Influence of the synthesis conditions on the preparation of titanium-pillared clays using hydrolyzed titanium ethoxide as the pillaring agent

Pillared clays are interesting materials with applications in catalysis and adsorption processes. To obtain these materials, several preparation procedures are necessary and must be optimized to tune the final properties of the resulting pillared clay. Therefore, this article reports the influence of synthesis parameters (temperature and concentration) of Keggin-Al13 polycations and different intercalation times (0.5 up to 72 h) on the structural properties of Al-pillared clays. The natural clays are from Brazil, and they are composed mainly of montmorillonite. By XRD, N2 sorption, XRF and 27Al NMR results of the Al-PILCs, we verified that the pillaring solution could be prepared at room temperature with an aging time of 24 h. For the cation exchange process, a period of at least 2 h is necessary to ensure the formation of pillared materials. The concentration of the Keggin-Al13 polycations was evaluated by using diluted pillaring solutions followed by applying re-pillaring procedures. After submitting the pillared clay to another pillaring process, the number of pillars in the interlamellar space increased; however, the micropore volume decreased concomitantly. Thus, by optimizing the synthesis conditions of the Keggin-Al13 polycations, Al-PILCs could be obtained with good values of basal spacing and specific surface area.

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Catalysts for hydrogenation of CO2 into components of motor fuels

Catalysis and petrochemistry ◽

10.15407/kataliz2020.30.001 ◽

2020 ◽

pp. 1-18

Author(s):

Yu.V. Bilokopytov ◽

◽

S.L. Melnykova ◽

N.Yu. Khimach ◽

◽

...

Keyword(s):

Carbon Dioxide ◽

Heterogeneous Catalysts ◽

Fossil Fuels ◽

Catalyst Stability ◽

Co2 Conversion ◽

Active Components ◽

Synthesis Conditions ◽

Hydrogenation Of Co2 ◽

Mesoporous Zeolites ◽

Motor Fuels

CO2 is a harmful greenhouse gas, a product of chemical emissions, the combustion of fossil fuels and car exhausts, and it is a widely available source of carbon. The review considers various ways of hydrogenation of carbon dioxide into components of motor fuels - methanol, dimethyl ether, ethanol, hydrocarbons - in the presence of heterogeneous catalysts. At each route of conversion of CO2 (into oxygenates or hydrocarbons) the first stage is the formation of CO by the reverse water gas shift (rWGS) reaction, which must be taken into account when catalysts of process are choosing. The influence of chemical nature, specific surface area, particle size and interaction between catalyst components, as well as the method of its production on the CO2 conversion processes is analyzed. It is noted that the main active components of CO2 conversion into methanol are copper atoms and ions which interact with the oxide components of the catalyst. There is a positive effect of other metals oxides additives with strong basic centers on the surface on the activity of the traditional copper-zinc-aluminum oxide catalyst for the synthesis of methanol from the synthesis gas. The most active catalysts for the synthesis of DME from CO2 and H2 are bifunctional. These catalysts contain both a methanol synthesis catalyst and a dehydrating component, such as mesoporous zeolites with acid centers of weak and medium strength, evenly distributed on the surface. The synthesis of gasoline hydrocarbons (≥ C5) is carried out through the formation of CO or CH3OH and DME as intermediates on multifunctional catalysts, which also contain zeolites. Hydrogenation of CO2 into ethanol can be considered as an alternative to the synthesis of ethanol through the hydration of ethylene. High activation energy of carbon dioxide, harsh synthesis conditions as well as high selectivity for hydrocarbons, in particular methane remains the main problems. Further increase of selectivity and efficiency of carbon dioxide hydrogenation processes involves the use of nanocatalysts taking into account the mechanism of CO2 conversion reactions, development of methods for removing excess water as a by-product from the reaction zone and increasing catalyst stability over time.

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Epoxy-titania composites of cationic polymerization: synthesis conditions and properties

Polymer journal ◽

10.15407/polymerj.37.04.402 ◽

2015 ◽

Vol 37 (4) ◽

pp. 402-407

Author(s):

S.V. Zhil’tsova ◽

◽

V.M. Mikhal’chuk ◽

N.G. Leonova ◽

R.I. Lyga ◽

...

Keyword(s):

Cationic Polymerization ◽

Synthesis Conditions

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Effect of synthesis conditions on the structure and properties of new SiCxNyMz materials for spintronics

Журнал структурной химии ◽

10.26902/jsc20170803 ◽

2017 ◽

Vol 58 (8) ◽

pp. 1543-1552

Author(s):

N.I. Fainer ◽

◽

R.V. Pushkarev ◽

V.A. Shestakov ◽

A.K. Gutakovsky ◽

...

Keyword(s):

Structure And Properties ◽

Synthesis Conditions

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SOME DIRECTIONS IN THE MODIFICATION OF AZOLES

SERIES CHEMISTRY AND TECHNOLOGY ◽

10.32014/2020.2518-1491.84 ◽

2020 ◽

Vol 5 (443) ◽

pp. 85-91

Author(s):

Ibrayev M.K., ◽

◽

Takibayeva A.T., ◽

Fazylov S.D., ◽

Rakhimberlinova Zh.B., ◽

...

Keyword(s):

13C Nmr Spectroscopy ◽

Biologically Active Compounds ◽

Biologically Active ◽

Active Compounds ◽

Synthesis Conditions ◽

Alkaloid Cytisine ◽

Azole Ring ◽

Cyclic Compounds ◽

New Compounds ◽

Derivatives Of

This article presents studies on the targeted search for new derivatives of azoles, such as benzthiazole, 3,5-dimethylpyrazole, 1,3,4-oxadiazole-2-thione, 1,3,4-thiadiazole. The possibility of combining in one molecule of the azole ring with other cyclic compounds: the alkaloid cytisine, morpholine, furan and some arenes has been studied. To obtain new compounds, the reactions of bromination, acylation, and interaction with isothiocyanates were studied. Optimal synthesis conditions were studied for all reactions. It was found that the reaction of 4-bromo-3,5-dimethylpyrazole with isothiocyanates, in contrast to the previously written derivatives of anilines, takes a longer time and requires heating the reaction mixture. The combination of a pirasol fragment with halide substituents often results in an enhanced therapeutic effect. The synthesized 2-bromine-N-(6-rodanbenzo[d]thiazole-2-yl)acetamide, due to the alkylbromide group, is an important synth in the synthesis of new benzthiazole derivatives. Its derivatives combine in one molecule the rest of rhodanbenzthiazole with alkaloid cytisine and biogenic amine morpholine and are potentially biologically active compounds, since the molecule structure contains several pharmacophoric fragments: benzthiazole and alkaloid (amine) heterocycles, rhodane and urea groups. The mechanism of formation of 1,3,4-oxadiazole-2-tyons from hydrazides under action on them by carbon disulfide was studied and assumed. It was shown that dithiocarbamates in acidic medium decompose with the release of hydrogen sulfide and the formation of highly reactive isothiocyanate group. Then, intra-molecular cyclization occurs, with the formation of end products - 1,3,4-oxadiazole-2-thions. The structures of the synthesized compounds were studied by 1H and 13C NMR spectroscopy. All synthesized substances are potentially biologically active compounds, since they contain several pharmacophore fragments in their structure.

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Ultrafine β-FeOOH: the Influence of Synthesis Conditions on the Morphological, Magnetic and Electrochemical Properties

Journal of Nano- and Electronic Physics ◽

10.21272/jnep.10(3).03029 ◽

2018 ◽

Vol 10 (3) ◽

pp. 03029-1-03029-6

Author(s):

L. V. Mokhnatska ◽

◽

V. O. Kotsyubynsky ◽

A. B. Hrubiak ◽

S. V. Fedorchenko ◽

...

Keyword(s):

Electrochemical Properties ◽

Synthesis Conditions

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Targeted Delivery of Cabazitaxel by Conjugation to Albumin-PEG-folate Nanoparticles Using a Cysteine-acrylate Linker and Simple Synthesis Conditions

Current Drug Delivery ◽

10.2174/1567201814666161122150302 ◽

2017 ◽

Vol 14 (8) ◽

Cited By ~ 5

Author(s):

Mohammad Kazem Khoeeniha ◽

Mehdi Esfandyari-Manesh ◽

Hossein Behrouz ◽

Mohsen Amini ◽

Behrang Shiri Varnamkhasti ◽

...

Keyword(s):

Targeted Delivery ◽

Simple Synthesis ◽

Synthesis Conditions

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Preparation and properties of green rust type substances

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19870093 ◽

1987 ◽

Vol 52 (1) ◽

pp. 93-102 ◽

Cited By ~ 27

Author(s):

Jaroslav Vinš ◽

Jan Šubrt ◽

Vladimír Zapletal ◽

František Hanousek

Keyword(s):

Chemical Composition ◽

Electron Diffraction ◽

Green Rust ◽

X Ray ◽

Synthesis Conditions ◽

Diffraction Patterns

A method has been worked out for the reproducible preparation of Green Rust substances involving SO42-, Cl-, Br-, and I- anions. The chemical composition of the substances prepared has been followed in dependence on the synthesis conditions. The powder X-ray and electron diffraction patterns and infrared and Moessbauer spectra have been measured and discussed.

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Metal Oxide Nanostructures Chemistry

10.1093/oso/9780190928117.001.0001 ◽

2019 ◽

Author(s):

Jean-Pierre Jolivet

Keyword(s):

Particle Growth ◽

General View ◽

Ceramic Powders ◽

Metal Hydroxides ◽

Synthesis Conditions ◽

Zirconium Oxides ◽

Oxide Nanostructures ◽

Metal Oxide Nanostructures ◽

Ordered Aggregation ◽

Size And Morphology

This much-anticipated new edition of Jolivet's work builds on the edition published in 2000. It is entirely updated, restructured and increased in content. The book focuses on the formation by techniques of green chemistry of oxide nanoparticles having a technological interest. Jolivet introduces the most recent concepts and modelings such as dynamics of particle growth, ordered aggregation, ionic and electronic interfacial transfers. A general view of the metal hydroxides, oxy-hydroxides and oxides through the periodic table is given, highlighting the influence of the synthesis conditions on crystalline structure, size and morphology of nanoparticles. The formation of aluminum, iron, titanium, manganese and zirconium oxides are specifically studied. These nanomaterials have a special interest in many technological fields such as ceramic powders, catalysis and photocatalysis, colored pigments, polymers, cosmetics and also in some biological or environmental phenomena.

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