Catalytic Deoxygenation of Stearic Acid and Palmitic Acid in Semibatch Mode

The deoxygenation experiments of different reactants, i.e., pure palmitic acid, stearic acid, and a technical grade stearic acid containing a mixture of 59% of palmitic and 40% of stearic acid were successfully performed over 4 wt% Pd/C mesoporous catalyst at 300 °C under 17 bar of 5% H₂ in argon. The main product in catalytic deoxygenation of saturated fatty acids, C16 and C18, were aliphatic chain length hydrocarbons containing one less carbon than the corresponding acid. Additionally it was found that the deoxygenation rates of different reactant were independent on carbon chain length of its fatty acids.     

Computer Modeling of Probable Decomposition Reactions: Cyclonitramines

An approach to computer synthesis and retrosynthesis of organic compounds was formulated, and the CASB (Computer-Assisted Structure Building) software for its computer implementation was created. The approach was evaluated by the example of computer generation of probable routes for reactions of homolytic decomposition. Elementary steps of homolysis reactions were modeled with the use of the “retrosynthetic” method. Each elementary reaction describes fragments that should be present in the structure and structural modifications that should be carried out to obtain reaction products. Target fragments are described in terms of production rules by specifying types of atoms, their formal charges and radical states, numbers of adjacent heteroatoms, hybridizations, etc. All possible intermediates of molecular homolysis reactions are generated by the program in a single step and then used in further search for probable pathways of decomposition during subsequent steps until the given maximum number of steps is achieved. Screening of advantageous pathways for these reactions was based on a set of empirical rules. The results obtained by the suggested approach and the corresponding program were illustrated by the example of some cyclic nitramines (RDX and HMX) and demonstrated good agreement with the experiment.     

Isothermal Section of Er-Ag-Sn System at 873 K

The isothermal section of the Er-Ag-Sn system at 873 K was constructed with the use of scanning electron microscopy, energy-dispersive x-ray microanalysis and x-ray powder diffraction. Two ternary compounds were confirmed at this temperature: ErAgSn (LiGaGe structure type, P6₃mc, Z = 2, a = 4.6595(2) Å, c = 7.2872(3) Å) and non-stoichiometric phase ErAg_1?xSn_2+x (Cu₃Au structure type, Pm-3m, Z = 1). For the last one homogeneity range was established (0.08 < x < 0.24) and lattice parameters were determined (a = 4.5007(4), 4.5040(2), 4.5107(1), 4.5412(1) Å for the compositions Er_25.4Ag_23.4Sn_51.2, Er_25.7Ag_23.0Sn_51.3, Er_25.7Ag_21.7Sn_52.6, Er_25.2Ag_18.6Sn_56.2 (at.%) respectively). Melting point of the phase Er_25.7Ag_21.7Sn_52.6 (at.%) was determined to be 1199 K by differential thermal analysis.     

Ascorbic Acid-Assisted Eco-friendly Synthesis of NiCo<Subscript>2</Subscript>O<Subscript>4</Subscript> Nanoparticles as an Anode Material for High-Performance Lithium-Ion Batteries

We have synthesized NiCo₂O₄ nanoparticles (NCO NPs) using an ascorbic acid-assisted co-precipitation method for the first time. When NCO NPs are used as an anode material for lithium-ion batteries, the cell exhibits superior lithium storage properties, such as high capacity (700 mA h g^?1 after 300 cycles at 200 mA g^?1), excellent rate capabilities (applied current density range 100–1200 mA g^?1), and impressive cycling stability (at 1200 mA g^?1 up to 650 cycles). The enhanced electrochemical properties of NCO NPs are due to the nanometer dimensions which not only offers a smooth charge-transport pathway and short diffusion paths of the lithium ions but also adequate spaces for volume expansion during Li storage. Hence, this eco-friendly synthesis approach will provide a new strategy for the synthesis of various nanostructured metal oxide compounds, for energy conversion and storage systems applications.     

Deformation-Induced Dissolution and Precipitation of Nitrides in Austenite and Ferrite of a High-Nitrogen Stainless Steel

Methods of Mössbauer spectroscopy and electron microscopy have been used to study the effect of the severe plastic deformation by high pressure torsion in Bridgman anvils on the dissolution and precipitation of chromium nitrides in the austenitic and ferritic structure of an Fe_71.2Cr_22.7Mn_1.3N_4.8 high-nitrogen steel. It has been found that an alternative process of dynamic aging with the formation of secondary nitrides affects the kinetics of the dissolution of chromium nitrides. The dynamic aging of ferrite is activated with an increase in the deformation temperature from 80 to 573 K.     

Sunflower oil coating on the nanoparticles of iron(III) oxides

High-temperature solution phase reaction of iron(III)-furoate in sunflower oil, in the presence of trichloroacetic acid and 1,2-hexadecylamine leads to iron(III) oxide (amorphous and γ-Fe2O3) nanoparticles with sizes about 1.3 nm in diameter (method “A”), and about 5.5 nm (amorphous Fe2O3) from the “sunflower oil/oxadiazol” system (method “B”).     

A Single Molecular Beacon Probe Is Sufficient for the Analysis of Multiple Nucleic Acid Sequences

Molecular beacon (MB) probes are dual‐labeled hairpin‐shaped oligodeoxyribonucleotides that are extensively used for real‐time detection of specific RNA/DNA analytes. In the MB probe, the loop fragment is complementary to the analyte: therefore, a unique probe is required for the analysis of each new analyte sequence. The conjugation of an oligonucleotide with two dyes and subsequent purification procedures add to the cost of MB probes, thus reducing their application in multiplex formats. Here we demonstrate how one MB probe can be used for the analysis of an arbitrary nucleic acid. The approach takes advantage of two oligonucleotide adaptor strands, each of which contains a fragment complementary to the analyte and a fragment complementary to an MB probe. The presence of the analyte leads to association of MB probe and the two DNA strands in quadripartite complex. The MB probe fluorescently reports the formation of this complex. In this design, the MB does not bind the analyte directly; therefore, the MB sequence is independent of the analyte. In this study one universal MB probe was used to genotype three human polymorphic sites. This approach promises to reduce the cost of multiplex real‐time assays and improve the accuracy of single‐nucleotide polymorphism genotyping.     

Development of Methods for Steel Surface Deformation Nanostructuring

Metal Science and Heat Treatment - Results are provided for studying deformation methods of steel surface nanostructuring and hardening with martensitic, pearlitic and austenitic structures. A new...