Activity Descriptors As Tools For Designing Highly Efficient Electrocatalysts For Water Splitting,
2024
American University in Cairo
Activity Descriptors As Tools For Designing Highly Efficient Electrocatalysts For Water Splitting, Aya Gomaa
Theses and Dissertations
There is an uprising urge to design efficient, active, and durable catalysts to achieve sustainable hydrogen production. The unambiguity of which material should be used pushed the scientific community to devote enormous efforts in exploring different elements with different ratios on trial and error bases. However, the bridge between the theoretical calculation and the experiments introduced a new realm of designing efficient catalysts by introducing the concept of activity descriptors. In the first part of the thesis, the ability to convert waste stainless steel (SS) 316L meshes into highly efficient and durable oxygen evolution reaction (OER) catalysts is demonstrated. The …
Electrochemical Nitrate Reduction To Ammonia On Cu Based Nanoparticles Using Quantum Mechanical Simulations,
2024
New Jersey Institute of Technology
Electrochemical Nitrate Reduction To Ammonia On Cu Based Nanoparticles Using Quantum Mechanical Simulations, Kathan Bhavin Shukla
Theses
Nitrate reduction to ammonia (NRA) is critical for environmental remediation and energy conservation, as it can remove harmful nitrate (NO3-) from water sources while producing usable ammonia (NH3). Cu represents one of the most promising non-noble-metal NRA electrocatalysts. However, the intrinsic catalytic activity of Cu facets and their influence under different pH conditions remain unclear, particularly in the presence of ions commonly found in wastewater such as Cl-, Na+, Mg2+, and Ca2+. Using density functional theory (DFT) calculations, we evaluated the nitrate reduction to ammonia (NRA) pathways …
Nickel-Catalyzed Α-Arylation Of Α-Cyanoacetates Enabled By Electrochemistry,
2024
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
Nickel-Catalyzed Α-Arylation Of Α-Cyanoacetates Enabled By Electrochemistry, Zi-Meng Li, Zhang-Jian Li, Anat Milo, Ping Fang, Tian-Sheng Mei
Journal of Electrochemistry
β-Amino acids have a wide range of applications in the field of pharmaceuticals. Utilizing a combination strategy of nickel catalysis and paired electrolysis, a catalytic α-arylation protocol of carbonyl compounds has been developed. This protocol affords various a-aryl-a-cyanoacetates, which can be reduced to high-value-added α-aryl-β-amino acids. The cross-coupling reaction of electron-deficient aryl bromides with a-cyanoacetates achieves the expected products with good yields and functional group compatibility under mild conditions. Excessive electron-richness in initial aryl bromides facilitates the self-coupling of desired products. DFT calculations confirm that the presence of electron-rich aryl substitutions decreases the reduction potentials of the product anions, making …
Comparison Of Ligands In Palladium-Catalyzed Electrochemical Allyl 4-Pyridinylation,
2024
a Department of Material Science and Technology, Taizhou University, Taizhou 318000, Zhejiang, China; b School of Chemistry and Chemical Engineering Nanjing University, Nanjing 210023, Jiangsu, China
Comparison Of Ligands In Palladium-Catalyzed Electrochemical Allyl 4-Pyridinylation, Wei-Jie Ding, Chun-Hui Yang, Zhong-Tao Feng, Shi-Rong Lu, Xu Cheng
Journal of Electrochemistry
4-CN-pyridine is a widely applied 4-pyridinylation reagent for diverse transformations. Conventionally, the reaction proceeds via an open-shell radical cross-coupling pathway. Following our previous study, in this work, we report the Pd-catalyzed allyl 4-pyrinylation reaction under electrochemical conditions. The reaction proceeds via radical-polar crossover pathway in which the role of phosphine ligand in reactivity and selectivity was extensively investigated.
Recent Advance In Electrochemical Dehalogenative Deuteration,
2024
State Key Laboratory and Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, China
Recent Advance In Electrochemical Dehalogenative Deuteration, Peng-Fei Li, Guang-Sheng Kou, Li-Ping Qi, You-Ai Qiu
Journal of Electrochemistry
In recent years, the incorporation of deuterium atoms into organic compounds has emerged as a vital focus in the development of pharmaceutical molecules. This trend is driven by the increasing recognition of the significance of compounds containing deuterium atoms across various domains, including materials and biopharmaceuticals, where they have found widespread applications in mechanistic studies within the realms of chemistry and biology. Meanwhile, organic electrochemistry, as a relatively environmentally friendly catalytic mode with broad adaptability to redox reactions, has emerged as a crucial alternative to traditional halogen-deuterium exchange in the context of the reduction deuteration of halides. This approach circumvents …
A Comprehensive Review Of Fischer-Tropsch Synthesis Processes To Produce Sustainable Diesel And Aviation Fuel,
2024
Georgia Southern University
A Comprehensive Review Of Fischer-Tropsch Synthesis Processes To Produce Sustainable Diesel And Aviation Fuel, Joseph C. Steinagel
Honors College Theses
The greatest threat known to humankind today is global warming. It affects every nation on the planet and the natural order of all living things. Consequently, this ongoing crisis necessitates action to scientifically revolutionize important areas of society, including researching modern adaptations of the transportation industry. In that regard, it has been determined that an effective short-term answer to eliminating carbon emissions is to produce sustainable fuels that run cooperatively with the well-established machines of today. Sustainable aviation fuel (SAF) is one such topic of interest, and the Fischer-Tropsch synthesis process is an effective way of producing SAF. To that …
Ionic Conductivity, Li+ Transference Number, And Diffusion Coefficient Of A Solid-State Electrolyte Composite,
2024
Brigham Young University
Ionic Conductivity, Li+ Transference Number, And Diffusion Coefficient Of A Solid-State Electrolyte Composite, Lizbeth Zurita
Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)
The design of solid-state electrolyte (SSE) composites involves the fundamental study of transport properties, such as ionic conductivity. This transport property is influenced by the transport mechanisms of the charge species inside the composite, such as diffusion and migration. In this work, we perform the measurement of these three parameters through defined techniques. The resulting parameters were: ionic conductivity, the diffusion coefficient, and the Li+ transference number.
An Overview Of How To Measure The Kinetic Properties Of An Anode Material For The Chlorine Evolution Reaction,
2024
Brigham Young University
An Overview Of How To Measure The Kinetic Properties Of An Anode Material For The Chlorine Evolution Reaction, Cameron Vann
Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)
The process of generating chlorine gas using electrolysis in aqueous systems is well established. However, a new process requires chlorine to be generated at high temperatures using molten salt. This harsh environment requires a new study of anode materials for the chlorine evolution reaction. Anode materials can be compared by their kinetic parameters, the transfer coefficient α and the exchange current i0. The basic theory of these properties as they relate to the chlorine evolution reaction has been detailed and an analysis method for finding these effective parameters has been shown and demonstrated.
Synthesis Of Acetylene Diols With The Participation Of The Bu4noh/Dmso/H2o Catalytic Systems,
2024
Chirchik State Pedagogical University, Chirchik, Uzbekistan
Synthesis Of Acetylene Diols With The Participation Of The Bu4noh/Dmso/H2o Catalytic Systems, Muyassar K. Salieva, Odiljon E. Ziyadullayev, Guzal K. Otamukhamedova, Rifkat F. Talipov, Lochin K. Ablakulov
CHEMISTRY AND CHEMICAL ENGINEERING
The purpose of this work in this study, acetylene alcohols containing heteroatomic substituents in their molecular composition- 2-(-thiophen-2-yl)but-3-yn-2-ol, 2-(3-methylthiophen-2-yl)but-3-yn-2-ol, 2-(furan-2-yl)but-3yn-2-ol, 2-(pyridin-4-yl)but-3-yn-2-ol, 2-(5-chlorothiophen-2-yl)but-3-yn-2-ol, 2-(5-bromothiophen-2yl)but-3-yn-2-ol acetylene diols were synthesized based on the reaction with acetone in a dimethyl sulfoxide solvent in the presence of the Bu4NOH/DMSO/H2O catalytic system. The influence of the molar ratio of starting materials, reaction duration, temperature, nature of the catalyst and solvents on the product yield was systematically studied. The composition, purity and structure of the new generation of synthesized acetylenediols have been confirmed by modern physicochemical methods. The mechanism of the reaction process …
Synthesis Of High Molecular Mass Resins Based On Furfuryl Alcohol,
2024
Tashkent Institute of Chemical Technology, Tashkent, Uzbekistan
Synthesis Of High Molecular Mass Resins Based On Furfuryl Alcohol, Boysayid U. Sayidov, Latif E. Jumanov, Muzaffar G. Alimukhamedov, Sherali A. Umarov, Farhod A. Magrupov
CHEMISTRY AND CHEMICAL ENGINEERING
The purpose of the work is to study the process of synthesis of furfuryl oligomers with high molecular weight at various ratios of furfuryl alcohol and hydroxyl-containing polyether polyol. The influence of the process method on the yield of high-molecular furfuryl oligomer is shown - with a one-step synthesis method with an increase in the amount of furfuryl alcohol from 20 to 50 moles per 1 mole of polyether polyol, the yield of the final product decreases from 75% to 56%, apparently due to high exothermic effects, causing gelation systems. In contrast to the one-time introduction of the catalyst, its …
Synthesis And Technology Of Vinyl Esters Of Aromatic Carboxylic Acids Based On Vinyl Acetate,
2024
National University of Uzbekistan, Tashkent, Uzbekistan
Synthesis And Technology Of Vinyl Esters Of Aromatic Carboxylic Acids Based On Vinyl Acetate, Askar B. Parmanov, Suvonkul E. Nurmanov, Saida S. Abdurakhmanova, Sarvinoz I. Tirkasheva, Begzod F. Adashev
CHEMISTRY AND CHEMICAL ENGINEERING
In this work the vinylation reactions of aromatic carboxylic acids with vinyl acetate, which contain various substituents, in the presence of 2-chloro-4,6-dimethoxy-1,3,5-triazine were studied for the first time. The influence of the nature of the starting materials, temperature, reaction duration, solvent and reagents - zinc triflate (Zn(OTf)2, 3,3-diphenylbinaphthol (3,3'-Ph2BINOL-2Li), tertiary potassium butylate (KOtrBu), butyllithium (BuLi) for the synthesis of vinyl esters. The synthesis of vinyl esters of aromatic carboxylic acids was carried out: benzoiс, 2-phenylacetic, 4-methylbenzoic, 4-methoxybenzoic, 3,4-dimethoxybenzoic, 2-brombenzoic, 4-brombenzoic, 4-fluorobenzoic, 3-nitrobenzoic, 4-nitrobenzoic, 4-tertiary butylbenzoic, 2-chlorobenzoic, 4-chlorobenzoic, 3-hydroxybenzoic and 4-hydroxybenzoic acids has been studied. …
Synthesis Of Internal Acetylene Alcohols Based On The Sonogashira Reaction Of Terminal Acetylene Alcohols And Benzolchloride,
2024
Chirchik State Pedagogical University, Chirchik, Uzbekistan
Synthesis Of Internal Acetylene Alcohols Based On The Sonogashira Reaction Of Terminal Acetylene Alcohols And Benzolchloride, Guzal K. Otamukhamedova, Odiljon E. Ziyadullayev, Abduvahob Ikramov, Sarvinoz I. Tirkasheva
CHEMISTRY AND CHEMICAL ENGINEERING
The purpose of the study is to develop a new catalytic system for the synthesis of internal acetylene alcohols from the Sonogastric coupling reaction of terminal acetylene alcohols and benzolchloride. For the first time in this work, internal acetylene alcohols have been synthesized based on reactions of some terminal acetylene alcohols – 3,4-dimethylpentin-1-ol-3, 3,4,4-trimethylpentin-1-ol-3, 1-ethynylcyclohexanol-1, 2-ethynyladamantanol-2, 2-phenylbutin-3-ol-2, 2-(naphthyl-2)butyn-3-ol-2, 2-(furanyl-2)butyn-3-ol-2 and 2-(pyridinyl-4)butyn-3-ol-2 with chloridebenzene. In order to achieve high product productivity in the Sonogashira reaction, alternative conditions have been identified by studying the molar ratios, spatial structure, induction effects of substituents, solvent and catalyst nature, as well as temperature, reaction duration …
Sol-Gel Synthesis And Microstructure Characterization Of Nio-Tio2 Semiconductor,
2024
Department of Chemistry, Mkwawa University College of Education, University of Dar es Salaam, P.O. Box 2513 Iringa, Tanzania
Sol-Gel Synthesis And Microstructure Characterization Of Nio-Tio2 Semiconductor, Godlisten N. Shao
Tanzania Journal of Engineering and Technology (TJET)
NiO-TiO2 is a fascinating p-n semiconducting binary metal oxide with unique electronic and optical properties. The NiO-TiO2 has been synthesized using complicated preparation methods and expensive precursors that hamper their large-scale production. The present study reports the preparation of NiO-TiO2 semiconductor with improved physicochemical properties. NiO-TiO2 samples were prepared through one-pot sol-gel synthesis process followed by sintering of the as-synthesized materials at temperatures ranging from 600 to 1000 °C. The role of thermal treatment and NiO content on the microstructures was exquisitely studied. The microstructure of the NiO-TiO2 samples was examined by Raman spectroscopy, XRD, XRF, SEM-EDAX, high resolution TEM, …
Thermogravimetric Analysis And Chemical Kinetics Of Waste Tires,
2024
University of Dar es Salaam
Thermogravimetric Analysis And Chemical Kinetics Of Waste Tires, Mahir Mohammed Said
Tanzania Journal of Engineering and Technology (TJET)
The focus of this paper is to analyse the pyrolysis reaction of waste tires. The pyrolysis was studied experimentally using thermal and chemical kinetics. The tires were pyrolyzed using thermogravimetry at a temperature range of 200 to 600°C, with heating rates of 10, 20, and 50°C/min. The activating energy was observed to increase with increased temperature. The highest activating energy was 101.02 kJ/mol at a heating rate of 50°C/min.
Sediment Characteristics And Hydrocarbon Composition Of Makukwa Seep In Southern Tanzania: Potential Implications For Subterranean Hydrocarbon Accumulation,
2024
University of Dar es salaam
Sediment Characteristics And Hydrocarbon Composition Of Makukwa Seep In Southern Tanzania: Potential Implications For Subterranean Hydrocarbon Accumulation, Makungu M. Madirisha
Tanzania Journal of Engineering and Technology (TJET)
Exploring the interplay between natural seeps and nearby sediment and hydrocarbon properties is key to unlocking subsurface hydrocarbon potential. This study presents findings on the hydrocarbon composition and sediment characteristics of the Makukwa seep in southern Tanzania, providing insight into subterranean hydrocarbon accumulation. Sediment analysis across areas A and B, located approximately 20 m apart, showed a decrease in porosity with depth, indicative of typical sandstone formations. Area A, near the seeps, exhibited porosity ranging from 23% to 36%, whereas Area B, further away, showed porosity ranging from 22% to 38%. This suggests that a lower cretaceous sandstone layer may …
Design And Optimization Of An Azeotropic Distillation Pilot Plant For The Production Of Pure Ethanol,
2024
Department of Chemical and Process Engineering, College of Engineering and Technology, University of Dar es Salaam, P.O. Box 35131, Dar es Salaam, Tanzania
Design And Optimization Of An Azeotropic Distillation Pilot Plant For The Production Of Pure Ethanol, Samwel V. Manyele
Tanzania Journal of Engineering and Technology (TJET)
This study aimed to design an azeotropic distillation plant using Aspen Plus® V10 software and determine optimal process conditions for producing pure ethanol greater than 95% from pre-concentrated near-azeotropic ethanol-water solution. The non-random two-liquid Redlich-Kwong thermodynamic model was the base method for property analysis and performance prediction. Modelling and simulation of the converged process were conducted for fixed column variables (R = 5, N = 12 and p = 1 atm). Plant operating parameters were varied in the range of 0 to 1 for the pre-heater vapour fraction, 2 to 10 for the column feed plates (NFP), 2 to 6 …
Effect Of Zr And W Doping On Microstructures, Transition Temperature And Solar Transmittance Modulation Of Thermochromic W/Zr Co-Doped Vo2 Thin Films,
2024
Department of Natural Sciences, The State University of Zanzibar, P.O. Box 146, Zanzibar, Tanzania
Effect Of Zr And W Doping On Microstructures, Transition Temperature And Solar Transmittance Modulation Of Thermochromic W/Zr Co-Doped Vo2 Thin Films, Haji F. Haji
Tanzania Journal of Engineering and Technology (TJET)
Thermochromic W/Zr co-doped VO2-based thin films with different concentrations of Zr were successfully deposited on soda lime glass substrates by direct current (DC) magnetron sputtering of V(99)W(01) alloy and Zr targets at a substrate temperature of 425 °C. The films were characterized by x–ray diffraction (XRD), atomic force microscopy (AFM), Rutherford backscattering spectroscopy (RBS), two-point probe and UV/VIS/NIR spectroscopy. The film’s structural properties evolution was significantly influenced by Zr concentration in the films. The transition temperature and hysteresis loop widths of the films were found to decrease with increasing Zr concentration. For the Zr concentrations of 0.21 at.%, 0.23 at.% …
Enhanced Post Deposition Annealing Conditions On The Fabrication Of High Quality Thermochromic Vanadium Dioxide Films,
2024
Department of Physics, University of Dar es Salaam, P.O. Box 35063, Dar es Salaam, Tanzania
Enhanced Post Deposition Annealing Conditions On The Fabrication Of High Quality Thermochromic Vanadium Dioxide Films, Nuru R. Mlyuka
Tanzania Journal of Engineering and Technology (TJET)
Sputter deposition of thermochromic VO2 thin films for smart window applications has been faced with several challenges including the need for high deposition temperature, extremely precise and narrow range of oxygen/argon flow ratio and target poisoning during sputtering. Deposition of VO2 at room temperature without oxygen followed by post-deposition annealing has been cited as one of the potential mitigations to the challenge. In this study, the effects of post-deposition annealing conditions on the structural, electrical and optical properties of VO2 thin films are reported. The films were prepared on soda lime glass substrates using DC magnetron sputtering of metallic vanadium …
Production Of Biofertilizer From Fruit And Garden Waste,
2024
Department of Chemical and Process Engineering, College of Engineering and Technology, University of Dar es Salaam, P.O. Box 351313, Dar es Salaam, Tanzania
Production Of Biofertilizer From Fruit And Garden Waste, Neema Msuya
Tanzania Journal of Engineering and Technology (TJET)
The project focused on the production of bio-fertilizer from fruit and garden waste, with a specific emphasis on utilizing pineapple tops in the composting process. The objective was to produce and assess the properties of the bio fertilizer obtained from this process and evaluate its potential application in agriculture. In this study, the composting process was done in a 0.7 m long, 0.85 wide and 1.1 m high vessel, and 0.238 m3 pineapple top wastes, resulting in 0.35 m3 of biofertilizer. The bio fertilizer produced exhibited favorable characteristics, including a moisture content of 36%, pH of 7.1, and a total …
Study Of The Effects Of Thermal Aging Coupled With Shot-Peening Treatment Of Carbonitrided Din 1.6587 Low Alloy Steel On Retained Austenite And Residual Stresses,
2024
Department of Mining and Mineral Processing Engineering, School of Mines and Geosciences, University of Dar es Salaam, P.O. Box 35052, Dar es Salaam, Tanzania
Study Of The Effects Of Thermal Aging Coupled With Shot-Peening Treatment Of Carbonitrided Din 1.6587 Low Alloy Steel On Retained Austenite And Residual Stresses, Richard J. Katemi
Tanzania Journal of Engineering and Technology (TJET)
This work investigated the effects of thermal aging and shot-peening of carbonitrided 1.6587 steel grade on retained austenite and residual stresses. After carbonitriding samples contained maximum of 0.87% carbon, 0.34% nitrogen and 50 mass. -% retained austenite. Thermal aging conditions investigated were -30°C, 90°C and 150°C while the aging period were 14, 96 and 720 hours. After thermal aging, some of the samples were subjected to shot-peening treatment using standard cut wire shots StD – G3 - 0.6 mm VDFI 8001 with intensity in the range of 0.25 to 0.30 mmA and coverage of 1.00 to 1.24 x 98%. It …
