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Reactions, Volume 3, Issue 3 (September 2022) – 9 articles

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48 pages, 15797 KiB  
Review
Advances for Biorefineries: Glycerol Hydrogenolysis to 1,3-Propylene Glycol
by Martin Nicolás Gatti, Nora Nancy Nichio and Francisco Pompeo
Reactions 2022, 3(3), 451-498; https://doi.org/10.3390/reactions3030032 - 19 Sep 2022
Cited by 8 | Viewed by 2581
Abstract
Humanity’s growing dependence on non-renewable resources and the ensuing environmental impact thus generated have spurred the search for alternatives to replace chemicals and energy obtained from petroleum derivatives. Within the group of biofuels, biodiesel has managed to expand worldwide at considerable levels, going [...] Read more.
Humanity’s growing dependence on non-renewable resources and the ensuing environmental impact thus generated have spurred the search for alternatives to replace chemicals and energy obtained from petroleum derivatives. Within the group of biofuels, biodiesel has managed to expand worldwide at considerable levels, going from 20 million tn/year in 2010 to 47 million tn/year in 2022, boosting the supply of glycerol, a by-product of its synthesis that can be easily used as a renewable, clean, low-cost raw material for the manufacture of products for the chemical industry. The hydrogenolysis of glycerol leads to the production of glycols, 1,2-propylene glycol (1,2-PG) and 1,3-propylene glycol (1,3-PG). In particular, 1,3-PG has the highest added value and has multiple uses including its application as an additive in the polymer industry, the manufacture of cosmetics, cleaning products, cooling liquids, etc. This review focuses on the study of the hydrogenolysis of glycerol for the production of 1,3-PG, presenting the main reaction mechanisms and the catalysts employed, both in liquid and vapor phase. Engineering aspects and the effect of the operating variables to achieve maximum yields are discussed. Finally, studies related to the stability and the main deactivation mechanisms of catalytic systems are presented. Full article
(This article belongs to the Special Issue Feature Papers in Reactions in 2022)
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9 pages, 1707 KiB  
Article
Thiol-Ene Reaction of Heparin Allyl Ester, Heparin 4-Vinylbenzyl Ester and Enoxaparin
by Richard T. Taylor and Dhruba P. Poudel
Reactions 2022, 3(3), 442-450; https://doi.org/10.3390/reactions3030031 - 05 Sep 2022
Viewed by 1560
Abstract
Heparin allyl ester and heparin 4-vinylbenzyl ester were prepared and examined for their potential for thiol-ene reaction using both free radical initiators and photochemistry. While both undergo reaction with mercaptoacetic acid, the allyl ester adduct proved to be somewhat more labile. Several more [...] Read more.
Heparin allyl ester and heparin 4-vinylbenzyl ester were prepared and examined for their potential for thiol-ene reaction using both free radical initiators and photochemistry. While both undergo reaction with mercaptoacetic acid, the allyl ester adduct proved to be somewhat more labile. Several more examples of adducts from heparin 4-vinylbenzyl ester are reported. Similar reactions on enoxaparin, where the reaction site is solely at the non-reducing end of the molecule, are also reported. These reactions may show promise as a strategy in the development of drug conjugates. Full article
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19 pages, 2158 KiB  
Review
Biogenic Synthesis of ZnO Nanoparticles and Their Application as Bioactive Agents: A Critical Overview
by Maria Chiara Sportelli, Caterina Gaudiuso, Annalisa Volpe, Margherita Izzi, Rosaria Anna Picca, Antonio Ancona and Nicola Cioffi
Reactions 2022, 3(3), 423-441; https://doi.org/10.3390/reactions3030030 - 17 Aug 2022
Cited by 8 | Viewed by 2720
Abstract
Zinc oxide is a safe material for humans, with high biocompatibility and negligible cytotoxicity. Interestingly, it shows exceptional antimicrobial activity against bacteria, viruses, fungi, etc., especially when reduced to the nanometer size. As it is easily understandable, thanks to its properties, it is [...] Read more.
Zinc oxide is a safe material for humans, with high biocompatibility and negligible cytotoxicity. Interestingly, it shows exceptional antimicrobial activity against bacteria, viruses, fungi, etc., especially when reduced to the nanometer size. As it is easily understandable, thanks to its properties, it is at the forefront of safe antimicrobials in this pandemic era. Besides, in the view of the 2022 European Green Deal announced by the European Commission, even science and nanotechnology are moving towards “greener” approaches to the synthesis of nanoparticles. Among them, biogenic ZnO nanoparticles have been extensively studied for their biological applications and environmental remediation. Plants, algae, fungi, yeast, etc., (which are composed of naturally occurring biomolecules) play, in biogenic processes, an active role in the formation of nanoparticles with distinct shapes and sizes. The present review targets the biogenic synthesis of ZnO nanoparticles, with a specific focus on their bioactive properties and antimicrobial application. Full article
(This article belongs to the Special Issue Nanoparticles: Synthesis, Properties, and Applications)
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8 pages, 1544 KiB  
Article
Preparation of Substituted Pyridines via a Coupling of β-Enamine Carbonyls with Rongalite-Application for Synthesis of Terpyridines
by Yung-Yuan Lee and Shiuh-Tzung Liu
Reactions 2022, 3(3), 415-422; https://doi.org/10.3390/reactions3030029 - 16 Aug 2022
Cited by 4 | Viewed by 1545
Abstract
A Hantzsch-type strategy for the synthesis of 2,3,5,6-tetrasubstituted pyridines via an oxidative coupling of β-enamine carbonyl compounds with rongalite was developed. This method employs rongalite as a C1 unit for the assembly of a pyridine ring at C-4 position, offering a facile method [...] Read more.
A Hantzsch-type strategy for the synthesis of 2,3,5,6-tetrasubstituted pyridines via an oxidative coupling of β-enamine carbonyl compounds with rongalite was developed. This method employs rongalite as a C1 unit for the assembly of a pyridine ring at C-4 position, offering a facile method for the preparation of substituted pyridine derivatives with a broad functional group tolerance. In particular, this method allows us to prepare terpyridine derivatives, which are important ligands or structural fragments for catalysts and 3D metal–organic frameworks. Full article
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23 pages, 4139 KiB  
Article
Expanding the Equilibrium Solubility and Dissolution Thermodynamics of Benzoic Acid in Aqueous Alcoholic Mixtures
by Sema Akay, Berkant Kayan, M. Ángeles Peña, Abolghasem Jouyban, Fleming Martínez and William E. Acree, Jr.
Reactions 2022, 3(3), 392-414; https://doi.org/10.3390/reactions3030028 - 01 Aug 2022
Cited by 1 | Viewed by 2989
Abstract
The equilibrium solubility of benzoic acid in water and ethanol, as well as in nine {ethanol (1) + water (2)} mixtures, was determined from T = (293.15 to 323.15) K. Benzoic acid mole fraction solubility in these aqueous-ethanolic mixtures was adequately correlated with [...] Read more.
The equilibrium solubility of benzoic acid in water and ethanol, as well as in nine {ethanol (1) + water (2)} mixtures, was determined from T = (293.15 to 323.15) K. Benzoic acid mole fraction solubility in these aqueous-ethanolic mixtures was adequately correlated with some well-known correlation/prediction models, obtaining mean percentage deviations of 2.2 to 7.6%. Apparent thermodynamic quantities, namely, Gibbs energy, enthalpy, and entropy, for the dissolution, mixing and solvation processes, were computed by means of the van ’t Hoff and Gibbs equations. The enthalpy–entropy compensation plot of apparent enthalpy vs. apparent Gibbs energy of dissolution was not linear, indicating enthalpy and entropy mechanisms for transfer. Ultimately, by using the inverse Kirkwood–Buff integrals, it is observed that benzoic acid is preferentially solvated by water molecules in water-rich mixtures but preferentially solvated by ethanol molecules in those {ethanol (1) + water (2)} mixtures of 0.24 < x1 < 1.00. Full article
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18 pages, 2311 KiB  
Article
Transient Behavior of CO and CO2 Hydrogenation on Fe@SiO2 Core–Shell Model Catalysts—A Stoichiometric Analysis of Experimental Data
by Christian Zambrzycki and Robert Güttel
Reactions 2022, 3(3), 374-391; https://doi.org/10.3390/reactions3030027 - 18 Jul 2022
Cited by 1 | Viewed by 1548
Abstract
The hydrogenation of CO and CO2 from industrial exhaust gases into CH4 represents a promising method for sustainable chemical energy storage. While iron-based catalysts are in principle suitable for that purpose, the active metal Fe undergoes a complex transformation during the [...] Read more.
The hydrogenation of CO and CO2 from industrial exhaust gases into CH4 represents a promising method for sustainable chemical energy storage. While iron-based catalysts are in principle suitable for that purpose, the active metal Fe undergoes a complex transformation during the chemical reaction process. However, only little is known about the change in catalytically active species under reaction conditions, primarily caused by structural changes in the catalyst material, so far. By using core–shell model materials, factors that alter the catalyst structure can be excluded, making it possible to observe the direct influence of the reactants on the activity in the present work. Furthermore, stoichiometric analysis was used as a key tool for the evaluation of individual key reactions in the complex reaction network purely from experimental data, thus making it possible to draw conclusions about the catalyst state. In the case of CO hydrogenation, the presumed Boudouard reaction and the associated carburization of the catalyst can be quantified and the main reaction (CO methanation) can be determined. The results of the CO2 hydrogenation showed that the reverse water–gas shift reaction mainly took place, but under an ongoing change in the catalytic active iron phase. Due to the systematic exchange between CO and CO2 in the reactant gas stream, a mutual influence could also be observed. The results from the stoichiometric analysis provide the basis for the development of kinetic models for the key reactions in future work. Full article
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22 pages, 4527 KiB  
Article
Chemical Conversion of Fischer–Tropsch Waxes and Plastic Waste Pyrolysis Condensate to Lubricating Oil and Potential Steam Cracker Feedstocks
by Philipp Neuner, David Graf, Niklas Netsch, Michael Zeller, Tom-Carlo Herrmann, Dieter Stapf and Reinhard Rauch
Reactions 2022, 3(3), 352-373; https://doi.org/10.3390/reactions3030026 - 06 Jul 2022
Cited by 5 | Viewed by 2420
Abstract
The global economy and its production chains must move away from petroleum-based products, to achieve this goal, alternative carbon feedstocks need to be established. One area of concern is sustainable production of synthetic lubricants. A lubricating oil can be described as a high [...] Read more.
The global economy and its production chains must move away from petroleum-based products, to achieve this goal, alternative carbon feedstocks need to be established. One area of concern is sustainable production of synthetic lubricants. A lubricating oil can be described as a high boiling point (>340 °C) liquid with solidification at least below room temperature. Historically, many lubricants have been produced from petroleum waxes via solvent or catalytic dewaxing. In this study, catalytic dewaxing was applied to potential climate neutral feedstocks. One lubricant was produced via Fischer–Tropsch (FT) synthesis and the other lubricant resulted from low temperature pyrolysis of agricultural waste plastics. The waxes were chosen because they each represented a sustainable alternative towards petroleum, i.e., FT waxes are contrivable from biomass and CO2 by means of gasification and Power-to-X technology. The pyrolysis of plastic is a promising process to complement existing recycling processes and to reduce environmental pollution. Changes in cloud point, viscosity, and yield were investigated. A bifunctional zeolite catalyst (SAPO-11) loaded with 0.3 wt% platinum was used. The plastic waste lubricants showed lower cloud points and increased temperature stability as compared with lubricants from FT waxes. There was a special focus on the composition of the naphtha, which accumulated during cracking. While the plastic waste produced higher amounts of naphtha, its composition was quite similar to those from FT waxes, with the notable exception of a higher naphthene content. Full article
(This article belongs to the Special Issue Feature Papers in Reactions in 2022)
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19 pages, 7041 KiB  
Article
Dry Reforming of Methane on Ni/Nanorod-CeO2 Catalysts Prepared by One-Pot Hydrothermal Synthesis: The Effect of Ni Content on Structure, Activity, and Stability
by Simonetta Tuti, Igor Luisetto, Umberto Pasqual Laverdura and Eleonora Marconi
Reactions 2022, 3(3), 333-351; https://doi.org/10.3390/reactions3030025 - 30 Jun 2022
Cited by 8 | Viewed by 1850
Abstract
The nanorod morphology of the CeO2 support has been recognized as more beneficial than other morphologies for catalytic activity in the dry reforming of methane. Ni/nanorod-CeO2 catalysts with different Ni contents were prepared by one-pot hydrothermal synthesis. Samples were characterized by [...] Read more.
The nanorod morphology of the CeO2 support has been recognized as more beneficial than other morphologies for catalytic activity in the dry reforming of methane. Ni/nanorod-CeO2 catalysts with different Ni contents were prepared by one-pot hydrothermal synthesis. Samples were characterized by X-ray diffraction (XRD), H2-temperature-programmed reduction (H2-TPR), H2-temperature-programmed desorption (H2-TPD), field emission scanning electron microscopy/energy dispersive spectroscopy (FE-SEM/EDS), Brunauer–Emmet–Teller (BET) and Barrett–Joyner–Halenda (BHJ) analysis. The effect of Ni content on the size and the intrinsic strain of ceria was analyzed by the Size–Strain plot and Williamson–Hall plot of XRD data. The average Ni particle size and Ni dispersion were determined by H2-TPD. XRD and H2-TPR analysis revealed a strong Ni–support interaction that limited nickel sintering. The activity for the dry reforming of methane was tested with the stoichiometric mixture CO2:CH4:N2:He = 20:20:20:140, gas hourly space velocity (GHSV) = 300 L g−1 h−1, and temperatures in the range of 545–800 °C. The turnover frequency (TOF) value increased linearly with the average Ni particle size in the range of 5.5–33 nm, suggesting the structure sensitivity of the reaction. Samples with Ni loading of 4–12 wt.% showed high H2/CO selectivity and stability over time on stream, whereas the sample with a Ni loading of 2 wt.% was less selective and underwent rapid deactivation. Only a small amount of nanotubular carbon was observed by FE-SEM after the time-on-stream experiment. Deactivation of the low-Ni-content sample is ascribed to the easier oxidation of the small Ni particles. Full article
(This article belongs to the Special Issue Feature Papers in Reactions in 2022)
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4 pages, 172 KiB  
Editorial
Special Issue Editorial: Catalytic Conversion of Carbonaceous Materials to Fuels and Chemicals
by Wenping Ma and Ajay K. Dalai
Reactions 2022, 3(3), 329-332; https://doi.org/10.3390/reactions3030024 - 27 Jun 2022
Viewed by 1247
Abstract
Conversion of syngas or CO2 greenhouse gas derived from various carbon-containing materials including coal, natural gas, biomass, waste plastics and biogas, or power plant, and petroleum is paramount to ensure global energy security, and recycle carbon in the earth and atmosphere and [...] Read more.
Conversion of syngas or CO2 greenhouse gas derived from various carbon-containing materials including coal, natural gas, biomass, waste plastics and biogas, or power plant, and petroleum is paramount to ensure global energy security, and recycle carbon in the earth and atmosphere and reach the global goal of carbon neutrality by 2050 [...] Full article
(This article belongs to the Special Issue Catalytic Conversion of Carbonaceous Materials to Fuels and Chemicals)
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