Editorial

2 pages, 171 KiB

Open AccessEditorial

by Sónia Alexandra Correia Carabineiro

Catalysts 2024, 14(2), 111; https://doi.org/10.3390/catal14020111 - 31 Jan 2024

Viewed by 826

The catalytic oxidation of hydrocarbons stands at the forefront of sustainable chemical transformations, offering pathways to selectively convert aliphatic and aromatic compounds into valuable oxygenated products [...] Full article

(This article belongs to the Special Issue Catalytic Oxidation of Hydrocarbons)

Research

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26 pages, 6913 KiB

Open AccessArticle

Hydrocarbon Oxidation Depth: H₂O₂/Cu₂Cl₄·2DMG/CH₃CN System

by Igor Yu. Shchapin, Andrey I. Nekhaev, Dzhamalutdin N. Ramazanov, Mohammed Al-Yusufi, Vadim O. Samoilov and Anton L. Maximov

Catalysts 2022, 12(4), 409; https://doi.org/10.3390/catal12040409 - 07 Apr 2022

Cited by 1 | Viewed by 1994

Abstract

The oxidation of hydrocarbons of different structures under the same conditions is an important stage in the study of the chemical properties of both the hydrocarbons themselves and the oxidation catalysts. In a 50% H₂O₂/Cu₂Cl₄·2DMG/CH [...] Read more.

The oxidation of hydrocarbons of different structures under the same conditions is an important stage in the study of the chemical properties of both the hydrocarbons themselves and the oxidation catalysts. In a 50% H₂O₂/Cu₂Cl₄·2DMG/CH₃CN system, where DMG is dimethylglyoxime (Butane-2,3-dione dioxime), at 50 °C under the same or similar conditions, we oxidized eleven RH hydrocarbons of different structures: mono-, bi- and tri-cyclic, framework and aromatic. To compare the composition of the oxidation products of these hydrocarbons, we introduced a new quantitative characteristic, “distributive oxidation depth D(O), %” and showed the effectiveness of its application. The adiabatic ionization potentials (AIP) and the vertical ionization potentials (VIP) of the molecules of eleven oxidized and related hydrocarbons were calculated using the DFT method in the B3LYP/TZVPP level of theory for comparison with experimental values and correlation with D(O). The same calculations of AIP were made for the molecules of the oxidant, solvent, DMG, related compounds and products. It is shown that component X, which determines the mechanism of oxidation of hydrocarbons RH with AIP(Exp) ≥ AIP(X) = 8.55 ± 0.03 eV, is a trans-DMG molecule. Firstly theoretically estimated experimental values of AIP(trans-DMG) = 8.53 eV and AIP(cis-DMG) = 8.27 eV. Full article

(This article belongs to the Special Issue Catalytic Oxidation of Hydrocarbons)

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13 pages, 3051 KiB

Open AccessArticle

Commercial Gold Complexes Supported on Functionalised Carbon Materials as Efficient Catalysts for the Direct Oxidation of Ethane to Acetic Acid

by Ana P. C. Ribeiro, Inês A. S. Matias, Sónia A. C. Carabineiro and Luísa M. D. R. S. Martins

Catalysts 2022, 12(2), 165; https://doi.org/10.3390/catal12020165 - 28 Jan 2022

Cited by 1 | Viewed by 2414

Abstract

The single-pot efficient oxidation of ethane to acetic acid catalysed by Au(I) or Au(III) compounds, chlorotriphenylphosphinegold(I) (1), chlorotrimethylphosphinegold(I) (2), 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidenegold(I) chloride (3), dichloro(2-pyridinecarboxylato)gold(III) (4), homogenous and supported on different carbon materials: activated carbon (AC), multi-walled [...] Read more.

The single-pot efficient oxidation of ethane to acetic acid catalysed by Au(I) or Au(III) compounds, chlorotriphenylphosphinegold(I) (1), chlorotrimethylphosphinegold(I) (2), 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidenegold(I) chloride (3), dichloro(2-pyridinecarboxylato)gold(III) (4), homogenous and supported on different carbon materials: activated carbon (AC), multi-walled carbon nanotubes (CNT) and carbon xerogel (CX), oxidised with nitric acid followed by treatment with NaOH (-ox-Na), is reported. The reactions were performed in water/acetonitrile. The materials were selective for the production of acetic acid, with no trace of by-products being detected. The best homogenous catalysts were complexes 2 and 3 which showed the highest ethane conversion and an acetic acid yield of ca. 21%, followed by 4 and 1. The heterogenised materials showed much better activity than the homogenous counterparts, with acetic acid yields up to 41.4% for 4@CNT-ox-Na, and remarkable selectivity (with acetic acid being the only product detected). The heterogenised catalysts with the best results were reused up to five cycles, with no significant loss of activity, and maintaining high selectivity for acetic acid. 4@CNT-ox-Na showed not only the best catalytic activity but also the best stability during the recycling runs. Full article

(This article belongs to the Special Issue Catalytic Oxidation of Hydrocarbons)

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12 pages, 3904 KiB

Open AccessArticle

Role of PhOH and Tyrosine in Selective Oxidation of Hydrocarbons

by Ludmila Matienko, Vladimir Binyukov, Elena Mil and Alexander Goloshchapov

Catalysts 2021, 11(9), 1032; https://doi.org/10.3390/catal11091032 - 26 Aug 2021

Cited by 2 | Viewed by 1635

Abstract

Earlier, we established that nickel or iron heteroligand complexes, which include PhOH (nickel complexes) or tyrosine residue (nickel or iron complexes), are not only hydrocarbon oxidation catalysts (in the case of PhOH), but also simulate the active centers of enzymes (PhOH, tyrosine). The [...] Read more.

Earlier, we established that nickel or iron heteroligand complexes, which include PhOH (nickel complexes) or tyrosine residue (nickel or iron complexes), are not only hydrocarbon oxidation catalysts (in the case of PhOH), but also simulate the active centers of enzymes (PhOH, tyrosine). The AFM method established the self-organization of nickel or iron heteroligand complexes, which included tyrosine residue or PhOH, into supramolecular structures on a modified silicon surface. Supramolecular structures were formed as a result of H-bonds and other non-covalent intermolecular interactions and, to a certain extent, reflected the structures involved in the mechanisms of reactions of homogeneous and enzymatic catalysis. Using the AFM method, we obtained evidence at the model level in favor of the involvement of the tyrosine fragment as one of the possible regulatory factors in the functioning of Ni(Fe)ARD dioxygenases or monooxygenases of the family of cytochrome P450. The principles of actions of these oxygenases were used to create highly efficient catalytic systems for the oxidation of hydrocarbons. Full article

(This article belongs to the Special Issue Catalytic Oxidation of Hydrocarbons)

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21 pages, 4182 KiB

Open AccessArticle

One-Stage Catalytic Oxidation of Adamantane to Tri-, Tetra-, and Penta-Ols

by Igor Yu. Shchapin, Dzhamalutdin N. Ramazanov, Andrey I. Nekhaev, Roman S. Borisov, Evgeny A. Buravlev and Anton L. Maximov

Catalysts 2021, 11(8), 1017; https://doi.org/10.3390/catal11081017 - 23 Aug 2021

Cited by 3 | Viewed by 2413

Abstract

Tertiary tetraols of adamantane (C₁₀H₁₆, Tricyclo[3.3.1.1(3,7)]decan) have been widely used for the synthesis of highly symmetric compounds with unique physical and chemical properties. The methods for one-stage simultaneously selective, deep, and cheap oxidation of adamantane to tetraols of different [...] Read more.

Tertiary tetraols of adamantane (C₁₀H₁₆, Tricyclo[3.3.1.1(3,7)]decan) have been widely used for the synthesis of highly symmetric compounds with unique physical and chemical properties. The methods for one-stage simultaneously selective, deep, and cheap oxidation of adamantane to tetraols of different structures have not yet been developed. In this research, chemically simple, cheap, and environmentally friendly reagents are used and that is the first step in this direction. The conditions, under which the impact of a hydrogen peroxide water solution on adamantane dissolved in acetonitrile results in full conversion of adamantane and formation of a total 72% mixture of its tri-, tetra-, and penta-oxygenated products, predominantly poliols, have been found. Conversion and adamantane oxidation depth are shown to depend on the ratio of components of the water-acetonitrile solution and the method of oxidizer solution introduction when using the dimer form of 1:1 dimethylglyoxime and copper dichloride complex as a catalyst. Under the conditions of mass-spectrometry ionization by electrons (70 eV), fragmentation across three C–C bonds of the molecular ions framework of adamantane tertiary alcohols Ad(OH)_n in the range n = 0–4 increases linearly with the rise of n. Full article

(This article belongs to the Special Issue Catalytic Oxidation of Hydrocarbons)

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12 pages, 3138 KiB

Open AccessArticle

Studies of Nickel/Samarium-Doped Ceria for Catalytic Partial Oxidation of Methane and Effect of Oxygen Vacancy

by Andrew C. Chien, Nicole J. Ye, Chao-Wei Huang and I-Hsiang Tseng

Catalysts 2021, 11(6), 731; https://doi.org/10.3390/catal11060731 - 14 Jun 2021

Cited by 5 | Viewed by 2695

Abstract

We investigated the performance of nickel/samarium-doped ceria (Ni/SDC) nanocatalysts on the catalytic partial oxidation of methane (CPOM). Studies of temperature-programmed surface reaction and reduction reveal that catalytic activity is determined by a synergistic effect produced by Ni metals and metal-support interaction. Catalytic activity [...] Read more.

We investigated the performance of nickel/samarium-doped ceria (Ni/SDC) nanocatalysts on the catalytic partial oxidation of methane (CPOM). Studies of temperature-programmed surface reaction and reduction reveal that catalytic activity is determined by a synergistic effect produced by Ni metals and metal-support interaction. Catalytic activity was more dependent on the Ni content below 600 °C, while there is not much difference for all catalysts at high temperatures. The catalyst exhibiting high activities toward syngas production (i.e., a CH₄ conversion >90% at 700 °C) requires a medium Ni-SDC interaction with an Sm/Ce ratio of about 1/9 to 2/8. This is accounted for by optimum oxygen vacancies and adequate ion diffusivity in the SDCs which, as reported, also display the highest ion conductivity for fuel cell applications. Full article

(This article belongs to the Special Issue Catalytic Oxidation of Hydrocarbons)

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17 pages, 4540 KiB

Open AccessArticle

Enhanced Performance of the OMS-2-Supported CuOx Catalysts for Carbon Monoxide, Ethyl Acetate, and Toluene Oxidation

by Zhidan Fu, Mengyue Chen, Qing Ye, Ning Dong and Hongxing Dai

Catalysts 2021, 11(6), 713; https://doi.org/10.3390/catal11060713 - 07 Jun 2021

Cited by 7 | Viewed by 2054

Abstract

Different Cu contents (x wt%) were supported on the cryptomelane-type manganese oxide octahedral molecular sieve (OMS-2) (xCu/OMS-2; x = 1, 5, 15, and 20) via a pre-incorporation method. Physicochemical properties of the OMS-2 and xCu/OMS-2 samples were characterized by [...] Read more.

Different Cu contents (x wt%) were supported on the cryptomelane-type manganese oxide octahedral molecular sieve (OMS-2) (xCu/OMS-2; x = 1, 5, 15, and 20) via a pre-incorporation method. Physicochemical properties of the OMS-2 and xCu/OMS-2 samples were characterized by means of the XRD, FT-IR, SEM, TG/DTG, ICP-OES, XPS, O₂-TPD, H₂-TPR, and in situ DRIFTS techniques, and their catalytic activities were measured for the oxidation of CO, ethyl acetate, and toluene. The results show that the Cu species were homogeneously dispersed in the tunnel and framework structure of OMS-2. Among all of the samples, 15Cu/OMS-2 sample exhibited the best activities with the T_50% of 65, 165, and 240 °C as well as the T_90% of 85, 215, and 290 °C for CO, ethyl acetate and toluene oxidation, respectively, which was due to the existence of the Cu species and Mn³⁺/Mn⁴⁺ redox couples, rich oxygen vacancies, good oxygen mobility, low-temperature reducibility, and strong interaction between the Cu species and the OMS-2 support. The reaction mechanisms were also deduced by analyzing the in situ DRIFTS spectra of the 15Cu/OMS-2 sample. The excellent oxygen mobility associated with the electron transfer between Cu species and Mn³⁺/Mn⁴⁺ redox couples might be conducive to the continuous replenishment of active oxygen species and the constantly generated reactant intermediates, thereby increasing the reactant reaction rate. Full article

(This article belongs to the Special Issue Catalytic Oxidation of Hydrocarbons)

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14 pages, 4582 KiB

Open AccessArticle

Selective Catalytic Oxidation of Toluene to Benzaldehyde: Effect of Aging Time and Calcination Temperature Using Cu_xZn_yO Mixed Metal Oxide Nanoparticles

by Khadijah H. Alharbi, Ali Alsalme, Ahmed Bader A. Aloumi and Mohammed Rafiq H. Siddiqui

Catalysts 2021, 11(3), 354; https://doi.org/10.3390/catal11030354 - 09 Mar 2021

Cited by 3 | Viewed by 3515

Abstract

Oxidation is an important organic transformation, and several catalysts have been reported for this conversion. In this study, we report the synthesis of mixed metal oxide Cu_xZn_yO, which is prepared by a coprecipitation method by varying the molar ratio [...] Read more.

Oxidation is an important organic transformation, and several catalysts have been reported for this conversion. In this study, we report the synthesis of mixed metal oxide Cu_xZn_yO, which is prepared by a coprecipitation method by varying the molar ratio of Cu and Zn in the catalytic system. The prepared mixed metal oxide Cu_xZn_yO was evaluated for catalytic performance for toluene oxidation. Various parameters of the catalytic evaluation were studied in order to ascertain the optimum condition for the best catalytic performance. The results indicate that aging time, calcination temperature, reaction temperature, and feed rate influence catalytic performance. It was found that the catalyst interfaces apparently enhanced catalytic activity for toluene oxidation. The XRD diffractograms reveal the crystalline nature of the mixed metal oxide formed and also confirm the coexistence of hexagonal and monoclinic crystalline phases. The catalyst prepared by aging for 4 h and calcined at 450 °C was found to be the best for the conversion of toluene to benzaldehyde while the reactor temperature was maintained at 250 °C with toluene fed into the reactor at 0.01 mL/min. The catalyst was active for about 13 h. Full article

(This article belongs to the Special Issue Catalytic Oxidation of Hydrocarbons)

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20 pages, 4818 KiB

Open AccessFeature PaperArticle

Oxidation of 5-Hydroxymethylfurfural on Supported Ag, Au, Pd and Bimetallic Pd-Au Catalysts: Effect of the Support

by Dmitrii German, Ekaterina Pakrieva, Ekaterina Kolobova, Sónia A. C. Carabineiro, Marta Stucchi, Alberto Villa, Laura Prati, Nina Bogdanchikova, Vicente Cortés Corberán and Alexey Pestryakov

Catalysts 2021, 11(1), 115; https://doi.org/10.3390/catal11010115 - 14 Jan 2021

Cited by 21 | Viewed by 3524

Abstract

Oxidation of 5-hydroxymethylfurfural (HMF), a major feedstock derived from waste/fresh biomass, into 2,5-furandicarboxylic acid (FDCA) is an important transformation for the production of biodegradable plastics. Herein, we investigated the effect of the support (unmodified and modified titania, commercial alumina, and untreated and treated [...] Read more.

Oxidation of 5-hydroxymethylfurfural (HMF), a major feedstock derived from waste/fresh biomass, into 2,5-furandicarboxylic acid (FDCA) is an important transformation for the production of biodegradable plastics. Herein, we investigated the effect of the support (unmodified and modified titania, commercial alumina, and untreated and treated Sibunit carbon) of mono- and bimetallic catalysts based on noble metals (Ag, Au, Pd) on selective HMF oxidation with molecular oxygen to FDCA under mild and basic reaction conditions. The higher selectivity to FDCA was obtained when metals were supported on Sibunit carbon (Cp). The order of noble metal in terms of catalyst selectivity was: Ag < Au < Pd < PdAu. Finally, FDCA production on the most efficient PdAu NPs catalysts supported on Sibunit depended on the treatment applied to this carbon support in the order: PdAu/Cp < PdAu/Cp-HNO₃ < PdAu/Cp-NH₄OH. These bimetallic catalysts were characterized by nitrogen adsorption-desorption, inductively coupled plasma atomic emission spectroscopy, high resolution transmission electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Hammet indicator method and X-ray photoelectron spectroscopy. The functionalization of Sibunit surface by HNO₃ and NH₄OH led to a change in the contribution of the active states of Pd and Au due to promotion effect of N-doping and, as a consequence, to higher FDCA production. HMF oxidation catalyzed by bimetallic catalysts is a structure sensitive reaction. Full article

(This article belongs to the Special Issue Catalytic Oxidation of Hydrocarbons)

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12 pages, 8460 KiB

Open AccessArticle

Reaction Mechanism for Methane-to-Methanol in Cu-SSZ-13: First-Principles Study of the Z₂[Cu₂O] and Z₂[Cu₂OH] Motifs

by Unni Engedahl, Adam A. Arvidsson, Henrik Grönbeck and Anders Hellman

Catalysts 2021, 11(1), 17; https://doi.org/10.3390/catal11010017 - 25 Dec 2020

Cited by 2 | Viewed by 2206

Abstract

As transportation continues to increase world-wide, there is a need for more efficient utilization of fossil fuel. One possibility is direct conversion of the solution gas bi-product CH

_{4}

into an energy-rich, easily usable liquid fuel such as CH

_{3}

OH. However, new [...] Read more.

As transportation continues to increase world-wide, there is a need for more efficient utilization of fossil fuel. One possibility is direct conversion of the solution gas bi-product CH

_{4}

into an energy-rich, easily usable liquid fuel such as CH

_{3}

OH. However, new catalytic materials to facilitate the methane-to-methanol reaction are needed. Using density functional calculations, the partial oxidation of methane is investigated over the small-pore copper-exchanged zeolite SSZ-13. The reaction pathway is identified and the energy landscape elucidated over the proposed motifs Z

_{2}

[Cu

_{2}

O] and Z

_{2}

[Cu

_{2}

OH]. It is shown that the Z

_{2}

[Cu

_{2}

O] motif has an exergonic reaction path, provided water is added as a solvent for the desorption step. However, a micro-kinetic model shows that neither Z

_{2}

[Cu

_{2}

O] nor Z

_{2}

[Cu

_{2}

OH] has any notable activity under the reaction conditions. These findings highlight the importance of the detailed structure of the active site and that the most stable motif is not necessarily the most active. Full article

(This article belongs to the Special Issue Catalytic Oxidation of Hydrocarbons)

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18 pages, 2168 KiB

Open AccessArticle

Increasing the Efficiency of Optimized V-SBA-15 Catalysts in the Selective Oxidation of Methane to Formaldehyde by Artificial Neural Network Modelling

by Benny Kunkel, Anke Kabelitz, Ana Guilherme Buzanich and Sebastian Wohlrab

Catalysts 2020, 10(12), 1411; https://doi.org/10.3390/catal10121411 - 02 Dec 2020

Cited by 11 | Viewed by 2190

Abstract

The present study investigates the possibility of improving the selective oxidation of methane to formaldehyde over V-SBA-15 catalysts in two different ways. In a classical approach of catalyst optimization, the in situ synthesis of V-SBA-15 catalysts was optimized with regard to the applied [...] Read more.

The present study investigates the possibility of improving the selective oxidation of methane to formaldehyde over V-SBA-15 catalysts in two different ways. In a classical approach of catalyst optimization, the in situ synthesis of V-SBA-15 catalysts was optimized with regard to the applied pH value. Among the set of catalysts synthesized, a higher amount of incorporated vanadium, a higher content of polymeric VO_x species as well as a less ordered structure of the support material were observed by increasing the pH values from 2.0 to 3.0. An optimum in performance during the selective oxidation of methane to formaldehyde with respect to activity and selectivity was found over V-SBA-15 prepared at a pH value of 2.5. With this knowledge, we have now evaluated the possibilities of reaction control using this catalyst. Specifically, artificial neural network modelling was applied after the collection of 232 training samples for obtaining insight into the influence of different reaction parameters (temperature; gas hourly space velocity (GHSV); and concentration of O₂, N₂ and H₂O) onto methane conversion and selectivity towards formaldehyde. This optimization of reaction conditions resulted in an outstanding high space-time yield of 13.6 kg_CH₂O∙kg_cat∙h⁻¹. Full article

(This article belongs to the Special Issue Catalytic Oxidation of Hydrocarbons)

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15 pages, 2369 KiB

Open AccessArticle

Newly Isolated Alkane Hydroxylase and Lipase Producing Geobacillus and Anoxybacillus Species Involved in Crude Oil Degradation

by Durratul Fatini Yusoff, Raja Noor Zaliha Raja Abd Rahman, Malihe Masomian, Mohd Shukuri Mohamad Ali and Thean Chor Leow

Catalysts 2020, 10(8), 851; https://doi.org/10.3390/catal10080851 - 01 Aug 2020

Cited by 16 | Viewed by 4888

Abstract

Isolation and studies of novel, crude oil biodegrading thermophilic strains may provide a wider knowledge in understanding their role in petroleum degradation. In this study, the screening of ten new thermophilic strains revealed that all strains were alkane hydroxylase producers and seven of [...] Read more.

Isolation and studies of novel, crude oil biodegrading thermophilic strains may provide a wider knowledge in understanding their role in petroleum degradation. In this study, the screening of ten new thermophilic strains revealed that all strains were alkane hydroxylase producers and seven of them produced lipase concurrently. Three best strains were characterized and identified through 16S rRNA sequence analysis as Geobacillus sp. D4, Geobacillus sp. D7, and Anoxybacillus geothermalis D9 with GenBank accession numbers MK615934.1, MK615935.1, and MK615936.1, respectively. Gas chromatography (GC) analysis showed that all three strains were able to breakdown various compounds in crude oil such as alkanes, toxic poly-aromatic hydrocarbons (PAHs), organosulfur, carboxylic acids, alkene, resins, organosilicon, alcohol, organochlorine, and ester. For the first time, alkane hydroxylase and lipase activity as well as crude oil degradation by A. geothermalis species were reported. Geobacillus sp. D7 is the best alkane degrader followed by A. geothermalis D9 and Geobacillus sp. D4 with 17.3%, 13.1%, and 12.1% biodegradation efficiency (BE%), respectively. The potential of thermophiles isolated can be explored further for bioremediation of sites polluted by petroleum and oil spills. Full article

(This article belongs to the Special Issue Catalytic Oxidation of Hydrocarbons)

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