scholarly journals Investigation of Synthesis of Sodium Aminodiborane in One Step and Its Reaction Kinetics

Molekul ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 219
Author(s):  
Meryem Sena Akkus ◽  
Goksel Ozkan
Keyword(s):  
Batch Reactor ◽  
Sodium Hydride ◽  
Ammonia Borane ◽  
Stoichiometric Ratio ◽  
Molar Ratios ◽  
Varied Temperature ◽  
Temperature Ranges ◽  
One Step ◽  
Wet Chemical ◽  
Chemical Reaction Method

In this study, sodium aminodiborane (NaNH2(BH3)2) synthesis was carried out in a constant volume batch reactor with a single feed at various temperatures and inlet molar ratios. It was synthesized, ammonia borane and sodium hydride as precursors, by a wet chemical reaction method using tetrahydrofuran which is a solvent under atmospheric pressure. These experiments were carried out at varied temperature ranges from 0 °C to 24 °C, and varied inlet molar ratios (AB/NaH) from 0.75 to 1.25. Sodium amidoborane is synthesized when the experiment is carried out in a stoichiometric ratio, but sodium aminodiborane is synthesized when the mole of ammonia borane is higher than the mole of sodium hydride. In order to characterize the products, FTIR, XRD, GC-MS/MS, and quantitative analysis techniques were utilized. In addition, sodium aminodiborane’s synthesis reaction kinetic was determined. r apparent = 0.8594 e ^ (- 4366 / RT) C AB ^ (0.8) C NaH ^ (0.2). The apparent activation energy, Ea, and frequency constant, k0, were calculated about 4366 J/mol and 0.8594 h-1, respectively

scholarly journals Construction of cost-effective bimetallic nanoparticles on titanium carbides as a superb catalyst for promoting hydrolysis of ammonia borane

RSC Advances ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 843-847 ◽  
Author(s):  
Zhangwei Guo ◽  
Tong Liu ◽  
Qingtao Wang ◽  
Guanhui Gao
Keyword(s):  
Chemical Method ◽  
Bimetallic Nanoparticles ◽  
Cost Effective ◽  
Ammonia Borane ◽  
Wet Chemical Method ◽  
One Step ◽  
Wet Chemical ◽  
Titanium Carbides ◽  
Hydrolysis Of

Bimetallic cost-effective CoNi nanoparticles are supported on MXene by a simple one-step wet-chemical method. The Co0.7Ni0.3/MXene shows the best performance toward catalyzing AB decomposition with TOF of 87.6 molH2molcat−1min−1at 50 °C.

Binding of lead and copper(II) cations to hemicelluloses of rye bran

1986 ◽  
Vol 51 (10) ◽  
pp. 2250-2258 ◽  
Author(s):  
Rudolf Kohn ◽  
Zdena Hromádková ◽  
Anna Ebringerová
Keyword(s):  
Uronic Acid ◽  
Equilibrium Solution ◽  
Glucuronic Acid ◽  
The Other ◽  
Carboxyl Groups ◽  
Stoichiometric Ratio ◽  
Molar Ratios ◽  
Free Ions ◽  
Uronic Acid Content ◽  
The Relationship

Several fractions of acid hemicelluloses isolated from rye bran were characterized by molar ratios of saccharides (D-Xyl, L-Ara, D-Glc, D-Gal) and 4-O-methyl-D-glucuronic acid and protein content. Binding of Pb2+ and Cu2+ ions to these acid polysaccharides was considered according to function (M)b = f([M2+]f), expressing the relationship between the amount of metal (M)b bound to 1 g of the substance and the concentration of free ions [M2+]f in the equilibrium solution and according to the association degree β of these cations with carboxyl groups of uronic acid at a stoichiometric ratio of both components in the system under investigation. Acid hemicelluloses contained only a very small portion of uronic acid ((COOH) 0.05-0.18 mmol g-1); the model polysaccharide, 4-O-methyl-D-glucurono-D-xylan of beech, was substantially richer in uronic acid content ((COOH) 0.73 mmol g-1). Consequently, the amount of lead and copper bound to acid hemicelluloses is very small ((M)b 0.017-0.025 mmol g-1) at [M2+]f = 0.10 mmol l-1. On the other hand, much greater amount of cations ((M)f 0.09-0.10 mmol g-1) was bound to the glucuronoxylan. The association degree β was like with the majority of samples (β = 0.31-0.38). The amount of lead and copper(II) bound to acid hemicelluloses from rye bran is several times lower than that bound to dietary fiber isolated from vegetables (cabbage, carrot), rich in pectic substances.

scholarly journals Hydrothermal synthesis of nanocrystalline hydroxyapatite–graphene nanosheet on Ti-6Al-7Nb: mechanical and in vitro corrosion performance

2021 ◽  
Vol 32 (4) ◽  
Author(s):  
Oktay Yigit ◽  
Burak Dikici ◽  
Niyazi Ozdemir
Keyword(s):  
Hydrothermal Reaction ◽  
Hybrid Coatings ◽  
Stoichiometric Ratio ◽  
Corrosion Performance ◽  
Graphene Nanosheet ◽  
Graphene Layers ◽  
Nanocrystalline Hydroxyapatite ◽  
One Step ◽  
Nano Size

AbstractThe hybrid coatings containing the graphene nano-sheet (GNS) and nano-hydroxyapatite (nHA) phases have been successfully synthesized on Ti6Al7Nb alloys by a one-step hydrothermal method. The hydrothermal reaction was carried out for 24 h at 200 °C. The GNS ratio has been altered as 1, 3, 5 and 7 wt.% in the coatings and, the results have compared with non- GNS containing coatings. The effect of the GNS ratio on the microstructure, hardness, and in vitro corrosion responses has been investigated in detail. The characterizations of the coatings were carried out by SEM, EDS, AFM, XRD and, FTIR. The corrosion behavior of the hybrid coatings was compared in Kokubo’s solution at 37 °C by using potentiodynamic polarization tests. The results showed that the hydroxyapatite phases were deposed on the graphene layers with nano-size nucleation with its Ca/P stoichiometric ratio. The best hydrophilicity (~52°) property has been obtained in nHA/3GNS coatings. In addition, the corrosion rates of coatings increased in the following order: nHA/3GNS < nHA/1GNS < nHA/7GNS < nHA/5GNS < only nHA.

scholarly journals Esterification of Crude Palm Oil Using H2SO4 and Transesterification Using CaO Catalyst Derived from Anadara granosa

2017 ◽  
Vol 17 (2) ◽  
pp. 309 ◽  
Author(s):  
Nurhayati Nurhayati ◽  
Sofia Anita ◽  
Tengku Ariful Amri ◽  
Amilia Linggawati
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Palm Oil ◽  
Reaction Times ◽  
Crude Palm Oil ◽  
Process Step ◽  
Molar Ratios ◽  
One Step ◽  
Esterification Reactions ◽  
Anadara Granosa

In this study biodiesel was produced from crude palm oil through two-step processes, namely esterification reactions using homogeneous H2SO4 catalyst and transesterification using the heterogeneous base CaO catalyst derived from Anadara granosa shell. Several parameters affecting to the yields of biodiesel were investigated including the amount of the catalysts, the molar ratios of oil to methanol, reaction times and reaction temperatures. The CaO catalyst was prepared by calcining the A. granosa shells at the temperatures of 800 and 900 °C for 10 h. The as-synthesized biodiesel was analyzed using GC and its characteristics were determined and the results were compared to Standard National for Biodiesel (SNI 04-7183-2006). The optimum condition for the esterification process (step 1) was as follows: reaction temperature of 65 °C, reaction time of 3 h and mol ratio of oil to methanol 1:24. For the transesterification (step 2) the optimum conditions were attained using the catalyst weight 3%, reaction temperature of 60 °C, reaction time of 3 h, mole ratio of oil/methanol 1:6 and the catalyst calcination time of 10 h with the conversion of 87.17%. This biodiesel yield by the two-step processes was higher (2.7%) than that using only one-step process (transesterification).

scholarly journals Nano-inclusion in one step: spontaneous ice-templating of porous hierarchical nanocomposites for selective hydrogen release

2019 ◽  
Vol 3 (2) ◽  
pp. 396-400 ◽  
Author(s):  
Simon Champet ◽  
Jan van den Berg ◽  
Robert Szczesny ◽  
Agata Godula-Jopek ◽  
Duncan H. Gregory
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Ammonia Borane ◽  
Onset Temperature ◽  
Hydrogen Release ◽  
Aqueous Suspensions ◽  
Reduced Graphene ◽  
One Step ◽  
Ice Templating

3-D nanocomposites of (reduced) graphene oxide and ammonia borane can be fabricated in a one-step ice templating process from aqueous suspensions. The nanocomposites release hydrogen at a reduced onset temperature, suppressing the release of diborane, borazine and ammonia.

Uniform flower-like BiOBr/BiOI prepared by a new method: visible-light photocatalytic degradation, influencing factors and degradation mechanism

2019 ◽  
Vol 43 (37) ◽  
pp. 14829-14840 ◽  
Author(s):  
Jianhui Li ◽  
Quan Zhou ◽  
Fan Yang ◽  
Lijie Wu ◽  
Wenying Li ◽  
...  
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Influencing Factors ◽  
Solvothermal Method ◽  
Degradation Mechanism ◽  
Degradation Efficiency ◽  
New Method ◽  
Molar Ratios ◽  
One Step ◽  
Visible Light Photocatalytic

BiOBr/BiOI photocatalyst with different molar ratios was synthesized via a simple one-step solvothermal method. The uniform flower-like BiOBr/BiOI (3 : 1) owns high photocatalytic degradation efficiency, excellent recyclability and stability.

scholarly journals Electrospun Bimetallic NiCr Nanoparticles@Carbon Nanofibers as an Efficient Catalyst for Hydrogen Generation from Ammonia Borane

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1082 ◽  
Author(s):  
Robert M. Brooks ◽  
Ibrahim M. Maafa ◽  
Abdullah M. Al-Enizi ◽  
M. M. El-Halwany ◽  
Mohd Ubaidullah ◽  
...  
Keyword(s):  
Carbon Nanofibers ◽  
Hydrogen Generation ◽  
Ammonia Borane ◽  
Catalytic Performance ◽  
Inert Atmosphere ◽  
Nicr Alloy ◽  
Efficient Catalyst ◽  
Nickel Acetate Tetrahydrate ◽  
One Step ◽  
Nanofiber Mats

In this study, we report on the fabrication and utilization of NiCr alloy nanoparticles (NPs)-decorated carbon nanofibers (CNFs) as efficient and competent non-precious catalysts for the hydrolytic dehydrogenation of ammonia borane (AB) at 25 ± 2 °C. The introduced NFs have been fabricated in one step using a high-temperature thermal decomposition of the prepared electrospun nanofiber mats (nickel acetate tetrahydrate, chromium acetate dimer, and polyvinyl alcohol) in an inert atmosphere. The chemical composition of the NFs with different proportions of Ni1−xCrx (x = 0.0, 0.1, 0.15, 0.2, 0.25, 0.3) was established via standard characterization techniques. These techniques proved the formation of disorder Cr2Ni3 alloy and carbon for all the formulations. The as-synthesized composite NFs exhibited a higher catalytic performance for AB dehydrogenation than that of Cr-free Ni–CNFs. Among all the formulations, the sample composed of 15% Cr shows the best catalytic performance, as more H2 was released in less time. Furthermore, it shows good stability, as it is recyclable with little decline in the catalytic activity after six cycles. It also demonstrates the activation energy, entropy (ΔS), and enthalpy (ΔH) with 37.6 kJ/mole, 0.094 kJ/mole, and 35.03 kJ/mole, respectively. Accordingly, the introduced catalyst has a lower price with higher performance encouraging a practical sustainable H2 energy application from the chemical hydrogen storage materials.

scholarly journals Perturbed and Unperturbed: Analyzing the Conservatively Perturbed Equilibrium (Linear Case)

Entropy ◽  
2020 ◽  
Vol 22 (10) ◽  
pp. 1160
Author(s):  
Yiming Xi ◽  
Xinquan Liu ◽  
Denis Constales ◽  
Gregory S. Yablonsky
Keyword(s):  
Inflection Point ◽  
Extreme Values ◽  
Chemical Elements ◽  
Batch Reactor ◽  
Chemical System ◽  
Essential Information ◽  
Detailed Mechanism ◽  
Chemical Relaxation ◽  
One Step ◽  
Equilibrium Concentrations

The “conservatively perturbed equilibrium” (CPE) technique for a complex chemical system is computationally analyzed in a batch reactor considering different linear mechanisms with three and four species. Contrary to traditional chemical relaxation procedures, in CPE experiments only some initial concentrations are modified; other conditions, including the total amount of chemical elements and temperature are kept unchanged. Generally, for “unperturbed” species with initial concentrations equal to their corresponding equilibrium concentrations, unavoidable extreme values are observed during relaxation to the equilibrium. If the unperturbed species is involved in one step only, this extremum is a momentary equilibrium of the step; if the unperturbed species is involved in more reactions, the extremum is not a momentary equilibrium. The acyclic mechanism with four species may exhibit two extrema and an inflection point, which corresponds to an extremum of the rate of the species change. These facts provide essential information about the detailed mechanism of the complex reaction.

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