonicotinic acid, 3-hydroxypicolinic acid, and 6-(1-piperidinyl)pyridine-3-carboxlic acid (PPCA). Both double bonds and pyridine groups can be reacted with noble metal compounds to form catalytically active species in the exterior of magnetic NPs, thus making them promising magnetically recoverable catalysts. We determined that both LLA and LEA stabilize magnetic iron oxide NPs, allowing the formation of π-complexes with bis(acetonitrile)dichloropalladium(II) in the NP shells. In both cases, this leads to the formation of NP aggregates because of interparticle complexation. In the case of pyridine-containing ligands, only PPCA with two N-containing rings is able to provide NP stabilization and functionalization whereas other pyridine-containing acids did now allow sufficient steric stabilization. The interaction of PPCA-based particles with Pd acetate also leads to aggregation because of interparticle interactions, but the aggregates that are formed are much smaller. Nevertheless, the catalytic properties in the selective hydrogenation of dimethylethynylcarbinol (DMEC) to dimethylvinylcarbinol were the best for the catalyst based on LLA, demonstrating that the NP aggregates in all cases are penetrable for DMEC. Easy magnetic separation of this catalyst from the reaction solution makes it promising as a magnetically recoverable catalyst.

Design of ruthenium/iron oxide nanoparticle mixtures for hydrogenation of nitrobenzene

Here we report novel catalysts for nitrobenzene hydrogenation based on Ru/RuO2 nanoparticles (NPs) and including iron oxide NPs, allowing magnetic recovery. The solvent type, reaction temperature, and the size and composition of initial iron oxide NPs are demonstrated to be the control factors determining synthesis outcomes including the degree of NP aggregation and catalytic properties. A complete characterization of the catalysts using transmission electron microscopy (TEM), X-ray powder diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and energy dispersive x-ray spectroscopy (EDS) allowed assessment of the structure–property relationships. It is revealed that coexistence of the Ru/RuO2 and iron oxide NPs in the catalyst as well as the proximity of two different NP types lead to significantly higher aniline yields and reaction rates. The catalytic properties are also influenced by the type of iron oxide NPs present in the catalytic samples.

Enhancing the Catalytic Activity of Zn-Containing Magnetic Oxides in a Methanol Synthesis: Identifying the Key Factors

A new family of Ni-, Co-, and Cr-doped Zn-containing magnetic oxide nanoparticles (NPs) stabilized by polyphenylquinoxaline (PPQ) and hyperbranched pyridylphenylene polymer (PPP) has been developed. These NPs have been synthesized by thermal decomposition of Zn and doping metal acetylacetonates in the reaction solution of preformed magnetite NPs, resulting in single-crystal NPs with spinel structure. For the PPQ-capped NPs, it was demonstrated that all three types of metal species (Fe, Zn, and a doping metal) reside within the same NPs, the surface of which is enriched with Zn and a doping metal, while the deeper layers are enriched with Fe. The Cr-doped NPs at the high Cr loading are an exception due to favored deposition of Cr on magnetite located in the NP depth. The PPP-capped NPs exhibit similar morphology and crystallinity; however, the detailed study of the NP composition was barred due to the high PPP amount retained on the NP surface. The catalyst testing in syngas conversion to methanol demonstrated outstanding catalytic properties of doped Zn-containing magnetic oxides, whose activities are dependent on the doping metal content and on the stabilizing polymer. The PPP stabilization allows for better access to the catalytic species due to the open and rigid polymer architecture and most likely optimized distribution of doping species. Repeat experiments carried out after magnetic separation of catalysts from the reaction mixture showed excellent catalyst stability even after five consecutive catalytic runs.

Nanosized Pt-, Ru-, and Pd-containing catalysts for organic synthesis and solution of environmental issues

Synthesis of Pt-, Ru-, and Pd-containing nanoparticles in the pores of polymeric matrix of hypercrosslinked polystyrene, their structure and catalytic properties are under consideration. Physicochemical studies have shown that metal nanoparticle formation depends on the properties of the polymeric matrix porous structure, the nature of metal precursors and the synthesis conditions. The study of catalytic properties of metal nanoparticles stabilized in mesoporous matrices showed promising applications of these systems in the reactions of selective oxidation and hydrogenation, which are intermediate stages in the synthesis of precursors of vitamins and medicines. In order to solve environmental problems, nanocatalysts were investigated in the processes of oxidative degradation of phenol and reductive denitrification of nitrates for purification of sewage and natural water.

Novel Nano Catalysts on the Base of Hyper-crosslinked Polystyrene for Carbohydrates Oxidation

The synthesis and catalytic properties of Pd, Pt, Ru nanoparticles in nanostructures of polymers are described. The controlled growth of metal nanoparticles in a polymer matrix was achieved. The catalytic systems have been studied in selective oxidation of monosaccharide. These processes are of particular interest because the products are the intermediates in the synthesis of biology active substances.

D-glucose catalytic oxidation over palladium nanoparticles introduced in the hypercrosslinked polystyrene matrix

Abstract This paper reports palladium (Pd)-containing nanoparticle (NP) formation in nanoporous hypercrosslinked polystyrene (HPS), using Pd acetate as a precursor. It was demonstrated that the NP size and composition can be controlled by Pd acetate loading and post-impregnation treatment with hydrogen gas. The catalyst structure was studied using transmission electron microscopy (TEM), X-ray fluorescence analysis, X-ray photoelectron spectroscopy (XPS) and nitrogen physisorption measurements. The catalytic properties of the catalysts developed have been studied in a green process of D-glucose oxidation to D-gluconic acid. The latter and its Ca salt are used for pharmaceuticals and food supplement production. The most active catalyst was found to contain 1.7 nm Pd/PdO NPs at 1.09 wt% Pd loading. It provided 99.6% selectivity at 93.6% conversion. Repeated use of the same catalyst demonstrated exceptional stability in D-glucose oxidation, making these catalysts promising for industrial applications in sustainable processes.

Correction to: Catalytic performance of the modified H-ZSM-5 zeolite in methanol transformation to hydrocarbons

The article was published without grant no in the acknowledgement. The complete acknowledgement is given in this correction.

Comparison of methanol to gasoline conversion in one-step, two-step, and cascade mode in the presence of H-ZSM-5 zeolite

ABSTRACT In this report, three technological modes for methanol-to-gasoline reaction in the presence of H-ZSM-5 catalyst are compared: (i) direct methanol transformation to hydrocarbons; (ii) two-step (methanol-dimethyl ether-hydrocarbons); and (iii) cascade pathway. Light hydrocarbon gases (methane, ethylene, propylene, and isobutene) and liquid aromatic hydrocarbons (benzene, toluene, xylene, cresol, durol, naphthalene, methylnaphthalene, ethyl naphthalene, isopropyl naphthalene, methyl isopropyl naphthalene, etc.) were found to be the main reaction products. The experimental results showed that the classical two-step methanol to gasoline (MTG) process nowadays remains the most effective for gasoline-range hydrocarbons production, while one-step and cascade schemes require further investigation and the development of reactor systems as well as the operating conditions. The product distribution of MTG synthesis after 120 h on stream in the case of two-step mode was found to be the following: liquid C6–C8 hydrocarbons – 23%; C1–C5 gaseous products – 65%; heavy C9–C12 hydrocarbons – 10%.

MODIFICATION OF ALUMOSILICATE H-ZSM-5 AND INVESTIGATION OF ITS CATALYTIC ACTIVITY IN TRANSFORMATION PROCESS OF METHANOL TO HYDROCARBONS

Приведены результаты исследования каталитической активности модифицированного алюмосиликата H-ZSM-5 в процессе трансформации метанола в углеводороды. Представлены результаты физико-химического анализа модифицированного H-ZSM-5 методами хемосорбции аммиака, сорбции азота, Рентгеновской фотоэлектронной спектроскопии, просвечивающей микроскопии. Показана зависимость активности модифицированного алюмосиликата H-ZSM-5 от его структурных характеристик.

Catalytic pyrolysis of peat with additions of oil-slime and polymeric waste

In this work the influence of natural and synthetic aluminosilicates, metal chlorides of iron subgroup on the peat low-temperature pyrolysis and co-pyrolysis of peat with oil-slime and polymeric waste was studied in variety of conditions (t = 350-650δC, catalyst loading: from 1 up to 30 % (wt.)). The use of bentonite clay (30 % (wt.)) at 460δC as a catalyst in peat pyrolysis resulted in increase of weight of gaseous and liquid products from 23 up to 30 % (wt.) and from 32 up to 45 % (wt.), respectively. Co-pyrolysis of peat and oil-slime in the presence of bentonite clay resulted in increase of gaseous product weight from 18 up to 26 % (wt.) and liquid fraction yield - from 45 up to 55 % (wt.) in comparison with precalculated value. The use of metal chlorides of iron subgroup (2 % (wt.) concentration) at 500 δC in the co-pyrolysis of peat and polymeric waste led to optimal conversion of substrate in desired products, 15 % increase of total weight of gaseous and liquid products formed during the pyrolysis ...