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Коваленко, А. С.; Chernenko, Zh. V.; Kochkin, Yu. N.; Алексеев, С. А.; Vlasenko, N. A.; Il’in, V. G.

doi:10.1023/a:1021701009584

Cited by 5 publications

(10 citation statements)

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“…Cases of using preliminarily prepared and specially formulated solubilization solutions in the MMS synthesis were only few. The other researchers took advantage of one of the alternatives: codissolution of a hydrocarbon in the micellar core of the freshly formed mesophase [8,10], introduction of a multicomponent template directly into the reaction [11], or utilization of cocondensing organic hydrophobic compounds in the synthesis [12]. In the latter case, localization of the hydrophobic3hydrophilic radicals in the surface layer of the micellar structures can be characterized as adsolubilization.…”

Section: Methodsmentioning

confidence: 99%

“…The ratio of the additives was varied and, since each additive was fixed at its specific place (cosurfactant was sorbed along the perimeter of the polar groups of the micelle, and TMB, codissolved in the CTMABr micelle core), these authors obtained composite mesostructures of Ti and Zr oxides with the pore diameter increased to 8.0 nm, while the degree of ordering of the hexagonal mesophase was not decreased. It was found that TMB increases the pore size more efficiently than toluene.Kovalenko et al [12] used organic hydrophobic cocondensing compounds in template synthesis for …”

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confidence: 99%

“…Kovalenko et al [12] preparing a diversity of functionalized MCM-41 materials. In hydrolysis of the ether groups of vinyl-or allyltriethoxysilane, the radicals formed were localized for the most part in the surface layer of the CTMABr micellar structures.…”

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confidence: 99%

“…In our previous work [14] we used a micellar solubilization solution (solubilized were monoethanolamides of medium and higher n-aliphatic acids EAC m with m = 10, 12,14,16) to increase the degree of ordering of the spatial organization of the substance rather that the mesopore diameter. This proved to be feasible under mixed solubilization conditions.…”

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confidence: 99%

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Solubilization compositions for template synthesis of mesoporous sorbents

Yaroshenko

Il’in

2004

Russ J Appl Chem

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The suitability of mixed solubilization compositions for template synthesis of mesoporous molecular sieves of various designations was demonstrated by analysis of published data and by the authors' experimental results.Scientific approach and experimental methods in physical and colloid chemistry of surfactants are developed and improved mostly for individual substances, idealized models, and simple systems. In practice, it is more expedient, however, to use surfactant-based compositions, as, e.g., in production of detergents, flotation reagents, defoliants, emulsifiers, pharmaceuticals, and cosmetics [137].The use of individual micelle-forming surfactants in template synthesis of mesoporous sorbents has been studied since 1992 [8,9]. Beck et al. [8] and Huo et al.[9] suggested a number of basic schemes of interaction between a skeleton-forming inorganic reagent (I) and a micelle-forming surfactant (S), template. These authors assumed that the assembly (selfassembly) is controlled by electrostatic interaction of the ions in solution, namely, between charged polar groups of the surfactant and inorganic counterions. This interaction is the most efficient in the case of long-chain surfactants based on quaternary ammonium cations (S + ) and anionic silicate precursors (I 3 ), yielding hexagonal, cubic, of lamellar mesostructures. More recently, this concept was extended to include the views on the synthesis routes involving inversely charged reagents (S 3 I + ), anionic surfactants such as sulfonates and phosphonates, as well as carboxylates and cations of inorganic precursors, buffer ions (S + X 3 I + , S 3 M + I 3 , where X is halogen, and M + , alkali metal cation).Irrespective of the scheme chosen, mesoporous sorbents are synthesized using insoluble/poorly soluble organic substances as auxiliary forming reagents. For example, Beck et al. [8] used trimethylbenzene (TMB) exerting a swelling (expanding) effect when added to a freshly synthesized template-containing mesophase: The diameter of the mesoporous molecular sieves (MMSs) increased from 4.0 to 6.5 nm. There is a good reason to assume that TMB is incorporated into the oil core of the micelle of the cationic surfactant.Nonpolar aliphatic and aromatic hydrocarbons, for the most part, efficiently promote structure formation when introduced into freshly synthesized materials. Hydrocarbons with linear and branched radicals (C 5 3 C 12 ) yield an M41S phase mixture and/or cause the pore size to increase. At the same time, polar organic substances, in particular, alcohols, aldehydes, ketones, ethers, and esters, generally did not efficiently increase the pore size of the MCM-41 mesophase and, moreover, often yielded amorphous materials [10].Kleitz et al. [11] prepared heat-resistant mesoporous oxides of transition metals (Ti and Zr) using binary organic additives, namely, 1-octanol as cosurfactant and toluene or TMB as swelling reagent. Both additives were introduced simultaneously with all the components (cetyltrimethylammonium bromide, CTMABr, acted as the basic t...

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Solubilization compositions for template synthesis of mesoporous sorbents

Yaroshenko

Il’in

2004

Russ J Appl Chem

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“…KCK silica (Russia, Stavropol) and Sg-60 silica (Merck) were used as initial materials for the covalent immobilisation of ethylsulphoacidic groups. Such acidic groups were obtained via the reaction of NaHSO 3 with vinyl groups immobilised on a silica surface [equation 1] as described previously by Kovalenko et al (2002) and Alekseev et al (2003):…”

Section: Experimental Materialsmentioning

confidence: 99%

Effect of Silanol Groups on the Acidic and Catalytic Properties of Alkylsulphoacidic Silicas and SiO₂/Nafion Nanocomposites

Алексеев

Zaitsev

Alekseev

et al. 2004

Adsorption Science & Technology

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Sets of silicas covalently modified with alkylsulphoacidic groups (SiO2-SO3H) and nanocomposites of silica with superacidic Nafion® polymer (SiO2/Nafion) were synthesised. End-capping the silanol groups with trimethylsilyl groups was used to obtain surface hydrophobisation. The materials obtained were characterised by nitrogen and water adsorption measurements, MAS NMR spectroscopy and dielectric relaxation spectroscopy (DRS). The acidity of the materials was tested by 31P MAS NMR spectroscopic examination of samples with adsorbed triethylphosphine oxide (TEPO). It was demonstrated that end-capping excluded part of the surface silanol groups from interaction with acidic groups, thereby causing the sulphonic groups to exhibit an increased acidity. With SiO2-SO3H, end-capping also increased their catalytic activity in the synthesis of ethyl t-butyl ether (ETBE). However, end-capping had a negligible effect on the catalytic properties of SiO2/Nafion, probably because the catalytic reaction occurred inside the Nafion polymer nanoparticles.

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Hybrid organic‐inorganic acid catalysts: The effect of active sites localization on catalytic characteristics in the processes of alcohols' etherification. A review

Vlasenko

Strizhak

2021

J of Applied Polymer Sci

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This article reviews the various types of hybrid organic–inorganic resin catalysts: mixed and co‐precipitated composites, loaded, and tailored systems. The review gives a generalization of the authors' results in the field of synthesis and research of organic–inorganic resin catalysts, in the context of the main trends in the development of this field of science. Based on a comparison of the productivity of organic–inorganic and commercial sulfonic resins, the role of acid sites localization for determining the catalytic characteristics of sulfonic resin catalysts in ethanol and isopropanol etherification with isobutylene is discussed. Studies showed that acid sites of loaded sulfonic resins, localized on the external surface, have the highest productivity. The effect of morphology on the differences in the activity of different types of sulfonic resins in the etherification reactions is more pronounced for materials with limited accessibility of acid sites due to internal diffusion. With an increase in the accessibility of acid sites, the polarity and molecule size of the reacting alcohols become the predominant factors. These findings have an impact on the design of organic–inorganic resin catalysts with high performance.

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Cited by 5 publications

References 4 publications

Solubilization compositions for template synthesis of mesoporous sorbents

Solubilization compositions for template synthesis of mesoporous sorbents

Effect of Silanol Groups on the Acidic and Catalytic Properties of Alkylsulphoacidic Silicas and SiO₂/Nafion Nanocomposites

Hybrid organic‐inorganic acid catalysts: The effect of active sites localization on catalytic characteristics in the processes of alcohols' etherification. A review

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Untitled

Cited by 5 publications

References 4 publications

Solubilization compositions for template synthesis of mesoporous sorbents

Solubilization compositions for template synthesis of mesoporous sorbents

Effect of Silanol Groups on the Acidic and Catalytic Properties of Alkylsulphoacidic Silicas and SiO2/Nafion Nanocomposites

Hybrid organic‐inorganic acid catalysts: The effect of active sites localization on catalytic characteristics in the processes of alcohols' etherification. A review

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Effect of Silanol Groups on the Acidic and Catalytic Properties of Alkylsulphoacidic Silicas and SiO₂/Nafion Nanocomposites