Vol 87, No 9 (2017)
- Year: 2017
- Articles: 52
- URL: https://journals.rcsi.science/1070-3632/issue/view/13677
Article
Betti base in the synthesis of chiral bisphosphorylated thioureas
Abstract
Phosphorylation of a naphthol hydroxy group of thiophosphorylated thiourea obtained by reaction of diethyl thiophosphoryl isothiocyanate with 1-(α-aminobenzyl)-2-naphthol (Betti base) afforded a number of chiral bisphosphorylated thioureas. Molecular structure of the obtained compounds was studied by single crystal X-ray diffraction. The capacity of the studied compounds for dimerization due to the intermolecular N–H···S hydrogen bonding was revealed.
Synthesis, structure, and antimicrobial activity of (carboxyalkyl)dimethylsulfonium halides
Abstract
Reactions of a series of ω-halocarboxylic acids (2-bromo-, 2-chloroethanoic, 3-bromo- and 3-chloropropanoic) with dimethyl sulfide resulted in the formation of stable (carboxylalkyl)dimethylsulfonium bromides and chlorides. Composition and structure of the salts obtained were established by a complex of chemical, physical and physicochemical methods. The sulfonium salts obtained showed high antibacterial and antimycotic activities with respect to the pathogenic microflora of humans and animals.
Reactions of dialkyl (3,5-di-tert-butyl-4-oxocyclohex-2,5-dienylidenemethyl)phosphonates with alcohols and some transformations of the adducts
Abstract
Reactions of dialkyl [(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)methyl]phosphonates with butyl, benzyl and propargyl alcohols in the presence of catalytic amounts of trifluoromethanesulfonic acid resulted in the formation of nucleophilic 1,6-addition products. Azide-alkyne cycloaddition reaction of dimethyl (3,5-di-tert-butyl-4-hydroxyphenyl)(prop-2-ynyloxy)methylphosphonate with benzyl azide and 1,3-bis-(2-azidoethoxy)benzene in the presence of copper sulfate and sodium ascorbate afforded 1,2,3-triazoles with sterically hindered phenol fragments.
Reactions of bicyclic phosphonates with halides of α-halocarboxylic acids
Abstract
Novel types of substituted framework phosphonates have been synthesized via functionalization of bicyclic compounds obtained in the reaction of 2-ethoxyvinyl dichlorophosphonate with different phenols. The reactions of functionalized bicyclic phosphonates with triphenyl phosphine have been studied; antimicrobial activity of the prepared compounds has been investigated.
Antiradical activity of benzazole-2-thiones
Abstract
Reaction of benzoxazole-2-thione with 3,5-di-tert-butyl-4-hydroxybenzylacetate in methanol affords S-(3,5-di-tert-butyl-4-hydroxybenzyl)-2-mercaptobenzoxazole as the major product. Antiradical activity of S- and N-3,5-di-tert-butyl-4-hydroxybenzyl derivatives of benzothiazole(oxazole, imidazole)-2-thione with respect to 2,2-diphenyl-1-picrylhydrazyl is varies widely. S-Benzyl derivatives exhibit higher reactivity at 30°C.
3-Phosphorylated thioazoles
Abstract
A novel procedure is reported for the synthesis of 3-phosphorylated N,S-heterocyclic systems by regio- and chemoselective reaction of chloroethynylphosphonates with the thio tautomers of various thioazoles. If the initial sulfanyl azole possesses labile protons or basic NR groups, partial or complete loss of chemoselectivity is observed, and the products are the corresponding acyclic 1,2- and 2,2-substituted alkenylphosphonates.
Reaction of 1,4-benzoquinones with PH-phosphonium salts
Abstract
A novel approach has been proposed to the synthesis of phosphonium salts containing a 1,4-dihydroxybenzo fragment via reaction of 2-methyl-1,4-benzoquinone or 2-isopropyl-5-methyl-1,4-benzoquinone with PH-phosphonium salts generated in situ from triphenylphosphine and trifluoromethanesulfonic or trifluoroacetic acid. The structure of the synthesized phosphonium salts was determined by NMR spectroscopy and X-ray analysis.
Synthesis of pillar[5]arenes with a PH-containing fragment
Abstract
The reactions of phosphorus(III) chloride and 2-chloro-1,3,2-dioxaphospholane with monohydroxypillar[5]arene afforded for the first time the corresponding PH-phosphonates. It was found that the newly formed P–O(Ar) bond is characterized by considerably reduced reactivity, which was rationalized by essential shielding of the phosphorus atom by the pillar[5]arene macrocycle. The pillar[5]arene scaffold stabilizes the highly reactive PIII–Cl fragment, so that the formation of macrocyclic dichlorophosphite can be detected under normal conditions.
Synthesis of new p-tert-butylcalix[4]arene derivatives containing photopolymerizable 1,3-butadiyne fragments
Abstract
Successive functionalization of p-tert-butylcalix[4]arene afforded a bifunctional derivative containing photopolymerizable pentacosa-10,12-diynoic acid fragments on the upper rim and propargyl groups on the lower rim of the macrocycle having a cone structure. The functionalization can be readily accomplished via copper-catalyzed azide–alkyne cycloaddition under mild conditions.
Chemoselective acylation of monosubstituted thiacalix[4]arene with di-tert-butyl dicarbonate
Abstract
Mono-, di-, and tetrasubstituted derivatives of p-tert-butylthiacalix[4]arene containing tert-butylcarbamate, tert-butylcarbonate, and tert-butyl fragments have been prepared for the first time. Depending on the reaction conditions (reagents ratio, temperature, and the presence of a base), the interaction of the monoamine derivative of p-tert-butylthiacalix[4]arene with di-tert-butyl dicarbonate can lead to the formation of mono-, di-, and tetrasubstituted products.
Synthesis of 1,3-diketo derivatives of calix[4]arene with nonyl substituents at the lower rim as novel efficient sensibilizers of Tb3+ luminescence
Abstract
Novel bis- and tetra-1,3-diketo derivatives of calix[4]arene with nonyl substituents at the lower rim have been synthesized. Their conformational and tautomeric composition have been determined; spectral parameters and complex formation properties with Tb3+ have been studied. Substitution of two 1,3-diketo groups with bromine under going from tetra- to bis 1,3-diketone derivatives was resulted in twofold increase luminescence intensity in their terbium complexes. Lifetime of the excited state of the terbium luminescence of the corresponding complexes as well as lifetime of excited triplet level of the 1,3-diketonate ligands have been determined.
Modification of silica nanoparticles with stereisomers of p-tert-butylthiacalix[4]arene containing four 2-oxo-2-{[3-(triethoxysilyl)prop-1-yl]amino}ethoxy substituents at the lower rim
Abstract
Three stereoisomers (cone, partial cone, and 1,3-alternate) of p-tert-butylthiacalix[4]arene bearing four anchor propyltriethoxysilane substituents at the lower rim were synthesized for the first time. Surface modification of silica nanoparticles (d = 12 nm) with the synthesized macrocycles gave novel hybride thiacalix [4]arene‒SiO2 particles. The obtained nanostructured adsorbents were found to efficiently extract nitroaromatic compounds from aqueous solutions. The partial cone and 1,3-alternate thiacalix[4]arene–SiO2 hybrid particles showed affinity to nitrophenols.
New amphiphilic multiheterocycle: Micelle-forming properties and effect on the reactivity of phosphorus acid esters
Abstract
Supramolecular systems based on a novel tetracationic amphiphilic multiheterocycle have been studied by tensiometry, conductometry, pH-metry, spectrophotometry, and dynamic and electrophoretic light scattering. The critical micelle concentration of the system has been determined (0.4 mM), and the possibility of open and closed association models realization has been demonstrated. A high solubilizing ability of the aggregates toward hydrophobic guest species has been revealed. Micellar catalysts based on the new multiheterocycle have shown substrate specificity in the hydrolysis of phosphonates possessing different hydrophobicities.
Formation of copper nanoparticles with hyperbranched polyesterpolyols as template
Abstract
New composite copper nanoparticles stabilized by hyperbranched polyesterpolyols of the second, third, and forth generations have been prepared via chemical reduction at different molar ratios of the precursors. The prepared stabilized copper nanoparticles have exhibited fungicide activity against Penicillium funiculosum, Penicillium ochro chloron, Paecilomyces variotii, Aspergillus niger, Aspergillus oryzae, and Aspergillus terreus strains. Copper nanoparticles stabilized by hyperbranched polyesterpolyols of the second and forth generations are hemocompatible.
Hyperbranched polyester poly[3-(morpholin-4-yl)propionates] and their copper(II) complexes
Abstract
Novel polydentate ligands on the basis of second- and third-generation hyperbranched polyesters containing terminal poly[3-(morpholin-4-yl)propionate] groups and their 6 : 1 and 13 : 1 polynuclear copper(II) complexes were synthesized. The degree of functionalization of the polyesters with morpholine increases in going from the second (56%) to third generation (68%). According to IR and electronic spectroscopy data, each coordination entity in the complexes is an isolated paramagnetic center of the formula CuN2O2Solv2 (Solv = H2O, DMSO).
Synthesis and inner-sphere hydrophosphorylation of (η1-N)-N-benzyl-N-(1,3-dimethylbut-2-enylidene)amine-(dicarbonyl)(1,3,5-triorganyl-1,3,5-triazacyclohexane) molybdenum(0) and -tungsten(0)
Abstract
Complexes of group VIb metals (Mo and W) has been prepared with N-benzyl-(3-methylbut-2-enylidene)amine, where the latter is coordinated with the dicarbonyl(1,3,5-triorganyl-1,3,5-triazacyclohexane)-metal(0) fragment exclusively through the lone electron pair of the imine nitrogen atom. The reactions of the synthesized metal complexes with diethyl phosphite in various conditions always involved the addition of the phosphite across the С=N bond to form, depending on the conditions, aminophosphonates or their inner-sphere rearrangement products amidophosphates. Both organophosphorus compounds remain in the coordination sphere of the transition metal complex.
Synthesis and antimicrobial screening of novel 9-{2-[(1H-1,2,3-triazol-4-yl)methoxy]phenyl}-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione derivatives
Abstract
A series of novel 9-{2-[(1H-1,2,3-triazol-4-yl)methoxy]phenyl}-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione derivatives were synthesized by a click chemistry approach. The structures of all the newly synthesized compounds were characterized by IR, MASS, 1H and 13C NMR spectral data. The final analogues showed good to excellent antibacterial and antifungal activities in an agar well diffusion assay. Compounds 6i and 6f were the most active against all the test bacterial and fungal strains.
Synthesis of hydrazone derivatives of benzofuran and their antibacterial and antifungal activity
Abstract
A series of benzofuran hydrazones 6a–6n were synthesized from benzofuran aldehyde and substituted aromatic hydrazides 5a–5n. Structures of all compounds were confimed by IR, 1H and 13C NMR, and Mass spectral data. These compounds were evaluated for their antibacterial activity against gram-negative bacteria (Escherichia coli, –ve), gram-positive bacteria (Bacillus Subtillis, +ve), and antifungal activity against Candida albicans. All compounds demonstrated considerable activity against bacteria and fungi.
Synthesis and antimicrobial activity of fused isatin and diazepine derivatives derived from 2-acetyl benzofuran
Abstract
Acetyl benzofurans 1a, 1b reacted with isatins 2a–2f in the presence of pyridine to give corresponding 3-[2-(1-benzofuran-2-yl)-2-oxoethyl]-3-hydroxy-1,3-dihydro-2H-indol-2-one derivatives 3a–3l. Dehydration of the latter in acidic media led to the corresponding α,β-unsaturated ketones 4a–4l. The structures of newly synthesized compounds 3a–3l and 4a–4l were established on the basis of analytical and spectral data. The synthesized compounds were screened for their antibacterial and antifungal activities. Compounds 5d, 5f, and 5h displayed excellent antimicrobial activity. The synthesized compounds were studied for docking on the enzyme, Glucosamine-6-phosphate Synthase.
One-pot three-component green synthesis of novel dihydrophthalazine-1,4-diones
Abstract
Green and efficient one-pot three-component synthesis of novel 2-(7-amino-2,2-dimethyl-4-oxo-5-phenyl-4,5-dihydropyrano[2,3-d][1,3]dioxin-6-ylcarbonyl)-2,3-dihydrophthalazine-1,4-diones have been developed by condensing 3-(1,4-dioxo-1,2,3,4-tetrahydrophthalazin-2-yl)-3-oxopropanenitrile with benzaldehydes and Meldrum’s acid using L-proline as catalyst in ethanol at room temperature. The products have been isolated as pure compounds in good yields without using column chromatography.
New complexes of 3,4-dimethoxyphenylacetic acid with selected transition metal ions: Spectral, thermal, and magnetic properties
Abstract
3,4-Dimethoxyphenylacetates of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) of general formula M(C10H11O4)2·nH2O, where n = 1, 2 or 4 depending on M(II) ions, are obtained. The complexes crystallize in monoclinic or triclinic systems. The carboxylate groups act as bidentate chelating or bridging ligands. On heating in the air (293–1173 K) they decompose in three steps finally forming oxides of the corresponding metals(II) or their mixtures. Magnetic moments of compounds were determined in the ranges of 76–303 and 4–300 K.
Synthesis and characterization of some novel aryl and heteroaryl chalcone derivatives of 3-(3,4,5-trimethoxyphenyl)-1-phenyl-1H-pyrazole-4-carbaldehyde for assessing their potentials as anticancer agents
Abstract
In the present study, a novel series of nine derivatives of 1-phenyl-3-(3,4,5-trimethoxyphenyl)-1H-pyrazole substituted chalcones 6a–6i were synthesized with an aim to assess their anticancer activities. The chalcone derivatives were synthesized by the Claisen condensation of 1-phenyl-3-(3,4,5-trimethoxyphenyl)-1H-pyrazole-4-carbaldehyde 4 with various aryl and heteroaryl acetophenones 5a–5i by treatment with alcoholic sodium hydroxide in methanol at reflux temperature in good to excellent yields. The newly synthesized derivatives were well characterized by IR, NMR, and HRMS spectroscopic techniques. The title compounds were evaluated for in vitro antibacterial activity against a panel of gram-positive and gram-negative bacteria and screened for anticancer activity employing EGFR lung protein based on in silico molecular docking studies. The study results showed IC50 value ranging between 39–94 μg/mL compared to the standard Camptothecin with an IC50 value of 47 μg/mL which indicates the anticancer potential of the majority of the synthesized compounds.
Synthesis, characterization and biological activity of new 3(4H)-quinazolinone derivatives
Abstract
Quinazolinylbenzoic acid 1 was used as a precursor for synthesis of many heterocyclic systems. Ethyl 4-[4-oxo-2-phenylquinazolin-3(4H)-yl]benzoate 2 upon reaction with hydrazine hydrate gave 4-[4-oxo-2-phenylquinazolin-3(4H)-yl]benzoate benzoylhydrazide 3. Compound 3 on treatment with 3-nitrobenzaldehyde, acetyl acetone, ethyl acetoacetate, and ammonium thiocyanate yielded compounds 4–8, respectively. Isothiocyanate 8 was used for the synthesis of other quinazoline derivatives 9–16 via the reactions with various reagents. All newly synthesized quinazolinone derivatives have been characterized by 1H NMR, IR, and mass spectroscopy. Most of the synthesized products were evaluated for their antibacterial and antifungal activities and some of those demonstrated high activity.
Synthesis, crystal structure, antibacterial, cytotoxic, and anticancer activities of new Pd(II) complexes of tri-p-tolyl phosphine with thiones
Abstract
Four Pd(II) complexes of general formula [Pd(L1)2(L2)2], where L1 = pyridine-2(1H)-thione, pyrimidine-2(1H)-thione, pyridine-4(1H)-thione, and pyridine-4(1H)-thione, L2 = tri-p-tolylphosphine, have been synthesized by direct reaction of K2[PdCl4] with phosphine and heterocyclic thiones ligands in 1 : 2 : 2 molar ratio. The complexes have been characterized by elemental analyses, FT-IR and multinuclear NMR spectroscopy. The complexes 1 and 2 were also characterized by single crystal X-ray diffraction which revealed that the Pd(II) atom adopted a nearly square planar geometry with two tri-p-tolyphosphine molecules bound in a trans fashion and also two pyridine-2(1H)-thione (1) or pyrimidine-2(1H)-thione (2) molecules trans to each other. The compounds were tested for antibacterial activity, DNA interaction by brine shrimp lethality bioassay, antitumor activity, and gel electrophoresis. The complexes demonstrated moderate activity against gram positive and gram negative bacterial strains in comparison with a standard drug imipenum. Their antitumor activity against MCF7 tumor cell line was determined to be comparable to that of doxorubicin. The investigated compounds demonstrated no cytotoxic effect in brine shrimp bioassay study.
Synthesis and reactions of some new (E)-2-сyano-N′-[1-(pyren-3-yl)ethylidene]acetohydrazide derivatives
Abstract
Some novel (E)-2-cyano-3-(substituted phenyl/dimethylamino)-N′-[1-(pyren-3-yl)]acrylohydrazides and benzochromenone-2-carbohydrazide derivatives were synthesized by reaction of (E)-2-cyano-N′-[1-(pyren-3-yl)ethylidene]acetohydrazide with several reagents. Chemical structures of the newly obtained products were determined by elemental and spectroscopic analysis.
Letters to the Editor
Reactions of vinylphosphonates with piperazines
Abstract
Dialkyl [2-(piperazin-1-yl)ethyl]phosphonates were obtained by the reactions of piperazine with dialkyl vinylphosphonates. The addition of 2-(piperazin-1-yl)ethanamine to diethyl vinylphosphonate involves the primary exocyclic amino group of the heterocyclic compound.
Synthesis, acid-base and complexing properties of N,N,N′,N′-tetrakis(O-butylhydroxyphosphorylmethyl)-1,2-diaminoethane
Abstract
A method of synthesis of organophosphorus analog of ethylenediaminetetraacetic acid (a common complexon), N,N,N′,N′-tetrakis(O-butylhydroxyphosphorylmethyl)-1,2-diaminoethane, has been elaborated. The product structure has been elucidated by means of NMR spectroscopy and X-ray diffraction analysis. Constants of the acid dissociation and the stability of the 1 : 1 complexes with Co(II), Ni(II), and Cu(II) ions have been determined.
Features of the reaction of some symmetrically substituted isoindigos with hydrazine hydrate
Abstract
Depending on the structure of the substituent at the nitrogen atom of the heterocycle, reaction of isoindigo derivatives with hydrazine hydrate leads to the formation of either oxindole derivatives, or to a substituted isatin-3-hydrazone.
Synthesis of new diarylmethanes on the basis of resorcinol derivatives and amino acetals containing an aminoethylidenebisphosphonate fragment
Abstract
New ethylenebisphosphorylated α-amino acetals were synthesized by the reaction of aminoacetaldehyde dimethyl acetal with ethenylidenebisphosphonates (Michael reaction). It was found that the synthesized compounds react with 2-methylresorcinol and resorcinol in the presence of HCl to form previously unknown diarylalkylammonium salts containing ethylidenebisphosphonate groups.
Novel calix[4]resorcinols with sulfamide fragments in the lower rim
Abstract
Novel calix[4]resorcinols modified by sulfamide fragments were synthesized via acid-catalyzed opening of the pyrrolidine ring in 1-sulfonyl-2-naphthylpyrrolidines in the presence of pyrogallol. A possibility of synthesis of calix[4]resorsinols without isolation of the intermediate naphthalene-2-ylpyrrolidines was demonstrated.
Effect of the alkylidene spacer and the p-tert-butylthiacalix[4]arene macrocyclic platform on the reactivity of the hydroxyl groups in the acylation reaction
Abstract
A series of cone and 1,3-alternate p-tert-butylthiacalix[4]arenes tetrasubstituted at the lower rim simultaneously by the amide, ester, and carboxyl functions were synthesized. The reactivity of the synthesized compounds depends on the length of the alkylidene spacer. The N-(hydroxyethyl)amide derivatives do not react with succinic anhydride, whereas the N-(3-hydroxypropyl)amide derivatives react to form acylation products.
Synthesis of p-tert-butylthiacalix[4]arene with spatially separated phosphoryl and amino groups
Abstract
The reactions of p-tert-butylthiacalix[4]arenes containing phthalimide fragments with diethyl-[(p-toluenesulfonyl)oxymethyl)]phosphonate were used to synthesize new phosphonate derivatives in the 1,3-alternate configuration. Hydrolysis and hydrazinolysis of the products gave the corresponding amido- and aminophosphonate thiacalixarene derivatives. 1H–1H NOESY NMR spectroscopy established a 1,3-alternate configuration of the synthesized macrocycles with spatially separated phosphoryl and amino groups.
Polarity of selected derivatives of diselenophosphinic acid
Abstract
Polarity of diselenophosphinates in benzene solution has been determined by second Debye method. We suggest that these compounds exist as a mixture of several conformers with cis and gauche arrangement of substituents at the phosphorus atom with respect to the P=Se bond.
Supramolecular polymer based on aminated monosubstituted pillar[5]arene
Abstract
The interaction of nonamethoxypillar[5]arene containing an ester fragment with a series of di- and triamines has yielded novel macrocyclic amide derivatives of pillar[5]arene. The data of NOESY 1H–1H and DOSY NMR spectroscopy, dynamic light scattering, and transmission electron microscopy have revealed that nonamethoxypillar[5]arene containing diethylenediaminoamide moiety can form a network supramolecular polymer with average pores size of 100 nm.
Ni(II) complex of bisthiophosphorylated thiourea prepared from the Betti base
Abstract
The interaction between bisthiophosphorylated thiourea with nickel(II) nitrate in the presence of potassium tert-butylate has afforded NiL2 complex with square-planar configuration of the nickel(II) ion and the 1,3-N,S-coordination of the trans-positioned similar heteroatoms.
N-substituted dibutoxyphosphorylacetimidates in phosphorylation reactions
Abstract
Reaction of N-substituted dibutoxyphosphorylacetimidates with sodium followed by phosphorylation of sodium derivatives with dialkyl chlorophosphates and phenyl dichlorophosphate proceeds selectively under mild conditions to form products of phosphorylation of the methylene group. The synthesized compounds possess potential antisecretory, immunosuppressive, hypolipidemic, and other types of biological activity.
Selected articles originally published in Russian in Rossiiskii Khimicheskii Zhurnal (Russian Chemistry Journal)
Analysis of the global and Russian markets of polypropylene and of its main consumption areas
Abstract
Factors responsible for the polypropylene consumption growth in the post-crisis period were analyzed, and the world’s largest polypropylene manufacturers and leading polypropylene-producing countries were listed. Preferential growth of polypropylene production in Asia and the Middle East and the specific features of development of the raw material base of polypropylene under the Russian market conditions were demonstrated. The key polypropylene consumption areas in North America, Europe, and the Russian Federation were identified as follows: films, packaging materials, components for automotive industry, plastic pipes, fibers and fibrous materials, sheets, plastic furniture, and construction elements.
Theoretical and practical aspects of original technologies of gray linen finishing
Abstract
Research results on the development of preparation and printing technologies for textile materials containing gray linen fibers were reported. The difficulty of finishing treatment of such fabrics consists in the need to preserve the self-color of flax while obtaining pure color patterns. This problem can be solved through the use of plasma-chemical processes in the preparation stage for imparting high hydrophilic properties to the fabric without affecting the chromophore structure of the natural dye of flax. Technologies for obtaining white and color patterns on self-colored silvery gray flax linen by oxidizing discharge printing were proposed. The influence of the process parameters (oxidant and dye concentrations and steaming temperature and time) on the resulting coloristic effect was evaluated.
Study of methods for improving the water permeability of ballistite compounds
Abstract
Processability of present-day highly filled ballistite-type compositions on regular equipment is a real-time issue in the production of powders and propellants. This poses a number of difficulties, in the wringing phase in particular. In this context, wringing the powder mass containing a hydrophilic filler, lead-nickel complex of phthalic acid (LNP), as burning modifier was considered. The main factors responsible for low water permeability of the powder mass and the major relationships in the filtration process were examined. An approach was proposed for improving the water permeability of the composition mass through the use of polyacrylamide (PAM) type water-soluble flocculants and hydrophobization of LNP with organosilicon compounds from among aryl-substituted orthosilicic esters.
The effect exerted by PAM of different grades with methyltriethoxysilane as hydrophobizer on the water permeability of the composition containing 5–10% LNP was examined. The method based on using PAM was shown to be the most preferable, with Praestol 650 BC cation-active polyacrylamide being the most efficient flocculant. An indisputable advantages of the approach proposed is that is allows improving the water permeability of a powder mass through using a small amount of the flocculant without affecting the main properties of the composition.
Stabilization of oil-in-water emulsions by highly dispersed particles: Role in self-cleaning processes and prospects for practical application
Abstract
Natural self-cleaning processes are a special focus area in searching for cost-effective and environmentally sound technologies for minimizing the oil spot effect on water areas. From this perspective, a viable alternative to existing soluble xenobiotic dispersants may be provided by highly dispersed solid particles. They can be used in technologies based on formation of stable oil-in-water emulsions that can sink down below the water surface to be further degraded by microorganisms. In this context, the formation conditions for oil-mineral aggregates, ways of stabilization of oil-in-water emulsions by highly dispersed solid particles, and factors affecting their formation efficiency were considered, as well as the prospects for their application in oil spill remediation technologies for open and coastal water areas.
Synthesis and coordination properties of nitro derivatives of 5,15-diphenyl-3,7,13,17-tetramethyl-2,8,12,18-tetraethylporphyrin
Abstract
Methods were developed for the synthesis of nitro derivatives of 5,15-diphenyl-3,7,13,17-tetramethyl-2,8,12,18-tetraethylporphyrin containing nitro groups at the meso positions of the porphyrin core and at the para positions of the phenyl substituents. The formation kinetics of the zinc, copper, and cobalt complexes of the resultant porphyrins in pyridine and in an acetic acid–benzene (7 : 3) mixed solvent was studied. It was found that the properties of the porphyrin ligands are determined both by the electronic effect of the nitro groups and by the effects of spatial distortion of the porphyrin core.
Volatility of some aromatic nitrosubstituted plasticizers for polymers
Abstract
Nine derivatives of nitrophthalic acids and nitrophenols were synthesized as potential plasticizers for polymers and structurally characterized by 1H NMR and elemental analysis. The time dependences of the weight loss for the nitro derivatives synthesized and for commercial plasticizers (dibutyl phthalate and dioctyl phthalate) were obtained by gravimetric method at 100ºC, and their volatilities and dipole moments were calculated. The resultant nitroplasticizers are considerably less volatile than dibutyl phthalate. Low volatility is associated not so much with high molecular weight as with high polarity. The nitroplasticizers are well compatible with cellulose esters and exhibit low rates of migration from polymer films.
Cyclic oligoesters as potential materials for polymer nanocomposite production
Abstract
Publications dedicated to cyclic oligoesters based on cyclic butylene terephthalate were analyzed and summarized. The features of their preparation and structure and their properties were considered with a special focus on advantages and disadvantages of the methods of their preparation: polycondensation at high dilution and depolymerization. The prospects of application of cyclic butylene terephthalate for polymer nanocomposite production were demonstrated. A development strategy for this research area was suggested.
Regularities of copper(II) and nickel(II) distribution in an aqueous solution‒modified flax fiber heterophase system
Abstract
The distribution of Cu2+ and Ni2+ ions in an aqueous solution — flax fiber heterophase system was investigated. The specific surface area of the sorbent and the average pore radius were determined. The sorption isotherms were processed in terms of the Langmuir and Freundlich models and the theory of volume filling of micropores. It was shown that the sorbent behaves as a weakly acidic cation exchanger with the α-hydroxycarboxyl groups as sorption sites. The modification of flax fiber with polyvinylpyrrolidone allows one to noticeably increase its sorption properties.
Thermal behavior of binary complex сompounds сontaining the hexacyanoferrate anion
Abstract
The thermal behavior of compounds with the general formula [MA6]x[Fe(CN)6]y (M = Со, Cu, Ni, A = NH3, 1/2 C3H10N2) in air, argon, nitrogen, and hydrogen at temperatures between 20 to 1000°C was studied. The study involved measurement of TG–DSC–DTG curves and analysis of solid and gaseous thermolysis products. It was found that the process is not affected by the nature of the atmosphere up to about 200°C. The coordinated cyanide ion partially releases as hydrogen cyanide. The destruction of diamines forms NH3, and a large amount of carbon remains in the solid phase.
Conditions of formation of iron molybdate(III) by ceramic and mechanochemical syntheses
Abstract
Ceramic and mechanochemical synthesis of iron molybdate Fe2(MoO4)3 was studied by simultaneous thermal and X-ray diffraction analysis. The mechanochemical synthesis was performed in medium- and high-power-density mills. An effect of mechanical impact conditions on the thermal synthesis of iron molybdate was revealed. Mechanochemical synthesis was found to significantly decrease the temperature and time of annealing of Fe2(MoO4)3.
Influence of reagents solvation on [Ag18C6]+ complex formation in methanol‒acetonitrile mixed solvents
Abstract
The influence of the composition of the methanol—acetonitrile (MeOH—AN) solvent on the solvation of 18-crown-6 ether (18C6) has been studied. Increasing fraction of AN in the binary solvent stabilizes the 18C6 solvation complex by increasing the exothermicity of 18C6 solvation. Analysis of the solvation contributions of the reagents to the enthalpies of complex formation of silver(I) ion with 18C6 in MeOH—AN mixtures has been performed to establish that the decrease in the exothermicity of complex formation in going from MeOH to AN is mostly associated with the solvation contribution of Ag(I).
Structuring oligodimethylsiloxanediols with trialkoxytitanium vanadates
Abstract
Kinetics of structuring oligodimethylsiloxanediols with trialkoxytitanium vanadates were studied. The apparent rate constants of structuring and the activation energies of the reactions were calculated. It was shown that during structuring the titanium and vanadium atoms embed into oligodimethylsiloxanediols to form polyelement organosiloxanes. The properties of the materials with coatings cured with trialkoxytitanium vanadates were investigated.
Polypropylene polymer blends
Abstract
Blending of polymers is a method for obtaining new materials with improved properties. Numerous studies have been carried out to characterize the structure, morphology, mechanical, thermal, and rheological behavior of polypropylene blends. The main ways to increasing the compatibility of polymer blends containing polypropylene as one of the components are considered. An important role of polymer compatibilization with the use of a third component is underlined. This article is a review of research on polypropylene blends.