Synthesis of High-Ratio Mordenite

Synthesis of a mordenite-like zeolite from reaction mixtures of composition 2.5R ·. (2.2-7.3)Na₂O · Al₂O₃ · (12-40)SiO₂ · (300-1200)H₂O, where R is monoethanolamine, was studied. The crystallization conditions under which mordenite with a SiO₂/Al₂O₃ ratio of 13 to 22 can be synthesized were determined.     

Physicochemical and Engineering Problems in Studies on Plasma–Solution Systems

The example of an atmospheric-pressure glow discharge with an electrolytic cathode was used to show a significant role of the processes of transfer of solution components to the plasma zone, which were induced by ion bombardment of the surface of the solution. These processes not only determine the chemical composition of the plasma zone but also initiate redox reactions in the gas phase. In turn, the gas discharge alters the properties of the solution, in particular, its acidity, interfering with liquid-phase chemical reactions.     

Alkyl-substituted dipyrrylmethenes and their oxa- and thia-analogs: “structure—solvation properties” correlations

New data on the spectral properties and solution enthalpies of unsymmetrically substituted 2-(alkyl-2-pyrrolylmethylidene)methylpyrrolium bromides (or ,-dipyrrylmethene hydrobromides), their ,-, ,-isomers, as well as their oxa and thia analogs, that is, 2-(2-furylmethylidene)- and 2-(2-thienylmethylidene)-3,4,5-trimethyl-1H-pyrrolium bromides, in solutions of organic solvents of different nature are presented. A decrease in the number of substituents, as well as replacement of the heteroatom (N) in one five-membered ring of the dipyrrylmetnehe by oxygen or sulfur atoms cause a monotonic hypsochromic shift of absorption bands in the electronic absorption spectrum and weakening of the chromophore properties of the compounds. The chromophore properties of isomers are weakened from the ,- to ,- and ,-dipyrrylmethenes. Main trends in the influence of structural factors on the specific features of thermooxidative destruction of the above-mentioned compounds were analyzed.     

Synthesis of carboxylic acid esters in the presence of micro- and mesoporous aluminosilicates

The catalytic properties of zeolites HY, HBeta, and HZSM-12 and of mesoporous amorphous aluminosilicate in liquid-phase esterification of aliphatic (monobasic C₁–C₁₈, dibasic C₆, C₁₀) and aromatic (benzoic, trimellitic, phthalic) carboxylic acids with butanol were studied. Zeolite HBeta appeared to be the most active catalyst. Procedures were developed for preparing esters in the presence of zeolitic catalyst HBeta, ensuring 100% selectivity of ester formation at 90–98% conversion of the acid.     

Dimerization and oligomerization of styrene in the presence of pentasils

Styrene is converted to dimers under the action of zeolite ZSM-12 both in the presence and absence of the solvent (chlorobenzene). This transformation is characterized by a high conversion of the monomer (up to 100 wt.%) and selective formation of linear isomers (704-75%). In the presence of zeolites ZVN and VKZ in chlorobenzene, styrene forms a mixture of oligomers (n = 24-7), among which the dimers prevailed, while without the solvent oligomers with an average molecular weight of-1510 are formed.     

Synthesis of Mordenite-like Zeolite from Secondary Silicon-containing Raw Materials

A low-waste method is proposed for synthesizing a mordenite-like zeolite from secondary silicon-containing raw materials.     

Synthesis of Mordenite with the Use of Aluminum Sulfate Solutions

A procedure has been developed for synthesis of a mordenite-type zeolite with high phase purity and high dispersity of crystals. The procedure is based on hydrothermal crystallization of aluminum-silicon hydrogels prepared from aluminum sulfate solutions serving as a source of Al(III).     

Zeolites in the synthesis of quinolines by the Skraup reaction

Russian Chemical Bulletin - A novel heterogeneous catalytic method for the synthesis of quinoline (1) and a mixture of 2- and 4-methylquinolines (2) by Skraup reaction in the presence of H-Y,...     

Possibilities of Microporous and Hierarchical MFI Zeolites in the Synthesis of Nitrogen Heterocyclic Compounds

Kinetics and Catalysis - The catalytic properties of a microporous H-ZSM-5 zeolite and a granular hierarchical H-ZSM-5h zeolite in the synthesis of basic pyridines and quinolines have been studied....