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CHEMICAL ENGINEERING (235 journals)            First | 1 2     

Showing 201 - 236 of 236 Journals sorted alphabetically
Nanochemistry Research     Open Access   (Followers: 1)
Natural Volatiles & Essential Oils     Open Access  
Noise Control Engineering Journal     Full-text available via subscription   (Followers: 4)
npj Science of Food     Open Access  
Ochrona Srodowiska i Zasobów Naturalnych : Environmental Protection and Natural Resources     Open Access  
Open Chemical Engineering Journal     Open Access  
Periodica Polytechnica Chemical Engineering     Open Access  
Petroleum Chemistry     Full-text available via subscription   (Followers: 1)
Physics and Chemistry of Glasses - European Journal of Glass Science and Technology Part B     Full-text available via subscription  
Plasma     Open Access   (Followers: 3)
Plasma Processes and Polymers     Hybrid Journal   (Followers: 2)
Polymer     Hybrid Journal   (Followers: 86)
Polymer Bulletin     Hybrid Journal   (Followers: 6)
Polymer Composites     Hybrid Journal   (Followers: 18)
Polyolefins Journal     Open Access  
Powder Technology     Hybrid Journal   (Followers: 13)
Reaction Chemistry & Engineering     Hybrid Journal  
Reactions     Open Access  
Research on Chemical Intermediates     Hybrid Journal   (Followers: 3)
Revista Cubana de Química     Open Access  
Revista ION     Open Access  
Revista Mexicana de Ingeniería Química     Open Access  
Russian Chemical Bulletin     Hybrid Journal   (Followers: 3)
Russian Journal of Applied Chemistry     Hybrid Journal  
Solid Fuel Chemistry     Hybrid Journal  
South African Journal of Chemical Engineering     Open Access   (Followers: 3)
Surface Engineering and Applied Electrochemistry     Hybrid Journal   (Followers: 7)
Sustainable Chemical Processes     Open Access   (Followers: 3)
Synthesis Lectures on Chemical Engineering and Biochemical Engineering     Full-text available via subscription  
The Canadian Journal of Chemical Engineering     Hybrid Journal   (Followers: 5)
The Chemical Record     Hybrid Journal   (Followers: 1)
Theoretical Foundations of Chemical Engineering     Hybrid Journal   (Followers: 3)
Transition Metal Chemistry     Hybrid Journal   (Followers: 6)
Transylvanian Review of Systematical and Ecological Research     Open Access  
Upstream Oil and Gas Technology     Open Access   (Followers: 1)
Visegrad Journal on Bioeconomy and Sustainable Development     Open Access   (Followers: 1)

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ISSN (Online) 2624-781X
Published by MDPI Homepage  [84 journals]
  • Reactions, Vol. 3, Pages 329-332: Special Issue Editorial: Catalytic
           Conversion of Carbonaceous Materials to Fuels and Chemicals

    • Authors: Wenping Ma, Ajay K. Dalai
      First page: 329
      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 reach the global goal of carbon neutrality by 2050 [...]
      Citation: Reactions
      PubDate: 2022-06-27
      DOI: 10.3390/reactions3030024
      Issue No: Vol. 3, No. 3 (2022)
       
  • Reactions, Vol. 3, Pages 333-351: 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

    • Authors: Simonetta Tuti, Igor Luisetto, Umberto Pasqual Laverdura, Eleonora Marconi
      First page: 333
      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 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.
      Citation: Reactions
      PubDate: 2022-06-30
      DOI: 10.3390/reactions3030025
      Issue No: Vol. 3, No. 3 (2022)
       
  • Reactions, Vol. 3, Pages 352-373: Chemical Conversion of
           Fischer–Tropsch Waxes and Plastic Waste Pyrolysis Condensate to
           Lubricating Oil and Potential Steam Cracker Feedstocks

    • Authors: Philipp Neuner, David Graf, Niklas Netsch, Michael Zeller, Tom-Carlo Herrmann, Dieter Stapf, Reinhard Rauch
      First page: 352
      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 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.
      Citation: Reactions
      PubDate: 2022-07-06
      DOI: 10.3390/reactions3030026
      Issue No: Vol. 3, No. 3 (2022)
       
  • Reactions, Vol. 3, Pages 374-391: Transient Behavior of CO and CO2
           Hydrogenation on Fe@SiO2 Core–Shell Model Catalysts—A
           Stoichiometric Analysis of Experimental Data

    • Authors: Christian Zambrzycki, Robert Güttel
      First page: 374
      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 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.
      Citation: Reactions
      PubDate: 2022-07-18
      DOI: 10.3390/reactions3030027
      Issue No: Vol. 3, No. 3 (2022)
       
  • Reactions, Vol. 3, Pages 392-414: Expanding the Equilibrium Solubility and
           Dissolution Thermodynamics of Benzoic Acid in Aqueous Alcoholic Mixtures

    • Authors: Sema Akay, Berkant Kayan, M. Ángeles Peña, Abolghasem Jouyban, Fleming Martínez, William E. Acree
      First page: 392
      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 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.
      Citation: Reactions
      PubDate: 2022-08-01
      DOI: 10.3390/reactions3030028
      Issue No: Vol. 3, No. 3 (2022)
       
  • Reactions, Vol. 3, Pages 415-422: Preparation of Substituted Pyridines via
           a Coupling of β-Enamine Carbonyls with Rongalite-Application for
           Synthesis of Terpyridines

    • Authors: Yung-Yuan Lee, Shiuh-Tzung Liu
      First page: 415
      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 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.
      Citation: Reactions
      PubDate: 2022-08-16
      DOI: 10.3390/reactions3030029
      Issue No: Vol. 3, No. 3 (2022)
       
  • Reactions, Vol. 3, Pages 423-441: Biogenic Synthesis of ZnO Nanoparticles
           and Their Application as Bioactive Agents: A Critical Overview

    • Authors: Maria Chiara Sportelli, Caterina Gaudiuso, Annalisa Volpe, Margherita Izzi, Rosaria Anna Picca, Antonio Ancona, Nicola Cioffi
      First page: 423
      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 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.
      Citation: Reactions
      PubDate: 2022-08-17
      DOI: 10.3390/reactions3030030
      Issue No: Vol. 3, No. 3 (2022)
       
  • Reactions, Vol. 3, Pages 442-450: Thiol-Ene Reaction of Heparin Allyl
           Ester, Heparin 4-Vinylbenzyl Ester and Enoxaparin

    • Authors: Richard T. Taylor, Dhruba P. Poudel
      First page: 442
      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 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.
      Citation: Reactions
      PubDate: 2022-09-05
      DOI: 10.3390/reactions3030031
      Issue No: Vol. 3, No. 3 (2022)
       
  • Reactions, Vol. 3, Pages 451-498: Advances for Biorefineries: Glycerol
           Hydrogenolysis to 1,3-Propylene Glycol

    • Authors: Martin Nicolás Gatti, Nora Nancy Nichio, Francisco Pompeo
      First page: 451
      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 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.
      Citation: Reactions
      PubDate: 2022-09-19
      DOI: 10.3390/reactions3030032
      Issue No: Vol. 3, No. 3 (2022)
       
  • Reactions, Vol. 3, Pages 233-253: Recent Progresses in the Preparation of
           Chlorinated Molecules: Electrocatalysis and Photoredox Catalysis in the
           Spotlight

    • Authors: Stefano Parisotto, Emanuele Azzi, Alberto Lanfranco, Polyssena Renzi, Annamaria Deagostino
      First page: 233
      Abstract: Among halogenated molecules, those containing chlorine atoms are fundamental in many areas such as pharmaceuticals, polymers, agrochemicals and natural metabolites. Despite the fact that many reactions have been developed to install chlorine on organic molecules, most of them rely on toxic and hazardous chlorinating reagents as well as harsh conditions. In an attempt to move towards more sustainable approaches, photoredox catalysis and electrocatalysis have emerged as powerful alternatives to traditional methods. In this review, we collect the most recent and significant examples of visible-light- or current-mediated chlorination published in the last five years.
      Citation: Reactions
      PubDate: 2022-04-03
      DOI: 10.3390/reactions3020018
      Issue No: Vol. 3, No. 2 (2022)
       
  • Reactions, Vol. 3, Pages 254-264: Regioselective Bond-Forming and
           Hydrolysis Reactions of Doubly Charged Vanadium Oxide Anions in the Gas
           Phase

    • Authors: Chiara Salvitti, Federico Pepi, Anna Troiani, Giulia de Petris
      First page: 254
      Abstract: The gas-phase reactivity of vanadium-containing dianions, NaV3O92− and its hydrated form H2NaV3O102−, were probed towards sulphur dioxide at room temperature by ion-molecule reaction (IMR) experiments in the collision cell of an ion trap mass spectrometer. The sequential addition of two SO2 molecules to the NaV3O92− dianion leads to the breakage of the stable V3O9 backbone, resulting in a charge separation process with the formation of new V-O and S-O bonds. On the contrary, the H2NaV3O102− hydroxide species reacts with SO2, promoting regioselective hydrolysis and bond-forming processes, the latter similar to that observed for the NaV3O92− reactant anion. Kinetic analysis shows that these reactions are fast and efficient with rate constants of the 10−9 (±30) cm3 s−1 molecule−1 order of magnitude.
      Citation: Reactions
      PubDate: 2022-04-05
      DOI: 10.3390/reactions3020019
      Issue No: Vol. 3, No. 2 (2022)
       
  • Reactions, Vol. 3, Pages 265-282: Catalytic Performances of Sn-Beta
           Catalysts Prepared from Different Heteroatom-Containing Beta Zeolites for
           the Retro-Aldol Fragmentation of Glucose

    • Authors: Ricardo Navar, Luca Botti, Giulia Tarantino, Ceri Hammond
      First page: 265
      Abstract: Beta zeolites with different heteroatoms incorporated into the lattice at two loadings (Si/M = 100 or 200, where M = Al, Fe, Ga, B) were hydrothermally synthesised and used as starting materials for the preparation of Sn-Beta using Solid-State Incorporation. 119Sn CPMG MAS NMR showed that various Sn species were formed, the distribution of which depended on the identity of the initial heteroatom and the original Si/M ratio. The final Sn-Beta materials (with Si/Sn = 200) were explored as catalysts for the retro-aldol fragmentation of glucose to α-hydroxy-esters in the continuous regime. Amongst these materials, B-derived Sn-Beta was found to exhibit improved levels of selectivity and stability, particularly compared to Sn-Beta catalysts synthesised from commercially available Al-Beta materials, achieving a combined yield of methyl lactate and methyl vinyl glycolate > 80% at short times on the stream. Given that B atoms can be removed from the Beta lattice in mild conditions without the use of highly concentrated acidic media, this discovery demonstrates that B-Beta is an attractive starting material for the future post-synthetic preparation of Lewis acidic zeolites.
      Citation: Reactions
      PubDate: 2022-05-12
      DOI: 10.3390/reactions3020020
      Issue No: Vol. 3, No. 2 (2022)
       
  • Reactions, Vol. 3, Pages 283-299: Valorization of Microcrystalline
           Cellulose Using Heterogeneous Protonated Zeolite Catalyst: An Experimental
           and Kinetics Approach

    • Authors: Samuel Kassaye, Dinesh Gupta, Kamal Kishore Pant, Sapna Jain
      First page: 283
      Abstract: This study aimed to valorize microcrystalline cellulose (MCC) using protonated zeolite catalysts such as (H-ZSM-5) and Cr/H-ZSM-5 (5%) in ionic liquid. The catalytic effect in synergy with 1-butyl-3-methylimidazolium Chloride ([BMIM] Cl) ionic liquid was studied in detail. The total reducing sugar (TRS) was determined using the 3, 5-dinitrisalcylic acid (DNS) array method. The catalysts were characterized using techniques such as Fourier transform infrared (FT-IR), X-ray diffraction analysis (XRD), temperature-programmed desorption of ammonia (NH3-TPD), and BET-surface area analyzer. H-ZSM-5 effectively depolymerized cellulose with a maximum yield of 70% total reducing sugar (34% glucose, 8% fructose, and 4.5% 5-HMF). Cr/H-ZSM-5 catalyst dehydrated fructose to 5-HMF with a yield of 53%. The use of ionic liquid significantly reduced the activation energy of formation and decomposition. The activation energy determined in cellulose hydrolysis was 85.83 KJ mol−1 for a reaction time of 180 min while the decomposition energy was found to be 42.5 kJ mol−1.
      Citation: Reactions
      PubDate: 2022-05-30
      DOI: 10.3390/reactions3020021
      Issue No: Vol. 3, No. 2 (2022)
       
  • Reactions, Vol. 3, Pages 300-311: C-N, C-O and C-S Ullmann-Type Coupling
           Reactions of Arenediazonium o-Benzenedisulfonimides

    • Authors: Achille Antenucci, Stefano Dughera
      First page: 300
      Abstract: Arenediazonium o-benzenedisulfonimides have been used as efficient electrophilic partners in Cu(I) catalysed Ullmann-type coupling. The synthetic protocols are mild and easy, and produced either N-alkylanilines, aryl ethers, or thioethers in fairly good yields (18 positive examples, average yield 66%). o-Benzenedisulfonimide was recovered at the end of the reactions and was reused to prepare the starting salts for further reactions. It is noteworthy that diazonium salts have been used as electrophilic partners in the Ullmann-type protocol for the first time.
      Citation: Reactions
      PubDate: 2022-06-02
      DOI: 10.3390/reactions3020022
      Issue No: Vol. 3, No. 2 (2022)
       
  • Reactions, Vol. 3, Pages 312-328: Application of Mixed Potential Theory to
           Leaching of Mineral Phases

    • Authors: César A. C. Sequeira
      First page: 312
      Abstract: Leaching is a central unit operation in the hydrometallurgical processing of minerals, which often occurs by means of electrochemical reactions. Application of mixed potential theory to explain the kinetics of oxidative and reductive leaching processes is a useful concept in explaining observed results. Native metals, selected oxides, and most base metal sulfides are electron-conducting phases. For these minerals, leaching may take place by normal corrosion, passivation or galvanic couple mechanisms, which provide individual electrode kinetics enabling the calculation of mixed potentials and overall reaction kinetics. Examples of the electrochemical nature of selected leaching processes are presented and include the effect of mixed potentials, geometry, and associated kinetic reactions.
      Citation: Reactions
      PubDate: 2022-06-18
      DOI: 10.3390/reactions3020023
      Issue No: Vol. 3, No. 2 (2022)
       
  • Reactions, Vol. 3, Pages 59-69: High Yielding, One-Pot Synthesis of
           Bis(1H-indazol-1-yl)methane Catalyzed by 3d-Metal Salts

    • Authors: Natalie M. Lind, Natalie S. Joe, Brian S. Newell, Aimee M. Morris
      First page: 59
      Abstract: Synthetic access to poly(indazolyl)methanes has limited their study despite their structural similarity to the highly investigated chelating poly(pyrazolyl)methanes and their potentially important indazole moiety. Herein is presented a high yielding, one-pot synthesis for the 3d-metal catalyzed formation of bis(1H-indazol-1-yl)methane from 1H-indazole utilizing dimethylsulfoxide as the methylene source. Complete characterization of bis(1H-indazol-1-yl)methane is given with 1H and 13C NMR, UV/Vis, FTIR, high resolution mass spectrometry and for the first time, single crystal X-ray diffraction. This simple, inexpensive pathway to yield exclusively bis(1H-indazol-1-yl)methane provides synthetic access to further investigate the coordination and potential applications of the family of bis(indazolyl)methanes.
      Citation: Reactions
      PubDate: 2022-01-04
      DOI: 10.3390/reactions3010005
      Issue No: Vol. 3, No. 1 (2022)
       
  • Reactions, Vol. 3, Pages 70-86: The Rearrangement of Alkylallenes to
           1,3-Dienes

    • Authors: Yassir Al-Jawaheri, Marc Colin Kimber
      First page: 70
      Abstract: 1,3-Dienes are vital building blocks in organic synthesis. They underpin many fundamental synthetic transformations and are present in numerous natural products and drug candidate molecules. The rearrangement of an alkylallene to a 1,3-diene is an atom efficient, redox neutral, transformation that provides a straightforward synthetic route to functionalized 1,3-dienes. Herein, we provide an account of this transformation using allenes that are not predisposed by the presence of heteroatoms or electron-withdrawing groups directly attached to the allene. Early reports of this skeletal rearrangement are acid-mediated approaches, with limited substrate scope, but they provide valuable mechanistic insights. More recent transition metal-mediated approaches that exhibit improved substrate scope are described, together with isolated examples that have utilized this rearrangement.
      Citation: Reactions
      PubDate: 2022-01-05
      DOI: 10.3390/reactions3010006
      Issue No: Vol. 3, No. 1 (2022)
       
  • Reactions, Vol. 3, Pages 87-88: Editorial for Special Issue
           “Hydrogen Production and Storage”

    • Authors: Valérie Meille, Luis M. Gandía, Sibudjing Kawi, Francesco Frusteri
      First page: 87
      Abstract: Hydrogen appears as an unavoidable energy vector and an almost miracle solution to global warming for many people [...]
      Citation: Reactions
      PubDate: 2022-01-17
      DOI: 10.3390/reactions3010007
      Issue No: Vol. 3, No. 1 (2022)
       
  • Reactions, Vol. 3, Pages 89-117: Thermal Input/Concentration Output
           Systems Processed by Chemical Reactions of Helicene Oligomers

    • Authors: Sheng Zhang, Ming Bao, Masahiko Yamaguchi
      First page: 89
      Abstract: This article describes thermal input/concentration output systems processed by chemical reactions. Various sophisticated thermal inputs can be converted into concentration outputs through the double-helix formation of helicene oligomers exhibiting thermal hysteresis. The inputs include high or low temperature, cooling or heating state, slow or fast cooling state, heating state, and cooling history. The chemical basis for the properties of the chemical reactions includes the reversibility out of chemical equilibrium, sigmoidal relationship and kinetics, bistability involving metastable states, positive feedback by self-catalytic chemical reactions, competitive chemical reactions, and fine tunability for parallel processing. The interfacing of concentration outputs in other systems is considered, and biological cells are considered to have been utilizing such input/output systems processed by chemical reactions.
      Citation: Reactions
      PubDate: 2022-01-25
      DOI: 10.3390/reactions3010008
      Issue No: Vol. 3, No. 1 (2022)
       
  • Reactions, Vol. 3, Pages 118-137: Bio-Oil: The Next-Generation Source of
           Chemicals

    • Authors: Henrique Machado, Ana F. Cristino, Sofia Orišková, Rui Galhano dos Santos
      First page: 118
      Abstract: Bio-oil, although rich in chemical species, is primarily used as fuel oil, due to its greater calorific power when compared to the biomass from which it is made. The incomplete understanding of how to explore its chemical potential as a source of value-added chemicals and, therefore, a supply of intermediary chemical species is due to the diverse composition of bio-oil. Being biomass-based, making it subject to composition changes, bio-oil is obtained via different processes, the two most common being fast pyrolysis and hydrothermal liquefaction. Different methods result in different bio-oil compositions even from the same original biomass. Understanding which biomass source and process results in a particular chemical makeup is of interest to those concerned with the refinement or direct application in chemical reactions of bio-oil. This paper presents a summary of published bio-oil production methods, origin biomass, and the resulting composition.
      Citation: Reactions
      PubDate: 2022-01-28
      DOI: 10.3390/reactions3010009
      Issue No: Vol. 3, No. 1 (2022)
       
  • Reactions, Vol. 3, Pages 138: Acknowledgment of Reviewers of Reactions in
           2021

    • Authors: Reactions Editorial Office Reactions Editorial Office
      First page: 138
      Abstract: Rigorous peer reviews are the basis of high-quality academic publishing [...]
      Citation: Reactions
      PubDate: 2022-01-29
      DOI: 10.3390/reactions3010010
      Issue No: Vol. 3, No. 1 (2022)
       
  • Reactions, Vol. 3, Pages 139-159: Engineering the 2-Oxoglutarate
           Dehydrogenase Complex to Understand Catalysis and Alter Substrate
           Recognition

    • Authors: Joydeep Chakraborty, Natalia Nemeria, Yujeong Shim, Xu Zhang, Elena L. Guevara, Hetal Patel, Edgardo T. Farinas, Frank Jordan
      First page: 139
      Abstract: The E. coli 2-oxoglutarate dehydrogenase complex (OGDHc) is a multienzyme complex in the tricarboxylic acid cycle, consisting of multiple copies of three components, 2-oxoglutarate dehydrogenase (E1o), dihydrolipoamide succinyltransferase (E2o) and dihydrolipoamide dehydrogenase (E3), which catalyze the formation of succinyl-CoA and NADH (+H+) from 2-oxoglutarate. This review summarizes applications of the site saturation mutagenesis (SSM) to engineer E. coli OGDHc with mechanistic and chemoenzymatic synthetic goals. First, E1o was engineered by creating SSM libraries at positions His260 and His298.Variants were identified that: (a) lead to acceptance of substrate analogues lacking the 5-carboxyl group and (b) performed carboligation reactions producing acetoin-like compounds with good enantioselectivity. Engineering the E2o catalytic (core) domain enabled (a) assignment of roles for pivotal residues involved in catalysis, (b) re-construction of the substrate-binding pocket to accept substrates other than succinyllysyldihydrolipoamide and (c) elucidation of the mechanism of trans-thioesterification to involve stabilization of a tetrahedral oxyanionic intermediate with hydrogen bonds by His375 and Asp374, rather than general acid–base catalysis which has been misunderstood for decades. The E. coli OGDHc is the first example of a 2-oxo acid dehydrogenase complex which was evolved to a 2-oxo aliphatic acid dehydrogenase complex by engineering two consecutive E1o and E2o components.
      Citation: Reactions
      PubDate: 2022-02-01
      DOI: 10.3390/reactions3010011
      Issue No: Vol. 3, No. 1 (2022)
       
  • Reactions, Vol. 3, Pages 160-171: Photocatalytic Degradation Pathways of
           the Valsartan Drug by TiO2 and g-C3N4 Catalysts

    • Authors: Feidias Bairamis, Ioannis Konstantinou
      First page: 160
      Abstract: The photocatalytic degradation of the valsartan (VLS) pharmaceutical using TiO2 and g-C3N4 catalysts under simulated solar light is studied in this paper by high-resolution Orbitrap mass spectrometry. •OH radicals were the major oxidant species for the degradation of valsartan using TiO2, while positive holes (h+), followed by a much lesser amount of •OH radicals, were the major species in the case of g-C3N4. Valsartan degradation followed first order kinetics by both catalysts with TiO2 being the catalyst with the better photocatalytic efficiency. The transformation products (TPs) and their evolution profiles are identified and monitored, respectively, by means of LC-HRMS. Based on TPs identification, the degradation mechanisms are discussed. The major degradation pathways for g-C3N4 include decarboxylation and subsequent oxidation, hydroxylation, and cleavage of C–N bond, while for TiO2 cyclization, TPs are abundant and the hydroxylation occurs in the first stage products. The study highlights the complex nature of TPs formed during such processes, the different mechanisms involved and the necessity for the identification of TPs for the assessment of the treatment and the tracking of such TPs in different environmental compartments.
      Citation: Reactions
      PubDate: 2022-02-03
      DOI: 10.3390/reactions3010012
      Issue No: Vol. 3, No. 1 (2022)
       
  • Reactions, Vol. 3, Pages 172-191: Synthesis and Reactivity of Cyclic
           Oxonium Derivatives of nido-Carborane: A Review

    • Authors: Marina Yu. Stogniy, Igor B. Sivaev
      First page: 172
      Abstract: Nucleophilic ring-opening reactions of cyclic oxonium derivatives of anionic boron hydrides are a convenient method of their modification which opens practically unlimited prospects for their incorporation into various macro- and biomolecules. This contribution provides an overview of the synthesis and reactivity of cyclic oxonium derivatives of nido-carborane as well as half-sandwich complexes based on it.
      Citation: Reactions
      PubDate: 2022-02-04
      DOI: 10.3390/reactions3010013
      Issue No: Vol. 3, No. 1 (2022)
       
  • Reactions, Vol. 3, Pages 192-202: N-4 Alkyl Cytosine Derivatives
           Synthesis: A New Approach

    • Authors: Mauro De Nisco, Antonio Di Maio, Michele Manfra, Carmine Ostacolo, Alessia Bertamino, Pietro Campiglia, Isabel M. Gomez-Monterrey, Silvana Pedatella
      First page: 192
      Abstract: The selective N-4 alkylation of cytosine plays a critical role in the synthesis of biologically active molecules. This work focuses on the development of practical reaction conditions toward a regioselective synthesis of N-4-alkyl cytosine derivatives. The sequence includes a direct and selective sulfonylation at the N-1 site of the cytosine, followed by the alkylation of the amino site using KHMDS in CH2Cl2/THF mixture, providing a fast and efficient approach consistent with pyrimidine-based drug design.
      Citation: Reactions
      PubDate: 2022-02-06
      DOI: 10.3390/reactions3010014
      Issue No: Vol. 3, No. 1 (2022)
       
  • Reactions, Vol. 3, Pages 203-212: Linear-Rate Reactions for the Thermal
           Devolatilization of Wheat Straw Based on Pseudo-Components

    • Authors: Carmen Branca
      First page: 203
      Abstract: Thermogravimetric curves are measured in the nitrogen of wheat straw heated up to 773 K with rates between 5–20 K/min. A five-step (or component) parallel reaction scheme was developed for the interpretation of the weight loss characteristics, which makes use of the lumped volatile products based on the volatiles released by the pseudo-macrocomponents. The volumetric rates show the usual Arrhenius dependence on temperature and a linear dependence on the mass fraction of the lumped volatile products. The wheat straw devolatilization mechanism consists of a single step for pseud-ocellulose (activation energies of about 180 kJ/mol) and two steps for the pseudohemicellulose, also including extractives, (activation energies of about 101 and 136 kJ/mol) and pseudo-lignin (activation energies of 189 and 126 kJ/mol). For the first two pseudo-macrocomponents, the activation energies were lower than those obtained through a similar approach for beech wood, owing to the much higher content of alkalis acting as catalysts for the decomposition reactions. These occur at lower temperatures and show an enhanced overlap between the pseudo-components.
      Citation: Reactions
      PubDate: 2022-02-07
      DOI: 10.3390/reactions3010015
      Issue No: Vol. 3, No. 1 (2022)
       
  • Reactions, Vol. 3, Pages 213-223: Grafting of Cellulose and
           Microcrystalline Cellulose with Oligo(L-lactic acid) by Polycondensation
           Reaction

    • Authors: Md. Hafezur Rahaman, Md. Anamul Haque, Md. Aminur Rahman, Md. Masud Rana, Md. Masud Parvez, S. M. Nur Alam
      First page: 213
      Abstract: Oligo(L-lactic acid) (OLLA) was synthesized by ring opening polymerization of L-lactides using stannous octoate (0.03 wt% of lactide). While this served as the initiator, L-lactic acids were the co-initiators at 140 °C for 10 h, wherein L-lactic acids were prepared by hydrolytic degradation of L-lactides at 100 °C for 1 h. The molecular weight or degree of polymerization was controlled with monomer/co-initiator ratio (mol/mol). α-cellulose and microcrystalline cellulose (MCC) were extracted from jute fiber by subsequent treatment with sodium chlorite (Na2ClO2), NaOH and H2SO4. Grafting of OLLA onto α-cellulose and MCC in toluene was carried out using para-toluene sulphonic acid as a catalyst and potassium persulphate (KPS) as an initiator at 130 °C under 380 mm (Hg) pressure for 3, 6, 9, 12, 15, and 18 h. New properties of α-cellulose and MCC were observed due to the successful grafting onto α-cellulose and MCC. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) were conducted in order to confirm grafting of OLLA onto cellulose and MCC. The FTIR analysis results showed there are some new characteristic absorption peaks appeared (1728 to 1732 cm−1) in the spectrum, which confirmed the grafting of OLLA onto α-cellulose and MCC was successful. SEM images of α-cellulose and MCC before and after grafting revealed significant changes in surface morphology. Grafting of MCC could be more effective for further application in comparison to α-cellulose.
      Citation: Reactions
      PubDate: 2022-03-12
      DOI: 10.3390/reactions3010016
      Issue No: Vol. 3, No. 1 (2022)
       
  • Reactions, Vol. 3, Pages 224-232: Calcination Temperature Induced
           Structural, Optical and Magnetic Transformations in Titanium Ferrite
           Nanoparticles

    • Authors: Abhishek Shukla, Subhash C. Singh, Abhishek Bhardwaj, Ravindra Kumar Kotnala, Kailash Narayan Uttam, Chunlei Guo, Ram Gopal
      First page: 224
      Abstract: Titanium ferrite represents one of the most promising magnetic materials that exhibits optical absorption in both ultraviolet and visible spectral regions with a range of applications in photocatalysis, giant magnetoresistance, sensors, high-frequency modern power supplies, etc. Here in the present work, we report synthesizing titanium ferrite NPs via the co-precipitation method. As obtained ferrite nanopowders were characterized using XRD, UV-Visible absorption, Raman scattering, and variable sample magnetometer techniques. The crystalline size of NPs lies between 35 to 50 nm. The as-obtained nanopowder samples were calcined at 200, 500, 800 °C temperatures, and the resulting change in the optical, structural, and magnetic properties are investigated. The saturation magnetization of 500 °C calcined sample is higher than that calcined at 200 °C, but the magnetization value drastically becomes reduced for powder calcined at 800 °C temperature. The results of the present work can be used to understand the effects of annealing temperature on the structural and magnetic properties of other ferrite nanomaterials.
      Citation: Reactions
      PubDate: 2022-03-19
      DOI: 10.3390/reactions3010017
      Issue No: Vol. 3, No. 1 (2022)
       
 
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