Catalysts Based on High-Vanadium Solutions of Molybdovanadophosphoric Heteropolyacids: Achievements,Challenges, and Prospects

Kinetics and Catalysis - A retrospective review based on the authors’ work is devoted to homogeneous catalytic systems based on aqueous solutions of Mo–V–P heteropolyacids (HPA-x,...     

Study of Medieval Russian Enamel Pendant Using a Complex of Nondestructive Methods

Crystallography Reports - A medieval Russian bronze pendant icon with enamel images, dated to the period from the 12th to the first half of the 13th century was studied. The investigation was...     

Synthesis of 1,4-Dimethyl-9,10-Anthraquinone from 1,4-Naphthoquinone and 2,4-Hexadiene in the Presence of Heteropoly Acids

Kinetics and Catalysis - The synthesis of 1,4-dimethyl-9,10-anthraquinone (DMAQ) from 1,4-naphthoquinone and 2,4‑hexadiene was studied based on a new one-step method developed by the authors...     

Preparation of Vitamin K3 in Mo–V–P Heteropoly Acid Solutions by Diene Synthesis

Kinetics and Catalysis - The possibility of obtaining vitamin K3 (2-methyl-1,4-naphthoquinone, menadione) by diene synthesis from accessible substrates such as 2-methylphenol (o-cresol) and...     

Selective oxidation of hydrocarbons into synthesis gas at short contact times: Design of monolith catalysts and main process parameters

This review summarizes the main achievements of the Boreskov Institute of Catalysis (Siberian Division, Russian Academy of Sciences) in the development of efficient and stable monolith catalysts for selective oxidation of hydrocarbons into synthesis gas at short contact times. Research in this field has included (1) design of new types of active component based on metal oxides, (2) design of new types of monolith support and development of supporting procedures for active components, and (3) optimization of process parameters for different types of fuel (natural gas, isooctane, and gasoline) and oxidant (air oxygen, including its mixtures with water and carbon dioxide), including the start-up regime. Design of active components (platinum, nickel, or their combination) supported on fluorite-like solid solutions based on cerium dioxide and rare-earth (samarium, gadolinium, and praseodymium) or zirconium cations has been aimed at separating hydrocarbon activation (on metal sites) and oxidation (on the support) and conjugating the separated steps of hydrocarbon oxidation at the metal-oxide interface. Optimization of oxygen mobility in the support lattice by varying the nature and concentration of doping cation along with optimization of hydrocarbon activation on supported metal clusters allow hydrocarbons to be completely converted into synthesis gas by selective oxidation or dry or steam reforming at contact times of a few milliseconds, ruling out undesirable carbon build-up on the catalyst surface. The development of new types of monolith support has targeted the enhancement of thermal shock resistance, including testing of supports based on thermally stable metal foils and composites (cermets). The main steps of the production of these supports have been refined, including unique technologies of blast dusting and hydrothermal treatment. The electric conductivity of these systems allows a quick startup of selective oxidation to be performed by passing electric current, and their thermal conductivity minimizes the temperature gradient arising from heat transfer in the bed. Procedures for loading monolith supports with active components have been developed, including impregnation, washcoating, or encapsulation in cermet matrices. The catalysts produced show a high efficiency and an operational stability adequate to the above tasks in the selective oxidation and steam-air autothermal reforming of natural gas (including processes under pressure), isooctane, and gasoline into synthesis gas.__________Translated from Kinetika i Kataliz, Vol. 46, No. 2, 2005, pp. 243–268.Original Russian Text Copyright © 2005 by Sadykov, Pavlova, Bunina, Alikina, Tikhov, Kuznetsova, Frolova, Lukashevich, Snegurenko, Sazonova, Kazantseva, Dyatlova, Usoltsev, Zolotarskii, Bobrova, Kuzmin, Gogin, Vostrikov, Potapova, Muzykantov, Paukshtis, Burgina, Rogov, Sobyanin, Parmon.     

One-Pot Process to Produce Anthraquinone Derivatives: Prospective Wood Delignification Catalysts

Derivatives of 9,10-anthraquinone (AQ) are widely used chemicals but the currently practiced methods for their production are inefficient and environmentally harmful. In the present work, an innovative method for synthesis of substituted AQ from hydroquinone (HQ) and substituted dienes (2,3-dimethylbutadiene, DMB) was studied with the synthesis of 2,3,6,7-tetramethyl-9,10-AQ (TMAQ) as an example. A solution of high-vanadium heteropoly acid H₁₇P₃Mo₁₆V₁₀O₈₉ (HPA-10) was used as the bifunctional (acid and oxidative) catalyst for the new one-pot process. The influence of a number of factors on the key process parameters was studied. An insoluble mixture of two products (80% TMAQ and 20% DHTMAQ—an underoxidized dihydroderivative of TMAQ) was synthesized in 24 h under the chosen conditions. The mixture can be used as an effective catalyst for wood delignification. The results obtained offer real possibilities for developing low-waste processes of substituted AQ synthesis from HQ and substituted 1,3-dienes in the presence of HPA-10 solutions. The catalysts are highly active, stable and effective.     

Effect of substituents on the chemical shift of the ring protons in the PMR spectra of monosubstituted sym-triazines

A correlation equation that links the relative chemical shift of the protons of the triazine ring with the F and R constants of the substituents was obtained on the basis of data from the PMR spectra of solutions of sym-triazine and its monosubstituted derivatives [OCH₃, N(CH₃)₂, CH₃, C₆H₅, COOC₂H₅, and CN] in dimethyl sulfoxide (DMSO). The equation was analyzed by comparison with the corresponding equations for monosubstituted benzenes and pyrimidines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 410–414, March, 1982.