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5 pages, 185 KiB

Open AccessEditorial

Catalysis by Hybrid Nanomaterials

by Leonid M. Kustov

Molecules 2021, 26(2), 352; https://doi.org/10.3390/molecules26020352 - 12 Jan 2021

Cited by 11 | Viewed by 2035

Abstract

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(This article belongs to the Special Issue Catalysis by Hybrid Materials)

Research

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22 pages, 18746 KiB

Open AccessArticle

Naphthalene-Based Polymers as Catalytic Supports for Suzuki Cross-Coupling

by Elena S. Bakhvalova, Alexey V. Bykov, Mariia E. Markova, Yury V. Lugovoy, Alexander I. Sidorov, Vladimir P. Molchanov, Mikhail G. Sulman, Lioubov Kiwi-Minsker and Linda Z. Nikoshvili

Molecules 2023, 28(13), 4938; https://doi.org/10.3390/molecules28134938 - 23 Jun 2023

Cited by 1 | Viewed by 1442

Abstract

In this work, for the first time, naphthalene (NA)-based polymers were synthesized by one-stage Friedel–Crafts crosslinking. The influence of NA functionalization by -OH, -SO₃H, and -NO₂ groups on the polymers’ porosity and distribution of the catalytically active phase (Pd) was [...] Read more.

In this work, for the first time, naphthalene (NA)-based polymers were synthesized by one-stage Friedel–Crafts crosslinking. The influence of NA functionalization by -OH, -SO₃H, and -NO₂ groups on the polymers’ porosity and distribution of the catalytically active phase (Pd) was studied. Synthesized catalytic systems containing 1 wt.% of Pd either in the form of Pd(II) species or Pd(0) nanoparticles supported on NA-based polymers were tested in a model reaction of Suzuki cross-coupling between 4-bromoanisole and phenylboronic acid under mild reaction conditions (60 °C, ethanol-water mixture as a solvent). These novel catalysts demonstrated high efficiency with more than 95% of 4-bromoanisole conversion and high selectivity (>97%) for the target 4-methoxybiphenyl. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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26 pages, 4285 KiB

Open AccessArticle

Polypropylene Nanocomposites Attained by In Situ Polymerization Using SBA-15 Particles as Support for Metallocene Catalysts: Effect of Molecular Weight and Tacticity on Crystalline Details, Phase Transitions and Rheological Behavior

by Rosa Barranco-García, Alberto García-Peñas, Enrique Blázquez-Blázquez, Jorge A. Ressia, Lidia M. Quinzani, Enrique M. Vallés, José M. Gómez-Elvira, Ernesto Pérez and María L. Cerrada

Molecules 2023, 28(11), 4261; https://doi.org/10.3390/molecules28114261 - 23 May 2023

Cited by 1 | Viewed by 1507

Abstract

In this study, nanocomposites based on polypropylene are synthesized by the in situ polymerization of propene in the presence of mesoporous SBA-15 silica, which acts as a carrier of the catalytic system (zirconocene as catalyst and methylaluminoxane as cocatalyst). The protocol for the [...] Read more.

In this study, nanocomposites based on polypropylene are synthesized by the in situ polymerization of propene in the presence of mesoporous SBA-15 silica, which acts as a carrier of the catalytic system (zirconocene as catalyst and methylaluminoxane as cocatalyst). The protocol for the immobilization and attainment of hybrid SBA-15 particles involves a pre-stage of contact between the catalyst with cocatalyst before their final functionalization. Two zirconocene catalysts are tested in order to attain materials with different microstructural characteristics, molar masses and regioregularities of chains. Some polypropylene chains are able to be accommodated within the silica mesostructure of these composites. Thus, an endothermic event of small intensity appears during heating calorimetric experiments at approximately 105 °C. The existence of these polypropylene crystals, confined within the nanometric channels of silica, is corroborated by SAXS measurements obtained via the change in the intensity and position of the first-order diffraction of SBA-15. The incorporation of silica also has a very significant effect on the rheological response of the resultant materials, leading to important variations in various magnitudes, such as the shear storage modulus, viscosity and δ angle, when a comparison is established with the corresponding neat iPP matrices. Rheological percolation is reached, thus demonstrating the role of SBA-15 particles as filler, in addition to the supporting role that they exert during the polymerizations. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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21 pages, 4127 KiB

Open AccessArticle

The Effect of Sodium Bentonite in the Thermo-Catalytic Reduction of Viscosity of Heavy Oils

by Zhichao Zhou, Wangyuan Zhang, Tao Yu, Yongfei Li, Alena Struhárová, Marián Matejdes, Michal Slaný and Gang Chen

Molecules 2023, 28(6), 2651; https://doi.org/10.3390/molecules28062651 - 15 Mar 2023

Cited by 10 | Viewed by 1991

Abstract

To study the synergistic catalysis of an ex situ catalyst and in situ clay in the aquathermolysis of heavy oil, in this paper, a series of bentonite-supported catechol-metal complexes were prepared, and the catalytic viscosity reduction performance in the aquathermolysis of heavy oil [...] Read more.

To study the synergistic catalysis of an ex situ catalyst and in situ clay in the aquathermolysis of heavy oil, in this paper, a series of bentonite-supported catechol-metal complexes were prepared, and the catalytic viscosity reduction performance in the aquathermolysis of heavy oil was investigated. Under the optimized conditions, the viscosity can be reduced by 73%, and the pour point can be lowered by 15.0 °C at most, showing the synergistic catalysis of the ex situ catalyst and in situ clay in this aquathermolytic reaction. Thermogravimetry, physical adsorption-desorption, and scanning electron microscopy were conducted to characterize the thermal stability and microstructure of the ex situ catalyst. The components of the heavy oil before and after the reaction were fully characterized. Six model compounds were used to simulate the aquathermolysis reaction process. In order to study the mechanism of viscosity reduction after the catalytic aquathermolysis reaction, the compounds were analyzed by GC-MS. It is believed that these results will be beneficial in the future for related research in this field. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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25 pages, 4139 KiB

Open AccessArticle

Design of Nickel Supported Hierarchical ZSM-5/USY Zeolite Bifunctional Catalysts for One-Pot Menthol Synthesis via Liquid-Phase Citral Hydrogenation

by Abdul Karim Shah, Ghulam Taswar Shah, Aqeel Ahmed Shah, Yeung Ho Park, Ayaz Ali Shah, Mooseok Choi, Shoaib Ahmed, Syed Nizamuddin Shah Bukhari, Ali Dad Chandio, Muhammad Atta Mahar, Muhammad Ali Shar and Abdulaziz Alhazaa

Molecules 2023, 28(2), 743; https://doi.org/10.3390/molecules28020743 - 11 Jan 2023

Cited by 1 | Viewed by 2229

Abstract

Nickel-supported hierarchical zeolite catalysts were prepared through a desilication reassembly process under optimized conditions and applied in one-pot menthol synthesis. In this work, the hierarchical zeolite-supported metal bifunctional catalysts were prepared with the help of desilication re-assembly and wetness impregnation techniques and applied [...] Read more.

Nickel-supported hierarchical zeolite catalysts were prepared through a desilication reassembly process under optimized conditions and applied in one-pot menthol synthesis. In this work, the hierarchical zeolite-supported metal bifunctional catalysts were prepared with the help of desilication re-assembly and wetness impregnation techniques and applied in menthol synthesis via citral hydrogenation. The prepared catalysts were characterized using PXRD, BET, FE-TEM, NH₃-TPD, H₂-TPR, pyridine adsorption, and ICP-OES techniques. As a result, the physicochemical and acidic properties, such as mesopore surface area, metal dispersion, acidity, catalytic activity, and strong Lewis acid sites of pure microporous ZSM-5/USY zeolites, were significantly improved. Consequently, with the occurrence of superior physicochemical and acidic properties, the Ni/HZ-0.5 M catalyst exhibited outstanding catalytic activity (100% conversion, TOF 7.12 h⁻¹) and menthol selectivity (83%, 4 h) with uniform stability at 100 °C, 1.0 MPa hydrogen. Similarly, the cracking rate decreased with the decrease in Bronsted acid sites. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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12 pages, 6615 KiB

Open AccessEditor’s ChoiceArticle

Low-Temperature Toluene Oxidation on Fe-Containing Modified SBA-15 Materials

by Ivalina Trendafilova, Manuel Ojeda, John M. Andresen, Alenka Ristić, Momtchil Dimitrov, Nataša Novak Tušar, Genoveva Atanasova and Margarita Popova

Molecules 2023, 28(1), 204; https://doi.org/10.3390/molecules28010204 - 26 Dec 2022

Cited by 3 | Viewed by 2245

Abstract

Transition metals as catalysts for total VOC oxidation at low temperatures (150–280 °C) are a big challenge nowadays. Therefore, iron-modified SBA-15, AlSBA-15, and ZrSBA-15 materials with 0.5 to 5.0 wt.% Fe loading were prepared and tested for toluene oxidation. It was found that [...] Read more.

Transition metals as catalysts for total VOC oxidation at low temperatures (150–280 °C) are a big challenge nowadays. Therefore, iron-modified SBA-15, AlSBA-15, and ZrSBA-15 materials with 0.5 to 5.0 wt.% Fe loading were prepared and tested for toluene oxidation. It was found that increasing Fe loading significantly improved the rate of oxidation and lowered the temperature of achieving 100% removal of toluene from above 500 °C for the supports (AlSBA-15 and ZrSBA-15) to below 400 °C for 5FeZrSBA-15. The formation of finely dispersed iron oxide active sites with a particle size less than 5 nm was observed on all the SBA-15, AlSBA-15, and ZrSBA-15 supports. It was found that the surface properties of the mesoporous support due to the addition of Al or Zr predetermined the type of formed iron oxide species and their localization on the support surface. Fe-containing SBA-15 and AlSBA-15 showed activity in total toluene oxidation at higher temperatures (280–450 °C). However, 5 wt. % Fe-containing ZrSBA-15 showed excellent activity in the total oxidation of toluene as a model VOC at lower temperatures (150–380 °C) due to the synergistic effect of Fe-Zr and the presence of accessible and stable Fe²⁺/Fe³⁺ active sites. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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18 pages, 5207 KiB

Open AccessArticle

Immobilization of Peroxo-Heteropoly Compound and Palladium on Hydroxyapatite for the Epoxidation of Propylene by Molecular Oxygen in Methanol

by Yanyong Liu

Molecules 2023, 28(1), 24; https://doi.org/10.3390/molecules28010024 - 20 Dec 2022

Cited by 1 | Viewed by 1778

Abstract

Peroxo-heteropoly compound PO₄[W(O)(O₂)₂] was synthesized on calcium-deficient hydroxyapatite using a reaction of surface [HPO₄]²⁻ groups on hydroxyapatite with a Na₂[W₂O₃(O₂)₄] aqueous solution. The vibration [...] Read more.

Peroxo-heteropoly compound PO₄[W(O)(O₂)₂] was synthesized on calcium-deficient hydroxyapatite using a reaction of surface [HPO₄]²⁻ groups on hydroxyapatite with a Na₂[W₂O₃(O₂)₄] aqueous solution. The vibration of [HPO₄]²⁻ at 875 cm⁻¹ became very weak, and the vibration of the peroxo-oxygen bond [O–O]²⁻ at 845 cm⁻¹ appeared in the FT-IR spectrum of the solid product, indicating that PO₄[W(O)(O₂)₂] was formed on the surface of hydroxyapatite. The formed solid sample was further reacted with PdCl₂(PhCN)₂ in an acetone solution to fix PdCl₂ between the O sites on the hydroxyapatite. Elemental analyses proved that the resultant solid contained 1.2 wt.% Pd, implying that PdCl₂ molecules were immobilized on the surface of hydroxyapatite. The hydroxyapatite-based hybrid compound containing Pd and PO₄[W(O)(O₂)₂] was used as a heterogeneous catalyst in a methanol solvent for propylene epoxidation by molecular oxygen in an autoclave batch reaction system. A propylene conversion of 53.4% and a selectivity for propylene oxide of 88.7% were obtained over the solid catalyst after reaction at 363 K for 8 h. The novel catalyst could be reused by a simple centrifugal separation, and the yield of propylene oxide did not decrease after the reaction for five runs. By prolonging the reaction time to 13 h, the highest yield of propylene oxide at 363 K over the solid catalyst was obtained as 53.8%, which was almost the same as that of the homogeneous catalyst containing PdCl₂(PhCN)₂ and [(C₆H₁₃)₄N]₂{HPO₄[W(O)(O₂)₂]₂} for the propylene epoxidation. Methanol was used as a solvent as well as a reducing agent in the propylene epoxidation by molecular oxygen. Small particles of Pd metal were formed on the surface of the hybrid solid catalyst during the reaction, and acted as active species to achieve the catalytic turnover of PO₄[W(O)(O₂)₂] in the propylene epoxidation by molecular oxygen in methanol. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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20 pages, 3808 KiB

Open AccessArticle

Facile Synthesis of Micro-Mesoporous Copper Phyllosilicate Supported on a Commercial Carrier and Its Application for Catalytic Hydrogenation of Nitro-Group in Trinitrobenzene

by Olga Kirichenko, Gennady Kapustin, Igor Mishin, Vera Nissenbaum, Elena Shuvalova, Elena Redina and Leonid Kustov

Molecules 2022, 27(16), 5147; https://doi.org/10.3390/molecules27165147 - 12 Aug 2022

Cited by 5 | Viewed by 2174

Abstract

Development of novel Cu-based catalysts has become one of the frontiers in the catalytic production of platform chemicals and in environment protection. However, the known methods of their synthesis are too complicated and result in materials that cannot be used instantly as commercial [...] Read more.

Development of novel Cu-based catalysts has become one of the frontiers in the catalytic production of platform chemicals and in environment protection. However, the known methods of their synthesis are too complicated and result in materials that cannot be used instantly as commercial catalysts. In the present work, a novel material has been synthesized by the facile method of deposition–precipitation using thermal hydrolysis of urea. The conditions for Cu phyllosilicate formation have been revealed (molar ratio urea:copper = 10, 92 °C, 8–11 h). The prepared Cu-based materials were studied by TG–DTA, SEM, TEM, XRD, N₂ adsorption and TPR-H₂ methods, and it was found that the material involves nanoparticles of micro-mesoporous copper phyllosilicate phase with a chrysocolla-like structure inside the pores of a commercial meso-macroporous silica carrier. The chrysocolla-like phase is first shown to be catalytically active in the selective reduction of the nitro-group in trinitrobenzene to an amino-group with molecular hydrogen. Complete conversion of trinitrobenzene with a high yield of amines has been achieved in short time under relatively mild conditions (170 °C, 1.3 MPa) of nitroarene hydrogenation over a copper catalyst. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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14 pages, 5416 KiB

Open AccessArticle

Hybrid Pd-Nanoparticles within Polymeric Network in Selective Hydrogenation of Alkynols: Influence of Support Porosity

by Linda Z. Nikoshvili, Alexander Y. Popov, Alexey V. Bykov, Alexander I. Sidorov and Lioubov Kiwi-Minsker

Molecules 2022, 27(12), 3842; https://doi.org/10.3390/molecules27123842 - 15 Jun 2022

Cited by 1 | Viewed by 1744

Abstract

This work is addressing the selective hydrogenation of alkynols over hybrid catalysts containing Pd-nanoparticles, within newly synthesized hyper-cross-linked polystyrenes (HPS). Alkynols containing C₅, C₁₀, and C₂₀ with a terminal triple bond, which are structural analogues or direct semi-products [...] Read more.

This work is addressing the selective hydrogenation of alkynols over hybrid catalysts containing Pd-nanoparticles, within newly synthesized hyper-cross-linked polystyrenes (HPS). Alkynols containing C₅, C₁₀, and C₂₀ with a terminal triple bond, which are structural analogues or direct semi-products of fragrant substances and fat-soluble vitamins, have been studied. Selective hydrogenation was carried out in a batch mode (ambient hydrogen pressure, at 90 °C, in toluene solvent), using hybrid Pd catalysts with low metal content (less than 0.2 wt.%). The microporous and mesoporous HPS were both synthesized and used as supports in order to address the influence of porosity. Synthesized catalysts were shown to be active and selective: in the case of C₅, hydrogenation selectivity to the target product was more than 95%, at close to complete alkynol conversion. Mesoporous catalysts have shown some advantages in hydrogenation of long-chain alkynols. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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7 pages, 670 KiB

Open AccessArticle

Kinetic Modeling of Hydrogen Production by Dehydrogenation of Polycyclic Naphthenes with Varying Degrees of Condensation

by Alexander N. Kalenchuk and Leonid M. Kustov

Molecules 2022, 27(7), 2236; https://doi.org/10.3390/molecules27072236 - 30 Mar 2022

Cited by 8 | Viewed by 1802

Abstract

The kinetics of reactions of dehydrogenation of polycyclic naphthenes (cyclohexane, decalin, bicyclohexyl, ortho-, meta-, and para-isomers of perhydroterphenyl) is modeled on the basis of a formal comparison of kinetic equations of the 1st and 2nd orders based on real experimental [...] Read more.

The kinetics of reactions of dehydrogenation of polycyclic naphthenes (cyclohexane, decalin, bicyclohexyl, ortho-, meta-, and para-isomers of perhydroterphenyl) is modeled on the basis of a formal comparison of kinetic equations of the 1st and 2nd orders based on real experimental data. It is shown that the reaction of the 1st order is predominating in the series of cyclohexane–bicyclohexyl–perhydroparatherphenyl. For all other substrates, the probability of describing the reaction in accordance with the equation of the 2nd order increases markedly, and for trans-decalin it becomes the predominant form of describing the kinetics of the reaction. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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10 pages, 2781 KiB

Open AccessArticle

Conversion of Phenol and Lignin as Components of Renewable Raw Materials on Pt and Ru-Supported Catalysts

by Aleksey E. Koklin, Nataliia A. Bobrova, Tatiana V. Bogdan, Igor I. Mishanin and Viktor I. Bogdan

Molecules 2022, 27(5), 1494; https://doi.org/10.3390/molecules27051494 - 23 Feb 2022

Cited by 14 | Viewed by 2015

Abstract

Hydrogenation of phenol in aqueous solutions on Pt-Ni/SiO₂, Pt-Ni-Cr/Al₂O₃, Pt/C, and Ru/C catalysts was studied at temperatures of 150–250 °C and pressures of 40–80 bar. The possibility of hydrogenation of hydrolysis lignin in an aqueous medium in [...] Read more.

Hydrogenation of phenol in aqueous solutions on Pt-Ni/SiO₂, Pt-Ni-Cr/Al₂O₃, Pt/C, and Ru/C catalysts was studied at temperatures of 150–250 °C and pressures of 40–80 bar. The possibility of hydrogenation of hydrolysis lignin in an aqueous medium in the presence of a Ru/C catalyst is shown. The conversion of hydrolysis lignin and water-soluble sodium lignosulfonate occurs with the formation of a complex mixture of monomeric products: a number of phenols, products of their catalytic hydrogenation (cyclohexanol and cyclohexanone), and hydrogenolysis products (cyclic and aliphatic C₂–C₇ hydrocarbons). Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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14 pages, 1774 KiB

Open AccessArticle

Zn Doping Effect on the Performance of Fe-Based Catalysts for the Hydrogenation of CO₂ to Light Hydrocarbons

by Nikolay Dmitrievich Evdokimenko, Gennady Ivanovich Kapustin, Olga Petrovna Tkachenko, Konstantin Borisovich Kalmykov and Alexander Leonidovich Kustov

Molecules 2022, 27(3), 1065; https://doi.org/10.3390/molecules27031065 - 4 Feb 2022

Cited by 19 | Viewed by 3015

Abstract

In this work, we studied the role of zinc in the composition of supported iron-containing catalysts for the hydrogenation of CO₂. Various variants of incipient wetness impregnation of the support were tested to obtain catalyst samples. The best results are shown [...] Read more.

In this work, we studied the role of zinc in the composition of supported iron-containing catalysts for the hydrogenation of CO₂. Various variants of incipient wetness impregnation of the support were tested to obtain catalyst samples. The best results are shown for samples synthesized by co-impregnation of the support with a common solution of iron and zinc precursors at the same molar ratio of iron and zinc. Catalyst samples were analyzed by various methods: Raman, DRIFT-CO, TPR-H₂, XPS, and UV/Vis. The introduction of zinc leads to the formation of a mixed ZnFe₂O₄ phase. In this case, the activation of the catalyst proceeds through the stage of formation of the metastable wustite phase FeO. The formation of this wustite phase promotes the formation of metallic iron in the composition of the catalyst under the reaction conditions. It is believed that the presence of metallic iron is a necessary step in the formation of iron carbides—that is, active centers for the formation and growth of chain in the hydrocarbons. This leads to an increase in the activity and selectivity of the formation of hydrocarbons in the process of CO₂ hydrogenation. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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9 pages, 3783 KiB

Open AccessArticle

Microwave Synthesis of Copper Phyllosilicates as Effective Catalysts for Hydrogenation of C≡C Bonds

by Anastasiya Shesterkina, Kseniia Vikanova, Egor Kostyukhin, Anna Strekalova, Elena Shuvalova, Gennady Kapustin and Tapio Salmi

Molecules 2022, 27(3), 988; https://doi.org/10.3390/molecules27030988 - 1 Feb 2022

Cited by 7 | Viewed by 2302

Abstract

For the first time, the new microwave-assisted method for the synthesis of copper phyllosilicates on a commercial SiO₂ carrier was developed. The application of microwave synthesis allowed to decrease the synthesis time from 9 to 6 h compared to the traditional DPU [...] Read more.

For the first time, the new microwave-assisted method for the synthesis of copper phyllosilicates on a commercial SiO₂ carrier was developed. The application of microwave synthesis allowed to decrease the synthesis time from 9 to 6 h compared to the traditional DPU method of preparing chrysocolla. The synthesized catalysts were studied by N₂ adsorption, TEM and XRD methods. Catalysts prepared by microwave method are highly effective in the selective hydrogenation of the С≡С bond in 1,4-butynediol to 1,4-butenediol and 2-phenylethinylaniline with a selectivity of 96.5% and 100% at full conversion for 2 and 0.5 h of the reaction, respectively. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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10 pages, 1990 KiB

Open AccessArticle

Nitrous Oxide Adsorption and Decomposition on Zeolites and Zeolite-like Materials

by Leonid M. Kustov, Sergey F. Dunaev and Alexander L. Kustov

Molecules 2022, 27(2), 398; https://doi.org/10.3390/molecules27020398 - 8 Jan 2022

Cited by 6 | Viewed by 2547

Abstract

Decomposition of N₂O on modified zeolites, crystalline titanosilicalites, and related amorphous systems is studied by the catalytic and spectroscopic methods. Zinc-containing HZSM-5 zeolites and titanosilicalites with moderate Ti/Si ratios are shown to exhibit a better catalytic performance in N₂O [...] Read more.

Decomposition of N₂O on modified zeolites, crystalline titanosilicalites, and related amorphous systems is studied by the catalytic and spectroscopic methods. Zinc-containing HZSM-5 zeolites and titanosilicalites with moderate Ti/Si ratios are shown to exhibit a better catalytic performance in N₂O decomposition as compared with conventionally used Cu/HZSM-5 zeolites and amorphous Cu-containing catalysts. Dehydroxylation of the HZSM-5 zeolite by calcination at 1120 K results in an enhancement of the N₂O conversion. The mechanism of the reaction and the role of coordinatively unsaturated cations and Lewis acid sites in N₂O decomposition are discussed on the basis of the spectroscopic data. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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15 pages, 11235 KiB

Open AccessArticle

Noble Metal Nanoparticles Stabilized by Hyper-Cross-Linked Polystyrene as Effective Catalysts in Hydrogenation of Arenes

by Elena S. Bakhvalova, Arina O. Pinyukova, Alexey V. Mikheev, Galina N. Demidenko, Mikhail G. Sulman, Alexey V. Bykov, Linda Z. Nikoshvili and Lioubov Kiwi-Minsker

Molecules 2021, 26(15), 4687; https://doi.org/10.3390/molecules26154687 - 3 Aug 2021

Cited by 4 | Viewed by 2574

Abstract

This work is addressing the arenes’ hydrogenation—the processes of high importance for petrochemical, chemical and pharmaceutical industries. Noble metal (Pd, Pt, Ru) nanoparticles (NPs) stabilized in hyper-cross-linked polystyrene (HPS) were shown to be active and selective catalysts in hydrogenation of a wide range [...] Read more.

This work is addressing the arenes’ hydrogenation—the processes of high importance for petrochemical, chemical and pharmaceutical industries. Noble metal (Pd, Pt, Ru) nanoparticles (NPs) stabilized in hyper-cross-linked polystyrene (HPS) were shown to be active and selective catalysts in hydrogenation of a wide range of arenes (monocyclic, condensed, substituted, etc.) in a batch mode. HPS effectively stabilized metal NPs during hydrogenation in different medium (water, organic solvents) and allowed multiple catalyst reuses. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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Review

Jump to: Editorial, Research

17 pages, 706 KiB

Open AccessReview

Microwave-Assisted Conversion of Carbohydrates

by Leonid M. Kustov, Alexander L. Kustov and Tapio Salmi

Molecules 2022, 27(5), 1472; https://doi.org/10.3390/molecules27051472 - 22 Feb 2022

Cited by 6 | Viewed by 2011

Abstract

Catalytic conversion of carbohydrates into value-added products and platform chemicals became a trend in recent years. Microwave activation used in the processes of carbohydrate conversion coupled with the proper choice of catalysts makes it possible to enhance dramatically the efficiency and sometimes the [...] Read more.

Catalytic conversion of carbohydrates into value-added products and platform chemicals became a trend in recent years. Microwave activation used in the processes of carbohydrate conversion coupled with the proper choice of catalysts makes it possible to enhance dramatically the efficiency and sometimes the selectivity of catalysts. This mini-review presents a brief literature survey related to state-of-the-art methods developed recently by the world research community to solve the problem of rational conversion of carbohydrates, mostly produced from natural resources and wastes (forestry and agriculture wastes) including production of hydrogen, synthesis gas, furanics, and alcohols. The focus is made on microwave technologies used for processing carbohydrates. Of particular interest is the use of heterogeneous catalysts and hybrid materials in processing carbohydrates. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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20 pages, 4700 KiB

Open AccessReview

Recent Advances in C₅ and C₆ Sugar Alcohol Synthesis by Hydrogenation of Monosaccharides and Cellulose Hydrolytic Hydrogenation over Non-Noble Metal Catalysts

by Elena Redina, Olga Tkachenko and Tapio Salmi

Molecules 2022, 27(4), 1353; https://doi.org/10.3390/molecules27041353 - 17 Feb 2022

Cited by 17 | Viewed by 3745

Abstract

A new reality of the 21st century is the transition to a new type of economy and energy concepts characterized by the replacement of existing petrochemical routes to a bio-based circular economy. The needs for new strategies in obtaining basic products from bio-based [...] Read more.

A new reality of the 21st century is the transition to a new type of economy and energy concepts characterized by the replacement of existing petrochemical routes to a bio-based circular economy. The needs for new strategies in obtaining basic products from bio-based resources with minimum CO₂ traces has become mandatory. In this review, recent trends in the conversion of biomass-derived molecules, such as simple monomeric sugars and cellulose, to industrially important C₅ and C₆ sugar alcohols on heterogeneous catalysts based on non-noble metals are discussed focusing on the influence of catalyst structures and reaction conditions used on the substrate conversion and product selectivity. The challenges and prominent ideas are suggested for the further development of catalytic hydrogenation of naturally abundant carbohydrates to value-added chemicals on non-noble metal catalysts. Full article

(This article belongs to the Special Issue Catalysis by Hybrid Materials)

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