Synthesis of β-(trifluoromethyl)furans and spiro-gem- dichlorocyclopropanes from cyclic 1,3-dicarbonyl compounds and α-(trihaloethylidene)nitroethanes

While 1,3-dicarbonyl compounds react with (E)-1,1,1-trifluoro-3-nitrobut-2- ene in the presence of sodium acetate to produce the target β- (trifluoromethyl)furans, their reaction with (E)-1,1,1-trichloro-3-nitrobut-2- ene, under the same conditions, took an entirely different course and gave spiro-gem-dichlorocyclopropanes bearing a 1-nitroethyl moiety, with high diastereoselectivity and in good yields. © 2013 Elsevier Ltd. All rights reserved

Domino reaction of 3-nitro-2-(trifluoromethyl)-2H-chromenes with 2-(1-phenylalkylidene)malononitriles: Synthesis of functionalized 6-(trifluoromethyl)-6H-dibenzo[b,d]pyrans and a rare case of [1,5] sigmatropic shift of the nitro group

A variety of functionalized 6-(trifluoromethyl)-6H-dibenzo[b,d]pyrans were easily synthesized in good yields under mild conditions by a domino reaction of 3-nitro-2-(trifluoromethyl)-2H-chromenes with 2-(1-phenylethylidene)- and 2-(1-phenylpropylidene)malononitriles. In the latter case, intermediate 7-amino-10-methyl-10-nitro-9-phenyl-6-(trifluoromethyl)-10,10a-dihydro-6H- benzo[c]chromene-8-carbonitriles were isolated as a result of a rare [1,5] sigmatropic shift of the nitro group. © 2013 Elsevier Ltd. All rights reserved

Synthesis of 5-(trifluoromethyl)-5H-chromeno[3,4-b]pyridines from 3-nitro-2-(trifluoromethyl)-2H-chromenes and aminoenones derived from acetylacetone and cyclic amines

Reactions of 3-nitro-2H-chromenes with aminoenones derived from acetylacetone and cyclic amines proceed diastereoselectively to give functionalized 2,3,4-trisubstituted chromanes as a result of nucleophilic addition of the vinylogous β-methyl group at the C-4 atom of the chromene system. From these compounds, under acidic conditions, 5-(trifluoromethyl)-5H- chromeno[3,4-b]pyridines and 4-acetoacetonyl-3-nitro-2-(trichloromethyl/phenyl) chromanes, depending on the substituent at the 2-position, were obtained in moderate to good yields. © 2013 Elsevier Ltd. All rights reserved

Highly regio-and stereoselective addition of ethyl 3-aminobut-2-enoates to 2-substituted 3-nitro-2H-chromenes

Ethyl 3-aminobut-2-enoates MeC(NHR)=CHCO2Et (R = H, Me, Bn) whose reaction site is C(2) atom add to 2-R-3-nitro-2H-chromenes at their C(4) atom to give the corresponding trans,trans-2,3,4-trisubstituted chromanes. Analogous substrates MeC(NR2)=CHCO2Et (NR2 is piperidin-1-yl or morpholin-4-yl) react by their C(4) methyl group to afford cis,trans-2,3,4-trisubstituted chromanes. The stereochemistry of the products was established by X-ray diffraction analysis. © 2013 Mendeleev Communications. All rights reserved

Modification of the microstructure of TiN-based columnar coatings in indentation zones

The columnar structure of titanium nitride–based coatings deposited by magnetron sputtering is studied. The structure–phase state of the coatings is analyzed after deposition and in the indentation zone. The type of dislocation structure, the grain size, the subgrain size, the misorientations at boundaries, and their change during coating growth are determined. The detected decrease (several tens of percent) in the coating thickness under an indenter indicates plastic deformation of a coating. On a microscopic level, this deformation manifests itself in an increase in the density, the misorientation, and the nonequilibrium of boundaries

Structure of Ti-Al-Si-N gradient coatings

The microstructure, the stresses, and the elemental composition of Ti-Al-Si-N gradient coatings are studied by transmission electron microscopy and electron-probe microanalysis of thin foils prepared in the cross section of the coatings. As the concentration of the elements that alloy titanium nitride increases across the coating thickness, the structure of the coating changes from submicrocrystalline columnar grains to nanocrystalline grains. In these structural states, the structural characteristics (lattice parameter, lattice bending-torsion, crystal size, type of intragranular defect structure) and the residual stresses change. The magnitude and the sign of residual stresses change when the type of structural state changes

Challenges and opportunities for energy recovery from municipal solid waste in the Russian Federation

Energy recovery from municipal solid waste (MSW) is currently a key factor in waste management in Russia, as can be seen from the corresponding changes in the state regulatory framework. The paper presents a comparative assessment of different waste flow characteristics; it focuses on pre-treatment options and the method of subsequent thermal treatment. It reflects the basic method of untreated MSW incineration and other advanced technologies which have different levels of waste preparation. Step-by-step research has been carried out in a large Russian city in order to determine different technological approaches to recovering energy from MSW. The study included: 1) field studies of the composition and characterization of MSW; 2) laboratory studies of MSW thermal properties, i.e. moisture, ash content and calorific value; 3) several options for waste treatment schemes with equipment of different technical specifications; 4) analysis of material flow, energy flow and key substance flow according to these considered schemes. The research revealed that for all seasons a significant proportion of MSW (almost 40%) is represented by fines (below 50 mm). On average, the energy potential of MSW (the total content of waste paper, polymers, textiles, wood, multilayer packaging, leather, rubber, footwear) amounts to about 40%. It was found that MSW calorific value depends on fraction size, since screening (over 50 mm) is characterized by high moisture and low content of valuable components, compared to MSW greater than 50 mm in size. Pre-processing and treatment of MSW allows solid recovered fuel (SRF) to be obtained with a calorific value similar to brown coal. The energy balance of the process allows the conclusion that 33.8% of initial MSW energy potential is concentrated in residues from the sorting process, since it has a relatively low calorific value of 4.8 MJ/kg, but a high mass fraction of 47.9%. In the process of MSW treatment and solid fuel production, most of the chlorine and mercury (80% and 55% respectively) is removed by the rest of the sorting process. The data obtained in the study can be used in selecting the optimal option for energy recovery from MSW. © 2019 WIT PressACKNOWLEDGEMENT The work was supported by Act 211 Government of the Russian Federation, contract № 02.A 03.21.0006

Thermal stability of Ti-C-Ni-Cr and Ti-C-Ni-Cr-Al-Si nanocomposite coatings

The results of the microstructure, mechanical and tribological properties investigations of Ti-C-Ni-Cr and Ti-C-Ni-Cr-Al-Si nanocomposite coatings based on amorphous carbon in the initial state and after the annealing to 900 °C are presented. The effect of annealing temperature on the microstructure, tribological and mechanical properties of Ti-C- Ni-Cr and Ti-C-Ni-Cr-Al-Si nanostructured coatings is discussed